Development of low cost supplementary cementitious materials utilizing thermally activated Pisha sandstone

Pisha sandstone was the main resource of Yellow river sediment mineral with a low pozzolanic activity. This paper reports an investigation of the possibility of development of low cost supplementary cementitious materials using Pisha sandstone via thermally activated. The decomposition of Pisha sandstone when thermally treated at 600 °C and 800 °C and the effect of this treatment on its physicochemical properties, pozzolanic reactivity in cementitious materials were studied. The hydration of the mineral component, reaction products and micromorphology were studied by TG-DTG, XRD and SEM-EDS technique, respectively. Compressive strength test was conducted to assess the mechanical property of modified pastes, and Mercury intrusion porosimetry (MIP) was employed to investigate the pore structure and pore size distribution. This work confirmed that Pisha sandstone could be acted as a kind of low cost supplementary cementitious materials via thermally activated, and the optimal calcination temperature was 600 °C. It was shown that the decomposition of clay mineral of Pisha sandstone via thermal treatment result in an enhance of hydration reaction and mechanical strength, and the sample (calcined at 600 °C) exhibited the highest compressive strength (21.9 MPa). The results of the investigation show that the amorphous aluminosilicate gels (C-A-S-H) were the main hydration products.