Crack-retardation Mechanism of Polymer-modified Micro-Surfacing on Bridge Deck Pavements in High-altitude Cold Regions: A 3D Thermal–mechanical Fracture Analysis

Abstract

Early-onset fracturing within deck layers poses a significant threat to the durability of composite steel-concrete structures, specifically those subjected to extreme multi-hazard environments characterized by extreme cold, intense solar radiation, and heavy traffic loads. This study explores the mechanism of polymer-modified micro-surfacing in inhibiting cracks on bridge decks. Utilizing the structural specifications of a representative composite girder span in northwestern China, a rigorous three-dimensional fracture mechanics model was established by integrating FRANC3D and ABAQUS. The results show that micro-surfacing acts as an excellent thermal barrier. It effectively reduces the temperature gradient within the pavement layer, thereby decreasing thermal stress accumulation at the steel-concrete interface. Furthermore, compared to conventional sealing materials, micro-surfacing has higher stiffness. It effectively disperses surface tensile stresses and significantly reduces the stress intensity at the crack tip. Therefore, micro-surfacing restricts crack opening through mechanical confinement and prevents the propagation of reflective cracks. Ultimately, this treatment significantly improves the fatigue life and structural resilience of the entire bridge system in extreme multi-hazard environments.