Study On Rheological Behavior And Constitutive Model Of Desert Sand EPS Concrete

In view of the current research on desert sand EPS concrete,the research on macroscopic mechanical properties of EPS concrete is mostly focused on durability,its rheological properties and its constitutive model are not comprehensive.The strength and deformation of concrete are the entry points.Based on the related research results of geotechnical mechanics and concrete materials,the combination of experimental research and theoretical analysis is adopted.The axial compression is the main method,and the center of gravity is concentrated in the desert under compressive stress.The conventional mechanical and rheological properties of desert sand EPS concrete were studied in the deformation evolution and strength attenuation of sand EPS concrete.Combined with the experimental results,the relevant constitutive model was established.The results show that compared with ordinary concrete,there is obvious compaction process in the front part of the stress-strain curve of desert sand EPS concrete.After the peak stress decays to40%~60% of the peak stress,it begins to show more ductility.There are many compaction-destruction processes,which are not applicable to desert sand EPS concrete before the common ordinary concrete constitutive model is modified.The creep curves of different density test blocks under different constant stress levels are similar and low.Under the stress level,the test block curve shows attenuated creep.Under the high stress level,the creep curve of the test piece exhibits attenuated creep and steady-state creep.Under the last stress,the test block curve shows accelerated creep;in the creep test The desert sand EPS concrete test block exhibits obvious viscoelastic characteristics and can be approximated as a nonlinear viscoelastic body.The Burgers model can better describe its creep characteristics;the stress of different density test blocks at different constant strain levels The relaxation curve and the stress relaxation law are similar.The curve consists of two parts: attenuation relaxation and stable relaxation,and the stress relaxation phenomenon of the test piece along with the strain level The increase and density increase are more and more obvious.The generalized Kelvin model can better describe the stress relaxation characteristics of desert sand EPS concrete.