Influence of Aggregate Packing on the Performance of Uncured and Cured Epoxy Asphalt Mixtures

The skeleton structure has a strong influence on the uncured and cured performances of the epoxy asphalt mixture. Based on the Bailey method, the different skeletal structures of the mixture have been obtained by varying the chosen unit weight ($CUW$), coarse aggregate ($CA$) ratio, and fine aggregate coarse fraction ($F{A}_c$) ratio. The performance experiments of these mixtures have been conducted in this paper. The results indicate that as the $CUW$ decreases from 105% to 80%, the epoxy asphalt mixture gradually changes from a skeleton dense structure to a suspended dense structure, and the strength and moisture resistance of the cured mixture gradually increase. The uncured strength of the mixture reaches a maximum at the $CUW$ of 95%. The skeleton structure of the mixture is gradually destroyed as the $CA$ ratio increases from 0.4 to 1.0, which also leads to a decrease in water stability given the difficulty in compaction. As the $CA$ ratio increases, the uncured stability of the mixture gradually reduces, but the stability and low-temperature performance of the cured mixture gradually increases. As the $F{A}_c$ ratio increases from 0.35 to 0.55, the fine aggregate fully fills into the skeleton, and the high-temperature performance, low-temperature performance, and moisture stability performance of the mixture improve. A dense gradation structure with a $CUW$ of 95%, $CA$ ratio of 0.4, and $F{A}_c$ ratio of 0.35 is recommended for an epoxy asphalt mixture applied in runway overlay or pavement maintenance without interrupting traffic.