By Bill Wolfe, Marketing & Technical Manager, Arcosa Lightweight
As part of the Federal Highway Administration’s (FHWA) Every Day Counts Initiative, a program has been developed to promote internal curing in concrete. The program, titled Enhancing Performance with Internally
Cured Concrete (EPIC2), was developed to demonstrate technologies to help improve the durability and longevity of infrastructure.
FHWA describes internal curing as a “material-level technology that can be employed in any concrete mixture with an adjustment to mixture proportions. The most widely used approach includes pre-wetted lightweight aggregates, which have a high-absorption capacity and are naturally compatible with common concrete production practices. A portion of the normal-weight fine aggregate is replaced with a pre-wetted lightweight fine aggregate. The saturated, porous fine aggregates in the concrete mixture distribute the curing water throughout the concrete body. As the concrete loses water naturally due to continued hydration or environmental exposure, water is pulled out of the lightweight aggregate and creates internal curing. This allows cementitious microstructure pores to be refilled before they become empty, avoiding the negative pore pressures that cause concrete to shrink.”
To give State Departments of Transportation (DOT) an opportunity to learn about internal curing, a Peer-to-Peer Exchange was conducted May 29-30, 2024, in Albany, N.Y. The group of 74 attendees included 29 different State DOTs, Federal Highway Administration officials, and representatives from the lightweight aggregate, ready-mixed concrete, and the concrete contracting industries. The program offered a forum for State DOT representatives to share their experiences with internal curing and to have open discussions about any concerns or questions they had. The program featured a full day of presentations and best practice sharing, followed by a half-day of demonstrations on testing, producing and placing internally cured concrete.
The conference proved to be a great success with a lot of valuable
information exchanged between the participants. The representatives took back information to share with their colleagues to develop programs in their individual states that will help to improve the concrete used in their infrastructure and improve the life span and sustainability of vital components of our transportation system.
Additional information on internal curing can be found at https://www.escsi.org/internal-curing/.