Compactability and Performance of Warm-Mix Additives at Lower Than Traditional Compaction Temperatures

Abstract

This study involves using warm-mix additives (WMA) to produce binders that can aid compaction at low temperatures during cold weather paving. For this purpose, a performance grade (PG) 58-28 asphalt binder was chosen as a control and was modified with four different WMA additives (Rediset, Evotherm, Zycotherm, and Sasobit Redux). The impact of WMA additives on binder properties was evaluated using PG, linear amplitude sweep, and asphalt binder cracking device (ABCD) tests. The use of WMA additives did not have any impact on the PG of the base binder, suggesting that WMAs can be used as a compaction aid. The ABCD results also showed that WMA did not negatively impact the low-temperature properties of the base binder. In addition to binder testing, this study involved conducting laboratory testing of mixtures to determine the impact of WMAs on the volumetric properties of asphalt mixtures when compacted at lower than tradition temperatures [i.e., 127°C (260°F), 104°C (220°F), and 82°C (180°F)]. The volumetric of the control and WMA-modified mixtures were satisfied at all compaction temperatures; thus, showing the potential for WMA additives to improve the compactability of asphalt mixtures. The cracking, rutting, and moisture susceptibility of the mixtures were also evaluated using cracking, rutting, and moisture damage tests, respectively. All the modified WMA asphalt mixtures performed better in terms of rutting, Cracking and moisture susceptibility compared to the control mixtures. Based on the performance ranking of the mixtures it is found that 104°C (220°F)–127°C (260°F) can be taken as the cutoff temperatures only for PG 58-28 binder grade to compact mixture under lab-controlled temperature.