Mining waste as an alternative aggregate in brick production for carbon capture and storage

Abstract

Abstract Production of waste rocks and overburden from ore mining in open-pit mines can cause undesirable environmental impacts. Thus, this study aims to tackle the issue of waste production from mining areas by utilizing mining waste to sequester CO2 and to evaluate its potential for carbon capture in cementitious material. This study attempts to evaluate the effect of mine waste ratio and carbonation curing time on physico-mechanical behavior of bricks. The bricks were fabricated using different ratios of mine waste, i.e. 20 – 40 % in the mix design. Carbonation curing between 1 – 3 hours was applied during the brick fabrication to estimate CO2 capture of the brick product. The brick performances were evaluated based on the compressive strength, water absorption and carbon capture capacity. It was found that curing time at 28 days provided the greatest compressive strength of the brick and greater performance was observed at 40 % replacement with the mine waste. Carbonation curing improved the brick performance with higher compressive strength and lower water absorption at longer exposure time of 3-hour carbonation. The resulting CO2 uptake was found to increase with the increase of carbonation time and at higher ratio of mine waste replacement. The CO2 capture capacity was between 0.45 – 0.58 % for bricks containing 20 – 40 % of mine waste, which corresponds to 9.4 – 16.3 g CO2/brick. Therefore, it has been shown that the use of mining waste as partial replacement for cementitious material was capable in improving the brick performance with incorporation of carbonation curing process.