Investigation on the influence of modified waste rubber powder on the abrasion resistance of concrete

The abrasion resistance of crumb rubber concrete (CRC) has always been a research hotspot. However, the large reduction in the mechanical properties of CRC limits the improvement of its abrasion resistance. In this study, a new method of modifying waste rubber powder (WRP) combining mechanochemical action, ultrasonic energy accumulation and the coating effect of the modified slurry was proposed. The mechanical properties of CRC with rubber volume fractions of 0%, 15%, 25% and 35% were determined. The abrasion resistance of CRC was studied by the ball bearing and ball milling methods. The abrasion mechanism of CRC was analysed, and abrasion mechanism models of the rigid and semirigid bodies were established. The results showed that the compressive and flexural strengths of modified CRC (MCRC) were increased by 74.2% and 45.7% respectively, compared with CRC. The abrasion resistance of concrete first increases and then decreases with increasing rubber content. Compared to the control concrete, the abrasion resistance of CRC and MCRC was increased by 14.9% and 24.8%, respectively. The mass loss rates of CRC and MCRC were 29.78% and 24.98% respectively, under the same volume replacement. The enhancement of abrasion resistance of the CRC is mainly due to the absorption of wear energy by rubber. The rubber-cement matrix (R-CM) interface played an important role in controlling the abrasion resistance of CRC.