Strength deterioration mechanism of concrete under dynamic and quasi-static load after being subjected to microwave treatment

Abstract

Microwave is a new technology for concrete damage and aggregate recovery. In this paper, the effects of microwave irradiation conditions and aggregate differences on heating results were investigated. The strength degradation mechanism of concrete under uniaxial compression, splitting tensile and dynamic loads after microwave irradiation were studied. The aggregate separation ratio under different crushing approaches was compared, and the optimization method of aggregate breaking and recycling was proposed subject to different aggregate types. The results indicated that the relative magnitude of the dielectric loss factor of aggregate and mortar influenced the region and extent of damage in concrete, affecting the degree of interface separation. Increased microwave energy input accelerated the degradation of concrete strength. In the impact tests, the elastic modulus of the specimens decreased with increasing microwave irradiation time, the yield strength and dynamic compressive strength decreased, and the plastic plateau increased. Results showed that microwave power significantly affects the degradation of concrete strength while has a smaller impact on improving the separation efficiency of aggregate recycling.