Permeability is one of the main factors that can affect the durability of the structure. Permeable structures can result for various reasons such as low cement content, poor compaction too much water during concrete mixing etc. The passage of water through cracks ,joints, voids, and inter connected capillaries in the mass concrete makes the concrete previous, ultimately leads to poor protection of structures, increases the rate of alkali aggregate reaction and also accelerates the rate of corrosion in the steel.
The impervious property of concrete can be improved by addition of admixture in the green concrete or by surface treatments and the phenomenon is generally known as waterproofing. The products used in both the stages of concrete are known as construction chemicals or admixtures and waterproofing is one of the aspects in construction aid. These products are required for modifying the properties of concrete or mortar to make them more suitable for the work at hand or for the economy for such purposes are saving energy.
Construction Chemical For Water Proofing
1) Integral water proofing compounds
2) Acrylic based polymer coatings
3) Mineral based polymer modified coating
4) Chemical DPC for rising dampness
5) Water proofing adhesive for tiles, marble and granite
6) Silicon based water repellent material
7) Injection grouted for cracks
8) Protective and decorative coatings
9) Joint sealants
New Innovative Products
Mainly Thermo set Polymer with Chemical cross linkage. Main characteristics of thermo set polymer are once they are fully cured they can be bonded to like material with an adhesive. The four common sub categories of thermo set roof membranes are Neoprene(CR), Chlorosulfonated Polyethylene (CPSE), Epychlorohydrine (ECH) and Ethylene Propylene Diene Monomer (EPDM).
Types of Integral Water Proofers
Water proofing admixtures can be broadly grouped as permeability reducers and Water repellents or hydrophobic (water hating) agents. Permeability reducers are pore filling and porosive reducing materials which can be further classified into very fine particulate matters, workability and air entering admixtures, accelerators.
Water repellent coatings, which can be applied on the concrete surface to impart water proofing to the concrete structure. Thermoplastic PU has been used in the water proofing of below grade structures building foundation, basements, reservoirs, ponds, walkways, tunnels, earthen shelters, bridge, abutments, retaining walls, landfills and water canals. Acrylic co polymer emulsion based additive for cement based coatings when mixed with cement gives excellent water proofing, excellent adhesion to concrete substrate, steel, asbestos, excellent resistance to ultra violet rays, excellent breathing properties and helps in reducing corrosion of reinforcement. Styrene butadiene co polymer emulsion have also been used as water proofing coating for concrete, which also increase adhesion strength, chemical resistance and abrasion resistance.