The Experimental Research On The Performance Of Cement Repair Mortar Reinforced By Basalt Fiber And Nylon Fiber

The damage of concrete often occurs during use due to environmental and artificial factors, so the study of concrete repair mortar is becoming more and more attentioned. In this paper, we mixed basalt fiber and nylon fiber into cement mortar, and improved the interface properties of fibers and cement mortar with silica fume. Then we researched the effect of adding one kind of fiber and different kinds of fiber on flexural strength, compressive strength, toughness( flexural-compression ratio),shear bond strength, drying shrinkage performance and consistency of mortar, and finally the highperformance fiber repair mortar was produced. The research results show that:The single length basalt fiber could increase the flexural strength, flexuralcompression ratio and dry shrinkage resistance of repair mortar significantly, and the optimal fiber content range was 0.1%~0.2%, the optimum fiber length was 15 mm. But the improvements of compressive strength and shear bond strength was not obvious. In the process of mixing different length basalt fiber, we found that the best hybrid mode was four lengths fiber(6mm、12mm、15mm、19mm) mixed with equal amounts, because the flexural strength, flexural-compression ratio, shear bond strength and dry shrinkage resistance were all better than the mortar reinforced with single length fiber.The single length nylon fiber could increase the flexural strength, flexuralcompression ratio, shear bond strength and dry shrinkage resistance of repair mortar significantly, and the optimal fiber content range was 0.1%~0.2%, the optimum fiber length was 15 mm. On the contrary, nylon fiber had significant negative effects on compressive strength. The test result of nylon fiber was same with basalt fiber when mixed different length fiber into mortar, the best hybrid mode was still four lengths fiber mixed with equal amounts.The best proportion of basalt fiber and nylon fiber was 1:1 and the best total content of fiber was 0.2% when mixed with basalt fiber and nylon fiber. In this case the flexural strength, shear bond strength and dry shrinkage resistance of repair mortar all had further improvement on the basis of single fiber reinforced mortar, the flexural strength and shear bond strength in 28 d increased by more than 10.43% and 29.12% respectively. In addition, the compressive strength was also increased. As for flexuralcompression ratio, the reinforcing effects was basically flat with mortar reinforced with four kinds of length basalt fiber mixed with equal amounts, but was slightly less than the mortar reinforced with four kinds of length nylon fiber mixed with equal amounts.The volcanic ash effect and micro aggregate filling effect of silica fume could improve the interface properties of fibers and mortar significantly. Adding silica fume into fiber mortar, the flexural strength, shear bond strength, dry shrinkage resistance and compressive strength of fiber repair mortar could be further improved, and they were all increased with the increase of silica fume content. The consistency value and flexural-compression ratio of mortar were decreased with the increase of silica fume content. The optimal content of silica fume was 8%.The best proportion of repair mortar with basalt fiber and nylon fiber was cement : sand : water : superplasticizer : silica fume = 1∶2.5∶0.4∶0.006∶0.08, both content of two kinds of fibers were 0.1% and four kinds of length of each fiber were mixed with equal amount. The mortar was applied to actual repairation, the repair effect was good and meet the demand of actual repairation.