Microwave heating is an encouraging heating technology for the maintenance, recycling, and deicing of asphalt pavement. To investigate the microwave heating properties of asphalt mixture, laboratory tests and numerical simulations were done and compared. Two types of Stone Mastic Asphalt (SMA) mixture samples (with basalt aggregates and steel slag aggregates) were heated using a microwave oven for different times. Numerical simulation models of microwave heating of asphalt mixture were developed with finite element software COMSOL Multiphysics. The main thermal and electromagnetic properties of asphalt mixture, served as the model input parameters, were measured through a series of laboratory tests. Both laboratory-measured and numerical simulated surface temperatures were recorded and analyzed. Results show that the replacement of basalt aggregates with steel slag aggregates can significantly increase the microwave heating efficiency of asphalt mixture. Numerical simulation results have a good correlation with laboratory test results. It is feasible to use the developed model coupling electromagnetic waves with heat transfer to simulate the microwave heating process of asphalt mixture.

The cohesive and adhesive bond strength of the asphalt-aggregate system, sensitive to environment temperature, will impact asphalt pavement rutting resistance. This paper used the Whihelmy plate method to test the change process of surface free energy of AH70 asphalt and SBS modified asphalt in the range of 20 to 70 Centigrade. Surface free energy of aggregates was measured by contact angle meter. The results show that the surface energy decreased as temperature increased. When the temperature exceeds the asphalt binder softening point, the adhesion bonding of asphalt-aggregate will reduce. The adhesion between asphalt and limestone or basalt is higher than that between asphalt and diabase or sandstone. By analyzing the correlation of surface energy parameters and dynamic stability of the six type asphalt mixture, a linear correspondence between the surface energy at 60 centigrade and rutting resistance is derived. This research may provide a theoretical basis for the optimization of selecting asphalt and aggregate and rutting preventive maintenance.

To improve the quality of wall-protective mud, performance of ecotypic wall-protective mud with feathers was studied in laboratory. Firstly, tests were conducted on mud without sands. Through graduated-cylinder tests, the influence of feathers on the volume and density of mud was analyzed. Then different kinds of mud with sands and feathers were prepared by crossed tests, whose influence to the mud was analyzed mainly through funnel viscosity tests. It is found that with the increase of feathers content, the volume of the mud increases slightly while the relative density decreases slightly. Clay content plays leading role on the quality of the mud. Sand content increases the density and decreases the viscosity of the mud. Feathers content has more influence on the viscosity and significantly improves the viscosity while it reaches more than 0.05%. In all, feathers can be used in wall-protective mud and adjust/offset the side effects by sands.