Research On Mechanical Properties Of Steel Fiber Semi-lightweight Concrete Based On Mesoscopic Level

As a new material,steel fiber semi-lightweight concrete is made by adding steel fiber and light aggregate to concrete.Compared with ordinary concrete,it has the advantages of smaller density,higher specific strength,and lower self-weight;compared to lightweight aggregate,it has the advantages of high modulus of elasticity and small deformation;and adding steel fiber,its mechanical properties are greatly improved promote.Macro-mechanics generally assume that concrete is an ideal homogeneous material,which is inconsistent with the complex internal structure of concrete,and it is difficult to study the process of crack generation,development and penetration of concrete under the action of external forces.From the perspective of meso-level,this paper studies the failure process and macro-mechanical properties of steel fiber semi-lightweight concrete.In this paper,the failure process and mechanical properties of steel fiber semi-lightweight concrete under uniaxial compression are studied.The main contents and conclusions areas follows:(1)Using MATLAB and ANSYS to program the finite element model of two-dimensional and three-dimensional steel fiber semi-lightweight concrete.Two-dimensional and three-dimensional steel fiber and aggregate collision detection methods were proposed.The random placement of aggregates and steel fibers in the modeling process was simulated.(2)Using the established finite edement model of two-dimensional steel fiber semi-lightweight concrete to simulate the uniaxial compression of concrete specimens with different factors and conditions,analyze the compression failure process and crack development of concrete specimens,and present the results and issues.The tests performed by the group were compared to compare the compressive strength of the concrete and the stress-strain curve during compression.(3)Compression simulation of concrete specimens with different steel fiber volume content and different ceramsite strength was carried out.The influence of steel fiber volume content and ceramsite strength on the compressive strength of steel fiber semi-lightweight concrete was studied,The fitting formulas for the effect of steel fiber volurne content,ceramic grain strength and compressive strength of concrete specimens were obtained.