Effects of steel fibre type and dosage on abrasion resistance of concrete against debris flow

The collision and friction between the coarse solid particle and the concrete surface are the main reason for the abrasion damage of concrete structures caused by debris flow. Fibre reinforcement can improve the shear resistance and toughness of concrete, however, their effects on debris flow abrasion mechanism are yet not well understood. In this study, the influences of the type and dosage of steel fibre, slurry concentration and gravel particle content of debris flow on the abrasion resistance of fibre-reinforced concrete are investigated using a developed rotating-drum abrasion device. Results show that the short straight fibre and medium hook-ended fibre show better resistance to debris flow abrasion owing to better distribution space and fibre bridging effect. The increase in the slurry concentration and a reduction in gravel particle content of debris flow reduce abrasion damage. The abrasion failure modes of fibre are mainly presented as polishing, fracture and peeling, and a new abrasion mechanism of fibre-reinforced concrete against debris flow is proposed. Based on the present results, the medium hook-ended fibre with a dosage of 1.5 vol% shows outstanding abrasion resistance, which is recommended for designing debris flow protective structures.