Experimental Study On Dynamic Splitting Tensile Properties Of Barite Concrete

Barite concrete is a new specialty material in recent years and which is widely used in medical and nuclear power engineering.It is of great significance to study the splitting tensile properties of barite concrete under dynamic load and explore the inherent laws between the fractal characters of barite concrete surface crack graph and its working load.In this paper,the dynamic splitting tensile properties of barite concrete is studied by carrying out the falling hammer impact splitting tensile experiment,and the fractal theory is introduced to analyze the fractal characteristics of the surface crack pattern.The main contents are as follows:?1?The static test of barite concrete and concrete were completed,which get its compressive strength and splitting tensile strength.The test results show that the compressive strength and splitting tensile strength of barite concrete are lower than that of ordinary concrete under the same water-cement ratio.?2?The splitting tensile strength test of barite concrete and concrete specimen was completed by using the drop hammer tester,with a strain rate from 1S^-1 to 4S^-1.The quality and height of the drop hammer are the change parameters.A high speed camera is used in tests to record the whole process of the specimen surface cracks development during the impact process,the force-time history and the tensile strain-time history are recorded by measuring.The test results show that the impact force peak and the load rate of the specimen increase with the increase of the quality and height of drop hammer.?3?In this paper,the experimental data of barite concrete and concrete under the same impact condition are analyzed.It is proved that both of them have good strain rate effect,and their dynamic enhancement coefficient?DIF?increase with the increase of the strain rate.?4?The experimental results indicate that the surface crack distribution of barite concrete under the impact load exhibits fractal properties,and the fractal dimension can be used as a description parameter of the damage degree.The fracture fractal dimension increases with time under the same impact condition,and when it is under different impact conditions,it increases with the increase of the quality and height of drop hammer.?5?The fractal dimension of the crack on the surface of the barite concrete under the impact load is related to the strain rate,which increases with the increase of the strain rate,but the fractal dimension of the first fracture of the specimen is almost the same.?6?When the box dimension is calculated using the conventional digital image method,the calculation result is liable to be affected by the width of the crack.After the edge detection operator is introduced,the box dimension value with more accurate and less error can be obtained.