Category Archives: Innovation Interview

Q&A: Update on EPIC2 in New Jersey

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In early 2024, we spoke with Jess Mendenhall and Samer Rabie from the New Jersey Department of Transportation (NJDOT) about the Enhancing Performance with Internally Cured Concrete (EPIC2) initiative, part of the Every Day Counts (EDC-7) program. They explained the benefits of internal curing, its methods, and its potential for New Jersey. At that time, NJDOT had identified eight bridges as candidates for a pilot project using internally cured High Performance Concrete (HPC) bridge decks, but had not yet secured approval or funding.

That changed in October 2024 when NJDOT initiated its first pilot project—an internally cured HPC bridge deck on the North Munn Avenue bridge over Route 280 in East Orange. This milestone marks a significant step in advancing the department’s efforts.

Additionally, NJDOT secured a $125,000 STIC Incentive Program grant to support further implementation. The funding will cover the purchase of testing equipment and construction materials, staff training on the new equipment, and third-party lab assistance for concrete sampling and testing during construction. To build on this momentum, NJDOT plans to continue collaborating with concrete suppliers, acquire additional testing equipment, and update High-Performance Internal Curing (HPIC) specifications.

With these developments underway, we’re reconnecting with NJDOT for an update on the department’s ongoing EPIC2 projects and its future plans.

Q. Can you provide a brief description of the EPIC2 Initiative, and how internally curing concrete can benefit construction projects?

The difference between conventional and internal curing

A. The EPIC2 initiative, part of the Federal Highway Administration’s (FHWA) EDC-7 innovations, focuses on Internally Cured Concrete (ICC), a proven yet underutilized technique that significantly enhances concrete durability by addressing shrinkage cracking, especially in mixes with a low water-to-cement ratio. Internal curing involves providing water from within the concrete itself, utilizing pre-wetted lightweight fine aggregates (LWFA) to supply moisture during the curing process. This approach is particularly beneficial for low permeability concrete mixes, where traditional external curing methods are less effective.

ICC offers numerous advantages for construction projects. It reduces the likelihood of shrinkage cracking, both autogenous and plastic, thereby decreasing the need for rehabilitation. Furthermore, it enhances the hydration of cement and the reaction of supplementary cementitious materials (SCMs), resulting in reduced porosity and improved durability. This method also allows for the incorporation of natural and recycled SCMs without compromising performance.

Our Bureau of Research, Innovation, and Information Transfer (BRIIT) is actively investigating internal curing in collaboration with Rutgers University, ensuring that we remain at the forefront of this innovation.

Q. At the December 2024 NJ STIC meeting, the Infrastructure Preservation CIA team mentioned that NJDOT has secured a $125,000 STIC Incentive Program grant for the EPIC2 initiative. How will the grant help NJDOT advance its goals for internally cured concrete?

A. The grant will enable the acquisition of centrifuge apparatuses and auxiliary equipment for the Bureau of Materials and the three construction regions. This equipment will allow NJDOT inspectors to conduct more accurate tests for determining moisture content in pre-wetted lightweight aggregations than our currently used paper towel method, which is crucial for producing high-quality ICC. The grant will also facilitate the training of NJDOT personnel to effectively use the centrifuge apparatus. During the transition period, NJDOT will conduct testing using both the centrifuge and paper towel method, ensuring a smooth adoption as inspectors become proficient with the new equipment.

Additionally, the grant will support the development of specifications, create training opportunities, and enable the preparation of lessons-learned reports during the assessment phase. These efforts will contribute to refining our processes and enhancing the overall quality of our specifications and implementation plan.

Q. Can you go into more detail describing the centrifuge apparatus and how it will provide more accurate measures for determining moisture content?

Centrifuge Apparatus

A. The current test we use, implemented and standardized by the New York State Department of Transportation (NYSDOT), is called the paper towel method ASTM C1761. In this method we take a representative sample of the pre-wetted aggregate, take the initial weight, and lay it out in a pan to extract the surface moisture using industrial-grade paper towels until the paper towels come out dry. Then we take the weight again to determine the surface moisture. Lastly, we oven dry the sample and weigh it again to find the absorbed moisture.

The centrifuge can determine the moisture of an aggregate in a single device by spinning the sample until all the moisture is extracted. Research studies comparing the paper towel method and the centrifuge have found that the centrifuge produces more accurate results with a lower margin of error at a significantly faster rate.

Q. Can you describe the pilot project for an internally cured High Performance Concrete (HPC) bridge deck at North Munn Avenue over Route 280 in East Orange? What steps will be involved in completing the project?

A. Our first pilot project, the superstructure replacement in East Orange, is underway with construction starting in March 2025 and we have several more projects in the pipeline. To ensure a cohesive approach, we started the pilot by organizing a coordination meeting involving the Bridge, Construction, Materials, and Project Management divisions. This meeting served to introduce the concept of internal curing and outline our implementation strategy. Concurrently, we engaged with concrete plants near the project sites and LWFA material suppliers to ensure their readiness. We then circulated draft specifications for internal review, and obtained feedback from NYSDOT, the individual project designers, and the FHWA Resource Center’s EPIC2 team.

A key component of introducing ICC into a pilot project involves incorporating project-specific special provisions. Our pilots use a performance specification similar to our current HPC specification, where the contractor submits a mix design and performs the necessary off-site laboratory testing, such as for compressive strength and durability properties. The contractor is permitted to develop a new ICC mix or convert an existing mix using ASTM C1761 procedures. If the mix meets the specification limitations and verification testing requirements, it will be accepted by NJDOT. The verification and acceptance testing align closely with current HPC specifications, with some exceptions to accommodate the unique aspects of internal curing.

Q. Will the pilot project require specialized training for NJDOT staff or contractors?

A. The production process for High Performance Internally Cured Concrete (HPIC) closely resembles that of conventional High Performance Concrete (HPC), with the key difference being the inclusion of LWFA. This aggregate requires pre-soaking and precise moisture adjustments to achieve optimal performance. Despite these modifications, HPIC mixtures maintain similar concrete properties and offer constructability comparable to HPC.

Workers installing an HPIC overlay

For our pilot projects, conducting a trial batch and test slab is crucial. This phase allows the concrete supplier and contractor to become familiar with the handling of LWFA, as well as the batching and placement of the HPIC mix. The trial batch and test slab are meticulously designed to replicate the conditions and processes of actual slab production.

Most of the work involved in producing HPIC happens at the batch plant, where the adjustments for LWFA take place. As a result, contractors and inspectors casting the deck are unlikely to notice substantial differences from standard HPC procedures.

Q. What key factors are considered when identifying candidate bridges for future projects?

A. We carefully evaluate active Capital Program Management projects to identify suitable candidates. Our selection criteria focus on projects with a limited scope in the Concept Development or Final Design phase, specifically targeting deck and superstructure replacements. We prioritize projects where Final Design Submissions have not yet been prepared and where timelines allow for integrating special provisions. Projects with cast-in-place or conventional decks are considered, while pre-cast decks are excluded to reduce design and constructability risks. We aim to select non-complex or major structures, targeting the implementation of HPIC on 10–15 bridge decks before institutionalization.

Q. In what ways do you think the pilot projects and new STIC funding could affect NJDOT policy going forward?

A. Our goal is to address the cracking we routinely observe in new HPC bridge decks by refining the HPC mix design in our standard specification to include internally cured provisions. If the pilot project is successful, we will collaborate with the Bureau of Materials to determine the next steps for advancing HPIC specifications for NJDOT projects. Ultimately, we aim to enhance the durability of bridge decks and other concrete components in New Jersey by incorporating new HPIC specifications.

As of 2024, only 104 ICC bridge decks are in service in the United States

Q. What do you think are the principal barriers, if any, to the adoption of internally cured concrete on bridge projects as the new standard?

A. Lack of Awareness and Education: Many engineers and decision-makers may not fully understand the benefits and techniques of ICC. This knowledge gap, coupled with concerns about potential impacts on construction schedules and quality, can lead to hesitation in adopting new methods.

Initial Cost Concerns: While ICC can lower long-term costs by improving durability and reducing maintenance, the higher upfront expenses, such as LWFA and the need for additional storage bins at batch plants—may discourage early adoption.

Technical Challenges: Precise moisture control and mix design adjustments can be technically challenging and require specialized training, which could pose a barrier for some organizations transitioning to ICC.

Supply Chain Limitations: The availability of materials like LWFA and the need for pre-soaking facilities may be limited, especially in certain regions.

Economies of Scale and Standardization: As seen with NJDOT’s HPC implementation in the early 2000s, achieving consistent production of specialty concretes is critical for efficiency. If pilot projects succeed, NJDOT plans to standardize ICC mixes for all bridge decks, which will require larger production quantities. This increased demand could drive greater industry investment in materials and production infrastructure, further supporting widespread adoption.

Q. What are the current approaches you are using to address the lack of awareness of the benefits and techniques of ICC?

NJDOT attended a peer exchange event in Albany, NY, on the EPIC2 Initiative.

A. We have engaged in extensive internal discussions with construction material staff, project management, and decision-makers to familiarize them with ICC and FHWA recommendations. We have also coordinated with concrete suppliers through the Utility and Transportation Contactors Association to gauge project feasibility. Additionally, in collaboration with Rutgers, we distributed questionnaires to multiple concrete plants, our consultants, and designers to gather insights and address concerns. Our primary approach has been open communication with all key stakeholders to ensure a well-informed transition to ICC.

Q. What are the current economic benefits of ICC given the barriers you described previously, and how do you expect this to change in the future?

A. Currently, with data from only one project, ICC carries higher initial costs due to factors like contractor-perceived risk and limited material availability. However, we are seeing substantial fine hairline cracking in conventional HPC decks, raising concerns about long-term durability. Addressing these cracks with sealers adds significant costs, and without frequent upkeep, leads to deterioration overtime. While HPC may have lower upfront costs, ICC has the potential to last much longer and require less maintenance, ultimately reducing lifecycle expenses.

Our implementation plan includes using ICC on at least 10 to 15 bridge decks, signaling to batch plants that we are serious about ICC. Once suppliers recognize this increased demand, they can expand production, improving efficiency and cost-effectiveness. This mirrors what happened when HPC was introduced around 25 years ago—initial costs were higher, but as adoption grew, economies of scale helped bring costs down. We anticipate a similar trend with ICC as it becomes more widely implemented.

Q. Are there any other recent developments or lessons related to EPIC2 that you would like to highlight?

Twin bridges that will be studied to compare performance between HPC and HPIC

A. As we are still in the early stages of implementing the EPIC2 initiative, we eagerly anticipate the upcoming deck castings, which will undoubtedly provide valuable lessons and insights. One particularly noteworthy upcoming project involves a pair of twin bridges, where we will use traditional HPC for one bridge deck as a control and HPIC for the other. After the deck placement, both bridges will undergo thorough surveys to assess early-age shrinkage, allowing us to directly compare performance and further refine our approach.

Resources

Extend Service Life of Concrete Bridge Decks with Internal Curing. 2023. https://rip.trb.org/View/2292366

Federal Highway Administration. 2023 Internally Curing Concrete Produces EPIC2 Results. https://www.fhwa.dot.gov/innovation/innovator/issue98/page_01.html

Federal Highway Administration. 2023. Enhancing Performance with Internally Cured Concrete. https://www.fhwa.dot.gov/innovation/everydaycounts/edc_7/docs/EDC-7FactsheetEPIC2.pdf

Federal Highway Administration. (2018, June). Concrete Clips: Internal Curing. https://www.youtube.com/watch?v=b6WREFmacaM

New York State DOT Standard Specifications (2021). Standard Specifications. New York State DOT. https://www.dot.ny.gov/main/business-center/engineering/specifications/busi-e-standards-usc/usc-repository/2021_9_specs_usc_vol2.pdf

National Concrete Pavement Technology Center Internal Curing Resources. (2022). Internal Curing. Iowa State University. https://cptechcenter.org/internal-curing/

Internal Curing. (2020). Oregon State University. https://engineering.oregonstate.edu/CCE/research/asphalt-materials-performance-lab/materials-research-concrete-materials/Internal-Curing

Pacheco, Jose. (2021, October). USDOT Workshop Report, Bureau of Transportation Statistics. Wisconsin Department of Transportation. https://rosap.ntl.bts.gov/view/dot/62607

Q&A: What’s EPIC2 about Internally Cured Concrete? (2024) https://www.njdottechtransfer.net/2024/02/07/internally-cured-concrete-qa-2/

Wang, Xuhao. (2019). Extended Life Concrete Bridge Decks Utilizing Internal Curing to Reduce Cracking. Ohio Department of Transportation. https://rosap.ntl.bts.gov/view/dot/62339

Weiss, Joseph. (2015, July). Internal Curing Technical Brief. Federal Highway Administration. https://www.fhwa.dot.gov/pavement/concrete/pubs/hif16006.pdf

Interview with 2024 Research Showcase “Best Poster Award” Winner

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We had the opportunity to speak with Swathi Malluru, a PhD candidate at Rowan University and recipient of the 2024 NJDOT Research Showcase Best Poster Award. Her research focuses on sustainable pavement rehabilitation, including the Full-Depth Reclamation (FDR) and Cold In-Place Recycling (CIR) processes that were the subject of the performance evaluation recognized with the Best Poster Award. In this interview, Ms. Malluru discusses her journey in transportation engineering, from her background in sustainable materials to her work optimizing stabilizers for FDR and CIR. She hopes that her research can provide economic and environmental benefits and shares how it could shape future NJDOT policies.

