Experimental Study On Mechanical Properties Of Basalt Fiber Reinforced Concrete With Different Sizes

Compared with traditional concrete,fiber-reinforced cement-based composites can significantly improve some of its inherent defects,and also can control the development of concrete cracks,so as to improve the durability of components in service period.As a new type of fiber material,basalt fiber has great potential in engineering application,because of its excellent mechanical properties and high capability-price ratio.However,whether basalt fiber composite cement-based materials can play its advantages depends not only on the properties of fiber and matrix itself,but also on the interfacial bonding properties of fiber matrix.At present,there are many researches on the basic mechanical properties and durability of basalt fiber,but the research on the influence of basalt fiber on the overall performance of composite materials after treated with different wetting agents has not been involved,and the change law of macro properties of composite materials has not been investigated from the perspective of the influence of wetting agents on the fiber matrix bonding properties.Therefore,starting from the essence of composite materials,this paper carried out experimental research and theoretical analysis on the bond and pull-out performance of fiber and cement-based materials,the basic mechanical properties,pore structure characteristics of basalt fiber reinforced concrete and the bending performance of basalt fiber reinforced test beam from the micro,meso and macro levels with four different wetting agents as variables.The main research contents are as follows:(1)Three kinds of curing environments(standard curing environment,low temperature environment and dry hot environment)were designed in the experiment.The interfacial bonding properties between basalt fiber and cementitious matrix were investigated by fiber pull-out test,theoretical analysis and SEM micro test technology with the length of fiber buried depth,age and type of sizing agent as variables,according to the experimental results,the influence of various parameters on the fiber cement bond performance was analyzed.The results showed that: through the analysis of the test and SEM micro morphology observation technology,the diversity of wetting agent,the bond failure form and bond strength of fiber cement matrix was obvious remarkably.Synthesizing the experimental results under different curing conditions,the order of bonding strength of basalt fiber with four kinds of sizing agents is as follows: 2 #DBF > 3 #FBF> 4 #ABF> 1 # CBF.(2)Through the experimental study on the basic mechanical properties of basalt fiber concrete mixed with different infiltrating agents in low temperature and normal temperature curing environment,the relevant parameters of internal pore space structure of basalt fiber concrete samples with different infiltrating agents are qualitatively and quantitatively analyzed by CT scanning technology,pore structure analysis software and MATLAB program,The results showed that the increase of fiber was more significant for ordinary concrete;Considering the influence of four kinds of infiltrating agent fiber on ordinary concrete under different curing environment,the properties influence of basalt fiber with four kinds of infiltrating agent is as follows: 2 # > 3 # > 4 # > 1 #,and the influence of different infiltrating agent fiber on the pore structure parameters of specimens was also evident from the micro level,Among them,2 #sizing agent fiber performed well,and the pore structure parameters were better than other sizing agent fibers.Therefore,the bond behavior of basalt fiber chopped cement-based materials with different wetting agents is consistent with that of basalt fiber ordinary concrete and BFRC beams,which verifies the importance of optimizing basalt fiber chopped strand wetting agent interface for improving the mechanical properties of basalt fiber concrete.(3)By making four kinds of short cut basalt fiber reinforced concrete beams with different wetting agents,the bending performance of the beams was investigated.In addition,DIC technology is used to monitor the whole process of the test beams,and the displacement vector field,strain and displacement field in the observation area are calculated and analyzed.The results showed that the flexural properties of BFRC beams with different wetting agents were notably different,but better than ordinary RC beams.Furthermore,the control of crack development and the ability of anti-deformation were prominently improved.Among them,2# and 3 # had the most conspicuous promotion effect.