Tensile strength of Hawkesbury sandstone exposed to high temperatures: considerations for exposed mine batters

Abstract

Infrastructure projects and mine site haul roads both often use heavy machinery transport. These high-powered machines are nearly always powered by fuel sources that are highly combustible and pose a fire risk to the surrounding rock structures. This scenario can also be seen in open pit coal mines where batters have the potential to combust spontaneously and are therefore exposed to high temperatures. This research aims to investigate the effects of exposure to high temperatures due to fires on the tensile strength of Hawkesbury sandstone by subjecting them to peak temperatures of 1,100°C -similar to the peak temperature of the hydrocarbon fire curves. The results of the Brazilian tensile strength test showed a 60% reduction in tensile strength due to high temperature exposure and less brittle characteristics when heated compared to untreated samples. The findings of this study can provide an initial understanding to slope stability assessments for fire-resilient slope design.