PCA-SRA is a liquid shrinkage-reducing admixture, designed for use in indoor concrete slab on grade construction.
PCA-SRA can be used, in any Portland cement-based product to significantly decrease drying shrinkage. PCA-SRA is a powerful air detrainer so it should not be used in exterior concrete. Even when good plastic air readings are obtained the bubble structure will not likely be conducive to adequate freeze thaw resistance.
PCA-SRA is not expansive material, but rather functions by blocking capillaries of pore water, which is the major mechanism that causes drying shrinkage in concrete. PCA-SRA when added to concrete at a rate of 2 % by weight of cementitious can reduce shrinkage (ASTM C 157) by up to 80% at 28 days of age and by up to 50% at one year of age.