Q. Congratulations on receiving the Best Poster Award at the 2024 NJDOT Research Showcase. Could you tell us about your prior educational and research experience, and how you came to be a PhD student at Rowan University?

A. First of all, I would like to thank you for your time. I pursued my master’s in Transportation Engineering from the Indian Institute of Technology. At the university, I learned about pavement materials, specifically pavement rehabilitation techniques and pavement design analysis. Then, I worked on a steel slag aggregates project. In this project, I completely replaced the conventional natural aggregates with steel slag aggregates in hot mix asphalt mixture and evaluated the performance to understand if slag could function as an alternative to the conventional natural aggregates. This motivated me to do further work in sustainability and that’s how my research journey started.

What drew me to Rowan University was the Center for Research and Education in Advanced Transportation Engineering Systems (CREATES), which deals with diverse research projects, and has a lot of facilities for conducting research on pavement materials. CREATES provides facilities where we can conduct our laboratory tests and evaluate the performance of various mixes. In the laboratory, we do everything in controlled conditions that may not exactly simulate field conditions but provide a good opportunity for a researcher to understand the behavior of a particular material and mix under different circumstances. CREATES also facilitates test sections and conducts Accelerated Pavement Testing (APT) using the Heavy Vehicle Simulator (HVS) to evaluate the field performance of the asphalt mixtures.

Q. What sparked your interest in sustainability related to pavement materials and rehabilitation?

A. I come from an industry background. After my master’s, I worked in construction for Larsen & Toubro and later as a highway designer for Jacobs. I worked on the geometric design of Texas Department of Transportation (TxDOT) projects. Based on my experience, I found that, especially in developed countries, roads have mostly been constructed. The future is in widening, rehabilitation, and maintenance of the existing roads. Additionally, we see that transportation is the largest global contributor to carbon emissions. These factors convinced me to focus on researching environmentally friendly and cost-effective pavement materials for sustainable development.

Q. The research in your poster focused on Full Depth Reclamation (FDR) and Cold In-Place Recycling (CIR). Can you describe some of the environmental or economic benefits that these processes provide?

Asphalt Milling Machine.

A. This project was funded by NJDOT Pavement Support Program (PSP) and led by Dr. Ahmed Saidi from CREATES, Rowan University. Cold In Place Recycling and Full Depth Reclamation are two rehabilitation techniques of deteriorated asphalt pavements. In the conventional process, whenever the pavement is highly distressed, we completely remove the materials and lay a new pavement stretch in that particular location. This process utilizes a Hot Mix Asphalt (HMA) mixture that requires asphalt, high mixing temperatures and large amounts of energy consumption, producing emissions. Production of HMA also involves a lot of volatile organic compounds, which can significantly impact the environment.

By replacing the process with a FDR or CIR, we can conserve the materials and reduce emissions. In FDR, the existing pavement is milled up to the unbound soil layers (at a depth up to 14 inches) and then laid into a single layer through pulverization and stabilization with additives. CIR involves reclamation of asphalt layer (at a depth up to 4 inches) and stabilization with additives. In this scenario, we see very little emissions, and it is also very quick. In our few trial stretches, which included some NJDOT projects, we observed that we could save $10,000 to $50,000 per mile. This is a huge achievement in cost savings and time savings, and is environmentally friendly. These are the benefits we get from implementing FDR and CIR.

Q. For the first two tasks in the research project, you conducted a literature review and a survey of different state DOTs. What did you find through these two tasks, and how did it prepare you for the lab tests?

A. We went through the various guidelines of different state DOTs and other state agencies. From this literature review, we observed that early on, state guidelines mentioned only the usage of cement for the FDR. But some states like Pennsylvania and Illinois started implementing the use of bituminous stabilizers to improve the performance of FDR. Through the state DOT literature review and the survey questionnaire, we learned more about the properties of emulsions and cement, the properties of RAP gradation, the types of cement that we have to select, and also how to cure and compact samples. We learned all these aspects of FDR and CIR from the literature review and the survey questionnaires, and then we tried to incorporate all these elements.

Q. You concluded with the research that 5 percent cement, or 3 percent emulsion, 1 percent cement and 3 percent water worked best for FDR, and 2 percent emulsion, or 1.5 percent foamed bitumen for CIR. How many different combinations did you try and how significantly did these combinations outperform the alternatives?

A. Based on the performance criteria from the literature review, we tried to understand what the optimum dosage should be. We considered three different stabilizer material types for FDR: a section with only cement varying from 4 to 5 percent with a 0.5 increment; a mix consisting of emulsion varying from 3 to 5 percent; and foamed bitumen varying from 3 to 5 percent. We decided to utilize these dosages based on the literature review. From the laboratory test, we observed that the 3 percent emulsion gave less rut depth and better fatigue performance compared to alternatives. Similarly, when we added 5 percent cement or 3 percent emulsion, we found it gave an equal performance.

Q. Did you experience any challenges during the lab tests?

A. Based on what we learned in the literature review, we were able to match the results and confirm it. Emulsions, and the inclusion of bituminous additives, can improve the performance of these mixtures. The challenges were during the mixing and compaction, but we managed to rectify those challenges over time.

Q. What additional research do you think should be conducted based on your findings from this project?

A. We have to conduct further work on the impact and performance of FDR and CIR and also evaluate any other alternatives that can be used as stabilizers. Currently, we are proposing FDR and CIR guidelines for minor roads, but maybe, if we try to improve and enhance its performance, we can extend it to the interstate highways and roads of higher priority. That is a major area for future research.

Q. What kind of impact do you hope this research will have on NJDOT construction and design policy moving forward?

A. I hope it helps NJDOT optimize cost savings, reduce labor, and construction time and, especially, aid in NJDOT becoming more environmentally friendly. This will help reduce emissions compared to using the conventional overlay method and help NJDOT achieve its sustainability goals.

Q. Moving toward your personal research, is there any kind of research that you specifically want to focus on going forward, or would it be something similar to this as you progress through your doctoral path?

A. After this, I want to try to conduct a test trial to evaluate the performance of FDR and conduct a life cycle assessment. And try to test the impact of low temperatures on the performance of FDR. Will there be a low temperature cracking effect from freezing? I would also like to work on developing design guidelines for the implementation of FDR and CIR throughout NJDOT.

Q. What are your career goals and aspirations for after you complete your PhD?

A. After my PhD, I would like to work in the industry, so I can implement my research and work to find solutions for major problems.

Interview with 2024 Research Showcase “Outstanding University Student in Transportation Research Award” Winner

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Traffic safety and mobility, two critical areas in transportation engineering, both require the collection and analysis of large data sets to produce proactive and comprehensive solutions. Transportation engineers have started to increasingly focus on using innovative technologies to efficiently and effectively process this data.

We had the opportunity to speak with Dr. Deep Patel, a former Ph.D. candidate and research fellow at Rowan University, whose work is at the forefront of this mission. Recently, Patel received the NJDOT Outstanding University Student Research Award for his contributions to transportation research. In this interview, Patel shares insights from his research journey, including his work on the Real-Time Traffic Signal Performance Measurement Study and the development and implementation of machine learning tools to predict high-risk intersections. His dedication to improving traffic operations and safety, along with his new industry role as a Traffic Safety and Mobility Specialist, highlights the significant impact of combining academic research with practical industry applications.

Q. Could you tell us about your educational and research experience and how you became a PhD candidate and research fellow at Rowan University?

A. First of all, thank you for your time and for considering me for the opportunity to be interviewed about my recent NJDOT award. I would also like to thank the NJDOT review committee members and my Ph.D. advisor Dr. Mohammad Jalayer, who supported me in receiving this award.

I started my master’s study in 2018 as a civil engineering student without a research focus. Then, during my first semester, I took a course called Transportation Engineering with Dr. Mohammad Jalayer. When he sought traffic counting assistance for a traffic analysis project, I eagerly joined him, becoming his first research student.

Deep Patel conducting roadside research. Courtesy of Deep Patel.

Through that experience, I started thinking about what could streamline the traffic counting process and the various uses for the data we collected. I went on to work on several research projects with Dr. Jalayer, both funded and non-funded, where we had frequent discussions, and I would present my ideas to him. Eventually, he asked me to join him as a researcher and to continue my master’s work with a research focus, which I did for two years. When he suggested I continue my studies to earn a Ph.D., I was initially surprised, but I decided to go for it since I had a lot of ideas for future research projects.

At the end of my master’s study, I began Phase One work for a Real-Time Traffic System Performance Measure Study led by Dr. Peter Jin, Dr. Thomas Brennan, and Dr. Jalayer. This project connected me with a team from Rutgers, TCNJ, and a few professionals from NJDOT and other industry folks. I represented Rowan’s end for this project, where our focus was on understanding the safety aspects including safety parameters and performance and how we could assist NJDOT transform this new technology to help save lives. For the first phase of the project, we worked on understanding the traffic signal system performance measures, and what had been adopted by other DOTs. My experience on this project drove me to pursue more research and to expand my knowledge in traffic safety.

Q. You worked on Phase One through Three of this Real-Time Traffic Signal Performance Measurement Study. What part of this project interested you the most?

A. My main takeaway from this project focused on learning more about how the transportation industry looks towards the research outputs and outcomes from the university teams. It is very interesting to understand how university-based research is being adapted for industry acceptance. Additionally, I learned what problem-solving features the industry looks for from the research component.

From a technical aspect, I learned how New Jersey signals can be enhanced and how we can optimize the performance of these signals and achieve cost savings. Let’s say you have a scenario where there is no vehicle at an intersection; how can we provide recommendations to change the signal to a red light and give the other side of the intersection a green light? So, we gathered several components in terms of mobility, safety, and economic parameters from the study that can help enhance our traffic signals in New Jersey, sharing this information with the NJDOT team.

Figure 1: An Example real-time performance monitoring on County Road 541 and Irwick Road, Burlington County, NJ
Example of real-time performance monitoring on County Road 541 and Irwick Road, Burlington County, NJ

Q. How did you see your role on the research project develop as you moved from the earlier phases to the latest phase?

A. In the first phase, we completed a comprehensive literature review to understand what is happening across the nation, which systems are being adapted, what are the best systems for providing traffic signal safety performance measures, and what are the kind of performance measures that can be adapted in an industry setting. In Phase Two, the team focused on developing mechanisms and performance measures aligned with NJDOT’s existing data, including deploying the Automated Traffic Signal Performance Measures (ATSPM) system to enhance traffic signal monitoring and optimization. To guide these efforts, an adaptability checklist was created to benchmark practices from other states and identify strategies that could be adapted to benefit NJDOT’s operations. Building on this foundation, Phase Three advanced to the demonstration and application of dashboards and performance measures, providing actionable recommendations to NJDOT on enhancing mobility and safety across various regions and corridors. These efforts aimed to save time and lives, while the integration of connected vehicle (CV) technologies remains a key focus for future work, ensuring NJDOT’s leadership in traffic management innovation.

Q. What were the specific corridors that you worked on?

A. We started with seven/eight intersections on U.S. 1. Then, we explored the whole corridor of U.S. 1 as part of Phase Three, and we also brought in Route 18, Route 130, and other intersections during this phase.

Q. Did you discover any particular surprising or noteworthy findings from this research?

A. This was a long project, extending from 2019-2024. As a result, each year we discovered new findings, and new components were often added to the project. For example, we added a CV systems component as part of the Phase Two and Phase Three projects to start planning for the future and understand what kind of data could be received and sent from CV technologies. The main benefit from this project is that it not only established current problem-solving measures but also looked into the future, helping to better understand what’s coming and how we can best face anticipated challenges that we need to start integrating at this moment. I find the combination of the present and future integration of systems and technologies interesting and important from the findings.

Q. What kind of impact do you think you and your research will have on NJDOT traffic operations and traffic safety, especially with your role now working in the industry?

A. With my previous experience as part of a university-led research team and now as a Traffic Safety and Specialist in the private sector, I am better positioned to facilitate the efficient and effective implementation of research findings.  A key factor enabling this transition is that Kelly McVeigh, who supervised the original research project, also oversees the current work that our firm is doing for NJDOT. Being on the industry side allows me to introduce and operationalize new ideas more rapidly, compared to the academic research side. This streamlined approach ensures that innovative performance measures can be deployed more quickly, and even a small modification has the potential to save lives, underscoring the value of this work.

Q. Moving to a different topic, your research frequently incorporates Machine Learning (ML) and Artificial Intelligence (AI) aspects. In your experience, what benefits does AI contribute to transportation research?

A. Over the past few years, AI and ML have undergone drastic modifications and growing levels of industry acceptance. Additionally, in research outcomes, AI and ML have played a key role in enhancing and providing new methodologies and new ways of problem-solving. As an engineer, the first thing we have to do is understand how we can solve an existing problem, and how fast, effectively, and efficiently we can do it.

Transportation is now highly reliant on big data and intensive analysis, so AI and ML back up the processing of this data, coming up with meaningful outcomes and enhancing solution measures much quickly than previous methods. In 2012 or 2013, a standard engineer would need to sit down to do a traffic study and go through manual counting, then process the data, then come up with solutions, which takes much longer to solve a problem. The problem may even change during the months-long process of developing a solution.

