Effect of bio-derived/chemical additives on warm mix asphalt compaction and mix performance at low temperature

- WMA additives achieved similar compaction effort to HMA.
- FP 2 did not improve WMA compactibility when polymer modified.
- FP 2 appeared to strengthen bond between SBS and base binder.
- At low temperature WMA additive groups performed similarly to HMA groups.

Two concerns for paving with asphalt in cold-regions include cool temperature paving and low-temperature cracking. Newly developed and commercially available bio-based warm mix asphalt additives were investigated for their compactability and low temperature cracking performance. A neat and polymer-modified binder was also investigated to understand the role of polymer in the compactability and low-temperature cracking resistance of a mixture. The study showed that using the WMA additives with asphalt mix at reduced temperatures help to achieve similar compaction effort to HMA when measured using shear effort energy and compaction force index. The results also showed an interaction between one of the additives and the polymer modified binder. The low temperature cracking properties were measured using the disk-compact tension test and showed that WMA polymer modified binder performed similarly to HMA.