Mechanical and Functional Self-Healing Characteristics of Hot-Poured Crack Sealant Exploiting Dynamic Shear Rheometer and Low-Temperature Tensile Tester

Abstract

As a kind of asphaltic material, hot-poured sealant with initial aging or failure will gradually self-heal during the change of ambient in the actual service process, so as to restore its service performance to a certain extent. Considering the requirements for the load-carrying and watertight capacity of crack sealant under multisource environmental and vehicle loads, this study proposed evaluation criteria for mechanical and functional self-healing using a dynamic shear rheometer (DSR) and a low-temperature tensile tester (LTTT). For mechanical self-healing, three healing indexes, HI, HI2, and HI3, were introduced by taking the modulus of sealant before and after intermittent loading, the loading times and the ratio of the two changes as parameters using DSR. The results showed that sealant with good low-temperature performance had a strong bearing capacity and could withstand more repetitions of driving load under the same conditions, while sealant with good high-temperature performance had great mechanical self-healing ability. When the modulus was reduced by the same amount, the lower loading times revealed the stronger mechanical self-healing ability of sealant. For functional self-healing, the effects of time, temperature, and bonding environment on the adhesive performance of sealant before and after self-healing were considered using LTTT. After self-healing at a certain temperature for a certain period of time, cracks between sealant and a crack wall can be healed, and the low-temperature tensile property can be recovered to different degrees. A higher self-healing temperature, longer self-healing time, and cleaner bonding environment signify a higher self-healing degree of a sealant. After self-healing, the service performance and watertight capacity of sealant can be largely recovered.