In traffic safety, we cannot wait for the four to five months it could take to solve a problem due to the pressing safety implications of doing so. Thus, we must start implementing countermeasures swiftly, and AI and ML components help us to quickly process data with more effective and efficient results.

During my early days as a student researcher, I would stand on the roadside, manually counting the vehicles and pedestrians to collect data for traffic studies. However. during my doctoral research, I developed my AI-driven tools that utilize advanced video systems for detection and analysis. This proactive approach enables the identification of intersections prone to high-crash scenarios well before crashes occur, allowing for timely interventions. By integrating AI and ML, my research introduced innovative methodologies for crash prediction and prevention, showcasing the feasibility of data-driven solutions to enhance roadway safety.

There is a certain chaos in human beings’ lives and surroundings that requires transportation to be a multidisciplinary field, which includes human-focused aspects. For some parts, AI is definitely required, but with other parts, we need to go through different approaches.

Q. Do you think that because of AI’s data collection and analysis possibilities, almost all engineers in the near future will need to start incorporating AI into their research?

A. It really depends. For our part of traffic engineering, very specifically, I would say yes, it would be one of the major requirements that an engineer would need to adopt. But if I was a traffic engineer working on policy or equity measures there might be some concerns related to data sharing or data privacy issues that might restrict them.

It depends on what side you are focusing on. When it comes to data collection, I would say AI incorporation is a must to collect and process data faster and more efficiently. But in terms of developing policies, rules, or statutes, there are certain psychological aspects that need to be in the thought process. Knowing human concerns and people’s approaches requires an emotional touch, which AI still lacks.

Transportation is a field connected with multiple disciplines; it touches on people’s emotions. For example, on a day when traffic does not work well when you’re returning home, you can get frustrated, and that frustration can end up in a fatal crash. There is a certain chaos in human beings’ lives and surroundings that requires transportation to be a multidisciplinary field, which includes human-focused aspects. For some parts, AI is definitely required, but with other parts, we need to go through different approaches.

Q. Congratulations on your recently approved dissertation. Could you give us some quick highlights of the research methods that went into producing your dissertation, “A Comprehensive ML and AI Framework for Intersection Safety”? What are the most important takeaways from your dissertation?

Deep Patel presenting his poster at the 2022 NJDOT Research Showcase Poster Session. Click image for PDF of the poster.

A. New Jersey is home to some of the most dangerous intersections in the United States, with four intersections ranked among the top 15 most dangerous, including the 1st, 2nd, and 3rd positions. Since 2019, there has been a trend of steadily increasing intersection-related crashes and correlated crashes within intersection boundaries. This prompted me to ask, “Why do we need to wait for crashes to happen to address the problem?”

To tackle this issue, I developed a proactive approach inspired by my work on the NJDOT research project. The approach focuses on analyzing near-miss incidents and traffic violations, using the concept of surrogate safety measures to identify potential risks before crashes occur. Surrogate safety measures help us detect near-miss events and violations, offering a predictive understanding of high-risk scenarios at intersections.

Using AI and ML, we developed tools that analyze vehicle and pedestrian trajectories in detail. These tools detect and classify conflicts, such as left-turn conflicts or yielding conflicts, enabling us to predict potential crash scenarios based on behavioral patterns at intersections. This proactive analysis allows us to recommend design changes and interventions before crashes occur.

Then, we explored the noncompliance component in a certain area, like red light violations or jaywalking. For instance, our analysis revealed that one in every four pedestrians does not use crosswalks. By integrating historical crash data, proactive trajectory analysis, and noncompliance trends, we developed a tool that ranks intersections based on multiple criteria. These include potential high-crash scenarios, contributing factors, and the economic impact of injury severity at specific locations.

Determining Key Factors Linked to Injury Severity in Intersection-Related Crashes in NJ. Deep Patel, Rowan University (2023 Research Showcase). Click image for slides.

Additionally, the research explored how emerging technologies, such as connected and autonomous vehicles, could be adapted to enhance intersection safety. By conducting trajectory analyses, we assessed how data from these technologies could inform future safety measures and interventions.

Overall, my research focused on identifying key factors within intersection boundaries to reduce crashes, improve mobility, and do so in a cost-effective manner. This comprehensive approach combines proactive analysis, advanced technologies, and human behavior insights to deliver practical and impactful solutions for roadway safety.

Q. So this tool seems to be one of the most important takeaways. Is the tool ready for NJDOT use to identify potential high crash risk intersections? Is that the main intent of the tool?

A. Yes, exactly. The tool is ready but not yet publicly available. We tested it on several intersections. It is currently a proprietary tool of my professor and myself at Rowan University. Anyone interested in using the tool can connect with us, but it is not yet publicly available and certain permissions are required.

Q. Is NJDOT using it or can they use it?

A. No, the department is not using it because this was part of my recent defense. They are aware of the tool’s capabilities because it was part of an innovative showcase. The tool’s documentation has been published through the University Transportation Center (UTC). Hopefully, in the near future, it could be applied by NJDOT.

Q. Looking ahead, you have your new position in an industry role. Would you like to continue with this sort of focus on transportation research, or are you anticipating a different career direction?

A. With my new position as a Traffic Safety and Mobility Specialist, I will be focused on transportation research, conducting high-quality industry research where I would help develop safety and mobility performance measures on certain corridors designed to move traffic more effectively and enhance safety on the roadways. My work will also include industry deployment and understanding the agencies’ concerns regarding the challenges they face.

Looking ahead, I see my career direction as a blend of research and practical implementation, ensuring that innovative solutions are not just developed but also applied to make a real-world impact. Ultimately, if my work can contribute to saving even a single life, I will consider it a meaningful and worthwhile achievement.

Resources

Jin, P. J., Zhang, T., Brennan Jr, T. M., & Jalayer, M. (2019). Real-Time Signal Performance Measurement (RT-SPM) (No. FHWA NJ-2019-002).  Retrieved at: https://www.njdottechtransfer.net/wp-content/uploads/2020/01/FHWA-NJ-2019-002.pdf

Jin, P. J., Zhang, T., Brennan Jr, T. M., & Jalayer, M. (2019). Real-Time Signal Performance Measurement Phase II. Retrieved at:  https://www.njdottechtransfer.net/wp-content/uploads/2022/08/FHWA-NJ-2022-002-Volume-I-.pdf

Patel, D., P. Hosseini, and M. Jalayer. (2024). A framework for proactive safety evaluation of intersection using surrogate safety measures and non-compliance behavior. Accident Analysis & Prevention, Vol. 192. https://trid.trb.org/View/2242428

Patel, D. (2024). “A Comprehensive ML and AI Framework for Intersection Safety: Assessing Contributing Factors, Surrogate Safety Measures, Non-Compliance Behaviors, and Cost-Inclusive Methodology.” Theses and Dissertations. 3305. https://rdw.rowan.edu/etd/3305

For more information about the 26th annual NJDOT Research Showcase, visit: Recap: 26th Annual NJDOT Research Showcase

Source: UHPC SOLUTIONS North America (top left); Midwest Roadside Safety Pool Fund (bottom left); Colorado Department of Transportation (right)

NJDOT’s Involvement with Transportation Pooled Fund Program

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For over 45 years, the Transportation Pooled Fund (TPF) Program has made it possible for public and private entities to combine resources for high‑priority transportation research. By pooling funds and expertise, participating organizations can support research that can lead to innovative solutions at a lower cost to agencies and extend the reach of their research budgets.

State DOTs often fund TPF Program studies using State Planning and Research (SP&R) funds, which can be applied to transportation studies as well as research, development, and technology (RD&T) transfer activities.

We spoke with Dr. Giri Venkiteela, Innovation Officer in the Bureau of Research, Innovation and Information Transfer (BRIIT), to learn about NJDOT’s recent involvement with the Transportation Pooled Funded Program.

Q. What is the primary goal of Transportation Pooled Fund (TPF) Program?

The Federal Highway Administration leads the Transportation Pooled Fund Program

A. The Transportation Pooled Fund Program, or TPF, makes it possible for state DOTs, the Federal Highway Administration (FHWA), and other organizations to partner when there is a shared interest in solving a transportation-related problem. Partners contribute funds and other resources to cost-effectively address problems through research, planning, and technology transfer activities.

The FHWA administers the TPF Program. Only the FHWA or a State DOTs may initiate and lead a pooled fund study. Local and regional transportation agencies, private industry, foundations, and institutes of higher education can partner with sponsoring agencies to conduct pooled fund projects.

Q. What is your involvement with the TPF Program?

A. I work in NJDOT’s Bureau of Research, Innovation and Information Transfer (BRIIT) and serve as the Transportation Pooled Fund Program’s project manager, or coordinator on behalf of NJDOT. Among my responsibilities, I disseminate information about new “open” solicitations for projects from sponsoring agencies to NJDOT’s subject matter experts (SMEs) to gauge their interest in participation. Sometimes NJDOT SMEs or our customers — who network with their peers at other agencies — will hear about an upcoming or worthwhile project and ask that I monitor its status so that NJDOT can join as a partner once the project is posted. Depending on the topic, I may also serve as the agency’s SME on a particular project.

Q. How does NJDOT select project topics from “open solicitations” to join through the TPF Program?

A. The FHWA pooled funded website is publicly available and anyone can view the many “open solicitations” for projects that seek funding. We have a research budget that can and does support participation in pooled funded studies, but we also must set-aside funds and commit to the projects we join for several years over the lifetime of the research. Our budget is not a static number but dynamic. The amount that we can commit depends on how many projects NJDOT is interested in joining.

BRIIT’s Research Manager works with leadership in departmental units seeking funding to ascertain the value potential of individual projects and I offer my advice during this process as a member of BRIIT.

Q. How do NJDOT staff participate in these studies, and what are the requirements for participation?

A. The NJDOT unit managers need to assign an SME for the research project study. I serve as the research program manager but we need to have an SME who is interested in being the participant. I coordinate with FHWA on our financial commitment and make sure the FHWA website is up-to-date with our participation.

Once the project receives the necessary financial commitments, the lead state is responsible for the administration of the research project, which may include the selection of universities or contractors to perform the research.

Once we all contribute the money, the project proceeds like a regular research project. The lead state holds quarterly meetings, prepares quarterly progress reports and disseminates the research. They keep the various participating agencies informed of progress. The lead state uploads progress reports to the FHWA’s website and the states will have their own websites to share project reports, latest news and other tools.

If SMEs or other researchers want to know what’s going on in any particular quarter, they can find the information that is shared. Our SMEs may also be involved in the development of a scope of work and, over the course of the project, may have specific needs that they would like for the selected research team to address — for example, such as thorough testing of materials.

Q. What are some examples of successful pooled funded studies and their outcomes that NJDOT has joined?

Researchers at Midwest Roadside Safety Facility state-of-the-art computer software, including LS-DYNA, to simulate real-life impact events. Using computer simulation, it is possible to reduce design costs and better understand system behavior. Click for examples.

A. The Midwest Roadside Safety Pool Fund program is a fantastic pooled fund study where a lot of crash testing of roadside barriers with different materials has been performed. The costs for such testing would be difficult for one state to bear so it makes sense for the states to come together so that more testing can be done. In this case, Nebraska DOT leads the research. Back in 1990, three Midwestern states started this pooled funded research effort, but it has grown to now include 22 lead and partnering states. The participating state DOTs collaborate with the Midwest Roadside Safety Facility at the University of Nebraska-Lincoln. So, if our SMEs see a new design or material that needs testing, they can put this request forward through this study.

Clear Roads Winter Maintenance Research TPF-5(353), led by the Minnesota Department of Transportation, was a 2024 Recipient of the FHWA Transportation Pooled Fund Excellence Awards.

The Clear Roads Winter Highway Operation — now in its third phase — is another great example. The Clear Roads pooled fund project began in 2004 with four members interested in snow clearance and related issues. The project performs real-world testing of winter maintenance materials, methods, and equipment and has grown to include 39 participating states. The Minnesota’s DOT leads the project, and was recently recognized with a TPF 2024 Excellence Award.

This is just a handful of examples — there are many others being driven by state DOTs, each of which have their own unique flavors.

Learn more about research on and use of Ultra-High Performance Concrete. David Hawes, Resident Engineer for Pulaski Skyway, NJDOT is featured at 2:13.

I would also like to mention one non-state DOT sponsored research project. The Structural Behavior of Ultra High Performance Concrete project is led by the FHWA itself through its Turner Fairbanks Research Center. The project conducts various experiments with UHPC. Every state wants to know what is happening with this relatively new material. The project objective is to develop knowledge on the structural performance of UHPC materials in highway bridges and structures. The test results are expected to inform proposed structural design guidance for UHPC components and support usage of UHPC by interested DOTs.

Q. How are the results and findings of these studies disseminated to the participating agencies, public or other stakeholders?

A. Some projects are ongoing like the Midwest Roadside Safety study. Information is flowing through their research hub with project reports and other materials posted on their website along with information on conference presentations, trainings, and newsletters. If you need any information, it will be conveyed through the program.

But for some pooled fund projects, they need to implement some of the tools that they are developing so that is how they would come to contact the states, such as to have something tested or looked at. The first priority would be given to the states that are participating in the pooled funded study.

For FHWA, if something new comes out of the pooled funded study, I think they may elevate the innovations into other areas such as through the Every Day Counts Program.

