Experimental Research On Flexural Behavior Of Sisal Fiber Self-compacting Lightweight Aggregate Concrete Beams

In recent years,with the sustained rapid development of the national economy,people had high demands for building functions and noise pollution,and the pursuit of high efficiency and high quality construction by various companies,self-compacting lightweight aggregate concrete has emerged,but because of its own weaknesses limited their expansion and reuse,and the incorporation of fibers increases the strength and toughness of self-compacting lightweight aggregate concrete,limited its early shrinkage and improved durability.However,the current research mainly focused on the mix design,work performance,and basic mechanical properties.The fiber types also focused on steel fibers,and the lack of plant fibers on the system of self-compacting lightweight aggregate concrete components.In this paper,static load tests of sisal fiber self-compacting lightweight aggregate concrete beams based on 12 different sisal fiber additions and different reinforcement ratios were completed on the basis of the mix design,work performance,and mechanical performance tests.Its bending performance was studied and analyzed.The main research contents and conclusions were as follows:(1)Determined the mechanical properties of raw materials according to the specifications,and configure the optimal mix ratio of the volume of the different sisal fibers with strength class C40.Used the slump spread test to measured the working performance of the mix,used the same batch of injection molds.Concrete mixes were tested for mechanical properties such as cubic compressive strength,cubic split tensile strength,prism axial compressive strength,and static modulus of elasticity test for each group of mix ratios.The results showed that the sisal fiber can effectively improve the failure mode of the self-compacting lightweight aggregate concrete test block,and enhance the splitting tensile strength,and the better the integrity of the sisal fiber as the amount of sisal fiber increases.The greater the increase in tensile strength.However,the effect of sisal fiber on the compressive strength and the axial compressive strength of the prism was less.(2)In this paper,the flexural performance test of sisal fiber self-compacting lightweight aggregate concrete beams was carried out.The damage phenomenon of the test beams was described in detail.The cracks of the test beams with different volumes of sisal fibers and different reinforcement ratios were studied.The effects of load,yield load,ultimate load,mid-span deflection and load,reinforcement strain and load,concrete strain and load relationships,and crack morphology confirm the conformity of sisal fiber self-compacting lightweight aggregate concrete beams to flat sections assumed.The results showed that all twelve test beams conformed to the flat section assumption.In the same reinforcement ratio,the impact of sisal fiber on the cracking load,yield load and ultimate load of the test beam was not significant.Only when the blending amount was 3kg/m~3,the sisal fiber obviously improveed the cracking load;The occurrence and expansion of cracks had obvious inhibitory effects,reducing the average crack spacing and width,making the crack distribution more uniform,improving the shape of cracks,and with the increase of sisal fiber content,the better its crack resistance.The bearing capacity of the test beam with the deflection deformation had the effect of increasing,when the dosage was 2kg/m~3,the maximum load,the best toughness.With the same mix ratio,the increase of the ratio of reinforcement had little effect on the cracking load,but it greatly increased the ultimate load and yield load,and reduced the crack width and crack spacing,and it is mixed with the reinforcement ratio and sisal fiber.The amount was proportional.(3)Based on the experimental results,compared the experimental results with the calculation results,this paper put forward some theoretical formulas such as cracking load,ultimate bearing capacity,deflection checking and crack width checking of sisal fiber self-compacting lightweight aggregate concrete beams.(4)The finite element method was used to numerically simulate the flexural behavior of sisal fiber self-compacting lightweight aggregate concrete beams with different volume content of sisal fibers and different reinforcement ratios,and the displacement map and load-deflection diagram of the test beams were obtained.The results of numerical analysis of cracking load and ultimate load are compared with the test results.The results showed that the analysis results using the finite element analysis method were in good agreement with the test results.