Q&A: Update on EPIC2 in New Jersey

Posted on April 23, 2025April 23, 2025

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?

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.

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

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

Posted on February 7, 2024February 8, 2024

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