Experimental Study on Functional Graded Concrete

Abstract

The ultimate bearing capacity of thick walled cylinder can be improved significantly by using the concrete functional graded material. The functional graded characteristic of concrete is achieved by the certain variations of the compressive strength and elastic modulus. In order to make use of the functional graded charac- teristic of concrete, orthogonal experiment are designed in a L16(45) orthogonal array with four factors, namely, “different addition of air-entraining agent (AE)”, “volume fraction of coarse aggregate (VA)”, “maximum size of the coarse aggregate (MS)”, and “water/blinder material ratio (W/B)” and three experimental indexes, namely, compressive strength, elastic modulus and density. The experimental results are analyzed by using the intuitive analysis and analysis of variance (ANOVA). The results show that the addition of air-entraining agent may cause the decrease of the compressive strength, elastic modulus and apparent density of concrete, but it has no signifi- cant impacts on the three indexes. The elastic modulus and apparent density are affected significantly by the volume fraction of coarse aggregate and the two indexes increase with the increase of the volume fraction of coarse aggregate. The maximum size of the coarse aggregate has no significant effect on three indexes. The compressive strength, elastic modulus and apparent density of concrete decrease significantly as the wa- ter/blinder ratio increase. The experimental results are used in the model test of thick-walled hollow cylinder. We find that the ultimate bearing capacity of functionally graded two-layered hollow cylinder is greater than that of the conventional thick-walled hollow cylinder.