What is Waterproofing Admixture for Concrete?
Waterproofing admixture is a type of admixture that prevents the passage of water through hardened concrete under a pressure head. It is also called as water resisting admixture or permeability reducing admixture or damp proofing admixture.
Requirement of Waterproofing Admixture for Concrete
Water is a vital part of concrete construction from the mixing of concrete to the curing of concrete. But once the concrete has gained its required strength, thereafter any moisture or water penetration in concrete can cause damage to the concrete. The damage can be due to corrosion of reinforcement or due to freeze thaw. When a concrete work has finished and curing completed, the water content evaporates and leaves voids inside the concrete. Thus for a good durable concrete construction, low water/cement ratio is recommended so that porosity of concrete can be reduced. But then also, a concrete cannot be completely made waterproof even by using the minimum water/cement ratio. Concrete is a porous material and water can penetrate through pores and micro-cracks of concrete due to capillary actions. Thus there is a need of an admixture which can control the porosity of concrete.