Preparation And Stress Analysis On Stitching Seam Of Lightweight Partition Board Made Of Gypsum-based Composite Materials

Industrial by-product gypsum was a kind of solid waste containing calcium sulfate dihydrate as the main component.After calcination,it can be converted into calcium sulfate hemihydrate with good gelling properties and used for the production of prefabricated partition boards,which was in line with the development needs of building industry that the comprehensive utilization of resources can be realized.Gypsum-based partition wall panels often have poor water resistance,prone to creep in water,the strength of the decline in large and other issues in practical engineering applications,and in the process of use,cracks will occur at the joint due to load or non-load factors.Therefore,this paper carried out preparation and stress analysis on stitching seam of lightweight partition board made of gypsumbased composite materials.The main contents were as follows:(1)The composition and content of water-repellent agent for building desulfurized gypsum were determined by single-blending and double-blending methods: 2.5% of redispersible polymer powder and 0.9% of silicone powder.Through the single factor and orthogonal experiment,the optimal ratio of gypsum-based composite wall material was determined and the sample was prepared,which was tested to meet the specification requirements.(2)The hydration products and micromorphology of the gypsum-based composite were analyzed by SEM and XRD.It was found that the first supporting skeleton composed of the dihydrate gypsum crystal provide the pre-strength for the composite material,and the second supporting skeleton composed of ettringite and C-S-H gel provide the long-term strength.The incorporation of water repellent can form a hydrophobic film on the surface of the crystal structure,while the incorporation of mineral admixtures can compact the crystal structure and improve the water resistance of the composite.The hydration of the composite material produced curing and adsorption,which can inhibit the efflorescence.(3)The volume stability of gypsum-based composites was observed.The rule of variation was expanded firstly and then contracted.With the increase of cement content or the decrease of the volume content of vitrified microspheres,the maximum expansion and stable expansion of values gypsumbased composites increased,and it decreased when the composites mixed with fiber.(4)Based on the finite element software ABAQUS,the maximum stress value of vertical and horizontal splicing joint of the partition board in the extreme temperature and humidity environment were analyzed when used different bond mortar and laid fiber mesh cloth.The calculation showed that the maximum stress value of the joint when laied fiber mesh cloth and used polymer bonded mortar was lower than that when unlaied fiber mesh cloth and used cement bonded mortar,which were decreased by 89.64%~93.38% and 70.30%~81.73% respectively.