Experimental Study on Mechanical Properties of Lightweight Concrete with Shale Aggregate Replaced Partially by Nature Sand

To study the basic mechanical properties of lightweight concrete incorporating shale aggregate replaced partially by nature sand (LCSARP), a variety of mixes were designed and the properties of the mixes were determined through a series of laboratory tests including compressive strength test, splitting tensile strength test, flextural strength test and tests to determine modulus of elasticity and poison’s ratio. The failure processes, failure modes and the influences of replacement rate of natural sand on essential mechanical properties of LCSARP were studied. The result show that the failure modes of LCSARP are different from ordinary Portland cement concrete. In General, the mechanical properties of LCSARP show an increasing trend with the incremental replacement rate of natural sand, including fcu, fc, splitting tensile strength, flexural strength, fc/fcu, tension and compression’s ratio, and the ratio (defined as similar flexure and compression’s ratio (SFCR)) between flexural strength and the square root of cube compressive strength. With the incremental replacement rate of natural sand, the elastic modulus of LCSARP increases gradually, while the reverse is true for the Poisson’s ratio. In terms of LCSARP, a precise and applicable relationship for the mechanical property parameter as fcu, fc, splitting tensile strength, flexural strength, fc/fcu at different replacement rates of natural sand was individually established by the regression analysis. A parabolic function between tension-to-compression ratio and Poisson’s ratio for LCSARP was established that correlates well to the experimentally measured results.