Experimental Study on the Mechanical Properties of Crumb Rubber Concrete after Elevated Temperature

To reduce the environmental damage caused by waste rubber, crumb rubber concrete (CRC) was prepared by replacing some fine aggregates with crumb rubber. The effects of elevated temperature as well as crumb rubber content on the mechanical properties of the prepared CRC were studied. The crumb rubber contents were 0%, 10%, and 20%, while CRC was subjected to atmospheric temperatures (AT) of 300 °C, 500 °C, and 700 °C. The concrete without crumb rubber content was used as the control group at the atmospheric temperature. The mass loss, thermal conductivity characteristics, compressive strength, splitting tensile strength, axial compressive strength, elastic modulus, and stress-strain characteristics of CRC at elevated temperatures were studied. The experimental results show that: (1) With the increase in crumb rubber content and temperature, the cracks on the surface of the specimen gradually widen while the mass loss of the specimen increases. (2) With the increase in crumb rubber content and temperature, the cube compressive strength, splitting tensile strength, axial compressive strength, and elastic modulus of CRC decrease, yet the plastic failure characteristics of CRC are more obvious. (3) The influences of elevated temperature on strength and elastic modulus are as follows: splitting tensile strength > elastic modulus > axial compressive strength > cubic compressive strength. (4) With the increase in temperature, the stress-strain curve of the CRC tends to flatten, the peak stress decreases, and the corresponding peak strain significantly increases. With the increase in crumb rubber content, there is a great decrease in peak stress, yet the corresponding peak strain is basically the same. The use of CRC can be prioritized in applications that increase toughness rather than strength.