Journal of Civil and Environmental Engineering

Effect of Recycled Aggregate on the Compressive Behaviour of Short Concrete Columns

Abstract

Hasan Hastemoglu

In this study, 12 specimens with three different lateral reinforcement ratios (ρ=0.022, 0.012 and 0.007) and four RG replacement ratios (0%, 30%, 50% and 100%) were prepared and tested under pure axial load in order to investigate the influence of recycled coarse aggregate (RG) and lateral tie reinforcement ratio (ρ) on the compressive behavior of a confined recycled aggregate concrete (RAC) column. The experimental data obtained from the tests are reported and compared with the predicted values obtained from the widely accepted Mander’s confined concrete model developed for conventional confined concrete to assess applicability of the model to recycled aggregate concrete. The results showed that the effect of RG on the compressive behavior of the RAC was negligible at low stress level, and it began to appear as the load increased at load levels above about 35% of Peak, regardless of ρ. The slope of the normalized compressive strength (f’cc/f’co) and normalized corresponding strain (εcc/εco) against ρ showed that the lateral reinforcement exerted the greatest effect on the stress and strain enhancement in the RG-30 series, and the smallest effect in the RG-50 series. The ratios of experimental values to those predicted from Mander’s model, ’cc_exp/f’cc_model and εcc_exp/εcc_model, showed that the model tended to give unconservative strength (f’cc) and strain (εcc) values for the RAC columns.