Experimental Study On Flexural Behavior Of HRB500 Reinforced LC40 High Performance Steel Fiber Reinforced All Lightweight Concrete T-beam

All Lightweight concrete(aLC)has been gradually applied to engineering structures due to its light weight,strong tensile strength and good compressive ductility.Steel Fiber Reinforced all lightweight concrete(SFRaLAC)prepared with steel fiber in LAC not only has the advantages of LAC,but also can significantly improve its brittleness.SFRaLAC can greatly reduce the weight of the structure,and has been widely used in the construction of super high-rise buildings,undersea tunnels and cross-sea Bridges.To popularization and application of steel fiber reinforced expanded-shale lightweight concrete(SFRaLAC)in structural engineering,ten reinforced SFRELC T--shaped beams were designed and experimental studied in this paper.The volume fraction of steel fiber was considered as the main parameter,which ranged from 0%to 2.0%with increment of 0.5%.This paper analyzed the cracking process,crack development,stress characteristics and failure morphology of SFRaLAC t-shaped beams,and studied the effect of steel fiber volume rate on the flexural performance of normal section of aLAC T-shaped beams.The conclusions are as follows:(1)The absolute volume method was used for SFRaLAC mix design to study the effect of the volume ratio of steel fiber on the basic mechanical properties of all-lightweight concrete.The results show that the mechanical properties of all-lightweight concrete can be improved by increasing the volume ratio of steel fiber.(2)The test results of normal section bending behavior of SFRaLAC T-shaped beam are as follows.The ultimate bending moment of the T-shaped test beam is consistent with the change trend of volume rate of steel fiber.According to the theoretical research and experimental analysis,the relevant model and corresponding calculation method of the force on the normal section of the T-shaped test beam studied in this paper are given,and the calculation formula of the ultimate bearing capacity based on the test results of the T-shaped test beam in this paper is proposed.(3)According to the cracking moment value of the pure bending section of 10 all-lightweight concrete T-shaped test beams in this paper,the effect of steel fiber on its crack resistance was studied.The test results show that SFRaLAC T-shaped beam has the same resistance to cracking as that of steel fiber.Combining theoretical calculation and analysis,the theoretical calculation formula of SFRaLAC T-shaped beam was presented.(4)Statistical analysis was made on the development and distribution of cracks in SFRaLAC T-shaped beams under normal conditions,and the classification method of cracks in T-shaped test beams was defined to conduct classification statistics.According to the number and distribution of each crack,the controlling factors affecting the T-shaped test beam were determined,and the number and distribution of the average crack width and the maximum crack width of the T-shaped test beam were statistically analyzed.The calculation method of SFRaLAC T-beam was proposed according to the statistical analysis results.(5)According to the deflection test results of SFRaLAC T-shaped beam,the flexural moment-deflection curve was drawn.The test results showed that the deflection of SFRaLAC T-shaped beam was low when the volume ratio of steel fiber increased under the same moment level.