Rheological behavior and early-age hydration performance of blended cement pastes incorporating recycled brick powder and slag

This study focuses on blended cement pastes incorporating recycled brick powder (RBP) and slag. The effects of RBP and slag on the rheological behavior and early-age hydration performance of blended cement pastes with different substitution levels ranging from 0 % to 40 % have been studied by testing mini-slump flow, rheological properties, hydration products, pore structure, and phase distribution. The results show that the incorporation of RBP reduces the fluidity by 3.8 %-24.6 % and increases the yield stress of pastes by 4.1 %-53.4 %, while the combined use of RBP and slag proves effective in controlling the rheological properties. Furthermore, the addition of RBP and slag significantly reduces the hydration products and increases the total porosity of blended cement pastes by 4.3 %-16.9 % at 24 h. Notably, RBP and slag accelerate Portland cement hydration in early-age stage, attributed to nucleation and dilution effects. These findings offer valuable insights for the application of RBP in low-carbon cementitious materials. •Effects of RBP and slag on rheology and early-age hydration were investigated.•The yield stress and apparent viscosity of pastes increase with addition of RBP.•Combination of RBP and slag proves effective in controlling rheological properties.•RBP and slag can accelerate Portland cement hydration in early-age stage.