Abstract
This paper reports an experimental study conducted to asses durability characteristics of concretes made using different types of recycled aggregates. Different types of recycled coarse aggregates comprising natural dolomite (DOL), crushed concrete (RCA), recycled rubble (RUBL) and brick (BRIC) were studied using concrete mixtures of water-cement ratios (w/c) = 0.60 and 0.45 containing 100% of the recycled stone. The same type of crushed natural sand was used in all the mixtures. In addition to compressive strength and workability, water sorptivity and oxygen permeability (K) properties of the concretes were measured. It is found that the recycled aggregates showed higher porosity than the control crusher dolomite aggregate. Oxygen permeability results of the recycled aggregate concretes were of the same order of magnitude, giving about K = 2.0 x 10-10 m/s. Recycled brick aggregates produced concretes of consistently higher permeability and water sorptivity than the others. The oxygen permeability values for the various recycled aggregate concretes increased in the order kDOL < KRCA < KRUBL < KBRIC. Permeability of brick aggregate concrete was four times higher than that of control dolomite concrete. The relatively adverse influence of recycled brick on concrete properties is attributed to its highly porous characteristics.