Optimization of rapid-repair material ratio and performance analysis based on orthogonal test

Abstract

Through orthogonal experimental design, the influence of the water-binder ratio, binder-sand ratio, ultrafine mineral admixture content, and steel fiber content on the fluidity and basic mechanical properties of rapidrepair materials was studied. The optimal mixing ratio parameters were determined, and its swelling and shrinkage performance and microstructure were analyzed. The results showed that the water-binder ratio and steel fiber content were the most significant factors affecting the properties of rapid-repair materials. The steel fiber content in the rapid-repair material led to pull-out failure and significantly affected flexural strength but had a relatively small effect on compressive strength. With the determined optimal mix proportion, the rapidrepair material had good fluidity and high early strength, bonding strength, and volume stability. At age 3 h, the material's flexural strength and compressive strength were 13.7 MPa and 27.8 MPa, respectively, and the adhesive strength was 3.65 MPa. The limited expansion rate of 56 d-age repair material was 326.5 × 10 −6 , which can better meet the requirements of repairing highway pavement and bridge expansion joints to reopen to traffic within 3 h of repair.