Effect of Recycled Sand Content on Characteristics of Mortars and Concretes

When recycled aggregate is used for concrete manufacture, in many cases these aggregates are accompanied by a recycled sand content. This research focuses on concretes prepared with recycled sand content. First, the research examined the effects of recycled sand content on the characteristics of mortar—density and compressive and flexural strength—by using recycled sand contents of 0, 5, 10, 15, 20, and 50%. Subsequently, the effect on the characteristics of recycled concretes made with a water/cement ratio of 0.50, when part of the recycled aggregate was replaced with recycled sand, was studied. The results obtained on mortars indicate that the use of up to 20% recycled sand caused a drop in the compressive and flexural strength. In concretes, the use of up to 100% recycled aggregate has no appreciable effect on compressive strength but does lower the modulus of elasticity, E, as the recycled aggregate content increases. If the recycled aggregate used in the manufacture of concretes contains up to 10% recycled sand, this sand has no appreciable effect on the compressive strength of the concrete, nor on its modulus of elasticity E.