Performance of fly ash concretes containing lightweight EPS aggregates

Non-absorbent man-made aggregates like expanded polystyrene (EPS) do not suffer with the disadvantage of water absorption, which makes production of the normal lightweight aggregate concrete difficult. The present investigation is directed towards the development and performance evaluation of the concrete composites containing EPS aggregates. Lightweight EPS concrete composites were produced by replacing the normal aggregate, either partially or fully, with EPS aggregates depending upon the density and strength required. The study covers the use of EPS beads as lightweight aggregate both in concrete and mortar, containing a fly ash replacement of 50% in the cementitious material. The concretes were designed to cover a wide range of densities (550–2200 kg/m3), through EPS replacements ranging from 95% to 0%. The results were compared with similar concrete composites, essentially having OPC as the binder, from the literature. The study indicates that the EPS mixes produced with fly ash show lower absorption values compared to the mixes with OPC reported earlier. These concretes were also found to have a better chemical resistance. The chloride permeability of these concretes was seen to be 50–65% lower compared to that of normal concretes having similar water cement ratios. The corrosion rates of these concretes were also lower compared to the normal concretes.