Effect of rubber surface treatment on damping performance of rubber-mortar ITZ in rubberized concrete

The reduction of the mechanical properties of rubberized concrete can be alleviated by surface treatment of rubber particles, which changes the interface between cement and rubber particles. The dynamic properties of the rubber-mortar interface under different bonding states were explored by performing four-point bending tests on the rubberized concrete beams. The free decay method was used to test the damping ratios of rubberized concrete beams with different interfaces and damage states. Isight was used to build an inversion analysis platform to determine the damping ratios of the rubber-mortar interfaces with different bonding states. The results show that: (1) Compared with the water treatment, the damping ratio of rubberized concrete modified by sodium hydroxide decreased by 3.01 %, while zinc stearate modification increased the damping ratio by 15.37 %; (2) The average increase in the damping ratio of zinc stearate rubberized concrete was 14.51 % for each damage level. Sodium hydroxide resulted in a 75.4 % decrease in the rubber-mortar interfacial damping ratio, while zinc stearate increased the interfacial damping ratio by 381.9 %; (3) The relationship among the normal bond strength, fracture energy and interface damping ratio was fitted by a planar relation formula.