The Research Of The Influence On Constitutive Relation Of Bearing And Thermal Insulation Glazed Hollow Bead Concrete By Freeze-Thaw

Bearing and thermal insulation glazed hollow bead concrete,which combines bearing with thermal insulation capacity,is a kind of green building material.It can not only be used as the structural bearing component of building like ordinary concrete,can but also meet the thermal insulation requirement of building with its low thermal conductivity after casting molding,and can more make the tricky hot and cold bridge in the other thermal insulation measures to be resolved.In the background of in the current society the development of energy-saving and emission-reduction to be advocated,the reduction of building energy consumption to be devoted and the promotion of new green building material to be focused on,the important practical significance and broad market prospect must to be possessed by bearing and thermal insulation glazed hollow bead concrete.In the concrete structural design and nonlinear analysis,the most basic physical-mechanical properties of concrete are reflected by its uniaxial compressive constitutive relation,which is the foundation of concrete structural analysis and technology as well as safety design.The durability of concrete in the chilling and cold area can be understood helpfully by the study of its constitutive relation,which can provide the foundation for the scientific assessment,life prediction and durability design of concrete structure.Departed from this focus,the uniaxial compressive constitutive relation of bearing and thermal insulation glazed hollow bead concrete and the influence produced by freeze-thaw are researched by the constitutive relation experiment of plain concrete and reinforced concrete before and after freeze-thaw.The main works are as follows:(1)The plain concrete freeze-thaw test is to be designed two strength grades and five freeze-thaw circle times,so that its freeze-thaw damage morphology can be analyzed,its mass loss rate and strength loss value can be determined and its stress-strain curve can be recorded,thus in this foundation the uniaxial compressive constitutive relation model of concrete before and after freeze-thaw can be established as well as the effect on physical-mechanical properties of thermal insulation concrete by freeze-thaw circle times can be confirmed.(2)The reinforced concrete specimens confined by stirrups are designed,and through the rapid freeze-thaw test,the failure characteristics of reinforced concrete specimens can be analyzed,as well as the similarities and differences of plain concrete and reinforced concrete in the respects of peak stress,peak strain and nonlinear feature can be compared.(3)According to the relevant specifications,the 12 standard prism specimens of the two groups of C35 and C40 are designed in order to determine the elastic modulus of bearing and thermal insulation glazed hollow bead concrete in normal temperature.Through the experiment and the post-processing and analysis of data,the conclusions received are as follows:(1)After 100 times and below freeze-thaw cycle,the surface morphology of bearing and thermal insulation glazed hollow bead concrete is almost intact,and the main phenomenon is the flaking of glazed hollow bead and the appearance of some small pot holes in the specimen surface.And after 300 times freeze-thaw cycle,it is only showed that the pot holes of specimen surface are increased,and compared with ordinary concrete,whose surface has been revealed most of the coarse aggregate after 300 times freeze-thaw cycle,the frost resistance of bearing and thermal insulation glazed hollow bead concrete is more excellent,and the surface spalling of thernal insulation is relatively minor as well as the effect produced by freeze-thaw damage is smaller after the same freeze-thaw times.(2)The elastic modulus of the groups of C35 and C40 c2.49×104MPa and 2.59×104MPa,which are the average values of the block test oncrete are data,and the poisson's ratio are 0.15 and 0.12.(3)The fitting of the uniaxial stress-strain curves of C35,C40 and C40A blocks is proceeded by using the software,so that the corresponding parameters of upward section and downward section can be received and the relevant constitutive model can also be established.For the C40A blocks,owing to the hoop effect of stirrups,the upward section of curve is plumper than the blocks of C35 and C40,and the restraint effect of downward section is more obvious.