The effect of rubber powder on asphalt adhesion and resistance to ultraviolet ageing

The addition of rubber powder (RP) to asphalt can improve its performance, thereby prolonging the pavement's service life. The properties of a matrix asphalt and asphalts modified with styrene–butadiene–styrene block copolymer (SBS), RP and SBS/RP composite after ultraviolet ageing (UVA) were studied in this work. Various characterisation methods were used to evaluate the surface free energy (SFE) and rheological properties. The UVA mechanism was explored through changes in functional groups. The experimental results showed that adding RP improved the anti-UVA property of asphalt. Notably, after 2–4 days of UVA, the RP-modified asphalt showed improved adhesion properties, with a remarkable 164.6% increase in SFE. The complex modulus of the modified asphalt was also enhanced by short-term UVA. However, long-term exposure to UV radiation resulted in reduced non-recoverable creep compliance compared with the control asphalt. Furthermore, carbonyl groups in both the RP-modified and SBS-modified asphalt exhibited minimal changes due to the effects of UVA. For the base asphalt and the SBS-modified asphalt, the addition of RP improved adhesion and delayed UVA. The findings of this work provide valuable theoretical insights into the use of RP for enhancing the UV resistance of asphalt.