Experiment On Basalt Fabric Reinforcement Polymer-fiber Reinforced Cementitious Matrix Mechanical Property

Fiber Reinforced Cementitious Matrix(as referred FRCM)and Basalt fabric Reinforced polymer(as referred BFRP)composite layer is universally used for reinforcement and renovation of existing buildings.However,research on the tensile and bending properties of reinforced layer is relatively rare.In this paper,mechanical properties of basalt fabric reinforced polymer-fiber reinforced cementitous matrix(BFRP-FRCM)reinforced layer are taken as the research target.The basic mechanical properties of the basalt mesh,the FRCM matrix and BFRP-FRCM reinforced layer’s overall uniaxial tensile mechanical properties are studied respectively.Bending mechanical properties of BFRP-FRCM reinforced layer were experimentally explored and theoretically analyzed.The effection of basalt mesh distribution rate,various matrix strength,polypropylene fiber,polyvinyl alcohol fiber and polyethylene fiber on the tensile and bending mechanical properties of the reinforced layer were discussed,and the uniaxial tensile stress-strain constitutive model of the reinforced layer was obtained.It provides a reference for the ratio design and calculation of optimal mesh distribution ratio of BFRP-FRCM composite layer reinforced masonry filling wall.Specific research results are as follows:(1)Through the tensile test of the BFRP-FRCM composite layer,it can be found that the cracking strain is the physical and mechanical property of the FRCM matrix material.PVA and PE fiber specimens have obvious tensile strain hardening effect,while PP fiber specimens exhibit tensile softening.The addition of grids can significantly improve the ultimate tensile strength of BFRP-FRCM specimens.After the distribution network rate reaches a certain value,continuing to increase the distribution network rate will reduce the ultimate tensile strain of the composite layer,indicating that the ultimate tensile strain of the composite layer does not increase with the increase in the distribution network rate,but there is an optimal distribution network rate.(2)Increasing the distribution rate can significantly improve the failure characteristics of the BFRP-FRCM bending specimen with fewer cracks at the bottom.The load deflection curve of the PP specimen only showed a bending-hardening trend when 2 and 3 layers of fiber mesh were incorporated.PVA specimens show a good bending-hardening tendency in all working conditions.Changing the distribution network rate,matrix strength,and fiber type has little effect on the cracking deflection of the composite layer,which is only related to the mechanical properties of the matrix material.The change of water-binder ratio will weaken the ultimate flexural strength of the composite layer,and the addition of mesh can significantly increase the ultimate flexural strength of the specimen.There is an optimal distribution network rate for the bending mechanical properties of the composite layer.For PVA specimens,when the waterbinder ratio is 0.30 and the two-layer fiber mesh is incorporated,the bending performance is the best,and its toughness index can reach 49.10.For PP specimens,when the water-binder ratio is 0.35 and the two-layer fiber mesh is incorporated,the toughening effect of the specimens is the best.(3)By modifying the bilinear model formula proposed by Kanda T.,the tensile stressstrain constitutive model suitable for BFRP-FRCM composite layer has been obtained,which can better fit the test results.Using the modified constitutive model to simulate and verify the tensile and bending test of composite layer,it can be found that the simulated tensile test results are close to the test values,but the simulated bending test results are less than the actual test results.