Recently FHWA started a pooled fund excellence awards to highlight the importance of collaboration and partnership in transportation research and encourage states to participate. Actually, I participated as a judge last year. We selected two projects for the inaugural TPF Excellence Awards. I already mentioned the Clear Roads Winter Maintenance Research project. The other award was given for an Indiana DOT project, Member-Level Redundancy in Built-up Steel Members, which led to new AASHTO Guide Specifications.

Q. How do NJDOT SMEs who are participating in the pooled funded studies share what they have learned?

A. We have started to ask that the SMEs share a short yearly progress report that reflects upon what they may be learning. Since NJDOT is obligating funding, we need to have some kind of justification for the commitment. The reporting can help us consider the benefits of the research or innovations being advanced, and to consider some of its possible implications for NJDOT practices.  

With a good and continuing dialogue with our SMEs, we should be able to determine if it makes sense to have the SMEs speak at a future NJ STIC meeting to share what they are learning and convey what is innovative about the pooled funded study’s research.

Q. Do you foresee opportunities for having selected researchers from funded projects for which NJDOT was a partner share their findings with NJDOT employees such as at a Tech Talk?

A. The SMEs are well-positioned to help us to identify whether it might make sense to invite a researcher from the study to speak. They can help identify how best to promote and disseminate the research and innovation through some other activity.

Q. Has NJDOT served as the lead organization on pooled funded research? Are there projects that NJDOT would like to lead?

A. We have not led a pooled funded research project yet, although we had some initial plans to do so before the pandemic.  At this point, we think it may be more productive to join as a participating organization. We think serving as participating organization may be a cost-effective way to direct some of our funds and have our SMEs connected to meaningful research.

Of particular note, we just joined the Northeast Transportation Research Consortium (NTRC), a pooled funded study for our AASHTO Region 1, that will support peer exchange activities. The effort seeks to enhance member state collaboration in solving our common problems. This is a pooled fund initiative that is just getting launched and is led by Vermont DOT. NJDOT is one of the six participating state DOTs in the Northeast.

Q. Are there any other projects that are you are thinking of joining at this time?

A. Yes. This is an ongoing process. There are a few projects that we are considering. Solicitations can pop up throughout the year.

Resources

National Cooperative Highway Research Program. 2023. “TPF: Transportation Pooled Fund” (website). https://www.pooledfund.org/

National Cooperative Highway Research Program. 2024. “Transportation Pooled Fund – Open Solicitations” (web page). https://pooledfund.org/Browse/open

National Cooperative Highway Research Program. 2024. “Clear Roads Phase II” (web page). https://pooledfund.org/Details/Study/604

National Cooperative Highway Research Program. 2024. “Midwest Roadside Safety Pooled Fund Program” (web page). https://pooledfund.org/Details/Study/653

National Cooperative Highway Research Program. 2024. “Structural Behavior of Ultra-High Performance Concrete” (web page). https://pooledfund.org/Details/Study/695

National Cooperative Highway Research Program. 2024. “TPF: National Transportation Research Consortium (NTRC) (website). https://pooledfund.org/Details/Study/783

National Cooperative Highway Research Program. 2024. “Member-level Redundancy in Built-up Steel Member” (web page). https://pooledfund.org/Details/Study/482

AASHTO. 2018. Guide Specifications for Internal Redundancy of Mechanically Fastened Built‑Up Steel Members. Washington, DC: American Association of State Highway and Transportation Officials.

AASHTO. 2018. Guide Specifications for Analysis and Identification of Fracture Critical Members and System Redundant Members. Washington, DC: American Association of State Highway and Transportation Officials.

Wildlife Corridors and Crossings in NJ’s Road Network: A Conversation with NJDEP & NJDOT

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Wildlife crossings help to bridge greenspaces divided by roads, streets, and highways through the creation of safe alternative pathways for wildlife. For the past forty years, wildlife crossings have been a part of New Jersey’s transportation network. The state’s first known crossing, a terrestrial overpass, was created during construction of Interstate 78. Since that time, the number of wildlife crossings has increased, and continues to do so with the support of the New Jersey Department of Transportation (NJDOT) and the New Jersey Department of Environmental Protection (NJDEP).

With myriad benefits for both nature and humans, wildlife crossings establish essential connections within a sustainable, resilient, and safe ground transportation network. To learn more about NJDOT and NJDEP’s effort to increase and improve wildlife crossings in New Jersey, we spoke with several staff members during a group interview.

From NJDOT:

  • Domenica Mousa, Environmental Specialist, North Environmental Team, Office of Landscape Architecture and Environmental Solutions
  • Rachel Dekovitch, Supervisor, North Environmental Team, Office of Landscape Architecture and Environmental Solutions 
  • Amber Cheney, Section Chief, North Environmental Teams, Office of Landscape Architecture and Environmental Solutions

From NJDEP Fish and Wildlife, Endangered & Nongame Species Program:

  • Gretchen Fowles, GIS specialist and wildlife biologist, , Co-lead of Connecting Habitat Across New Jersey (CHANJ)
  • Brian Zarate, wildlife biologist, CHANJ Co-lead
  • Mackenzie Hall, wildlife biologist, CHANJ Co-lead

The following Q&A is a summary of the conversation which has been condensed and edited for clarity.

Q.  It is estimated that there are over one million annual wildlife vehicle collisions nationwide involving large wildlife. The need for, and related benefits from, wildlife crossings vary but can include benefits to both human safety and wildlife survival, as well as cost savings. What other potential benefits come to mind when you think of roadway wildlife crossings?

NJDOT:  New Jersey is a densely populated state with an intricate network of roadways, often cutting between greenspaces. These greenspaces, including forests, fields and streams are home to a variety of species, many of which travel and explore. Unfortunately, these two realities cause a significant amount of traffic collisions; the most serious of which are caused by deer. These collisions can be very unsafe for drivers, passengers, and wildlife. Fortunately, wildlife crossings can be implemented to keep fauna away from the roadway. The result? Safer drivers, passengers, and wildlife.

A figure from the CHANJ Guidance Document (page 64) that illustrates key design elements of effective wildlife crossings.

NJDEP:  From the Department of Environmental Protection’s perspective, wildlife crossings provide important environmental benefits in addition to reducing wildlife fatalities. The division of greenspaces by roads and highways is considered habitat fragmentation. Habitat fragmentation worsens the conditions of endangered species, affects ecosystem function, and reduces the ecosystem’s resiliency. In short, it keeps species from moving, mating, and finding food. The implementation of wildlife crossings helps to reduce habitat fragmentation and improve connectivity. Often this improved connectivity creates healthy ecosystems where populations can behave and survive naturally and move about as they wish. Connectivity also contributes to the maintenance or restoration of ecosystem function and ensures rare species have a chance to recover. Even non-rare species can help maintain their health and population with improved connectivity. The NJDEP team wants to build all these redundancies into the ecosystem to allow the more imperiled species to have opportunity to recover, while also maintaining populations of existing species that are seemingly doing well.

Q. Many New Jersey highways and roadways fragment wildlife habitats and challenge migratory paths. With one of the densest road networks in the country, how does your department address concerns of biodiversity and habitat connectivity within the context of road and bridge development?

NJDOT: Each bridge or road project goes through an environmental review to identify any environmental issues or constraints within that project area. As a part of the analysis, we screen for federally and state-listed threatened or endangered species. If such species are found, restrictions or guidelines are specified. For example, if the proposed area has birds that are listed under the Migratory Bird Treaty Act, or has endangered or threatened bats, we put a time restriction on when tree clearing may take place. These efforts help to preserve the habitat by limiting tree cutting to periods when animals are less present, typically from November 16h to March 31st.  

The NJDOT Office of Landscape Architecture (OLA) started a Pollinator Program in 2020 to help promote biodiverse connectivity throughout the State along our appropriate right of way while considering alternate mowing opportunities. Our Capital Program projects seek to enhance the native species of the specific location, and we use our Pollinator Program to supplement and create more locations. Each year OLA applies for funding through State funds for these plantings. Many times, these locations are chosen based on the best management practices (BMP) of the Maintenance yards that reach out to us for consideration of locations. These created sites help offset and maintain assurances of our Department’s compliance with the Endangered Species Act. 

NJDOT is increasing the number of pollinator habitats along roadways. Recognized benefits include more pollinators (bees, birds, butterflies, etc.), roadside beautification, increased carbon intake, less mowing and herbicide maintenance, and soil erosion prevention. Source: NJDOT.

In 2023 we became more proactive in establishing habitat for the Monarch Butterfly and created the 100,000 Milkweed Initiative.  With the funding set aside for pollinators we planted over 100,000 of 3 types of Milkweed species throughout the State.  To date we have created over 11 Acres of Milkweed Specific habitat and over 40 Acres of additional Pollinator and reduced mowing areas through the Pollinator Program.  NJDOT Lands are significant in creating a linear and ideal habitat for Pollinator activities which is also why we address Pollinator Habitat through Capital Program Projects.

Q. In a recent “Lunch and Learn” presentation, it was noted that changes to the NJ Flood Hazard Control Act Regulations require that NJDOT evaluate new and existing bridges, culverts, or roadways for fragmentation of habitat for threatened and endangered and/or any species of special concern and provide a wildlife species passage if a project is determined to cause fragmentation of habitat. How has this requirement affected your work program? Has this change heightened interest in wildlife connectivity?

NJDEP: The NJDEP Flood Hazard Area Act regulation has led to a significant increase in the number of permitted and implemented terrestrial wildlife crossings. It has also fostered more projects and collaborations across NJDOT, other NJDEP divisions, as well as with counties and municipalities, and non-profit organizations.

However, the regulation can sometimes create challenges. For example, while habitat fragmentation might be occurring, the feasibility of installing a wildlife crossing might be difficult because of other infrastructure in the area or the stream’s hydrology. In such cases, NJDEP and NJDOT work together to determine the best course of action.

Q. As noted, this topic is of interest nationwide. The FHWA Wildlife Crossing Pilot Program (WCPP) has $350 million in federal aid funding available through 2026 for state DOTs and others. FHWA plans to release the next NOFO shortly. Has NJDOT considered pursuing one of these grants for a construction or non-construction wildlife corridor project?

NJDOT has pursued this competitive grant, unsuccessfully. The FHWA grant focuses on human and driver safety and projects where large mammal collisions are occurring, making projects for smaller wildlife species, less likely to be awarded a grant, and most of our projects focus on smaller animals. Losing smaller animals poses a risk to the health of the ecosystem, and future justifications will consider this.

The Wildlife Crossings Pilot Program grant is just one of many options within the Bipartisan Infrastructure Law, which offers historic support to tackle habitat fragmentation and wildlife mortality. Other opportunities within the law may be more helpful to pursue, such as eligible formula allocations, rather than competitive grants. That said, NJDEP Fish and Wildlife successfully applied for a Transportation Alternatives Program grant that is resulting in the construction of an amphibian crossing in northern New Jersey, but it took ten years of work to get to this stage. The crossing has not yet been constructed but anticipated in the next year or so.

Q. Can you tell us a little bit about the North Atlantic Aquatic Connectivity Collaborative?  How does NJDOT participate with NAAAC?

We are participating with the North Atlantic Aquatic Connectivity Collaborative (NAAAC) program to survey current culverts and bridges and evaluate possible wildlife passages. Once surveyed, this information becomes available on the Connecting Habitat Across New Jersey (CHANJ) online mapping tools and via online or downloadable GIS services. The use of these maps can help to identify when there is an existing barrier for terrestrial or aquatic species. We also use other GIS layers, such as the NJDEP Landscape Project and CHANJ, that is also included on the map to determine if there are any terrestrial species of concern and suitable habitat on either side of the culvert/bridge or in the area. For each project that requires an NJDEP Flood Hazard Area permit and involves a bridge or a culvert, we use this map to write up a brief analysis, which we then send to NJDEP.

CHANJ Web Viewer is used to determine habitat fragmentation. Source: NJDEP

Q. According to research, the evaluation and development of road crossing projects are mostly being led by several organizations including the NJ Department of Environmental Protection, North Atlantic Aquatic Connectivity Network, and other localized, environmentally-focused organizations. What role does NJDOT have with these organizations and projects?

NJDOT works with NJDEP to prioritize and list culvert and/or bridge sites that need to be surveyed for NAACC. This year, NJDOT employees will join in the analysis, conducting site surveys to enhance the online dataset for future projects that may require crossings. By collaborating with NJDEP Fish and Wildlife and various watershed groups across the state, NJDOT and its NAACC partners have assessed about 700 culverts so far. Each has been mapped on the CHANJ web tool, which identifies wildlife habitats, cores, and the corridors that connect them.

NJDEP and NJDOT use the CHANJ mapping tool and NAACC generated layers to understand connectivity for both land use and transportation projects, including NJDOT projects.

“By collaborating with NJDEP Fish and Wildlife and various watershed groups across the state, NJDOT and its NAACC partners have assessed about 700 culverts so far.”

Regulatory officials evaluate the map when assessing Flood Hazard Area permits. The map also helps provide a general sense of connectivity within the state, aiding in targeting areas for road improvements, land acquisition, and habitat restoration. These actions are crucial for creating a functionally connected network of land. The CHANJ mapping of habitat cores and corridors, along with all NAACC culvert data, help prioritize sites.

NAACC culvert analysis is often conducted by trained watershed groups and NJDEP Fish and Wildlife seasonal employees. Montclair State University serves as the state lead and coordinator, offering training for interested parties. Free training and resources are also available online from the University of Massachusetts.

