A multi-scale experimental investigation of the feasibility of using integrated coal gasification combined slag as a supplementary cementitious material

Abstract

As thermal plants are being upgraded, integrated gasification combined cycle (IGCC) slag is emerging as a promising supplementary cementitious material (SCMs). The performance of IGCC slag as SCM was comprehensively compared with blast furnace slag (BFS) and fly ash (FA) in various aspects, including material characterisation, pozzolanic reaction and cement paste performance investigation. Characterisation results show that the IGCC slags comprised of calcium-rich aluminosilicate glass with minimal carbon content. The pozzolanic reactions of the IGCC slags were similar to that of BFS but superior to FA. The IGCC slag-blended cement pastes therefore showed similar compression strength as the BFS-blended cement paste, while showing reduced water loss, shrinkage and chloride diffusion, and were superior to the FA-blended cement paste. Economic and environmental evaluation revealed that substituting cement with IGCC slag is beneficial to reduce the cost, embodied energy and CO2 emissions of concrete.