Design and Performance Investigation of Drainage Ultra-Thin Wearing Course Based on Diatomite-Supported Epoxy-Modified Asphalt Mixture

Abstract

The high-performance epoxy resin–modified asphalt has been widely applied in the development of steel deck pavement and roads with heavy traffic. However, the poor compatibility between the epoxy resin and matrix asphalt has never been solved completely. In this study, epoxy resin was supported on diatomite with a large pore structure, so that epoxy resin was evenly dispersed into asphalt for improving the compatibility. The diatomite-supported epoxy-modified asphalt (DEA) binder was prepared and applied to the drainage ultra-thin wearing course mixture (DUWM). Six different DEA-DUWM were designed with a 2.36-mm sieve size, which was the key sieve size. The general asphalt content was calculated by the asphalt film thickness test. The optimal asphalt content was determined by the Cantabro test and the Schellenberg binder drainage test. The best curing time was determined by the Marshall test. Taking the Japanese epoxy resin–modified asphalt (TAF) as the comparison group, the high-temperature rutting test, low-temperature bending beam test, immersion Marshall test, freeze-thaw splitting test, immersion Cantabro test, water seepage test, surface friction coefficient test, and Manual sand laying test were carried out for DEA-DUWM and TAF-DUWM under the same gradations and test conditions. The results indicate that DEA-DUWM has excellent high-temperature rutting resistance; the maximum low-temperature bending strain is nearly 25 % less than that of TAF-DUWM, but the low-temperature cracking resistance can still meet the specification requirements of China. The addition of diatomite and the air void of the mixture have an effect on the low-temperature anticracking performance of DUWM, and DEA-DUWM has a remarkable high-temperature and low-temperature moisture resistance, drainage, and skid resistance. The air void of the mixture has a great influence on the freeze-thaw resistance of DUWM. The asphalt type has a marginal effect on the drainage and antiskid properties. It is suggested that the DUWM design’s target air void content should not be less than 17 %, and it can be improved properly in an area with heavy rainfall.