Durable coloured concrete roofing tiles - consist of pigmented portland cement mixes with extruded or rolled on covering of similar cement mix plus specified type of polymer

摘要

A concrete roofing tile consists of a mixture of hydraulic binders such as Portland cement, sand with particle sizes up to 4 mm, water, and colouring pigments, e.g. in the ratio of 1:2.8-3.5:0.38-0.22 plus usual pigmenting, and a suitable surface covering. This covering is an extruded and/or rolled layer up to some mm thick, made from hydraulic binder such as Portland cement, additives such as sand, and polymeric -compounds which are compatible with cement and have particle sizes up to 2 mm. These polymers are preferably produced fromunsaturated compounds e.g. vinyl acetate, acrylic ester, vinyl propionate, styrene, butadiene, plus fillers such as microsilicate powder. ADVANTAGE - The products have a covering with a minimum service life of 25-30 years which has a considerable resistance to the chemical and physical agents liable to arise and which preserves its visual appearance virtually unchanged.