Study on the effects of replacing mineral powder with HGM on the cooling performance and road performances of asphalt pavement

In order to alleviate the rutting and urban heat island effect due to the high temperature of asphalt pavement, this study replaces part of mineral powder with hollow glass microspheres(HGM), and investigates its effects on the road performances of asphalt pavement. In this study, micron-sized hollow glass microspheres with different replacement rates (0%, 25%, 50%, 75%, 100%) are mixed into AC-13 and SMA-13 mixtures by replacing mineral powder with equal volume, and the optimal replacement volume of HGM, the cooling performance and road performances of the two mixtures are studied by laboratory simulated radiation test, rutting test, freeze-thaw splitting test and Schellenberg binder drainage test, etc. The results show that for AC-13 mixture, with the increase of replacement rate of HGM, the cooling effect is improved up to 5.2°C, the high temperature performance and low temperature crack resistance are improved and moisture damage resistance is decreased. When the replacement rate reaches 100%, the freeze-thaw splitting strength ratio has exceeded the specification requirements. For SMA-13 mixture, with the increase of replacement rate of HGM, the cooling effect is also improved and the highest is 9.0°C, the high temperature performance is improved and the anti-scattering performance is increased, but the moisture damage resistance, low temperature crack resistance and the drainage resistance are decreased. When the replacement rate reaches 100%, the freeze-thaw splitting strength ratio of the mixtures can no longer meet the specification requirements. In addition, the incorporation of HGM reduces the fatigue resistance of AC-13 and SMA-13 mixtures. According to the effects on both of cooling performance and road performance, it is suggested that the best replacement rate of HGM is 40%-60%, at which time AC-13 mixture and SMA-13 mixture can be cooled down about 2.4°C-3.2°C and 3.7°C-6.1°C respectively.