Study on utilization of red brick waste powder in the production of cement-based red decorative plaster for walls

Current management for red brick waste is insufficient, and a new method is needed. We sought to develop a new approach for effective management. Red cement-based decorative plasters were prepared with red brick waste powder (RBWP), white Portland cement, quartz sand, redispersible emulsion powder, hydroxypropyl-methyl cellulose ethers and silicone hydrophobic agent. The colors, water absorptions and strengths of different plasters were investigated, and the mechanisms responsible for their performance variations were explored by high-resolution transmission electron microscopy, X-ray powder diffractometry and scanning electron microscopy. The relative economic and environmental benefits were also analyzed. The feasibility of recycling RBWP in the production of cement-based red decorative plaster for walls was evaluated. The resulting plaster provided appropriate color adjustment, and the water resistance of the plaster was not greatly affected. The compressive and flexural strengths of plaster were improved. However, the improvement decreased as the sand replacement ratio increased. The tensile bond strength of the plaster is related to the RBWP content. More RBWP negatively affects the tensile bond strength of the plaster. Calcium hydroxide in the hardened paste varies with RBWP content. This variation correlates with the appearance and level of pozzolanic reaction in the plaster with RBWP. Plaster with RBWP has a denser microstructure than the control. In addition to the pozzolanic reaction, this denser microstructure also contributes to performance improvements such as compressive and flexural strengths. To improve the economic and environmental efficiencies, it is also feasible to recycle RBWP in the production of cement-based red decorative plaster for walls. These results demonstrate the effective use of red brick waste. They also provide a reference strategy for the management of red brick waste in other developing countries that are carrying out or will carry out urbanization activities.