Study of the relationship between the water binder ratio and strength of mixed recycled aggregate concrete based on brick content

High-value recycling of mixed recycled aggregate (MRA) has attracted the attention of researchers in the worldwide, but its influence on the Bowromi formula is still unclear, which hinders its in concrete. Against this background, this research focuses on the basic physical properties of MRA and the effect of brick content on the properties and microstructure of MRA and mixed recycled aggregate concrete (MRAC) under different water binder ratios (W/B). The results showed that the compressive and splitting tensile strengths of MRAC decreased with an increase in the brick content; however, the splitting tensile strength was more sensitive to changes in the brick content than the compressive strength. In microscopic analysis, it was found that although the addition of the recycled brick aggregate could enhance the internal curing effect of the MRAC, it was still insufficient to compensate for the adverse effects of the pore structure deterioration and original cracks in MRA. Finally, based on the above results, this study provides an effective method to predict the compressive strength of MRAC with different brick contents, and optimizes the Bowromi strength and MRAC strength development formulas. This research result is helpful in promoting MRA applications in the real-world construction projects.