| At present,China is vigorously promoting the development of prefabricated buildings.In this process,the development of external wall panels as an important part of prefabricated buildings is relatively lagging,which seriously restricts the rapid development of prefabricated buildings.Currently,external wall panels commonly used in engineering exist.The following shortcomings:(1)The weight of the single material wallboard is too large,and the thermal insulation performance is difficult to meet the requirements;(2)The out-of-plane mechanical performance of the composite sandwich insulation wallboard needs further research;(3)Most The material properties of the thermal insulation layer and the inner and outer leaf wallboards of the combined sandwich insulation wallboard are quite different,which affects the prefabricated production efficiency.In order to solve the above problems,this article relies on the Jiangsu Construction System Science and Technology Project "Research on the Integrated Composite Exterior Wall System for Prefabricated Frame Structure Housing Enclosure and Insulation"(2018ZD096),and the Yangzhou Science and Technology Plan Project "Energy-saving Decoration Integrated Composite Concrete Exterior Wall Panel Design And production key technology research "(2017062),proposed a new type of composite thermal insulation hanging wall panel-dark rib sandwich composite concrete hanging wall panel(referred to as:dark rib sandwich external wall panel).The wallboard uses light aggregate concrete as the structural layer(hereinafter,the inner structural layer and the outer structural layer are called inner leaf and outer leaf,respectively).The inner and outer structural layers are framed with reinforced truss to form a cavity,and the cavity is filled with polyphenyl particles The concrete acts as an insulation layer,and the steel truss forms dark ribs to ensure that the wall panels work together under internal and external structural layers.The material characteristic of the wallboard is that the wallboard structure layer is made of lightweight aggregate concrete,and the thermal insulation layer is made of polystyrene particle concrete.The structural characteristics of the wallboard are that the inner and outer leaves of the wallboard and the four frames are made of lightweight aggregate concrete,and the polystyrene particle concrete is filled in the closed cavity inside the wallboard.The piece can more effectively connect the inner and outer leaf wall panels to form a dark rib cavity structure,and improve the mechanical performance of the wall panel.The research work and results of this paper have the following aspects:(1)Preparation of wallboard materials.The single factor analysis method was used to prepare LC30 grade,dry density less than 1800kg/m3,slump 80～100mm,good workability of lightweight aggregate concrete,and meet JGJ/T458-2018 "Precast concrete external wall panel application technology The technical requirements of the Standard.Studies have shown that the optimal water-to-binder ratio is 0.27,the optimal sand rate is 34%,and the cementitious material is 460 kg/m3.Based on the previous research on the mixing ratio of polystyrene particle concrete,the preparation process of polystyrene particle concrete was improved to prepare polystyrene particle concrete that meets the requirements of JGT 158-2013 "Rubber powder polystyrene particle exterior insulation system materials".(2)Basic performance research of wallboard materials.The test measured the compressive strength,axial compressive strength,splitting strength,elastic modulus,Poisson’s ratio,and uniaxial compressive stress-strain curve of the lightweight aggregate concrete cube.The research shows that the compressive strength of the lightweight aggregate concrete cube is 38.3MPa,the splitting strength is 2.67MPa,the axial compressive strength is 33.65MPa,and the elastic modulus is 2.47×1010Pa,which satisfies JGJ/T458-2018 "Precast Concrete External Wall The mechanical performance requirements of "Slab Application Technical Standard",and fit the light-weight aggregate concrete uniaxial compressive stress-strain full curve.The thermal conductivity of the lightweight aggregate concrete measured by the test is 0.328～0.385W/m·K,and the thermal conductivity of the polystyrene granular concrete is 0.083～0.092W/m·K,both of which are in line with JGJ134-2010 Thermal performance requirements of the "Regional Residential Building Energy Efficiency Design Standards".(3)Experimental study on the flexural performance of dark rib sandwich external wall panels.In order to reasonably design the structure of the wallboard,study th e influence of the thickness of the inner and outer leaves of the wallboard and the layout of the middle steel truss truss on the mechanical performance of the wallboard,four 1/2-reduced-size wallboards were designed.Mechanical performance under out-of-plane loading.The research shows that the bearing capacity of the wallboard is more sensitive to the thickness of the inner and outer blades.At the same time,the arrangement of steel truss inside the wallboard can effectively improve the performance of the inner and outer blade wallboards working together and increase the bearing capacity of the wallboard.(4)Finite element simulation of the bending performance of dark rib sandwich external wall panels.With the help of ABAQUS finite element simulation software,the finite element model of 4 wall panels was established.Based on the method of nonlinear analysis,the simulation results of the wall panel were compared with the test results.Degree is good.(5)Research on the application of dark rib sandwich external wall panels.Compare the advantages of the dark rib sandwich external wall panel made in this paper with the ordinary concrete external wall panel in terms of mechanical performance and thermal performance,and give the future dark from the five aspects of material,design,production,transportation and installation.It is recommended that rib sandwich wall panels are used for mass production. |
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