High fire stability cement composite cementitious material based on semi‐dry gas desulfurized ash/blast furnace slag system: The synergistic effect of nano‐TiO2 and nano‐SiO2.

Cement is an important way to digest industrial waste. Semi‐dry gas desulfurized ash (SGDA) and granulated blast furnace slag (GBFS) as solid waste both have pozzolanic activity as well as small particle size and continuous particle size distribution, which allow their use as cement mixtures. In the present work, a cement matrix with 60% Portland cement, 20% SGDA, and 20% GBFS, including 3% nano‐TiO2 and 2% nano‐SiO2 as dopants, was produced via cement slurry mixing process. The obtained matrix was found to have the better 3‐ and 28‐day age compressive strength (by 104% and 116%, respectively) as compared with the pure Portland cement; the mortar compressive strength is also improved. The imaging and mineralogical analysis revealed that the nanomodified cement matrix had a more compact structure along with a well‐developed crystal form and the uniform micropore distribution. Furthermore, the doped cement mixture exhibited good fire resistance: Even after exposure to simulated fire conditions for 2.5 h at 450°C, the compressive strength of the composite was 98.27% of its initial value (57 MPa) and the microstructure remained undestroyed. The findings of this study open up new prospects for collaborative use of SGDA and GBFS as solid waste along with nano‐TiO2 and nano‐SiO2 as dopants, therefore providing outstanding fire stability of related composites. [ABSTRACT FROM AUTHOR]