Design method of warm mix asphalt based on Marshall test under variable temperatures and compaction times

In order to establish the mixture design method for warm mix asphalt(WMA),Marshall test was conducted under variable temperatures and compaction times to prepare AC-13C WMA specimens,and the volume characteristics of WMA specimens were researched.Analysis result indicates that the air void volume(VV) and the percent voids in mineral aggregate(VMA) increase with the decrease of compaction temperatures and compaction times,but the percent voids in mineral aggregate that are filled with asphalt(VFA) decrease.Compared with hot mix asphalt(HMA),the asphalt content absorbed by aggregates,the effective asphalt content(mass fraction) and the thickness of asphalt film in WMA differ a little,and the optimum asphalt content of AC-13C WMA is 4.7%.According to the volume characteristics,the compaction temperatures of WMAs are determined,and the compaction temperatures of WMAs with matrix asphalt and SBS modified asphalt decrease by about 10 ℃-20 ℃ and 10 ℃ respectively.WMA compactibility is better,and the compaction times of WMAs with matrix asphalt and SBS modified asphalt decrease by about 20% and 10% respectively.4 tabs,10 figs,13 refs.