Thoughts on the Service Life of Internally Cured Concrete Considering ASR and FT

Abstract

Internal curing has been proven as a solution to reduce early-age shrinkage and related cracking in concrete. Internal curing can reduce the risk of built in stress, cracking, and curling in concrete pavements. However, the benefits of internal curing go beyond just shrinkage and cracking mitigation. Research by the author’s has shown the incorporation of fine lightweight aggregate-FLWA can significantly reduce the risk of deleterious alkali-silica reaction. When the FLWA replaces a reactive aggregate a dilution effect occurs, but other benefits also exist. The curing provided by internal curing can react a greater percentage of cementitious material allowing a reduction in cement and an increase in the amount of binder fillers thereby reducing the alkali loading of the mixture. Additionally, the internal curing was shown to reduce the pH of the internal concrete pore solution and led to a refinement of the interfacial transition zone, possibly due to a pozzolanic reaction. The FLWA provides a porous inclusion which appears to enable a reaction product, similar to ASR gel to form however with limited expansion.