Performance Of Concrete At Elevated Temperatures Made With Crushed Rock Dust As Filler Material

Abstract

Abstract This experimental study presents the effect of partial replacement of cement by crushed rock dust (CRD) as filler material in concrete when subjected to elevated temperatures. Ordinary Portland cement (OPC) is partially replaced with CRD in five percentages: 0%-control concrete: (CC), 10% (CR1), 20% (CR2), 30% (CR3) and 40% (CR4)) by weight. The CC and CRD concrete specimens were subjected to elevated temperatures of 200 oC to 800 oC for 2 hours using an electrically controlled furnace. Ultrasonic pulse velocity (UPV), Mass loss, compressive strength, surface cracking and colour change are evaluated at elevated temperatures. Additionally, the micro-structural properties of CC and CRD concrete at ambient and at elevated temperatures is analyzed using scanning electron microscope (SEM). At ambient temperature, the test results of concrete with CRD up to 30% showed enhanced UPV and compressive strength values than CC. No visible cracks are observed on CC and CRD concrete surface exposed up to 400 oC. UPV values obtained at elevated temperatures with CC and CRD concretes are in good agreement with mass loss and compressive strength values. The results signify that the partial replacement of cement up to 20% with CRD showed the best performance than CC at elevated temperatures and are supported by SEM analysis.