Study On Performance And Application Of Fiber Reinforced Self Compacting Lightweight Concrete

In recent years,with the introduction of environmental protection policies such as energy conservation and emission reduction and sustainable development in urban construction,engineering technology in the construction industry is also undergoing continuous innovation.Taking Huoshenshan/Leishenshan hospital,which miraculously completed the modular construction within 10 days,prefabricated building construction is becoming the development trend of construction industrialization.Although ordinary concrete has the disadvantages of self weight,insufficient toughness and poor crack resistance,these shortcomings greatly restrict the application of traditional concrete in prefabricated building structures.The self compacting lightweight concrete studied in this paper is based on the optimal mix proportion obtained by using Design-Expert 10.0,adding different kinds of fibers,and adjusting the dosage of superplasticizer to achieve excellent self compacting performance.Meanwhile,the self compacting light aggregate(SCLC)reinforced by polyvinyl alcohol fiber,steel fiber and polypropylene fiber is compared and analyzed.In this paper,the working performance,basic mechanical properties and shrinkage performance of concrete are analyzed,and the bending performance of profiled steel sheet fiber reinforced SCLC composite floor is analyzed by numerical simulation,which provides experimental basis and theoretical support for the application of this new type of profiled steel sheet concrete composite floor in prefabricated structure.The specific conclusions are as follows:(1)By using BBD analysis in design expert 10.0 software,the workability and mechanical properties of self compacting lightweight concrete are tested and studied by selecting three influencing factors:Volume sand ratio,cementitious material dosage and net water consumption.The optimal prediction of mixproportion of self compacting lightweight concrete is found out by variance analysis of linear model,interaction response surface and contour map The volume sand ratio of the benchmark self compacting lightweight concrete is 45.9%,the dosage of cementitious material is 518.5kg/m3,and the net water consumption is 183.6kg/m3.(2)On the premise of meeting the working performance requirements of fiber reinforced self compacting lightweight concrete,the optimal dosage of each fiber and superplasticizer are determined as follows: polyvinyl alcohol fiber 0.05% + water reducing agent 1.2%,steel fiber 0.6% + water reducing agent 0.9%,polypropylene fiber 0.06% + water reducing agent 1.1%.(3)Through the comparative analysis of the workability test,mechanical property test and shrinkage test results of benchmark SCLC,polyvinyl alcohol fiber reinforced SCLC,steel fiber reinforced SCLC and polypropylene fiber reinforced SCLC,it is found that the incorporation of fiber will significantly affect the working performance of SCLC,while on the premise of ensuring the self compacting performance of SCLC,polyvinyl alcohol fiber reinforced SCLC and polypropylene fiber reinforced SCLC are improved The cube compressive strength of olefin fiber reinforced SCLC increased by 1.6% and 1.9% respectively,while that of steel fiber reinforced SCLC decreased by 0.79%.The splitting tensile strength and flexural strength of fiber reinforced SCLC were significantly improved,and the increase of steel fiber reinforced SCLC was the most obvious.The splitting tensile strength and flexural strength were increased by 18.4%and 16.7%,respectively.The axial compressive strength and elastic modulus of polyvinyl alcohol fiber reinforced SCLC and steel fiber reinforced SCLC slightly increased by 3%,3.3% and 6.7% and 7.5%,respectively,while polypropylene fiber reinforced SCLC decreased by 1% and 0.94%.The shrinkage test results showed that the addition of steel fiber,polyvinyl alcohol fiber and polypropylene fiber significantly inhibited the early expansion and shrinkage of SCLC,and the effect of steel fiber was the most obvious.(4)ABAQUS software is used to analyze the bending performance of profiled steel sheet fiber reinforced SCLC composite floor,and the equivalent stress nephogram and load deflection curve under different section forms of profiled steel sheet and different types of fiber reinforced SCLC floor are obtained.The analysis results show that when the thickness of profiled steel sheet and fiber reinforced SCLC floor are fixed,compared with dovetail profiled steel sheet fiber reinforced s The bearing capacity of CLC composite floor and closed profiled steel sheet fiber reinforced SCLC composite floor are better.The flexural capacity of the normal section of the closed profiled steel sheet fiber reinforced SCLC composite floor increases with the increase of the thickness of the fiber-reinforced SCLC floor,and the deflection at the peak load decreases obviously.That is to say,the thickening of the fiber-reinforced SCLC floor can significantly improve the overall bending capacity of the composite floor and reduce the deformation.Although the self weight of the composite floor increases to a certain extent,but the Fiber reinforced SCLC floor is just to make up for this defect,so it has a broad application prospect in prefabricated building.