Mechanical Behaviour and Microstructural Investigation of Geopolymer Concrete After Exposure to Elevated Temperatures

In the present study, the mechanical properties and microstructure of the geopolymer concrete (GPC) after exposure to elevated temperatures have been investigated. The GPC and ordinary Portland cement (OPC) concrete specimens were exposed to high temperatures and tested for the mechanical properties and microstructure. The findings of this investigation indicate that the GPC has better compressive strength, develops minor cracks, and undergoes slight damage in the mass at the elevated temperature as compared to OPC concrete. For ambient-cured and heat-cured conditions, the experimental results of the GPC after exposure to high temperatures (600 °C onward) show almost the same mechanical properties, while the OPC concrete significantly loses the strength along with large cracks developed above 400 °C. Moreover, the scanning electron microscope test shows that the OPC concrete developed a lot of cracks and started losing the bonds between the matrix at 400 °C, while the GPC holds over its strength until 800 °C.