Preparation and properties of sustainable magnesium phosphate cement composites with recycled tire rubber particles

The disposition of the discarded tire rubber has become a worldwide problem with the quick development of auto industry. The application of recycled tire rubber (RTR) particles in cement-based materials is effective method for large-scale treatment of discarded tire rubber. Magnesium phosphate cement (MPC) is a repairing material commonly used in road and bridge engineering. In order to investigate the effects of RTR particles on the properties of MPC, sustainable rubberized MPC mortars with three different sizes were designed and prepared. The workability, mechanical properties, capillary water absorption and durability of rubberized MPC mortars were measured, and the interface zone between RTR particles and MPC matrix was characterized by Back-scattered Electron Detector (BSE). Test results indicate that the presence of RTR particles decreases the fluidity, compressive strength and bonding strength of MPC mortar at different levels, and it also decreases the capillary water absorption, increases the water resistance and volume stability to some extent. Both the content and fineness of RTR particles are key factors influencing the properties of rubberized MPC mortar. From one perspective, the difference in the interface zone between RTR particles and MPC matrix can explain the different effects of the three types of RTR particles. And MPC mortar with middle-size RTR particles has the most homogeneous microstructure. (C) 2020 Elsevier Ltd. All rights reserved.