Internal Stress Development and Fatigue Performance of Normal and Crumb Rubber Concrete

This paper focuses on early-age internal stress evolvement under restraining conditions and the fatigue behavior of ordinary concrete and crumb rubber concrete. The internal strain development in ordinary concrete and crumb rubber concrete slabs was monitored after the casting of concrete. Results show that the internal stress that developed in restrained rubber included concrete was lower than that in ordinary cement concrete. The stress relaxation effect due to the low elastic modulus of rubber included concrete may account for this result. A fatigue test of both concretes at room temperature and elevated temperature was conducted. At room temperature, crumb rubber concrete possessed much longer fatigue life than ordinary concrete. At 70°C, the fatigue life of both ordinary concrete or crumb rubber concrete is much lower than either concrete at normal temperature, no matter if the specimens are dry or water saturated. The moisture contained in the specimens during the fatigue test plays an important role in decreasing the fatigue life of both types of concrete. Furthermore, crumb rubber concrete always performs better than ordinary concrete under comparable conditions. With the help of acoustic emission (AE) analysis, it is revealed that the incorporation of rubble particles in the concrete alleviated the damage process of concrete.