Experimental Study On Dynamic Mechanical Properties Of Desert Sand Concrete Under Impact Load

In actual engineering construction,in addition to static load during service,concrete may also suffer damage and damage caused by dynamic loads such as earthquakes and impacts.Therefore,the research on the performance characteristics of concrete under impact load is particularly important.In recent years,with the construction and development of infrastructure,the amount of concrete has increased dramatically,and there is a serious shortage of construction sand.Northwest China has abundant desert resources.If the abundant local desert sand can be used to replace construction sand to prepare desert sand concrete suitable for engineering applications,it will be of great significance to the rational use of resources and the reduction of project costs.In this paper,a drop-weight impact testing machine is used to study the mechanical properties of desert sand concrete with different desert sand replacement rates under impact load.The main research contents are as follows:(1)The dynamic flexural strength test of desert sand concrete under impact load was carried out,and the influence of impact load,deflection,dynamic strength growth factor and strain rate on the dynamic flexural strength of desert sand concrete was analyzed.The test results show that the impact load of desert sand concrete increases linearly with the increase of the height and weight of the drop hammer.Under the impact load,the deflection of desert sand concrete increases with the increase of drop hammer height and weight;the deflection of the specimen first increases and then decreases with the increase of the desert sand replacement rate.When the desert sand replacement rate is 40%,the impact After the load,the desert sand concrete has the largest deflection.The dynamic strength growth factor of desert sand concrete under impact load increases with the increase of the strain rate of desert sand concrete,which reflects the rate effect of desert sand concrete.(2)By analyzing the energy absorption of desert sand concrete under impact load,observe the specimen cracks after impact,and study the relationship between energy absorption rate and drop hammer height,hammer weight and desert sand replacement rate.The relationship between the damage degree of sand concrete and impact energy.Research shows that the energy absorption rate of desert sand concrete decreases with the increase of the height of the falling hammer,and increases with the increase of the weight of the falling hammer.With the increase of the desert sand replacement rate,it first increases and then decreases.As the impact energy increases,the damage degree of the specimen is greater.(3)The compressive strength test of desert sand concrete after impact load was carried out,and the factors affecting the compressive strength were analyzed.The test results show that the compressive strength of desert sand concrete increases first and then decreases with the increase of desert sand replacement rate after impact load,and gradually decreases with the increase of drop hammer height and weight.