Strength Development Characteristics of Concrete Using Coal Gasification Slag Fine Aggregate

Coal gasification slag (CGS) fine aggregate is a byproduct of integrated coal gasification combined cycle (IGCC) power plants. In Japan, the Japanese Industrial Standard JIS A 5011–5:2020 [3] was established in 2020, and the use of CGS as a concrete aggregate was considered. This study investigated the strength properties of concrete in the standard strength range (approximately 20–40 N/mm2) and high-strength concrete with water-to-cement ratios of 25% and 30% when CGS was used as a fine aggregate. In the case of CGS concrete, the amount of additional admixture to obtain the same workability could be less than that of natural sand concrete. CGS concrete of 20–40 N/mm2 strength exhibited lower initial and long-term strength than the natural sand aggregate. Moreover, the high-strength concrete was found to have lower strength than natural sand concrete for the same water-to-cement ratio. Young's modulus was higher than that of the natural sand concrete, regardless of the strength properties.