| In order to promote the scientific utilization of aeolian sand resources in concrete frame structures,this paper proposes basalt fibre aeolian sand concrete columns.Aeolian sand from the Kubuqi Desert and chopped basalt fiber were selected as the test materials,and basalt fiber aeolian sand concrete cube test blocks and standard prismatic test blocks were produced,and the mechanical properties and stress-strain relationship of basalt fiber aeolian sand concrete were studied.After completing the above material test content,4specimens of basalt fiber aeolian sand concrete column were designed and manufactured and various test data of 4 specimens of ordinary aeolian sand concrete column specimens produced by this research group in the same batch were introduced.The low-cycle repeated load test was carried out under the same test conditions,the seismic performance of each specimen was compared and analyzed,and the damage model of the basalt fiber aeolian sand concrete column was established on the basis of the test to analyze the seismic damage of the specimen degree.Finally,the ABAQUS finite element simulation software is used to perform nonlinear analysis on the basalt fiber aeolian sand concrete column,and then the simulation results are compared with the test results to study the influence of different parameters on the seismic performance of the specimen.Suggestions are given for the composite application of the two materials.The specific research result as follows:1.Experimental study on the stress-strain relationship of basalt fiber aeolian sand concrete.The basalt fibre aeolian sand concrete specimens and the ordinary aeolian sand concrete specimens were made for mechanical performance test,its compressive performance and stress-strain relationship were studied.The stress-strain curve measured in the test was fitted with data,and the stress suitable for this study was stress-strain relationship.The test results show that with the increase of the aeolian sand replacement percentages(10%-50%),the compressive strength of the concrete specimens increase first and then decrease,and research the peak when the aeolian sand replacement percentage is30%.The incorporation of basalt fibre is beneficial to increase the compressive strength by12.3%.2.Seismic damage behaviour of aeolian sand concrete column mixed basalt fiberFour specimens of basalt fiber aeolian sand concrete column were designed and manufactured(The same basalt fiber content and different aeolian sand replacement percentage).Low-cycle repeated load tests were carried out under the same test conditions.The test data of the 4 ordinary aeolian sand concrete column specimens that was completed in the previous stage of research is introduced.The failure process,hysteresis characteristics,bearing capacity,ductility performance,and stiffness degradation of each specimen were compared and analyzed.The damage model of the basalt fibre aeolian sand concrete column was established on the basis of the experiment.The research results show that the quantitative addition of 0.15% basalt fiber can effectively improve the seismic performance of aeolian sand concrete columns,reduce the width of cracks and the damage of the specimens.It can effectively prevent concrete spalling and improve the brittleness of concrete.The combination of the two materials is the best when the aeolian sand replacement percentage is 30%,the damage model established is in good agreement with the test results,which can provide a basis for related research.3.Finite element analysis of aeolian sand concrete column mixed basalt fibreThe low-cycle cyclic loading simulation analysis of the basalt fibre aeolian sand concrete column was carried out by the ABAQUS finite element simulation software.Then,comparing the simulation results with the test results,it is found that the skeleton curve obtained by the simulation has the same changing trend as the test skeleton curve,which can better reflect the failure process and characteristics of the specimen under actual test conditions.It is confirmed that the simulation results are in good agreement with the experimental phenomena,and the rationality of the built model is verified.The stress and strain cloud diagrams in the simulation results are analyzed to further reveal the seismic damage mechanism of basalt fiber aeolian sand concrete columns.On this basis,by changing the material parameters and test conditions of the model,the influence of other factors on the simulation results is analyzed.The results show that with the increase of concrete strength grade and longitudinal reinforcement diameter,the seismic performance of the model has been improved differently;Within a certain range,as the axial compression ratio increases,the load-bearing capacity of each stage is improved,but the ductility performance is not significantly improved.Among them,the effect of improving the strength level of concrete to improve the seismic performance is the most significant. |
