| Steel fiber reinforced full light weight aggregate concrete（SFRFLAC）has the advantages of high strength and good toughness as well as the characteristics of light weight,energy saving and environmental protection.It is a popular new functional material in modern building structures.The mechanical properties and constitutive relations of all lightweight steel fiber concrete are the important basis for numerical analysis and structural calculation.At present,the research on the uniaxial tensile constitutive relations of all lightweight steel fiber concrete is not clear at home and abroad and needs to be further improved.In this paper,a series of experimental studies have been carried out on the basic mechanical properties and the uniaxial tensile full curve of steel fiber all-light concrete.The main research results are as follows:（1）The cubic compression and splitting tensile strength tests of steel fiber all-light concrete were carried out using standard cube specimens.The effects of steel fiber type and volume ratio on the failure mode and strength of steel fiber all-light concrete were studied.The experimental results show that the brittle failure of concrete specimens is gradually transformed into plastic failure after the addition of steel fiber.Compared with all-light concrete,when the volume fraction of steel fiber increases from 0.6%to 1.8%,the cubic compressive strength of concrete specimens increases by 8.94%to 15.73%,and the splitting tensile strength increases by 30.33%to 116.67%.（2）The axial compressive strength and elastic modulus of steel fiber all-light concrete were tested using standard cylinder specimens,and the effects of steel fiber type and volume ratio on the axial compressive strength and elastic modulus of steel fiber all-light concrete were studied.The test results show that when the volume fraction of steel fiber increases from0.6%to 1.8%,the axial compressive strength and elastic modulus of concrete specimens increase by 3.7%-24.26%and 6.33%-12.65%respectively.（3）600mm×196mm×100mm large-head specimen[1]was used to carry out the uniaxial tensile stress-strain full curve test of SFRC,and the effects of steel fiber type and volume ratio on the uniaxial tensile strength and constitutive relationship of SFRC were studied.The test results show that when the volume ratio of steel fiber increases from 0.6%to 1.8%,the uniaxial tensile strength of large head specimens increases by 3.15%-56.3%,and the peak stress and peak strain of the uniaxial tensile stress-strain complete curve also increase,and the whole curve becomes fuller.The results show that the steel fiber significantly improves the uniaxial tensile strength and toughness of the lightweight concrete.（4）Through the data fitting of the whole curve of uniaxial tensile stress-strain test,the variation rule of the whole curve of rising and falling section was analyzed,the expression of the characteristic parameters of rising and falling section was given,and the uniaxial tensile constitutive model of steel fiber all-light concrete was established. |
