SPECTROSCOPIC AND MICROSCOPIC STUDIES OF A COMMERCIAL CONCRETE WATER PROOFING MATERIAL

In the Arabian Gulf countries where soil and groundwater has high cont ents of sulfates an chlorides, underground reinforced concrete structu res deteriorate, due to chloride-induced corrosion of reinforcing stee l bars, within a fraction of their design life. One way of overcoming this deterioration problem is by applying a water proofing material (W PM) on the exposed surface of underground concrete structures. The obj ective of this study was to characterize the WPM and validate the manu facturers claim regarding the growth of crystals and thus assess the c hemistry and mechanism involved in the formation of such corrosion pro tection of the reinforced concrete. Spectroscopic studies of the WPM s howed that it is made up of the normal constituents of cement such as calcium carbonates, sulfates, silicates etc. plus some organic product s such as sodium fumarate, fumaric acid and melamine-formaldehyde poly mers. The mechanism of protection seems to be dual i.e one by controll ing the pH of the concrete by providing buffering effect with the fuma ric/fumarate combination and second one by reducing permeability of th e concrete and thus preventing further ingress of deleterious and corr osive species from outside sources.