The NAACC collaboration spans 13 states in the Northeast region. The NJ NAACC map allows users to select squares on the map (which indicate a culvert) in order to access the regional database. Once the user is redirected to the regional database, they are able to access the corresponding pictures of the culvert, if it has been surveyed, as well as the culvert’s dimensions. This innovation helps users understand what lies under specific road stretches simply by the click of a mouse.

Q.  The Connectivity Habitat Across New Jersey (CHANJ) interactive mapping tool catalogues current and completed projects, the passability of road culverts for aquatic and terrestrial species and other details. This map is partly a product of the NAACC 13 state map that aims to compile wildlife connectivity information into one database, and relies on culvert assessments using the NAACC culvert inventory. The map does not include information about roadkill or auto collisions with wildlife, which limits the basis on which a project could be installed. Are there plans or current processes to collect data on wildlife collisions and roadkill? 

Screenshot of CHANJ Web Viewer. Source: NJDEP

NJDOT maintains crash records based on police reports that may refer to wildlife collision. However, NJDOT does not currently collect any data regarding roadkill.  NJDEP Fish and Wildlife collects roadkill location data, but only for select species like bobcats, bears, coyotes, otters, and beavers. Those data are combined into a roadkill dataset.  For some species, like the state listed bobcat, biologists collect the carcass, and sample it to glean as much information as possible that contributes to their understanding of the health of the population.

Q. Maine Audubon worked with Maine DOT and UC Davis Road Ecology Center to build a crowdsourcing tool that drivers could use to report the location of roadkill. Is NJDOT currently using any type of crowdsourcing in this way? Are there plans to record more information about roadkill and collisions? 

The new NJ Wildlife Tracker tool expands NJDEP’s data by collecting resident reports of rare species sightings and observations. For instance, someone can report seeing a turtle by a stream using this mobile-friendly web application. Reporting is also open to all species, rare or not, that are on roads. This tool aims to increase awareness of roadkill, and to help identify roadkill ‘hot spots.’ 

CHANJ Web Viewer can be accessed on smart phones, a convenient application for those working in the field. Source: NJDEP

The NJ Wildlife Tracker and NJ Fish and Wildlife data mining help identify road mortality hotspots. Between the two we currently have around 7,000 roadkill records in our database.  We are developing a standardized roadkill collection tool, where individuals monitor important road segments bisecting habitat cores and corridors identified by the CHANJ map and report wildlife sightings. Regular commuters can report on specific road segments, providing detailed data for rigorous hotspot studies.

This data is useful for pursuing grants or projects. For example, the upcoming Waterloo Road Amphibian Crossing Project in Byram Township, Sussex County, was justified by years of collected data.

Beyond data collection, we use other tools to interpret and analyze findings. Animal data points require careful interpretation due to their constant movement. One key tool is the NJDEP Landscape Project mapping, which uses wildlife observation location data to infer valuable habitats.

However, there are concerns about crowdsourcing and public data access, particularly regarding the illegal wildlife trade. Detailed mapping tools can be exploited by poachers. At this time, this information is only accessible by NJDEP.

Q. Are there any technologies that have been useful in designing and modifying infrastructure to better suit wildlife? 

Sometimes simple modifications to infrastructure can ensure effective wildlife crossings. For instance, adding a ledge to a culvert can allow animals who avoid water to cross. Bobcats are one species that benefit from this inclusion. The ledge is ideally a natural stream bank within the bridge or culvert, but can also be constructed of concrete or gravel, and  can be tailored to the species present and their needs. All design modifications require hydrology and hydraulics analysis to determine if the modification is feasible.

Through CHANJ, there are two main tools: a map and a guidance document. The guidance document includes best management practices for designing wildlife passages across different taxa. While not high-tech, these practices significantly improve the effectiveness of crossings.

Q.  The NJ Pilot Road/Stream Crossing Assessment focuses on culverts to improve connectivity for aquatic wildlife; however, NJ is also home to terrestrial wildlife that require special crossings. How do you approach this divide in your work, and what are some ways that transportation agencies can design passages that are suitable for both terrestrial and aquatic wildlife? 

Designing wildlife crossings can be complex, especially when dealing with driveways and land use constraints. Studies have shown that incorporating effective fencing is crucial for directing animals towards crossings and preventing wildlife from accessing the roadway. Innovative designs include using flexible recycled plastic fencing directly attached to structures, which helps prevent animals from breaching gaps. Some designs feature a protective lip to deter animals from climbing over.

Advancements in monitoring technology, such as infrared cameras, are proving invaluable. NJDOT is initiating a project to monitor several highway underpasses not originally designed for wildlife but identified as potential crossings. Infrared motion detection captures warm-blooded animals, while specialized setups capture cold-blooded animals. These technologies provide crucial data on wildlife usage of these crossings.

Resources

  • Connecting Habitat Across New Jersey (CHANJ). (u.d.). NJDEP Fish & Wildlife. [Website]. Guidance Document and Mapping Web Viewer Tool. Accessed here.
  • Connecting Habitat Across New Jersey (CHANJ). (u.d.). NJDEP Fish & Wildlife. NJ Wildlife Tracker Public Survey. Report sightings of (1) Rare Species and (2) Wildlife on Roads/Roadkill. [Tool]. Accessed here.
  • Crowdsourcing for Wildlife Road. (2019). Maine Audobon. [Presentation]. FHWA Local Aid Support Exchange Webinar. Retrieved here.
  • Flood Hazard Areas. (u.d.). NJ Department of Environmental Protection. [Website]. Accessed here.
  • Fowles, G., Zarate, B., and Hall, M. (2023). Connecting Habitat Across New Jersey (CHANJ) Assessments. Final Report for September 1, 2017–August 31, 2022. Project Number: W-78-R-1. 1. NJDEP Fish & Wildlife. Retrieved here.
  • North Atlantic Aquatic Connectivity Collaboration (NAACC). (u.d.). [Presentation]. NJDOT Lunch and Learn. Retrieved here.
  • North Atlantic Aquatic Connectivity Collaboration (NAACC). (u.d.). [Website]. Retrieved here.
  • North Atlantic Aquatic Connectivity Collaboration (NAACC). (2019). Culvert Condition Assessment Manual. [Report]. Prepared in association with UMASS-Amherst Engineering, UMASS-Amherst The Center for Agriculture, Food and the Environment and The Nature Conservancy. Retrieved here.
  • Wildlife Crossings Program. (u.d.). [Website]. Federal Highway Administration. Retrieved here.
  • Weber-Leaf, Pamela. “New Jersey’s Animal Crossings Protect Our Wildlife from Dangerous Traffic”. (October 9, 2024). New Jersey Monthly. [Article]. Retrieved here.

Interview with “Best Poster Award” Winner at 2023 Research Showcase: “Properties of Cementitious Materials with Reclaimed Cement”

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Concrete production is energy intensive, and requires materials that are both challenging, and expensive to acquire. Material engineers are seeking alternative materials that are more cost-effective and carbon-friendly, but also operate successfully as road and building material.  

We spoke with Alyssa Yvette Sunga, a graduate researcher at Rowan University who won the Best Student Poster Award at NJDOT’s 2023 Research Showcase. Her research, “Properties of Cementitious Materials with Reclaimed Cement,” evaluated the characteristics of cementitious materials mixed with varying percentages of reclaimed cement. Sunga and her fellow researchers examined each mixture’s initial setting time, heat of hydration and compressive strength and compared it against ordinary Portland cement. The purpose: to determine if adding reclaimed cement has any effect on the durability and use of cementitious materials. If there is little to no adverse effect, reclaimed cement may help reduce the need for new materials and can reduce the carbon bi-product of concrete. Dr. Shahriar Abubakri (Shah), Ms. Sunga’s supervisor at Rowan University, also joined us for the interview. 

Q. Could you tell us a little bit about your educational and research experience and how you got where you are now as a graduate research fellow at Rowan? 

A. I’m an international student from the Philippines. I graduated from the University of the Philippines – Los Banos in 2017 with a Bachelor of Science in Civil Engineering. After that, I worked in industry from 2018 to 2022. My former undergraduate professors, who were graduate students here [at Rowan], reached out to me asking if I was interested in pursuing graduate studies. I applied and began my Master’s in Civil Engineering in January 2023. 

Q. What interested you about researching the properties of reclaimed cement? Do you hope to continue research in pavement materiality? 

A. The environmental impact of reclaimed materials like cement is interesting to me. Cement production is a significant contributor to carbon emissions, so finding ways to reuse it is essential. Additionally, reclaimed cement presents unique challenges and opportunities in terms of material properties, durability, and performance. 

So, in a way, we’re helping produce less carbon emissions; that’s what interested me about this study. 

I’m currently working on a lot of different concrete projects. We’re hoping to develop more efficient construction approaches, but I also aim to contribute to the development of innovative techniques and solutions that will optimize reclaimed materials in construction projects. We also aspire to collaborate with industry partners and government organizations, so that we can implement these sustainable practices on a full-scale project in the future. 

Alyssa Sunga received the Best Poster Award for Student Research At the 25th Annual NJDOT Research Showcase in October 2023.

Q. Was there anything particularly noteworthy or surprising to you discovered from this research? 

A. Yes, there’s potential for reclaimed cement and enhancing the performance of unsustainable construction materials. We did not expect that we could use it as a replacement cement or as a supplementary cementitious material. Through various experiments, we found that using this reclaimed cement or incorporating it in cementitious mixtures resulted in comparable properties such as durability, strength, and workability. 

Q. Your research looked at cement paste and mortar specimens incorporated with up to 20% Reclaimed Cement and found no significant difference for the flow measurement and setting time. Should further research be done with higher percentages of reclaimed cement? Why did your research cap it at 20%? 

A. We’re planning to do further research on larger amounts of reclaimed cement. We just used 20% as a cap to get a general idea of the effect of partially replacing ordinary Portland cement with reclaimed cement. Now that our research with 20% is showing good results, we plan on doing tests with higher percentages in the future. 

Q. Your research found that cement paste specimens with up to 20% Reclaimed Cement (RC) saw a 4% reduction in compressive strength after 90 days. What does this mean for applicability (i.e. is 4% a significant reduction? does this make cement paste with 20% RC not suitable for pavement?) 

A. A 4% reduction may seem small, but it must still be taken into consideration. However, as long as the strength is within a recommended range, then it is suitable for pavement applications. 

Q. Is there a percentage of reclaimed cement that is most likely not suitable for pavement? 

A. Alyssa: My advisor would like to jump in to answer that. 

Shah: The acceptable percentage of reduction in concrete strength depends on the specific application and the assumptions made by the designer. For instance, practical standards like the American Concrete Institute (ACI 301.1.6.6) typically require that the average strength of three samples meets or exceeds the specified compressive strength. Additionally, each individual sample within this set should not fall below 500 psi of the designed strength. It’s important to note that concrete’s compressive strength can vary widely, ranging from 2500 psi to 5000 psi, and even higher in residential and commercial structures. Some applications may require strengths exceeding 10,000 psi. So, in cases where the required strength aligns with the design strength, even higher reductions may be acceptable. 

Q. Mortar specimens with 20% RC had a different result and surpassed the strength after 28 days. Why do you think this was a different result from cement paste specimens? What does this mean for applicability? 

A. This difference in result may be due to different factors, but mortar differs from cement paste due to the additional materials like sand. So, this can influence the hydration and the strength development, but we still need to do further research to understand the long-term performance and durability or the effect of adding different materials to the cementitious materials.  

We still must do further research to see the effects of adding different materials like sand and gravel to cement paste. If we’re going to use it in concrete, that’s another additional material like an aggregate. It’s just a matter of the specific materials. There are a lot of factors — like the temperature where you make your specimens. So, it’s always just trial and error. There’s no trend to it really. 

Q. Your poster suggests that incorporating up to 20% RC has some promising benefits including reducing carbon emissions. What are some of the other benefits?  

A. Incorporating the 20% RC will help mitigate supply shortages because we’re able to provide an alternative source of material instead of just using cement. It also promotes eco-friendly construction practices, contributing to sustainable transportation infrastructure, and research on reclaimed cement enables ongoing enhancements in material performance and construction methods. 

Q. You have mentioned throughout this interview where there’s a need for more research. Can you describe some specific things that you would really like to research about incorporating reclaimed cement into cementitious materials? 

A. The most important part of this research is determining what is the optimal mix proportions to use and then studying the effects on fresh properties and assessing the long-term durability like compressive strength, the tensile strength. These investigations are crucial for understanding the full potential of reclaimed cement in construction. Personally, I’m deeply interested in exploring these research areas further. 

Q. What kind of impact do you hope this research will have on material selection by transportation agencies? 

A. I hope this research convinces transportation agencies to use reclaimed cement in pavements. It’s sustainable, cost effective and performs well — aligning with transportation agencies’ goals and standards. This could lead to a greener and more resilient transportation infrastructure. 

Resources

Sunga, A., Abubakri, S., Lomboy, G., Mantawy, I. (2023). “Properties of Cementitious Materials with Reclaimed Cement”. Rowan University Center for Research & Education in Advanced Transportation Engineering Systems. Poster.

