Mechanical properties of aerated lightweight aggregate concrete

This paper presents the results of an experimental programme to investigate the effects of the concrete mix parameters on the mechanical properties of aerated lightweight aggregate concrete (ALAC). The compressive strength, modulus of elasticity, split tensile strength and Poisson ratio were investigated for 60 different concretes, with densities ranging from 551 to 1948 kg/m3. The two primary mix design variables studied were the volume percentage of air in the matrix (A/M) and the volume percentage of matrix of the total mix (M/T). The test results indicate that both the compressive strength and modulus of elastic are strongly dependent on A/M. However, the effect of M/T depends on the relative strength of the matrix and aggregate. Both compressive strength and modulus increase with matrix content, for the aggregate used and for A/M ratios of approximately 22% and less; otherwise, they decrease. The coefficient of the split tensile strength as a function of density for the aggregate used is lower than that for normal weight concrete. Regression techniques were used to derive models for the properties of the concrete which give adequate predictions.