Extending the Lifespan of Concrete Superstructures via Alkali-Silica Reaction Mitigation

Mitigation of deleterious alkali-silica reaction (ASR) in concrete is one of the priorities of the Federal Highway Administration (FHWA) as sources of non-reactive aggregates have been significantly depleted across the U.S. Traditional methods for mitigating ASR involve the use of supplementary cementitious materials (SCMs). Recent research by FHWA (i.e., FHWA-PROJ-08-0078) has marked the need for new and more efficient materials in mitigating ASR in concrete pavements. Preliminary studies have shown that new types of SCMs, such as calcined clay-based materials, and nanomaterials, such as nanosilica, nano-metakaolin, nanotubes, and graphene can present a great potential to mitigate ASR. The effectiveness of ASR prevention depends on the threshold and optimum dosage of nanomaterials, as well as mixing and dispersion of the nano-additives. This project aims at establishing protocols and practices for the design of ASR-resistive concrete with calcined clay-based SCMs and nanomaterials, with application to superstructures (pavements, bridge decks, piers). Deliverables include the development and deployment of standard guidelines about mixture design, ASR resistance evaluation, and life cycle assessment of nanoengineered concrete.