Mechanical Properties Of Steel Fiber Lightweigh Aggregate Concrete

Lightweight aggregate concrete is researched widely throughout the world by its advantage of reduce dead load of the structure.But the brittleness and low compressive strength of this kind of material restrict its application.During the research in decades,one of solutions is adding fibers into lightweight aggregate concrete to increase its mechanical properties according to many literature.Steel fibers are widely used for it enhancing the tensile strength an toughness of lightweight aggregate concrete.Flow table test,compressive test and flexural test had been applied in the experiment to evaluate the influence when the dosage of fibers and the density class of concrete changed.Two steps are followed: trial mixture and formal mixture.In the first step,seven series of lightweight aggregate concrete cubes with density class of D1.2 and D1.6 were made to optimum the respect mixtures,for ever batch,four cubes were made to test its compressive strength.In the second step,four batches of steel fiber lightweight aggregate concrete with 40 kg/m3 and 80kg/m3 steel fiber content were investigated.For ever batch,four cubes,three cylinders and seven beams were contained.The results of fresh properties and hardened properties of four batches were reported,and the influence of steel fiber and density class on the flow property,bulk density,compressive strength,modulus of elasticity,flexural strength and post crack behavior also been evaluated.Some conclusions of this paper are followed: The addition of fibers can reduce the workability of the lightweight aggregate concrete;The addition of fiber with a lower content has a slight effect to the bulk density and elastic module of the lightweight aggregate concrete.But in the case of higher fiber dosage,the elastic module increasing obviously;the tensile strength and flexural strength of lightweight concrete enhanced with the addition of steel fibers;the toughness of lightweight concrete might decreased when a higher content steel fibers added.The results and conclusion in this paper might be used for the application of steel fiber lightweight aggregate concrete in the future.The experiment finished in Leipzig when I took part in a international program between our collage and the University of HTWK.Additionally,expanded clay and expanded glass particles used as lightweight aggregate with different combination in the process and the test methods according to the European code.