Mechanical Properties And Finite Element Analysis Of PP Fiber Reinforced Volcanic Scoria Concrete After High Temperature

Volcanic scoria concrete has attracted more and more attention because of its light weight,high temperature resistance,energy saving and environmental protection characteristics,and its engineering application also conforms to the national policy of vigorously developing green buildings.Volcanic scoria concrete not only has good heat insulation and high temperature resistance,but also can meet the load-bearing requirements of general structure.Based on the relevant results of lightweight aggregate,the basic mechanical properties of volcanic scoria concrete are studied through experiments.On the basis of the basic mechanical parameters,the seismic performance of the beam column joints after high temperature is analyzed,which provides a reference for the follow-up research on the fire resistance of the structure1.Taking ordinary concrete as the control group,the experimental phenomena and apparent characteristics of volcanic scoria concrete at high temperature were studied.In the high temperature test,it is observed that the two kinds of concrete show similar change rules in the process of heating up,and the apparent characteristics of the test block after high temperature are obtained.2.In order to analyze the working mechanism of polypropylene fiber in volcanic scoria concrete,the micro images of volcanic scoria concrete samples under different temperatures were obtained by scanning electron microscope.Through the temperature acquisition instrument to record the internal temperature changes of concrete blocks,according to the test results,the temperature difference between the two kinds of concrete core area is analyzed,which shows that the volcanic scoria concrete has better fire resistance than ordinary concrete.3.In this paper,the basic mechanical properties of normal temperature and after high temperature volcanic scoria concrete are studied.The compressive strength,splitting tensile strength,elastic modulus and stress-strain curve of normal temperature and after high temperature volcanic scoria concrete are obtained.The advantages and disadvantages of high temperature volcanic scoria concrete compared with ordinary concrete are analyzed.The results show that:after high temperature,the strength of volcanic scoria concrete and ordinary concrete show a downward trend,and the splitting tensile strength of the test block is higher than the compressive strength.In the prism axial compression test,with the increase of temperature,the stress-strain curve flattens,the peak point of the curve moves down,the peak strain increases and the elastic modulus decreases.However,the flattening rate and peak value of the stress-strain curve of volcanic scoria concrete are lower than that of ordinary concrete.4.ABAQUS finite element software is used to simulate the high temperature test of concrete test block.According to the known thermal parameters,the calculation model of temperature field is established according to the actual working conditions,and the correctness and feasibility of the temperature field model are verified.The distribution law of internal temperature field of volcanic scoria concrete test block after high temperature is analyzed and summarized,which provides the seismic model for subsequent volcanic scoria concrete beam-column joints It lays a foundation for calculation and analysis.5.Considering the bond slip between reinforcement and concrete after high temperature,the spring element is used to simulate the bond slip between reinforcement and concrete.According to the thermodynamic parameters obtained from the test,the seismic simulation calculation of the concrete beam-column joint after high temperature is carried out based on the finite element numerical simulation method.The correctness and feasibility of the seismic model of the beam-column joint are verified by comparing with the experimental data of other scholars.This method is used to establish the seismic calculation model of concrete beam-column joint after high temperature,and analyze the seismic performance of volcanic scoria concrete beam-column joint after high temperature.