Effect of Vehicle–Bridge Coupled Vibration on the Performance of Magnesium Phosphate Cement Repair Materials

Abstract

This study evaluates the effect of vehicle–bridge coupled vibration on the mechanical properties of fiber-reinforced magnesium phosphate cement (FR-MPC) composites and the bonding properties of repaired systems. By means of compressive and flexural bond strengths, fiber pullout, mercury intrusion porosimeter (MIP) and backscattered electron imaging (BSE) analysis, an enhanced insight was gained into the evolution of FR-MPC performance before and after vibration. Experimental results showed that the compressive strength and flexural strength of FR-MPC was increased when it was subjected to vibration. However, the effects of vibration on the flexural strength of plain magnesium phosphate cement (MPC) mortars was insignificant. The increased flexural strength of FR-MPC after vibration could be due to the high average bond strength and pull-out energy between the micro-steel fiber and the MPC matrix. Moreover, BSE analysis revealed that the interface structure between FR-MPC and an ordinary Portland cement (OPC) substrate was more compacted after vibration, which could possibly be responsible for the better bonding properties of FR-MPC. These findings are beneficial for construction project applications of FR-MPC in bridge repairing and widening.

Damage resistance of calcium sulfoaluminate cement-based engineered cementitious composites (CSA-ECC) under vehicle-bridge coupling vibration

“…It can be inferred that part of the coarse air bubbles at the bottom layer in the specimen tends to move upward to the middle layer and the upper layer and eventually over ow. In addition, it is worth noting that the total air bubbles content decreases from 2.13-1.61% after vibration, the result is consistent with previous studies [32,33]. Therefore, the redistribution of air bubbles caused by the coupling vibration re nes the pore structure in the matrix and improves its microstructure, which increases the CSA-ECC strength.…”

“…Series were the speci cally amplitude set as 2-4 mm, while series were the speci cally frequency set as 3-9 Hz. According to the situation in construction sites, the mixtures were vibrated for 15 s and stood for 45 s as one cycle [33].…”