Study on cooling effect of large gap asphalt pavement

In order to investigate the effect of void ratio on the cooling effect of porous asphalt pavement (PAC pavement), the study was carried out from three aspects: thermophysical properties of porous asphalt mixture, numerical simulation analysis of temperature field and sunlight simulation test under windless condition, firstly, through relevant tests and calculations, the heat conduction coefficient of PAC asphalt mixture with different void ratios was measured realistically by using heat flow meter and compared with Then, the ABAQUS finite element model was established to simulate the temperature field changes of the pavement structure at different void ratios within 24 h. The temperature peaks at the road surface, 4 cm below the road surface and 10 cm below the road surface within one day were compared for each structure form to quantify the cooling effect of PAC pavement was quantified by fitting the data of void ratio and cooling magnitude to obtain the calculation model between the cooling effect and void ratio at each depth of single-layer PAC pavement, and finally the cooling effect of PAC pavement was verified by simulating sunshine test under windless condition. The results show that the specific heat capacity and thermal diffusion coefficient of PAC asphalt mixture with the same maximum particle size show a decreasing trend with the increase of void ratio. The calculation model of the heat transfer coefficient of PAC asphalt mixture with the void ratio and the volume proportion of each component material was obtained. The numerical simulation shows that the cooling effect of PAC pavement increases with the increase of void ratio, and there is a good linear positive correlation between the cooling effect and void ratio. The sunlight test data show that PAC pavement has obvious cooling effect compared with ordinary AC pavement, which can effectively improve the high temperature stability performance of the pavement to a certain extent.