Recycling of dolomite powder in clay bricks: Effects on characteristics and gas release

Abstract

This paper evaluates the influence of dolomite industrial waste (dolomite powder (DP) on the properties, structure and durability of clay bricks. Four clay samples fired at 900 ◦C and 1000 ◦C containing 0 wt%, 10 wt%, 20 wt% and 30 wt% DP were prepared and investigated to measure their properties (shrinkage, bulk density, water absorption, thermal conductivity, apparent porosity, compressive strength), structure and durability (compressive strength after freeze thaw). The results showed a decrease in bulk density, compressive strength and an increase in apparent porosity and water absorption of the clay bricks produced by mixing 70–90 wt% clay and 10–30 wt% DP compared to the control bricks. Also, a significant improvement in the thermal conductivity of clay bricks produced by 70 wt% clay and 30 wt% DP (0.407–0.420 W/(m⋅K) compared to the control clay bricks (0.839–0.845 W/(m⋅K). As clay mixtures contain DP (chemical composition: CaO-49.68%, Loi-42.80%), CO2 emissions during the firing process are increased (decarbonation reactions). However, the thermal conductivity of the fired clay bricks is significantly reduced (to 50%). These results showed the potential of DP for the manufacturing of clay masonry units.