Strength and microstructure of seawater and sea sand mortar after exposure to elevated temperatures

Abstract

This study investigated the influence of high temperatures on the mechanical behavior and microstructure of seawater and sea sand mortar (SSM). Compressive and flexural strength was obtained and analyzed after high temperatures ranging from 200, 400, 600, to 800 °C. The alteration of the microstructure due to high temperatures was examined using the scanning electron microscope, X-ray powder diffraction, and thermogravimetric and differential scanning calorimetry analyses. Results indicated that the reduction in flexural strength of SSM was larger than that in compressive strength due to high temperature exposure. Meanwhile, a framework based on information criteria was proposed to capture the uncertainty of strength, and the Weibull distribution was finally selected for constructing the probabilistic compressive strength model for SSM after high temperatures. Furthermore, analysis on the microstructure demonstrated the significant influence of high temperatures. The micrographs along with the phase change identifications could help to understand the strength variation of SSM after the high temperature exposure.