Yvette Sunga, A., Abubakri, S., Lomboy, G., & Mantawy, I.M. (2024). Properties of Cementitious Materials with Reclaimed Cement. Presented at IABSE Symposium: Construction’s Role for a World in Emergency, Manchester, United Kingdom, 10-14 April 2024, published in IABSE Symposium Manchester 2024, pp. 428-434. Retrieved at: https://structurae.net/en/literature/conference-paper/properties-of-cementitious-materials-with-reclaimed-cement

For more information about the 25th Annual NJDOT Research Showcase, and to see other award-winning posters, visit: Recap: 25th Annual NJDOT Research Showcase – NJDOT Technology Transfer (njdottechtransfer.net)

Testing Biometric Sensors for Use in Micromobility Safety

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Biometric sensors have long been used in cognitive psychology to measure the stress-level of individuals. These sensors can measure a variety of human behaviors that translate as stress: the movement of eyes, stress-induced sweat, and heart rate variability. Recently, this research strategy has moved beyond psychology and into disciplines like transportation planning, to provide an alternative approach to researching micromobility and stress.  

We spoke with Dr. Wenwen Zhang, associate professor at the Edward J. Bloustein School of Planning and Public Policy at Rutgers University, about her experience learning about and using biometrics for a micromobility study. Dr. Zhang’s research, “Rider-Centric Approach to Micromobility Safety” examines the stress levels of micromobility users as they transverse a varied path through an urban space.  

Q. How is your research funded? 

A. Funding comes from multiple sources. The first source is a seed grant from the Rutgers Research Council which supports an interdisciplinary pilot project. Through this grant, we purchased biometric sensors and hired students to conduct a literature review and develop a research design. We also processed the collected pilot data and paid for participation incentives under this funding. I presented preliminary findings from this study, Rider-Centric Approach to Micromobility Safety, at the 2023 NJDOT Research Showcase. At the time that I presented it, I had 24 samples. The presentation ended up inspiring several people who attended the Research Showcase to volunteer as participants—which increased the sample size to 30.

Our other source of funding came from an external grant from the C2Smart University Transportation Center (UTC) at NYU. We used this resource to support obtaining additional stress sensors, data analysis, cleaning, preprocessing, and modeling, as well as collecting more sample data for the E-scooter and bicycle experiments.

Q. How did you get interested in using biometrics sensors (e.g., eye tracking glasses, galvanic skin sensor, heart rate monitors) to study micromobility safety? How does this research differ from your past work? 

A. Before I used biometric sensors, most of my work used passive travel behavior data. For example, to determine the revealed preferences of mode and route choices and risk factors, we used travel trajectory or existing crash big data to develop statistical models. I have found that the entire process is very passive, especially since we only explore risk factors after traffic accidents. It’s surprising that in the research field today we know so little about how human beings actually navigate urban environments while using different travel modes and how it relates to perceived safety. I wanted to explore questions like what is their gaze behavior? How do they feel while they travel using different modes? How do they feel traveling on roads with different design features and how is that going to influence their travel satisfaction or experience overall? 

Dr. Robert Noland, Distinguished Professor at the Rutgers Bloustein School, suggested I investigate the use of biometrics in planning studies. As I dug more into the literature, I realized that biometrics in transportation is a very fascinating topic that I wanted to get into. Once I did experiments in the field, I realized that I really enjoyed talking with different people about how they perceive the built environment while they travel. Biometrics provide richer data compared with revealed preference data that I used to work with.

Q. In your research, you noticed that some corridors were more stress-inducing (according to biometric sensors) than expected, despite properly designed safety infrastructure. How do you think this discovery may affect how planners and engineers look at urban road design and micromobility safety? 

 A. This study collected one-time cross-sectional data. We asked people to walk around an area and tell us whether they feel stressed or not. If they are feeling stress, even in the presence of a safety improvement, it does not necessarily mean that the implemented safety design is not working. For example, in New Brunswick, we observed that a lot of people found it stress-inducing to cross Livingston Avenue, although it has been the subject of a road diet and has several pedestrian safety features incorporated into the new design. While outside our scope of research, one way to understand the impact of the safety infrastructure would be to conduct a “before” and “after” study. This leaves an opportunity for more research, to see how effective the pedestrian-only infrastructure is in reducing stress level. Potentially, it can provide evidence to support pedestrian-only design. Biometric sensors used in a “before and after” study can help us to answer which infrastructure is more preferred. 

Q. You are in the process of collecting data for cyclists and e-scooters using the same method, what are your principal objectives in addressing this segment? Do you expect the results to be different?

Dr. Zhang conducted one pilot e-scooter experiment at Asbury Park, NJ in 2022 to test out the devices and examine how to set up research experiments. She equipped the e-scooter rider, Dr. Hannah Younes, post-doc researcher at the Rutgers Bloustein School, with an eye tracking glass, a GSR sensor on the hand, and a 360-degree camera on top of the helmet.

A. Yes, absolutely, different travel modes will likely alter a person’s expectation for a safe travel environment. For example, we noticed a big difference in the enjoyment of pedestrians and e-scooters on the same path through a park. We had thought that the e-scooter users would enjoy the ride as the pedestrians had, however, the pavement was too rough for the small wheels of the e-scooters. Although the park was walking-friendly, it was not friendly for e-scooters. This shows that each of these micromobility modes needs different kinds of support to feel safe and comfortable.

Q. What are the limitations to this study? Do you have plans for future research to address this? How would you like to expand your research in this topic?

A. Each of the biometric sensors has limitations. For example, eye trackers face some difficulty when identifying the pupils of a participant in direct sunlight. As a result, the eye tracker renders a low eye tracking rate. Eye trackers also work better with darker eyes as the eye movements are more readily recognized. The eye trackers, kept on glasses, also restrict individuals who wear glasses from participating. The unfortunate result of this is that it often excludes a lot of senior people from the experiment. This issue may be alleviated as we are obtaining additional funding to obtain prescription lenses for eye trackers.

GSR sensors use low voltage on skin to measure skin conductivity, which may interfere with electric health devices. This limits individuals from participating if they have an electric health device like a pacemaker on or in their body. We purposefully excluded this population from participating to align with IRB (Institutional Review Board) protocol and to mitigate any risks.

Another limitation of the study is that we must collect sample data one by one, which is a time-consuming process. We can only collect a very small sample compared to a traditional statistical model kind of study, which may have access to thousands of records in the sample. From our literature review, biometrics sensor studies typically involve 20 to 30 participants, but for each participant we have a very rich dataset. For each participating volunteer, we end up with over one gigabyte of data. The limited number of participants may make it harder to generalize results to the entire population, and people may question the results applicability. In some ways this data is similar to the results of qualitative studies, where we have richer information but small sample size, rendering some generalizability issues. 

Feelings of safety were measured using the traditional self-report survey as well as biometric trackers like Heart Rate Trackers, Eye trackers and GSR (pictured above).

Q. What challenges have you found in working with biometrics sensors, or in the interpretation of output measures?

A. The eye tracker and heart rate measures are reliable, but some biometrics have posed challenges. The GSR (galvanic skin response sensor), which tests your sweat level, is very sensitive to humidity and time of the day. The sensor also picks up on sweat resulting from physical exertion, making it difficult to distinguish between stress-induced sweat and physical sweat.

Interpretation of output measures for this metric requires data cleaning and processing to eliminate the effect of sweating from physical exertion. We try to decompose the data to separate the emotional peak from the sweating caused by physical activity using various algorithms. We are still underway testing out different algorithms to clean up the data. So far, we have found that GSR data are very real-time in nature and a good indicator for stress level but are very noisy data and requires some manual processing. This means we spend a lot of time preprocessing the collected data before conducting data analysis. 

Q. How do you expect this research to inform transportation agencies in New Jersey and elsewhere?

A. This type of research captures such rich data on travel behavior itself. Most of the literature using biometrics has been focused on driving, so this research expands the perspective. Here we’re focusing on slow mobility, like active travel and micromobility. Individuals who participate in slow mobility are more vulnerable road users, and we want to see how they behave in different travel environments. This can help agencies gain more insights into how to design safety infrastructure. Beyond that I can also envision the technology being used to evaluate whether certain improvements or infrastructure designs help to improve travel satisfaction or improve people’s experience at the same location by doing “before and after” studies. This type of study also allows you to measure and quantify the effect of the improvement. 

The use of biometric sensors in the field can also be used to foster meaningful public engagement processes to show the lived experience of different people in a neighborhood or traveling through a different corridor, which can be very powerful.

Q. Do you feel the research methods are at a stage where they are “ripe” for use on other demonstration projects, planning or project development studies?

A. After one year of experimentation, our project team can readily work with biometrics. We have a good understanding of sensor limitations and how to set up the sensors to correctly reduce noise as much as possible. Our experience has also helped determine what kind of metrics can be extracted successfully and reliably through the sensors.  

The most useful case for those sensors is to evaluate before and after, so that we can quantify how much people appreciate those implementations in a more accurate way. Beyond that, the sensors can also be effective infrastructure assessment tools. For example, imagine that you ask people to wear biometric sensors and do a bicycle infrastructure evaluation; the agencies can get more realistic and rich data compared with a more traditional survey approach. This rich data can help determine the most effective improvement. It ends up being more inclusive that way.

The tools can be very useful for fostering community engagement with vulnerable populations. For example, if agencies want to improve the accessibility for wheelchair users, they can ask individuals in wheelchairs to wear the sensors and move about an area. Recording and reviewing how they experience a journey is more powerful compared with just asking individuals with needs about their travel patterns. It’s going to be a more straightforward way to show the world how we can make the streets more inclusive for those vulnerable populations. 

Q. Do you think local governments and non-governmental organizations could make use of biometrics sensors as a strategy to promote community engagement and outreach to local communities, or to address specific community safety or livability issues?  Would it be cost-prohibitive to employ such tools for such community-based planning issues at this time?  

A.  From my point of view, the most effective way would be for the agencies to identify where there are needs and promising projects and then work with skilled researchers or practitioners who have these sensors already and have begun to climb the learning curve in the use of sensors and interpretation — for example, they could work with us. They would need to pay for the researchers’ time and participation incentives, or if they were to collaborate with a UTC (University Transportation Center) to conduct such research collaboratively.  

The sensors are not the most expensive part of the study. The most expensive item is the researcher’s time to collect and analyze the data. The data are very complicated to analyze in the first place because it’s a large amount of data with noises. The researchers need to put in a lot of time to get it to the state where you can extract the relevant variables out and start to interpret them.

Q. How would you characterize the “state-of-training” in using biometrics for students or early career or mid-career professionals in transportation?    

A. The biometric sensor itself is not very new, but new to the transportation field, especially for slow modes. It has been widely used in cognitive psychology, where there are classes to interpret those as well. Generally, I don’t think the current transportation and urban planning curriculum for students includes enough classes to cover those sensors. We probably need to teach not only biometric sensors, but urban sensing in general. 

In an ideal course, students could get their hands dirty by putting those sensors in the field and then once the data are collected, they can learn how to preprocess and analyze the data. It would have to be a one-year kind of curriculum design to get people involved and ready for it. Of course, instruction on the use of sensors will differ by topic. For example, if you are working in the air quality field, then there are many different air quality sensors and each of them come with different data formats and require different experiment design and analytic skills.

Regarding the mid-career transportation professional, at this moment I believe the research is more in the academic field and focusing on testing and evaluation. I wouldn’t suggest that the research is so ripe that a mid-career transportation or urban planner professional should need to invest their time in learning how to use biosensors unless they have a research project that may benefit substantially from using the sensors.  

Resources

To learn more about the use of biometrics in the field of active transportation, see:

Ryerson, M., Long, C., Fichman, M., Davidson, J.H., Scudder, K.N., Kim, M., Katti, R., Poon, G. & Harris, M., (2021). Evaluating Cyclist Biometrics to Develop Urban Transportation Safety Metrics. Accident Analysis & Prevention, Volume 159, 2021. Retrieved from https://www.sciencedirect.com/science/article/pii/S0001457521003183?via%3Dihub

Fitch, D.T., Sharpnack, J. & Handy, S. (2020). Psychological Stress of Bicycling with Traffic: Examining Heart Rate Variability of Bicyclists in Natural Urban Environments. Transportation Research Part F: Traffic Psychology and Behavior, Volume 70, 2020, Pages 81-97. Retrieved from https://www.sciencedirect.com/science/article/pii/S1369847819304073?via%3Dihub.

To read more on Dr. Zhang’s work, see:

Zhang, W. (2023). Rider-centric Approach to Micromobility Safety. 25th Annual NJDOT Research Showcase. Presentation. Retrieved from https://www.njdottechtransfer.net/wp-content/uploads/2023/11/Zhang-Safety-2nd-Presentation.pdf.

Zhang. W. 25th Annual NJDOT Research Showcase. Recording starts at: 59:00. Retrieved from https://youtu.be/D_rQP-Dv8gU

Zhang, W., Buehler, R., Broaddus, A. & Sweeney, T. (2021). What Type of Infrastructures do E-scooter Riders Prefer? A Route Choice Model. Transportation Research Part D: Transport and Environment, Volume 94, 2021. Retrieved from https://www.sciencedirect.com/science/article/pii/S1361920921000651.

