Application of High‐Density Polyethylene as a Modifier to Prepare Desulfurized Rubber Asphalt With Excellent Storage Stability

ABSTRACT

To address the issues of poor temperature sensitivity and unstable storage performance in rubber asphalt, this paper proposes a formulation that blends high‐density polyethylene (HDPE) with desulfurized rubber. The goal is to develop high‐performance desulfurized rubber asphalt that exhibits excellent storage stability. The study found that adding HDPE not only enhances the temperature sensitivity of the asphalt but also significantly improves the high‐temperature viscosity of the rubber asphalt. The asphalt modified with 3% HDPE showed an increase of 31.8% in viscosity–temperature indices compared to the desulfurized rubber asphalt. HDPE facilitates the formation of a structure in the mixture where rubber particles are encapsulated by polyethylene. This structure restricts the movement of particles within the modified asphalt, reducing asphalt deformation and rubber particle agglomeration, thus enhancing the uniformity and stability of the desulfurized rubber asphalt. Rheological tests indicate that HDPE not only enhances the elasticity of the entire asphalt system but also significantly improves the rutting resistance of rubber asphalt under dynamic strain loads. Specifically, at 46°C, the asphalt modified with 3% HDPE showed an increase of 34.1% in rutting factor and 35.6% in complex modulus compared to the desulfurized rubber asphalt. Furthermore, HDPE improves the low‐temperature crack resistance and aging resistance of rubber asphalt. This is because HDPE promotes vulcanization reactions between sulfur bonds in the asphalt and free sulfur or other sulfur‐containing functional groups in the rubber, forming new sulfur bonds and creating a cross‐linked structure within the rubber. This phenomenon can be verified through fluorescence microscope images.