EFFECT OF APPLICATION QUANTITY OF WATER-ABSORPTION-CONTROLLING MATERIAL ON ADHESIVE STRENGTH PROPERTIES AND CARBONATION RESISTANCE OF POLYMER-MODIFIED MORTAR COATED CONCRETES

<p>This paper deals with the effect of the application quantity of water-absorption-controlling material on adhesive strength properties and carbonation resistance of polymer-modified mortar coated concretes. Two types of the polymer-modified mortar are prepared with the polymer-cement ratios of 0 and 5％ as coating mortars. The base concrete surface is treated by the water-absorption-controlling materials with the application quantity of 20, 25 and 30g/m² as solids. Then the base concretes are coated by the polymer-modified mortars with coating thickness of 2.5mm, and cured under prescribed conditions for 28d. The adhesive strength of the coated polymer-modified mortar is measured with failure modes. The polymer-modified mortar coated concrete specimens are stored in the carbonation chamber with 30℃, 60％（RH） and CO₂ concentration of 60％. After the coated polymer-modified mortar layer is completely carbonated, the carbonation depth of the base concretes are measured at storage periods of 28, 56 and 84d. As results, the adhesive strength of the polymer-modified mortar and carbonation resistance of the base concrete are improved by applying the water-absorption-controlling material to the base concrete. The adhesive strength and the carbonation resistance are increased with increasing the application quantity of the water-absorption-controlling material. The polymer-modified mortar layer still inhibits CO₂ penetration after the layer is completely carbonated. Such carbonation resistibility of the polymer-modified mortar layer and by the application of the water-absorption-controlling materials improve the carbonation resistance of the base concrete coated with the polymer-modified mortar.</p>