Jinming Zhang, Hongliang Zhang, Kongfa Zhu
To overcome the limitations of existing UV-shielding materials and further enhance the UV-ageing resistance of asphalt, two types of UV absorbers, 2,3-dihydroxynaphthalene-6-sodium sulfonate and 2-phenylbenzimidazole-5-sulfonic acid, were intercalated into Mg–Al layered double hydroxides (LDHs) via an ion exchange method to prepare novel composite UV-shielding materials. The prepared materials were characterised in terms of crystal phase, functional groups, microstructure, UV absorbance and thermal stability. Then, melt blending was utilised to develop composite UV-resistant modified asphalt and LDHs-modified asphalt. Subsequently, the resistance to UV ageing, high temperature, low temperature and fatigue resistance performances of them and the matrix asphalt were evaluated and compared. Characterisation confirmed successful intercalation without disrupting the LDH structure while improving UV absorbance and thermal stability. The performance tests showed that the modified asphalts exhibited significantly enhanced resistance to UV ageing, with 2,3-dihydroxynaphthalene-based materials performing best. All modified asphalts also demonstrated improved high- and low-temperature properties compared to matrix asphalt, with notable gains in fatigue resistance. This work provides a scalable strategy to synergistically combine physical shielding (LDHs) and chemical absorption (organic UV absorbers) for durable asphalt pavements in high-solar-radiation regions.