Compressive strength, modulus of elasticity and drying shrinkage of concrete with coarse recycled concrete

Recycling of construction and demolition waste (CDW) has come up as a way of reducing the waste harmful effect in the urban environment through the use of CDW recycled aggregates in new products such as road pavement bases, concretes and mortars. Concrete waste is seen as an alternative source of raw materials in conventional concrete through the incorporation of recycled concrete aggregates. This paper presents a research work that has been developed at the Technical University of Lisbon (IST), concerning the properties of concretes made with coarse recycled concrete aggregates (RCA). In this work the aim was to examine original concrete influences on RCA characteristics, to compare mechanical properties like compressive strength, modulus of elasticity and drying shrinkage of conventional concrete mixes made from coarse natural aggregates (NA) with those of similar mixes incorporating RCA. Tests using coarse RCA produced from two original concretes with different compositions and compressive strengths showed that the compressive strength of RCA concretes does not depend on the compressive strength of original concretes. Regarding properties related with deformability (dry shrinkage and Modulus of elasticity), differences in RCA properties caused by original concrete characteristics can modify the performance of RCA concretes.