Stress-Strain Relations and Modulus of Elasticity of Two-Stage Concrete

Two-stage concrete is made by packing the forms with coarse aggregate and then pumping in a cement-based grout to fill the voids. The two-stage concrete is characterized by a higher proportion of coarse aggregate. As the coarse particles are in close contact, the applied load is transmitted from particle to particle while the grout is simply filing in the interstices. Thus, the mechanical characteristics of the two-stage concrete in failure conditions are distinctly different from those of ordinary concrete. Contrary to the ordinary concrete, there is no background information for evaluating the two-stage concrete elastic modulus. This paper presents the results of some experimental tests of three types of coarse aggregates and three different mix proportions of grout. Stress-strain relations in the function of water-cement and cement-sand ratios are elaborated. A relationship between the elastic modulus and the compressive strength of two-stage concrete is statistically derived.