Research On Properties Of Thermal Insulation Formwork Based On Graphite Polystyrene Board

During the winter construction of concrete,due to the external low temperature,the cement hydration process is slow during the curing period,and the mixing water is frozen,which affects the performance and strength of concrete materials.However,there are still some problems in the existing thermal insulation and maintenance measures: complex form,high cost,low turnover rate,not conducive to energy conservation and emission reduction.In this paper,a practical thermal insulation formwork with simple structure is designed by combining formwork and thermal insulation materials,and its thermal performance and mechanical performance under different load conditions are studied to optimize the size of formwork components and the thickness of thermal insulation material layer.The purpose of this study is to provide design ideas for practical projects.The specific research contents and conclusions are as follows:(1)The overall structure is sandwich embedded type.The components of the formwork from the inside to the outside are: internal formwork,thermal insulation core material,and external formwork.The back of the internal and external formwork is welded with thin-walled steel ribs to provide support for the formwork.The adjacent formwork joints are covered with flexible thermal insulation cotton with back glue;At the same time,the density,thermal conductivity and cost per cubic meter of common thermal insulation materials are analyzed,and the insulation core material is determined to be graphite polystyrene board.Finally,the strength,stiffness and durability of the overall formwork are considered,and the internal and external formwork is determined to be steel formwork.(2)The thermal performance formula is used to calculate the equivalent heat release coefficient of the insulation layer of the thermal insulation formwork and the joint,and a scaled down test piece is made to verify the theoretical calculation results.After further research,it was found that the proportion of factors affecting the equivalent heat release coefficient of the template is in order of the height,width,and spacing of the steel ribs.Then,the concrete cooling temperature calculation and strength prediction program is designed based on Python language,The limit value of the equivalent heat release coefficient when the concrete reaches the freezing critical strength is 1.3412.Finally,according to the weight of the influencing factors,the reasonable form and size range of steel bars are obtained.(3)ANSYS software is used to model the combined assembly of thermal insulation formwork and the corresponding support system in the actual project,and the stress of each component of the formwork under different working conditions is studied.It is concluded that the maximum deformation and maximum stress occur in the inner steel formwork;Secondly,change the size and spacing of steel bars in the internal steel formwork.According to the proportion of factors affecting the strength and stiffness of the formwork,optimize the size in order within the scope of thermal performance analysis,and determine the spacing of internal steel bars as 200 mm ×300mm,15 mm and 3mm in height and width,and the thickness of insulation layer is reduced to 30mm;Finally,keep the above dimensions unchanged,and then study the influence of the size and spacing of the steel ribs of the external steel formwork on the overall strength and stiffness of the formwork,and determine the spacing of the external steel ribs as 200 mm × 300 mm,30mm and 3mm in height and width.Figure [90] Table [29] Reference [80]...