Mechanical response of a mine composite material to extreme heat

The use of cemented paste backfills (CPB, a mine composite tailings material) in underground mining is currently increasing in importance globally. However, despite the tremendous progress made in understanding the factors affecting the performance of CPB, little attention has been devoted to the impact of high temperatures on its mechanical properties. This article presents the results of experimental investigations into the mechanical responses of CPB when subjected to high thermal loads. Samples made with silicate and pure cement or a mix of 50/50 cement and slag or fly ash were heated at 100, 200, 400 and 600°C, and the unconfined compressive strength, tensile strength, modulus of elasticity, stress–strain behaviour and microstructure evaluated by laboratory tests. The results show that high temperatures have a significant influence on the mechanical properties of CPB, which should be taken into account when determining an appropriate mix for the binder.