Mechanical Behaviour of Concrete with Recycled Aggregate

This study is aimed at evaluating the mechanical behaviour of recycled aggregate concretes (RAC). An extended experimental investigation has been carried out on RAC prepared by replacing variable amounts of “virgin” aggregates with recycled concrete aggregates (RCA) deriving from building demolitions. The mechanical properties measured on RAC specimens are compared to the corresponding ones obtained for a conventional concrete with 100% of natural aggregates. The watercement ratio (W/C) has been kept constant in all specimens. Some key concrete properties (i.e. strength and permeability) as well as some durability-related parameters have been measured with the aim of assessing feasibility and suitability of a RAC for structural use. Furthermore, the possible replacement of fine sand aggregates with Fly Ash has been also considered and compared. Stress-strain curves and the compressive strength values of both RACs and conventional concretes having different curing ages, have been evaluated and compared.