EXTENSION OF SERVICE LIFE OF REINFORCED CONCRETE STRUCTURES BY SURFACE IMPREGNATION WITH SILANE

摘要

Service-life of steel reinforced concrete structures is often limited by penetration ofaggressive compounds into the porous structure of the cement-based material and subsequentdeteriorating chemical reactions. Moisture content and water migration play an important rolein almost all damage mechanisms in concrete. Capillary suction of water is a most efficientmechanism for transport of dissolved salts into the porous structure of concrete. Capillarysuction can be significantly reduced if not totally prevented by surface impregnation withliquid silane. Then ingress of aggressive ions such as sulphates,chlorides and ammoniumcompounds dissolved in water is minimized. In this contribution results of three research projects will be presented and discussed:(1) determination of the depth of penetration of silane in concrete and silicon resin profiles insurface treated concrete,(2) relation between the silicon resin profile and effectiveness of waterrepellent treatment as a chloride barrier,and (3) the effectiveness of surface impregnation ofchloride-contaminated concrete. It has been found that surface impregnation of concrete withliquid silane reduces the ingress of chlorides substantially. An efficient,reliable and durablechloride barrier can be established by deep impregnation (7 mm to 10 mm). When concrete isalready chloride contaminated the effectiveness of surface impregnation is to be tested beforeapplication of a protective measure.