Enhancing performance with internally cured concrete (EPIC2)

Shrinkage cracking in concrete is a key issue for long-term performance in concrete bridges, roads, and repairs. When this cracking occurs early on, it leaves the concrete and embedded reinforcement exposed to degradation, reducing the service life of the structure.

Enhancing Performance with Internally Cured Concrete (EPIC²) promotes internal curing, which increases concrete’s resistance to early cracking, allowing the production of higher-performance concretes that may last more than 75 years. Unlike conventional curing where water is supplied on the concrete’s surface, internal curing provides a source of moisture from inside the concrete mixture, improving its resistance to cracking and overall durability.

Over the last 30 years, extensive studies have shown that internal curing addresses the root cause of self-drying shrinkage that is particularly problematic in lower water-to-cementitious materials ratio concretes. This technology can be used in any concrete mixture with an adjustment to mixture proportions.

The most widely used internal curing approach includes pre-wetted lightweight aggregates, which have a high-absorption capacity and are naturally compatible with common concrete production practices. The pre-wetted lightweight fine aggregate replaces a portion of the normal-weight fine aggregate. The saturated, porous fine aggregates distribute the curing water throughout the concrete. As the concrete loses water, water is pulled out of the lightweight aggregate and creates internal curing.

EPIC² offers agencies several benefits. This innovation can be implemented anywhere traditional concrete is used. Agencies that use this process will help mitigate shrinkage cracking, which improves concrete durability. Additionally, internally cured concrete mixtures can last several times longer than traditional concretes, reducing rehabilitation or replacement needs over a structure’s life-cycle, which results in life-cycle cost-savings. Finally, internally cured concrete mixtures can be designed with lower water-to-cementitious materials ratios and increased use of natural, waste, or alternative recycled cementitious products without reduced performance or increased risk of cracking.

Stay up to date on EPIC² and subscribe to EPIC² e-news.  To learn more about EPIC², contact Tim Barrett, FHWA Turner-Fairbank Highway Research Center. Information courtesy of FHWA.