Mechanical properties analysis of polypropylene foamed concrete for tunnel damping layer
Tunnel damping layer is an important measure to improve the seismic performance of tunnels in high-intensity earthquake areas.The material performance of damping layer is an important factor affecting the damping effect of tunnels.In order to explore a polypropylene foam concrete suitable for tunnel damping layer,its preparation process and mechanical energy absorption characteristics were analyzed.Based on the volume content index of polypropylene foam,a variety of volume content of polypropylene foam concrete was prepared by substitution stone method.The changes of apparent density,compressive strength,elastic modulus,Poisson's ratio,static and dynamic energy absorption characteristics with the volume content of polypropylene foam were verified by experiments.The results show that when the volume content of expanded polypropylene(EPP)increases from 0 to 28%,the apparent density is from 2 331 kg/m3 to 1 451 kg/m3,the compressive strength is from 54.5 MPa to 11.2 MPa,the tensile strength is from 3.6 MPa to 1.6 MPa,the elastic modulus is from 34.0 GPa to 16.0 GPa,and the Poisson's ratio is from 0.19 to 0.28.The relationship between the physical and mechanical properties and the volume content of EPP is established.With the increase of EPP volume content,the static energy absorption of concrete increases first and then decreases and then increases.When the EPP volume content is 11%,the static energy absorption effect is the best.With the increase of EPP volume content,the dynamic energy absorption of concrete gradually increases.When the EPP volume content is 28%,the dynamic impact energy absorption effect is the best.The research results can provide theoretical basis for the application of polypropylene foam concrete as energy absorption material.
tunnel damping layerpolypropylene foam concretephysical and mechanical propertiesenergy absorption characteristics
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