Evaluation Method and Influence Law of UV-Cured Polyurethane on the Self-Healing Performance of Asphalt and Asphalt Mixtures

Abstract

To explore the effect of UV-curable polyurethane (UV-PU) on the self-healing performance (SHP) of asphalt and asphalt mixtures, this article conducted research in this area of the evaluation method and influenced the law. polyurethane (PU), Styrene-Butadiene-Styrene Block Copolymer (SBS Ι-C) and 70# asphalt and asphalt mixtures were introduced as the example of comparison. A method for evaluating the SHP of asphalt, sand asphalt mixture, and medium particle asphalt mixture using the healing index (HI) as an evaluation index was proposed, and the healing performance of various materials under different healing conditions was tested and analyzed. The research results indicate that, HI based on asphalt complex shear modulus (HIA), HI based on sand type asphalt mixture (AC-5) flexural tensile strength (HIAC-5), and HI based on medium grained asphalt mixture (AC-16) bending stiffness modulus (S) HIAC-16 can effectively reflect the SHP of asphalt, AC-5, and AC-16 under different healing conditions, and can be used as an evaluation indicator for SHP. The asphalt SHP is related to the asphalt type and the degree of initial loss and is highly correlated with the healing time. Compared to other asphalt types, the sensitivity of UV-PU or PU modified asphalt to initial loss is lower than that of SBS Ι-C modified asphalt, but higher than 70# asphalt. Under the same light healing time and initial degree of loss, the SHP of UV-PU modified asphalt AC-5 and AC-16 is significantly superior to other types of asphalt mixtures. Compared to asphalt, the self-healing time of AC-5 grade AC-16 is longer. The SHP of AC-16 is highly correlated with the loss degree associated with the initial S. The larger the initial loss degree of the S, the greater the loss rate of the HI.