Performance of mortars containing recycled fine aggregate from construction and demolition waste

Waste from construction and demolition accumulates in large quantities in the modern world. Recycled coarse aggregates derived from this waste can replace virgin aggregates used in the production of new concretes but the studies on the effect of using the fine fraction of this waste on the properties of new concrete have not yet led to clear conclusions. The present study evaluated the properties of recycled fine aggregates derived from two recycling plants using two different waste treatment procedures, as well as their effects on the properties of fresh and hardened mortars prepared using these aggregates at two water-to-cement ratios and three replacement ratios. It was found that the recycled aggregates were more porous than the natural aggregates and may have contained some organic matter. Setting times were longer when recycled aggregates replaced natural aggregates and strength and durability were reduced as well. Partial replacement of the fine aggregate is possible if an appropriate compensation of the water to cement ratio is applied.