A novel polyurethane-based mortar for pavement crack repair: Development, characterization, and performance evaluation

Abstract

In light of the severe hazards posed by pavement cracks on traffic safety and infrastructure longevity, the development of a convenient and effective pavement repair material has become essential. The excellent cohesive strength and resilience of PU offer significant potential as a crack repair material, ensuring enhanced durability and reliability in pavement crack repairs. This study systematically explored the workability, mechanical properties, interface bonding performance, and fracture behavior of PUM as a pavement repair material through mechanical strength tests, interfacial tensile tests, and three-point bending tests based on DIC. The results indicate that the fluidity of PUM can be adjusted through the binder-sand ratio and PD content, enabling customization for various repair scenarios. PUM demonstrates exceptional one-day compressive and flexural strengths, achieving 18.8 MPa and 7.1 MPa, respectively. Furthermore, the bond tensile strength of PUM reaches 4.3 MPa, exhibiting accelerated strength development that meets the requirements for vehicle traffic after repairs. The lower elastic modulus of PUM, ranging from 0.28 to 0.63, indicates improved deformation adaptability. SEM analysis reveals a complex interfacial bonding network between PU and aggregates, considerably enhancing the energy dissipation capacity of PUM with a peak GF value of 205.05 N/m. DIC technology robustly captured the crack progression, revealing significantly reduced stress concentration at the crack tip of PUM, with no through-thickness cracks detected during the three-point bending fracture process. It is recommended that PUM be prepared with an 80 % binder-sand ratio and 5 % PD to achieve an optimal balance of workability, mechanical, and fracture properties.