Compression test on curves and constitutive model of crumb rubber concrete for structural purposes

Crumb rubber concrete(CRC) used in structures should be designed with equal strength as ordinary concrete, but the study on uniaxial compression test and constitutive model of this kind of concrete are limited. This paper conducted three groups of compression test with CRC cubes and prisms. The size was 1-2 mm and the rubber content ranged from 0 to 100 kgm^-3. The results show that by pretreating the rubber particles with NaOH aqueous alkali and optimizing the mix proportion of concrete, CRC can accurately reach the same strength as ordinary concrete, while the peak strain and the ultimate strain increase obviously. The failure process of CRC specimens are mild and slow, and the specimens keep their integrity well at the failure moment. At the same time, the existing ordinary CRC constitutive models under uniaxial compression are not suitable for CRC in this study. Although Carreira-Chu constitutive model of ordinary concrete is consistent with the experimental curves, the scope of application for CRC need to be verified. Finally, through the curve fitting, the proposed values of the constitutive parameters of CRC based on the GZH model were obtained and applied in the analysis and design of CRC structural members.