For more information about the use of biometrics in the broader transportation field, see NYU’s C2SMART’s research project on Work Zone Safety:

Exploring the Future of Environmental Product Declarations at NJDOT: Q&A Interview with NJDOT’s Project Lead

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Under the FHWA’s Climate Challenge, state DOTs and local agencies receive training and work with various stakeholders including those from industry and academia to implement projects that quantify the environmental impacts of pavements using Life Cycle Assessment (LCA) and Environmental Product Declarations (EPDs). EPDs provide an in-depth look at the use effects and environmental impacts of materials, processes, and mixtures. With a general goal to reduce carbon emissions, DOTs are moving towards the use of EPDs for selecting pavement uses and processes.

We spoke with Nusrat Morshed, Project Engineer in the Pavement Design & Technology Unit at NJDOT, about two FHWA project grants funded under the Climate Challenge initiative that she supervises. Both projects focus on the potential use of EPDs and LCA in New Jersey and will allow for NJDOT to develop a strong baseline understanding of EPD use.

FHWA – Funded Climate Challenge Projects

Q. Can you tell us about two FHWA-funded Climate Challenge projects listed for New Jersey. How is NJDOT currently involved in these FHWA funded projects? What are tasks for these projects?

A. NJDOT applied for this research project funding in early 2023 after the advertisement was released. I had spoken with representatives from Rowan University and Rutgers University to gauge their interest in this research, and both were on board. EPDs is a very new concept and term within the transportation field. This made it challenging to determine what the project scope should be for our grant applications. We received funding from FHWA immediately, but there were some technical issues in the allocation of state and federal funding shares that we needed to sort out before we could proceed. Both research teams officially began work in September and October of 2023 and they will have until the end of 2024 to carry out the work.

The research team for Project 1, Utilization of EPDs and LCAs to Promote Sustainability in NJ’s Pavements, is led by Dr. Yusuf Mehta from Rowan University and they are teamed with the research sub-consultant, Advanced Infrastructure Design (AID). The objective of this project is to utilize EPDs and LCAs to promote consideration of sustainability in maintaining NJDOT’s pavement infrastructure. The tasks within this project scope include: conducting a literature review, defining the goals and scope of the comparative LCA analysis, data collection, and analysis of results and interpretation.

The research team for Project 2, Improve Sustainability of Asphalt Pavement Overlay in NJ, is led by Dr. Hao Wang from Rutgers University. The research project objective is to improve the sustainability of asphalt pavement overlay in New Jersey. The project’s basic tasks include: documenting experiences and lessons of using FHWA’s LCA PAVE tool based on analysis of pavement overlay project in New Jersey DOT, evaluating quantification methods for calculating carbon emissions at the use phase of pavement, providing recommendations for use of LCA in decision making of pavement overlays, and preparing a final report and presentation.

Example EPD summary, retrieved from USDOT FHWA Tech Brief: Building Blocks of Life-Cycle Thinking

I am the key point person for both projects.

Q. What is the status of these FHWA funded projects? What resources have been helpful so far?

A. Both projects are underway now but still in the early stages. I received a status report from Project 1 about a month ago and expect a status report from Project 2 before March. For both projects, the focus has been to complete a literature review. One resource that was particularly helpful was the National Asphalt Pavement Associations (NAPA) website, as they have a lot of information on EPDs — 15 EPDs thus far have been identified — which are NJDOT specifications. We have also reached and had a meeting with the Port Authority of New York and New Jersey (PANYNJ) to get information on their own EPD process.

Q. The FHWA Climate Challenge program seems like it has established an approach to promote knowledge sharing and fostering a community of practice. Can you tell us about it?
A. Every quarter, FHWA conducts a climate challenge webinar, and on this webinar there is usually a featured presentation from an expert and then brief update presentations from climate challenge project teams. These project teams extend beyond New Jersey, so other states can hear how NJDOT is doing with these projects and we can learn from our peers in other states.

Previously our updates have been limited to 2 or 3 slides, however, later this spring I will have two reports to base our presentation upon, which will be more comprehensive and reflective of NJDOT’s progress.

Attendees at a Climate Challenge Training session. source: FHWA

The quarterly webinars have been helpful and instructive. EPDs and sustainable resiliency are also very hot topics and several other resources are emerging that we can reference. For example, there was an entire session on EPDs at the Transportation Research Board’s Annual Meeting. Published literature has also been very helpful.

As a part of the project grants, FHWA is providing EPD-specific trainings. Both research teams and I have brainstormed about trainings our teams require. I have coordinated with FHWA as a Climate Challenge member and explained our training needs for accomplishing these two projects. FHWA and I drafted an agenda based on these research needs and we have scheduled a day and a half in-person training for March 2024. I requested that both of my teams submit their findings, as a status report before that training. So it also will be our official first status meeting for both project teams.

As a Project Engineer overseeing these projects, I am not able to work directly with the research, but I provide guidance to the universities and have been the communication bridge between them and FHWA. The training is hosted by FHWA and conducted by FHWA and a third-party organization that specializes in EPDs. These trainings are hosted throughout the U.S. To make this happen, FHWA provided us with their schedule, and we negotiated a time for them to do the training in March 2024.

Q. Who was in attendance for this training?

The training was done on March 12-13, 2024 at NJDOT. This training was focused on team members from both projects. There were representatives from the NJDOT Bureau of Materials, NJDOT Bureau of Statewide Strategies and NJDOT Division of Environmental Resources who participated.

Q. How has this funding assisted with NJDOT’s Every Day Counts (EDC) EPDs related goal?

Unless a NJ STIC Incentive Grant is awarded, FHWA does not provide any funding directly for advancing the EDC-7 innovation, but instead supports the deployment goals through the mobilization of FHWA resource specialists or subject matter experts who are farther along with innovation’s deployment. Luckily, the research of EPDs is a goal within EDC-7, so both of the funded Climate Challenge projects are indirectly supporting that EDC-7 goal.

Q. Have any pilot programs begun?

As we are still in the research stage for EPD use, we have not created any pilot programs yet.

Environmental Product Declarations in the Future

Q. Can you describe the status and implementation goal for NJDOT’s EDC-7 goal for advancing EPDs in New Jersey?

NJDOT’s EDC-7 goal for advancing EPDs in New Jersey is still in the preliminary stages of information gathering. Both of these climate challenge projects will assist with building up a robust set of literature that is necessary for next steps. Our goal is to get ideas for future recommendations. As of now, I would say we need to identify a few plants or suppliers and get some real-time data for different types of considerations based on research needs. Then we need to identify which way we can achieve EPD targets like lowering carbon emissions.

The stages of Pavement’s life cycle. Retrieved from USDOT FHWA Sustainable Pavements Program.

Q. What challenges, if any, has NJDOT faced while working to incorporate EPDs into pavement considerations?

EPD is based on many stages, which require their own literature review. For example, a product category rule, or a set of rules for measuring life-cycle analysis must be developed first. EPDs have different stages that all must be measured — specifically, the production stage, transportation stage and construction stage, or as they are called the A1, A2, A3. Achieving the goal of reduction in carbon emissions through EPDs requires a lot of research and literature review, and it will not be easy to get all the needed information, even when speaking with experts. Starting from scratch, the ability to quantify an EPD could take at least two years. So, it’s not that you will be getting something very quickly. We are just exploring now what is out there and how we can think about something in terms of New Jersey’s pavement mixes.

Q. How does NJDOT use or reference the published EPDs in New Jersey as reported by the National Asphalt Pavement Association’s Emerald Eco-Label tool?

We have looked at the National Asphalt Pavement Association (NAPA) website and reviewed their own PAVERS tool. It has been helpful to see how they do life-cycle analysis. They have their own LCA tool and we use the FHWA LCA tool — so there will most likely be differences. The FHWA LCA tool is expected to be updated soon.

Q. Do you foresee NJDOT having an embodied carbon clause added to NJDOT contract specifications? Will contractors be expected to submit an asphalt mix that provides EPDs to be considered for future contracts?

LCA PAVE Tool assists with analysis and quantification of the environmental impacts of existing products or processes. Retrieved from USDOT FHWA

Yes, definitely, we can dream, but it will take time. We need to identify and set the product category rule. More research is needed, maybe there will be future training opportunities on this topic from FHWA.

Q. Where is the biggest research gap when it comes to the incorporation and use of EPDs? Is it research on the pavement itself, or life cycle analysis, or something else?

EPD is not a single term, but a combination of a lot of things. In the process of determining an EPD for one pavement treatment, you must consider the process of installation, the type of pavement or asphalt mix, the binder and aggregate within the mix, etc. Because each of these processes require their own considerations, we must make the decision on what process and pavement, or asphalt mix should be evaluated first. We can then use our results to determine where the use of EPDs would be most helpful, or which process should be studied next. In other words, we cannot do everything at once, but rather start very specifically and focused, and then move out.

The five steps of developing Environmental Product Declarations (EPD). Retrieved from Tech Brief: Building Blocks of Life Cycle Thinking

 Q. Has NJDOT had an opportunity to use or test the FHWA LCA Pave Tool? If so, how does it use the tool?

I have used that tool before, but I just use it as a general gauge as I don’t have any real-time data currently. I will need training in the future on how to efficiently use the tool based on actual data. I also think this tool will be helpful in the future for determining if our results are realistic. Our research team members are using this tool.

 Q. How are you feeling about this initiative?

As a state government employee, I see this initiative as an effort that will help NJDOT be aligned with NJ’s clean energy policies. EPDs are a new topic for us, and everyone is very interested in learning more about it, including me. The funding opportunity that FHWA provided allows DOTs throughout the U.S. to explore this new topic and determine its applicability in the future of pavement and asphalt design.

Resources

FHWA Climate Challenge – Quantifying Emissions of Sustainable Pavements. FHWA webpage. Retrieved at https://www.fhwa.dot.gov/infrastructure/climatechallenge/projects/index.cfm

LCA Pave Tool. FHWA webpage. Retrieved at https://www.fhwa.dot.gov/pavement/lcatool/

Emerald Eco-Label. Webpage. Retrieved at https://asphaltepd.org/published?state=NJ

What is Environmental Product Declaration (EPD) for Sustainable Project Delivery? Webpage. Retrieved at: https://www.njdottechtransfer.net/epds-for-sustainable-project-delivery/

Life Cycle Assessment: Part I Fundamentals. Webinar, FHWA Sustainable Pavements Webinar Series. Retrieved at: https://youtu.be/uaJ8wGMAPD0?si=oBHnBSN2K1589JEa

An Introduction to Life Cycle Assessment: Part II – EPDs and PCRs, FHWA Sustainable Pavements Webinar Series. Retrieved at: https://www.youtube.com/watch?v=Y4OqVR6U2Us

Sustainable Pavements Program. FHWA Webpage. Retrieved at https://www.fhwa.dot.gov/pavement/sustainability/

Sustainability Analysis: Environmental. Life Cycle Assessment (LCA). FHWA Webpage. Retrieved at: https://www.fhwa.dot.gov/pavement/sustainability/environmental/

Meijer, J., Harvey, J., Butt, A., Kim, C., Ram, P., Smith, K., & Saboori, A. (2021). LCA Pave: A Tool to Assess Environmental Impacts of Pavement Material and Design Decisions-Underlying Methodology and Assumptions (No. FHWA-HIF-22-033). United States. Federal Highway Administration. Retrieved at: https://www.fhwa.dot.gov/pavement/lcatool/LCA_Pave_Tool_Methodology.pdf

Milleer, Lianna; Ciaviola, Benjamiin and Mukherjee, Amlan. (February 2024). EPD Benchmark for Asphalt Mixtures, SIP-108. Prepared for National Asphalt Pavement Association by WAP Sustainability. Retrieved at: https://www.asphaltpavement.org/uploads/documents/EPD_Program/NAPA-SIP108-EPDBenchmarkForAsphaltMixtures-Feb2024.pdf’

Ultra High-Performance Concrete (UHPC) Applications in New Jersey – An Update

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UHPC for Bridge Preservation and Repair is a model innovation that was featured in FHWA’s Every Day Counts Program (EDC-6).  UHPC is recognized as an innovative new material that can be used to extend the life of bridges. Its enhanced strength reduces the need for repairs, adding to the service life of a facility.   

This Q&A article has been prepared following an interview with Jess Mendenhall and Samer Rabie of NJDOT, who provided an update on the pilot projects of UHPC around the state. The interview has been edited for clarity. 

Q.  While EDC-6 was underway, we spoke with your unit about the pilot projects being undertaken with UHPC.  Some initial lessons were shared subsequently in a featured presentation given to the NJ STIC.  Can you update us on results of those projects, and did they yield any benefits in the fields of safety or environmental considerations?

For the NJDOT Pilot Project, the thickness of the overlay was limited by the required depth for effectiveness, as well as the cost of the UHPC material and environmental permitting. To mitigate environmental permitting, we avoided any modifications to the existing elevations and geometry of the structure. Essentially, any removal of asphalt and concrete needed to be replaced to its original elevations.

UHPC overlays can significantly extend the service of bridge decks and even increase a structure’s capacity. Although safety improvements were not the primary objective of this application, there were rideability and surface drainage considerations in the design to enhance the conditions for the road users.

The environmental impacts of structural designs must be compared on the cradle-to-grave use cycle of the design at a project scale.  Having a focus on sustainability is imperative; however, it is more meaningful when resiliency is also considered.  While the greenhouse gas emissions of a volume of UHPC are higher than those of the same volume of concrete, UHPC enables the reduction in the amount of material required in structural designs and improves the durability of structures. Its exceptional compressive strength and toughness allow for the reduction of material usage. By minimizing maintenance requirements and extending the lifespan of infrastructure, UHPC reduces the consumption of materials, energy, and resources over time.

