Application of Carbide Slag in Autoclaved Aerated Concrete

Carbide slag is a solid waste which is difficult to handle. When it is used to substitute for lime to produce autoclaved aerated concrete (AAC) block without necessary treatments, the aeration efficiency is low and density of the AAC block is high. Besides, the initial mechanical strength of the block is lower because of lower curing temperature in static placing stage. The influence of hot water and pre-curing process (50 degrees C, 5 h) before static placing phase were investigated in this paper. The results show that when the substitution ratio of carbide slag for lime is below 50%, the performance of the AAC block is good enough to reach the level of standard WGB11968-2006. As the substitution ratio is 38%, the compressive strength is 5.55 MPa with a dry density of 620 kg/m(3). The application of carbide slag as substitution for lime is realized in production of AAC block and the production cost is well reduced.