The major class of integral waterproofing is crystalline technology.   In the presence of water, the ingredients of these products react with calcium hydroxide and other by-products of cement hydration to form non-soluble crystals that fill and plug the pores and microcracks in concrete—even years after it was poured. This is especially useful on large concrete pours, as it is enough to waterproof most cold joints with no additional treatment needed. Crystalline products can be applied in several different ways, but adding it to the mix at the batch plant is the most common. Crystalline waterproofing is also extremely durable