For example, we installed this overlay on 4 bridges as a preservation technique. Had we done nothing, they would have lasted approximately 10 more years. During that time they would have needed routine deck patching resulting in further contamination of the decks and in a condition that is no longer preservable and requires total deck replacement, with large volumes of concrete and much more environmental impact.

UHPC allowed us to take these decks that are still in decent shape and preserve them now with a relatively thin layer to make them exceed the service life of the superstructure and substructure.

Q. Has UHPC been incorporated into the design manual?

Figure 1. UHPC being placed by workers

It is not in our current design manual, but we are working on the revised design manual. UHPC is presently being used for all closure pores between prefabricated components, overlays, and link-slabs. I don’t think we are ready to standardize it quite yet. We used it on the 4 bridges and it will continue to be used, but we will not standardize it until the industry is more predictable and we get more experience to develop thorough guidelines and specifications. It is incorporated into projects as a special provision with non-standard items.

Q. Have you been receiving more requests to use this technology from around the state?

It is much more commonly specified by designers or requested for use on many of our projects. We have responded to nationwide inquiries from state transportation agencies and universities seeking our specifications or input on specific testing and procedures.

Q. What efforts do you think can be taken to encourage more adoption amongst local agencies, counties, etc.?

We are keen on inviting the counties to any training or workshop that we are hosting as well as sharing our lessons learned thus far.  I think they are aware of it.

Q. What kind of hurdles do you think exist that may limit widespread adoption?

It is possible that initial cost and industry experience with the material are still major limiting factors in adoption. We have also learned from specialty UHPC contractors that the innovation and availability of construction equipment geared for UHPC implementation are also lacking.  Bringing into focus the life cycle costs and with more implementations, we think many of these hurdles will be overcome. Additionally, once UHPC is used more in routine maintenance the implementation would be more frequent and widespread; we know there is interest specifically in UHPC shotcrete once it is available.

Q. Are you familiar with any training, workshops, or conferences that have been done for staff or their partners on this topic?

We participated in the Accelerated Bridge Construction (ABC) conference in Miami, Florida, the International Bridge Conference (IBC) in Pittsburgh, Pennsylvania and the New York State DOT Peer Exchange. In Delaware, we presented at the Third International Interactive Symposium on UHPC. We also participated in the development of a UHPC course for the AASHTO Technical Training Solutions (TTS formerly TC3) which is now published on the AASHTO TTS portal and available on our LMS internally. 

Q. Do you think there is any special training needed for the construction workforce to start using this technology?

Absolutely, the AASHTO TTS course and the EDC-6 workshops are geared towards the design and construction, TTS is more focused in the Construction. It’s an introduction to what to expect and how to implement it. UHPC is often used for repair projects, and many contractors may not have the experience or comfort with using the material.

Figure 2. UHPC Testing at Rutgers’ CAIT

Q. What are the results of the pilot projects of UHPC?

This Pilot projects program demonstrated that UHPC overlays can be successfully placed on various structures, the work can be completed rapidly to minimize traffic impacts — we estimated roughly four weeks of traffic disruption per stage, and the benefits of UHPC can help preserve the existing infrastructure. Compared to deck replacement, UHPC overlays can rehabilitate a bridge deck at exceptional speeds with unique constructability and traffic patterns, as implemented in all four structures. However, limitations exist, and further research is necessary to investigate the issues identified in the pilot project, but the potential of this material outweighs the existing limitations.

Q. Has there been long-term testing data developed to gather performance data?

To assess the performance of the UHPC overlay, we put together a testing program to include NDT as well as physical sampling and lab testing. This objective will be accomplished by first establishing baseline conditions through an initial survey followed by periodic monitoring of the UHPC-overlaid bridges over succeeding years. This will help NJDOT assess the performance of UHPC as an overlay. Overall, the results show the overlay bond is performing well.

Q. Has the data from the pilot project been used to research further applications?

Further applications for UHPC overlay are on new bridge decks/superstructures, and the data from UHPC overlay research project are being used for these projects. There is an interest in header reconstruction with UHPC. If deck joints need to be replaced, they should be constructed with conventional HPC with UHPC at the surface to provide the same overlay protection over the entire structure. Also, self-consolidating and self-leveling UHPC was preferred for the full-depth UHPC header placement to ensure proper consolidation around tight corners and reinforcement. This will be further explored for maintenance operations as well.

For future projects, in lieu of full-depth header reconstruction in a single lift, a partial depth header removal and reconstruction or alternatively two lifts of header concrete should be evaluated to coincide with the deck overlay, in which case the benefits of the fast cure times from UHPC can still be realized. Two of the four bridges experienced air voids throughout the placement. A UHPC slurry with no

fibers was placed in the identified air voids; since the voids contained exposed fibers, they were considered to create adequate bonding with the UHPC slurry.

Resources

NJDOT Technology Transfer (2021, November). Stronger, More Resilient Bridges: Ultra High-Performance Concrete (UHPC) Applications in New Jersey.  Interview with Pranav Lathia, Retrieved from:  https://www.njdottechtransfer.net/2021/11/29/uhpc-stronger-more-resilient-bridges/

Mendenhall, Jess and Rabie, Samer. (2021, October 20). UHPC Overlays for Bridge Preservation—Lessons Learned. New Jersey Department of Transportation. https://www.njdottechtransfer.net/wp-content/uploads/2021/11/NJDOT-UHPC-Overlay-Research-Project-EDC-6-Workshop.pdf

New Jersey Department of Transportation. (2021, October 20). NJDOT Workshop Report. New Jersey Department of Transportation. https://www.njdottechtransfer.net/wp-content/uploads/2021/11/NJDOT-UHPC-Workshop-Final-Report.pdf

Rabie, Samer and Jess Mendenhall (2022, December). Design, Construction, and Evaluation of UHPC Bridge Deck Overlays for NJDOT.  NJ STIC Presentation and Recording.  Retrieved from:  https://www.njdottechtransfer.net/2022/12/18/nj-stic-4th-quarter-2022-meeting/

Q&A: What’s EPIC2 about Internally Cured Concrete?

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Enhancing Performance with Internally Cured Concrete (EPIC2) is a model innovation in the latest round of the FHWA’s Every Day Counts Program (EDC-7). EPIC2 is recognized as an innovative new technique that can be used to extend the life of concrete bridges and roads. Internal curing increases concrete’s resistance to early cracking, allowing the production of higher-performance concretes that may last more than 75 years.

This Q&A article has been prepared following an interview and follow-up correspondence with Samer Rabie and Jess Mendenhall of the New Jersey Department of Transportation. The Q&A interview has been condensed and edited for clarity.

Q. What is Internally Cured Concrete, and how does it differ from traditional concrete?

A common issue with high performance concrete (HPC) bridge decks is that soon after the curing is done, they develop fine shrinkage cracks spread throughout the deck. Even this fine cracking can reduce the service life. In the past, we have used crack sealing materials as a mitigation effort, but when we learned about internally cured concrete, we shifted our focus to see if we could adopt it in New Jersey.

Figure 1. Illustrating the difference between conventional and internal curing

Autogenous or chemical shrinkage is specific to HPC concrete, where the w/c ratio is less than 0.42. It is due to self-desiccation, which is water consumed by the cementitious materials after setting, and that is one where internal curing can help.

There are multiple methods to implement internal curing. The method that we are considering involves  modifying a conventional concrete mixture to an internally cured concrete mixture by replacing a portion of the fine aggregate (sand) with lightweight fine aggregate. This lightweight fine aggregate (LWFA) is saturated with internal curing water, typically estimated at 7lbs of water for every 100lbs of cementitious materials used in the mixture. Next, the amount of LWA required for this amount of internal curing water is determined based on the mass of the internal curing water and the absorption of the LWFA. Once the total volume and mass of lightweight aggregate are determined, the volume (and mass) of the fine lightweight aggregate are adjusted so that the volume of LWFA and fine aggregate in the internally cured mixture is equal to the volume of the fine aggregate in the original mixture.

The LWFA will provide internal curing water within the concrete mix during curing, and prevent a condition that occurs in low W/CM ratio systems where the capillary water within the concrete matrix pores will be consumed without complete cement hydration, which can lead to cracking of the concrete matrix.

Q. How does Internally Cured Concrete improve performance?

Internal curing improves the performance of concrete by increasing the reaction of the cementitious materials and reducing internal stresses that typically develop in high-cementitious content mixtures if insufficient internal curing water is present. However, in addition to conventional curing which supplies water from the surface of concrete, internal curing provides curing water from the aggregates within the concrete. This provides a source of moisture from inside the concrete mixture, improving its resistance to cracking and overall durability.

Q. Are there any limitations on the use of internally cured concrete?

Internal curing is extremely versatile and  can generally be used anywhere traditional concrete is used. Most of the process is the same, and aggregates can be pre-saturated as needed. It follows the norms of industrial concrete production, making it accessible to any producer already familiar with the state of practice. Most of the implementation process is similar to conventional concrete.

Figure 2. Workers applying internally cured concrete to a bridge deck.

Q. What New Jersey sites were picked for use in internally cured concrete, and why?

We started with a list of all of our bridge projects, specifically projects that needed deck replacement and superstructure replacement. We then further targeted projects that allowed us to focus on implementation and quick delivery time rather than constructability and other additional challenges. We looked at projects with straightforward staging and geometry and prioritized projects with twin bridges (for example, northbound and southbound). This would allow us to do one bridge with traditional HPC and the other with internally cured HPC, providing us with an excellent controlled opportunity to study and compare the results.

Various sites have been screened throughout the state. Currently, eight bridges are under consideration, with a project scope of work of deck and superstructure replacement. The rationale included the project scope of work, CIP deck slabs, project schedule, staging constraints, and avoiding heavily skewed bridges.

Q. Have any life cycle cost analyses been performed?

We have not prepared one ourselves, but we do plan on doing so in the future. First, we will need to get these projects out to construction and get actual cost data. We’re expecting higher upfront costs, but if cracking is reduced then the life cycle costs and future maintenance and reconstruction needs can be significantly reduced.

Q. In what ways do you think people can be better educated on the implementation of EPIC2?

We have presented to many of our stakeholders in our capital program to discuss the topic, and now that it is an EDC initiative,  decision makers are acknowledging its value. The Federal Highway Administration is also planning on conducting workshops and peer exchanges between contractors, concrete suppliers, and other agencies like New York State DOT, which have already done this. All of these are extremely valuable.

We first heard about internally cured concrete during a peer exchange in 2021 with the New York State DOT. It was under the banner of EDC-6, and they took us out on several bridges where we noted that they have significantly reduced the typical shrinkage cracking that is common with High Performance Concrete. So that was an eye opening experience for us, and I know it would be valuable to others. The fact that it is now its own initiative in EDC-7 helps facilitate implementation.

Q. Is special training needed for contractors to work with internally cured concrete?

From our research and experience with other agencies, the finishing should not be significantly different from conventional HPC. The process at that point will be almost identical to placing traditional concrete, so there won’t be any learning curve or time spent on getting workers to learn how to deal with a new material. In fact, most contractors say that the mixture is easier to work due to improved pumpability as the material is quite smooth. I think the crucial step will be to coordinate with concrete production plants that are creating the mixes.

Figure 3. States that have implemented EPIC2 on their roads or bridges

Q. Where else has internally cured concrete been implemented?

So far it has been used in bridge decks in many states, including New York, Ohio, and North Carolina, among others. It has also been used in pavement and pavements in Kansas, Texas and Michigan.

Q. What is the future of internally cured concrete in New Jersey?

We hope these projects will be successful, and that our current crop of projects will result in some valuable lessons learned. In the long term, I believe the goal would be that all of the bridge decks would use an internally cured mixture. I can also see this being used for patching and deck repair jobs. But ultimately, the goal would be for this to become the new standard for bridge decks across the state.

Resources

Federal Highway Administration. 2023 Internally Curing Concrete Produces EPIC2 Results. https://www.fhwa.dot.gov/innovation/innovator/issue98/page_01.html

Federal Highway Administration. 2023. Enhancing Performance with Internally Cured Concrete. https://www.fhwa.dot.gov/innovation/everydaycounts/edc_7/docs/EDC-7FactsheetEPIC2.pdf

Federal Highway Administration. (2018, June). Concrete Clips: Internal Curing. https://www.youtube.com/watch?v=b6WREFmacaM

New York State DOT Standard Specifications (2021). Standard Specifications. New York State DOT. https://www.dot.ny.gov/main/business-center/engineering/specifications/busi-e-standards-usc/usc-repository/2021_9_specs_usc_vol2.pdf

National Concrete Pavement Technology Center Internal Curing Resources. (2022). Internal Curing. Iowa State University. https://cptechcenter.org/internal-curing/

Internal Curing. (2020). Oregon State University. https://engineering.oregonstate.edu/CCE/research/asphalt-materials-performance-lab/materials-research-concrete-materials/Internal-Curing

Pacheco, Jose. (2021, October). USDOT Workshop Report, Bureau of Transportation Statistics. Wisconsin Department of Transportation. https://rosap.ntl.bts.gov/view/dot/62607

Weiss, Joseph. (2015, July). Internal Curing Technical Brief. Federal Highway Administration. https://www.fhwa.dot.gov/pavement/concrete/pubs/hif16006.pdf