Performance Impact Analysis And Acoustic Characterization Of Basalt Fiber Reinforced Reactive Powder Concrete

With the increasing demand for new building materials around the world,Ultra-high Performance concrete has gradually gained wide attention and research applications.Among them,the Reactive Powder Concrete(RPC)as one of the most innovative of Ultra-high Performance concrete,with its extremely low porosity,high strength and high durability and other characteristics,to become the hot topic which the domestic and foreign researchers and engineers,and has a good application prospect.In this paper,the reactive powder concrete is modified with basalt fiber instead of steel fiber to further improve the performanc..The advantages of high corrosion resistance,good anti-permeability and high tensile strength of basalt fiber make up the disadvantages of easy corrosion and poor durability of steel fiber.A high performance road engineering material is designed to suit the climate characteristics of seasonal frozen zone.Acoustic emission,as an important nondestructive testing method,has many advantages such as high sensitivity,timely response and full cycle on-line monitoring.It has important research value and wide application prospect in the field of material and structural health monitoring.Unlike other technologies,acoustic emission is caused by the damage of material itself,which makes it more credible and is a hot research issue in the field of nondestructive testing.However,the research on acoustic emission characteristics of basalt fiber active powder concrete(BFRPC)is urgently needed.In this paper,based on the transportation science and technology project"Basalt Fiber Reactive Powder Concrete performance evaluation and the design method of structure research"of Jilin province transportation department.Using acoustic emission testing technology to studied the preparation methods,mechanical properties and acoustic emission properties of BFRPC,and explore the influence of different blending conditions on the performance of the pieces to provide basis for optimization of BFRPC configuration scheme.At the same time,it provides basic data and theoretical reference for the application of acoustic emission technology in the field of new concrete materials and structural health monitoring.The main research work carried out in this paper includes:(1)The proportion of water-binder ratio,sand,cement,silica ash and basalt fiber content is the factor,set the corresponding level,and 9 groups of experiments are designed to study the mix proportion of reactive powder concrete.The influence of the above factors and relative level on the working performance and mechanical properties of RPC mixer was determined.The effects of curing methods and aggregate types on BFRPC performance were studied.According to the experimental results,it is suggested that the optimal mix ratio of the active powder concrete with good fluidity and strength is water/cement ratio is 0.18.The ratio of sand,cement and silica fume is 1.3:1:0.4.Basalt fiber content is 10kg/m~3.Quartz sand as aggregate,60?hot water curing 48 h.(2)Based on the mixture ratio test of basalt fiber reactive powder concrete.By using acoustic emission technology,the influence of each proportion factor on the fracture is analyzed,and the fracture state is characterized.The bending fracture of concrete is divided into three stages:micro-crack generation stage,crack stable expansion stage,and fracture instability expansion stage.With the decrease of the ratio of water cement,the concrete specimen will produce less shear crack and more tensile crack during bending fracture.With the optimization of silica ash content,the number of cracks in the large stress interval(0.9-1.0stress interval)and the average value of each crack can be reduced.When the addition of silica fume is good,the shear fracture caused by the load fracture increases and the tension crack decreases.With the increase of quartz sand content,the average release energy of each crack gradually increased and the proportion of shear crack increased significantly within the range of 0.9-1.0 stress level.With the increase of fiber content,the shear crack in the fracture process of concrete specimens is increasing.(3)The acoustic emission parameters are processed by outlier analysis method,and the acoustic emission outlier is obtained and the warning values are determined based on it.When the outlier exceeds the warning value,the basalt fiber ractive powder concrete is seriously damaged.