Research On Key Technologies Of Prestressed Lightweight Aggregate Concrete Sandwich Wall

With the government vigorously promoting the construction of new urbanization and sustainable development of buildings,assembly building has been more and more widely used.Most of the prefabricated sandwich thermal insulation wallboards are made of ordinary concrete,which is small in scale,heavy in weight and difficult to hoist.The application of high performance lightweight aggregate concrete in thermal insulation wallboard can effectively reduce the self-weight of wallboard.However,the shrinkage of prefabricated lightweight aggregate concrete members is large,and cracks are easy to occur during production and transportation.Therefore,this paper proposes a sandwich thermal insulation wallboard of pre-stressed lightweight aggregate concrete.Prestressing in lightweight aggregate concrete sandwich insulation wallboard can improve crack resistance,expand the surface tension of prefabricated wallboard,and meet the requirements of light weight,high strength,building energy saving and green building materials.Therefore,this paper has important practical significance to study the basic mechanical properties of the pre-stressed lightweight aggregate concrete sandwich insulation wallboard.Firstly,on the basis of reading the relevant literature,through the use of theory to design the initial mix ratio of lightweight aggregate concrete,the orthogonal experimental study of lightweight aggregate concrete was carried out.The effects of sand ratio,water cement ratio and water reducing agent on the mechanical properties of lightweight aggregate concrete were mainly studied,and the mix ratio was optimized with engineering experience to determine the final mix ratio.Secondly,based on the finite element analysis software ABAQUS,a refined model of pre-stressed lightweight aggregate concrete sandwich thermal insulation wallboard was established.The effects of the layout of pre-stressed tendons,the spacing of pre-stressed tendons and the tension force on the mechanical properties of the pre-stressed lightweight aggregate concrete sandwich wallboard were mainly studied,and the design scheme of the specimens was selected.Thirdly,the out-of-plane bending test of the pre-stressed lightweight aggregate concrete sandwich thermal insulation wall slab specimens was carried out to observe the crack development,width and displacement changes of the specimens,and to collect the out-of-plane load,mid-span displacement,joint strain and reinforcement strain of the specimens.Based on the analysis of experimental phenomena and data,the effects of prestressing on crack resistance,bearing capacity,ductility and composite properties of lightweight aggregate concrete were studied.Compared with the numerical analysis results,it was found that the experimental results were in good agreement with the numerical analysis results,which indicated that prestressing could effectively improve the crack resistance and bearing capacity of lightweight aggregate concrete sandwich wall slabs.Aggregate concrete sandwich insulation wallboard showed good ductility and high degree of combination.It showed that the mechanical performance of the wallboard meets the design requirements.Finally,combined with the preparation and construction technology of lightweight aggregate concrete,the manufacturing method of pre-stressed lightweight aggregate concrete sandwich insulation wall board was proposed.