Preparation and Properties of Microwave-Absorbing Asphalt Mixtures Containing Graphite and Magnetite Powder
Abstract
The concept of microwave-absorbing asphalt concrete has been proposed to create an asphalt mixture with high microwave heating efficiency. A mixture of 20 % graphite powder and 80 % magnetite powder was used as the microwave-absorbing composite to replace the common mineral filler in asphalt mixtures to improve its microwave absorption capacity. This study aimed to evaluate the effect of proposed absorbent composite on the properties and microwave heating efficiency of asphalt mixtures. The results indicate that the addition of graphite and magnetite powder exhibited an improvement in the microwave heating efficiency of asphalt mixtures. The heating rate of asphalt mastic was improved by more than 10 times, whereas the heating rate of asphalt mixtures containing the absorbent composite was improved by 47.8 %. The pavement performance test results show that the mechanical performances including the dynamic stability, bending strain, residual Marshall stability, and ratio of splitting tensile strength after and before the freeze-thaw cycle satisfy the relevant specification requirements.