Behavior of combined fly ash/GBFS-based geopolymer concrete after exposed to elevated temperature

Geopolymer is an emerging cementitious material characterized by better mechanical performance and more environmentally sustainable properties than ordinary Portland cement (OPC). Previous work mainly highlighted thermal behavior of metakaolin or fly ash-based geopolymers. This paper provides experimental data of geopolymer concrete manufactured with granulated blast furnace slag (GBFS) and fly ash after high temperature exposures of 400 degrees C, 600 degrees C, 800 degrees C and 1 000 degrees C in terms of ISO834. Residual compressive strength and splitting strength, as well as the effects of standing time were examined and compared with equivalent OPC concrete findings. The results revealed that both kinds of strength improved about 14% and 9% after being exposed to 400 degrees C, and the reduction was less than OPC concrete. Additionally, the residual compressive strength after different exposures evolved variously with prolonging of standing time. On the basis of the results, the empirical equations of residual compressive strength and splitting strength of GC are established.