Wear characteristics of the pipeline transporting cemented paste backfill containing coarse aggregate

Abstract

Cemented paste backfill (CPB) offers unique advantages for managing tailings and underground mining voids, sometimes incorporating coarse aggregate. The pipeline is crucial for transporting CPB that contains coarse aggregate (CPBC), and excessive wear can compromise safety and continuity of transportation. However, the wear characteristics of the pipeline that transports CPBC are not well understood. In this study, wear tests were conducted using a novel self-designed instrument to investigate the impact of CPBC mass fraction (76–84%), flow velocity (1.0–2.5 m/s), coarse aggregate content (0–35%), and coarse aggregate particle size (1.05–7.34 mm). The results indicate that the wear rate increases in a power-law manner with both flow velocity and the size of coarse aggregate particles. The wear rate exhibits a non-monotonic trend with increasing CPBC concentration, initially rising, then declining before sharply increasing. With an increase in coarse aggregate content, the wear rate initially decreases slowly and then increases rapidly. The inflection point in the wear rate is associated with the interconversion between abrasion and erosion, which is governed by the yield stress of CPBC. Given the same material composition and wear type, and minimal variation in aggregate particle size, a higher yield stress of CPBC results in a higher wear rate. Abrasion and erosion dominate the total wear, contributing an average of 71.3%. The findings facilitate the selection of CPBC recipes and pipe materials to mitigate excessive pipe wear, while also providing significant potential for predicting pipe wear based on yield stress of paste.