Experimental Study on Physical Properties of High Quality Recycled Concrete Aggregate

摘要

The research beneficiated the concrete waste from two different sites to get the recycled concrete aggregates by the microwave-assisted mechanical beneficiation technology. Then, the author systematically studied the physical properties of recycled coarse aggregates and natural coarse aggregates from both macro and micro perspectives. The results show that: (1) in this experiment, the irradiation time per unit mass is about 5min/kg ～ 10min/kg, and the beneficiation rate is in 30% ～ 70%; (2) macroscopic physical experiments show that the recycled coarse aggregates obtained by the microwave-assisted mechanical beneficiation technology is basically the same with natural coarse aggregates in terms of water absorption, apparent density and mass loss., and its physical properties are the most optimal compared with other techniques. (3) from the microscopic point, the scanning electron microscope test shows that the mechanical process poses more damage to the recycled coarse aggregates than the microwave-assisted mechanical beneficiation technology through which the recycled coarse aggregates appears only several micro cracks in the cases after being magnified 5000 times, which is much equal to the natural coarse aggregates. In conclusion, this research validated the high quality of recycled coarse aggregates in the microwave-assisted mechanical beneficiation technology.