Research On The Impact Of Viscoelastic Layer On The Impact Resistance Of Cement-Based Materials

General cement-based materials,such as cement concrete,cement mortar,etc,commonly have greater brittleness,leading to the disadvantage of poor impact resistance,which makes the application of cement-based materials in structures subjected to dynamic and impact loads restricted to a great extent.So doing researching on improving the impact resistance of cementbased materials has important engineering practical significance.Viscoelastic material is a kind of excellent performance damping material,which has the dual characteristics of elastic energy storage and viscous energy consumption under impact,this characteristic makes viscoelastic materials still have good impact resistance in a small thickness range.According to the characteristics of viscoelastic materials and the theory of composite materials,this paper studies the method of incorporating viscoelastic materials in ordinary cement-based materials,the viscoelastic material layer is incorporated into the cement-based material as a structural sandwich to try to improve its impact resistance.When a cement-based test specimen containing a viscoelastic layer is subjected to an impact,the viscoelastic layer can absorb and consume impact energy through its own viscoelasticity,on the other hand,it can also block the expansion of impact energy and impact damage.This paper first introduces the mechanical characteristics of viscoelastic materials and then analyses the principle of damping energy consumption,based on this,firstly use the ABAQUS finite element analysis software to conduct a simple simulation analysis on the impact resistance of the cement-based material mixed with the viscoelastic layer,the analysis results initially confirmed the feasibility of the viscoelastic layer to improve the impact resistance of the cement-based material.Subsequently,the impact resistance of cement-based materials mixed with viscoelastic layer was tested,using cement mortar as the cement substrate and rubber layer as the viscoelastic layer,a cement mortar test piece containing a viscoelastic layer was prepared by using a self-made mold,the impact resistance of ordinary cement-based test specimens and cement-based test specimens containing viscoelastic layer was compared by drop weight impact test,and the effects of the thickness of the viscoelastic layer and the distribution position of the viscoelastic layer on the test specimens were studied.The test results show that the viscoelastic layer has the effect of improving the impact resistance of cement-based materials,and the degree of improvement is related to the thickness of the viscoelastic layer and the distribution position of the viscoelastic layer in the cement-based specimen.When the total size of the test piece and the position of the viscoelastic layer are constant,properly increasing the thickness of the viscoelastic layer will improve the impact resistance of the cement-based material,but when the thickness exceeds a certain range,the impact resistance of the test piece will no longer increase but will decrease;When the total size of the piece and the thickness of the viscoelastic layer are constant,the closer the viscoelastic layer is to the impact surface of the test piece,the better the impact resistance of the specimen,the impact resistance is best when the viscoelastic layer is located on the impact surface of the test piece,compared with ordinary mortar specimens,the strength loss rate after impact is reduced by about 92%,as the viscoelastic layer moves downward from the impact surface of the test piece,the impact resistance of the test piece gradually decreases.The test results are basically consistent with the numerical simulation results,demonstrating the effect of viscoelastic layer on improving the impact resistance of cement-based materials,so it provides a basis for the application of cement-based materials in structures subjected to dynamic and impact loads.