Bentonite-Based Zeolite-Like Foaming Warm-Mix Additive: Synthesis, Characterization, and Rheological Evaluation on Virgin and Asphalt-Rubber Binders

In the past, Montmorillonite K10 (MMT K10), an acid-activated clay, was successfully used as a raw material to synthesize zeolite-like warm-mix asphalt (WMA) additive. The major objective of this research was to synthesize a foaming zeolite with bentonite as an alternative to MMT K10 and assess the physicochemical characteristics of additive through fundamental and advanced binder tests on virgin and rubber-modified binders. Fundamental binder consistency tests revealed that the additive modification resulted in stiffer binders, which could offer higher resistance to rutting at higher temperatures. Furthermore, the asphalt mixtures produced with the WMA additive-based asphalt cement demonstrated a reduction of compaction temperature by 6 ℃ compared to the virgin and rubber-modified mixtures. The WMA additive-based binders offered more resistance to rutting when subjected to traffic loads and elevated temperatures as the failure temperatures were higher compared to virgin and rubber-modified binders. Morphological analysis of the synthesized additive confirmed the presence of hexagonal shaped particles whereas thermal analysis confirmed the release of water into the binder from 70–200 ℃, consequential of decreasing the viscosity of the binder and production temperatures. Overall, the replacement of MMT K10 with bentonite indeed improved rheological parameters over the conventional binders and mixtures while also being an economical alternative to MMT K10.