Field Aging and Development of Aging Model for Hot-Poured Crack Sealants

Abstract

An investigation was conducted to evaluate the long-term field aging effects of hot-poured crack sealants by differential aging testing. An analysis of rheological and mechanical properties to implement two performance-based tests was used to characterize aging of sealants. A set of eight types of crack sealants was exposed to approximately 2 years of weathering conditions. Aging mechanisms were investigated by a comparison of the critical properties with those obtained at the time of installation inside a small kettle. Samples were collected every 6 months after installation for laboratory characterization. Laboratory characterization included low-temperature stiffness, cohesion, adhesion, and viscosity. According to the results of the experimental program, a consistent increase was observed in the low-temperature stiffness of crack sealants as a result of weathering. The study showed that the low- and high-temperature properties of the surface portion were significantly influenced by weathering effects even within a short period of time. A superposition rule analogous to time–temperature superposition for viscoelastic materials was applied to develop master curves. A phenomenological aging model was developed as a function of aging time and represented shift factors used in the master curve development. Sealants were categorized as Type A, B, or C on the basis of increasing aging potential.