Waterproofing admixtures are porous materials that have the ability to absorb water and water-borne contaminants. Hydrophobic and pore-blocking ingredients react with products of the cement hydration process to produce a hydrophobic material that resists external water, decreasing absorption into the concrete.
Waterproofing admixtures protect structures from degradation. They increase durability and reduce maintenance costs. Different types of admixtures are used for different parts of a structure namely the roof, basement or walls, as well as for different locations, climatic conditions, and purpose of the structure. Waterproofing admixtures have a broad range of applications in construction and infrastructure development.
The 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 the 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, a low water/cement ratio is recommended so that the 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 for an admixture that can control the porosity of concrete.