EFFECTS OF COAL GANGUE ON THE SULFATE ATTACK RESISTANCE OF CEMENT-BASED MATERIALS

Coal gangue contains a certain amount of active ingredients; it can be used as an addition to cement-based materials after activation. However, the durability of cement-based materials with a calcined coal gangue addition should be studied. In this paper, the sulfate attack resistivity of cement-based materials with a calcined coal gangue addition was studied and compared with ordinarily used fly ash. The effects of the sulfate attack resistance on the strength development, volume change and microstructure of the cement paste, mortar and concrete were studied. It was found that calcined coal gangue effectively improved the sulfate attack resistivity of cement-based materials, specifically expressed by the reduction in the strength loss or volume expansion of the mortar or concrete under the sulfate attack. When compared with the fly ash added samples, coal gangue exhibited a better improvement in the sulfate attack resistivity through the analysis of the strength loss and expansion results.