The only possible option to reduce or negate the ingress of water, and water containing dissolved deleterious ions is to decrease permeability. Several options are available. Partial replacement of Ordinary Portland Cement using mineral admixtures such as pulverized fly ash and slag cement is known to have improved properties of concrete in relation to its durability and hence its water tightness.
Of late, designers have resorted to the use of chemical admixtures such as cement-based waterproof coatings and water permeability reducing admixtures. New chemical admixtures which are designed based on crystalline waterproofing technology are effective in improving waterproofing and durability of concrete by sealing pores, capillaries and micro-cracks with a non-soluble highly resistant crystalline structure. During the hydration process, the reaction between water and cement results in the gelling and hardening of the cement paste. A number of other chemical by-products which lie dormant are also produced in the process.
Crystalline waterproofing admixtures when mixed with these by-products during hydration produce a non-soluble crystalline structure. This phenomenon is only possible in the presence of moisture. The formation of crystals follows the path taken by water as in the pores, capillary tracts and micro-cracks. When applied in the form of a surface coating on a freshly cast slab, the crystalline waterproofing is able to chemically diffuse through from a solution of high density to a solution of lower density until there is an equilibrium. The formation of crystals or crystallization will continue until the crystalline chemicals are either depleted or the concrete becomes dry. As the crystalline formation is within the concrete (or integral) and therefore not exposed at the surface, they cannot be punctured or damaged like other waterproofing surface coatings or membranes.
For more information on Xypex please click here.