PROLONGING THE LIFE OF REINFORCED CONCRETE STRUCTURES BY SURFACE TREATMENT . PROTECTION OF CONCRETE. PROCEEDINGS OF THE INTERNATIONAL CONFERENCE HELD AT THE UNIVERSITY OF DUNDEE, SEPTEMBER 11-13, 1990

This paper provides an indepth evaluation of the various types of surface treatments that can be utilised in the protection of concrete structures. Penetrants are low viscosity liquids that penetrate into the concrete, line the pores and provide an effective barrier to chloride salts. The majority of commercially available penetrants are based on either silanes or siloxanes. Silanes are claimed to be more penetrative than siloxanes but from the work undertaken at Fosroc no discernable difference in penetration could be found between the systems except when the concrete samples tested were completely dry. The lower volatility of siloxanes means that under site conditions more active material is retained in the surface of the concrete. Acrylic/methacrylic pigmented coatings provide a very effective physical barrier to carbon dioxide and other acidic gases. In addition these have excellent UV resistance, colour stability and a minimum life expectancy of 15 years. The most effective method of ensuring long term protection to a reinforced concrete structure is to use a combination system which consists of a siloxane/acrylic blend primer and a pigmented acrylic topcoat. This system acts synergistically to produce the equivalent of an extra 500 mm of concrete cover over the reinforcement and, in addition, enhances the appearance of the structure. (Author/TRRL)