Microstructural and mechanical evolutions of sustainable cement blends containing fly ash and calcium carbonate whiskers induced by high temperature

A novel kind of cement blend with high temperature resistance and favorable sustainability was developed in this paper. The physical and chemical changes due to high temperature exposure were examined in this sustainable cement paste containing fly ash (FA) and aragonite calcium carbonate whiskers (CW) as supplementary cementitious materials. High flexural strength is demonstrated before 400 °C because FA has pozzolanic effect, self-cementitious properties and potentials to react with CW under hydrothermal condition. When the exposure temperature is above 400 °C, especially above 800 °C, high residual properties and less deterioration are observed in flexural and compressive strengths and elastic modulus, mainly because FA is involved in the sintering process and formation of ceramic phases. In summary, the sustainable cementitious composites studied in this paper are very promising to have high temperature resistance to reduce fire damage on constructions and at the same time lower carbon dioxide footprint of cement manufacture.