Effect of Nano Hydrotalcite on the Aging Resistance of a High Binder Content Stone Mastic Asphalt

Abstract

Hydrotalcite, a type of layered double hydroxide (LDH), reveals an interesting potential for the modification of bitumen. The LDH can induce a barrier effect that prevents the loss of volatiles, retards oxidation, and protects against ultraviolet radiation. Such properties can enhance the aging resistance of the bitumen. However, there is a gap in knowledge regarding the effects of the modification with hydrotalcite in the properties of the asphalt mixture. To contribute to fill such a gap, the current study presents a characterization of the effects of the modification with nano hydrotalcite in the surface characteristics, mechanical performance, and aging resistance of an asphalt mixture. To better explore the effects of the modification, the selected asphalt mixture was a high binder content (7.5%) Stone Mastic Asphalt (SMA). The experimental study indicates that the binder-rich SMA presented adequate performance for application in surface courses. If compared to conventional mixtures, the binder-rich SMA presented better initial mechanical performance (unaged conditions). Furthermore, it presented smaller variation in the parameters between unaged and aged conditions, indicating enhanced aging resistance. The modification with nano hydrotalcite induced smaller evolution in the fatigue resistance parameters, indicating enhanced aging resistance; however, in the remaining tests, the trends were not clear.

Physical, Rheological, and Anti-Ultraviolet Aging Performance of Layered Double Hydroxides + Styrene Block Copolymer-Modified Asphalt Binders

“…Layered double hydroxide (LDH) is a layered material with a supramolecular structure [22]. Studies [23,24] have shown that LDHs can heighten the anti-UV aging performance of ABs, which is attributed to their unique structure that provides physical shielding and chemical absorption of UV light [18]. Zhang et al [25] showed that dodecyltrimethoxysilane surface organic modified LDHs (OLDHs) were significantly more compatible with SBS MABs than LDHs, and the OLDH-modified SBS MABs exhibit a superior high-temperature performance and UV aging resistance.…”

“…They can increase the compatibility of LDHs with ABs and heighten the anti-UV aging performance of OLDH MABs. Furthermore, LDHs can improve the road performance of asphalt mixtures [23]. Zhao et al [27] concluded that adding LDHs can significantly heighten the resistance to water damage and freeze-thaw splitting of UV-aged SBS MA mixtures and thus enhances their high-temperature and long-term low-temperature properties.…”