Experimental Study On Mechanical Properties And Toughening Mechanism Of SFRLWAC

The excellent toughness is the most obvious characteristics of steel fiber reinforcement lightweight aggregate concrete (SFRLWAC) beside lower density, higher strength and insulating. This subject is to combine the steel fiber reinforced concrete with the lightweight aggregate concrete to form a steel fiber reinforced pumice lightweight aggregate concrete, which owns the advantages of high toughness of steel fiber reinforced concrete and the light weight of lightweight aggregate concrete.In this paper, pumice lightweight aggregate concrete (LWAC) of LC30, LC35 and LC40, which are compounded with the method of the steel fiber, super plasticizer, high-quality air-entraining agent and mineral admixtures. Strength and deformation as mechanical properties of the new concrete material were studied. The influence to SFRLWAC caused by the change of volume ratio of steel fiber was analyzed by the test of cube compressive strength, axial compressive strength, modulus of elasticity, splitting-tensile strength and modulus of rupture. The experimental results indicated that the tensile strengh and bending strengh of SFRLWAC can be improved significantly by the addition of steel fiber; to some extent ,the addition of steel fiber can also increase the compressive strength ,although little,it radically improves the compressive toughness,and the SFRLWAC will not fall apart with cracks; with the increase of the volume fraction of steel fiber, the elastic modulus is also rising somewhat; surface density is influenced little the effect . Furthermore,.A new formula is educed to calculate the compression strength and modulus of SFRLWAC, and gains a good linear relativity.At the same time, this paper introduces the composite theory of SFRC accompanied with crack preventing effect, the formula of toughness calculation of SFRLAC was derived theoretically, and the choosing of the parameters was discussed particularly. Thus, a corresponding quantitative expression between toughness and steel fiber content and matrix strength of SFRLWAC under the typical condition was given. An evaluating method of toughness of SFRLWAC is primarily founded as well.