Tie-Arch Model of PVA Fiber–Reinforced Cement Used in Cement Pavement Repair

Analyzing the stress conditions in different load-bearing sections of damaged road surfaces is essential for evaluating repair effectiveness. This study utilizes polyvinyl alcohol (PVA)-reinforced magnesium phosphate cement (FRMPC) as a repair material, which is characterized by early strength and high toughness. Its composite flexural strength when used to repair both the tensile and compressive zones of road surfaces is systematically investigated. A tie-arch model is established based on the fundamental model of stress in a three-hinge arch, combined with acoustic emission and digital image testing of specimens. The results indicate that the composite flexural strength of FRMPC repair material is greater when used in a tensile zone than in a compressive zone. In both cases, it significantly exceeds the flexural strength of cement mortar and approaches its own inherent flexural strength. Acoustic emission signals reveal that compression failure predominantly occurs on the upper surface, showing an arch-shaped distribution. Digital image analysis demonstrates that tensile failures are mainly concentrated on the lower surface. The tie-arch model of composite flexural strength exhibited an error margin of less than 10%. This approach offers viable road repair using early-strength, high-toughness materials. It also introduces a novel method for adverse load calculations and can simulate real-world engineering stress scenarios. Thereby, this approach provides a valuable reference for further studies on engineering repair materials.