Effect of Using Copper Tailings as Replacement of Fine Aggregate for Concrete Pavement

Abstract

AbstractThe accumulation of copper tailings in China has reached 2.4 billion tons, with much, and the comprehensive use rate was only 8.2%. Natural river sand was a non-renewable in a short time. Natural river sand distribution has strong regional limits. This study was focused on prepared C30 concrete pavement with copper tailings as fine aggregate. It could not only ease the pressure of natural sand shortage but also improve the comprehensive use rate of copper tailings and reduce environmental pollution. The range of copper tailings particles was 0.15–0.075 mm, which belongs to ultra-fine sand. There were still obvious differences between copper tailing and natural sand in compositions, shape, and particle grading. In this study, copper tailings were mixed with natural river sand as fine aggregates to mix the mixture of C30 concrete. The particle graduation and MB value of mixed sand after replacement of 30 wt.% and 100 wt.% copper tailings in river sand were conducted. The effect of 0 wt.%, 30 wt.%, and 100 wt.% replacement rate on the mechanical properties of C30 concrete, dry shrinkage performance, resistance to sulfate erosion durability were studied and evaluated. The experimental results show that: 30 wt.% and 100 wt.% mixed sand has more fine aggregate, poor grading, and the measured MB value is greater than 1.4. With the increase of the content of copper tailings, the dry shrinkage rate increased to 15.94 μm, and the compressive strength decreased by 55.7%.KeywordsCopper tailingsFine aggregateMixed sandC30 concrete