In order to improve the properties of recycled aggregate resulted by the crushing of concrete from construction and demolition waste stream, a thermo-mechanical treatment was applied. This treatment, performed in a muffle furnace and a Los Angeles machine, simulates the conditions specific for a rotary kiln. Recycled concrete aggregate (RCA) was obtained by the crushing of a concrete C20/25 class. The crushed concrete aggregate (RCA), the one resulted after the thermo-mechanic treatment of RCA and the initial natural aggregate where compared from the point of view of physical properties (apparent and bulk specific gravities). A good efficiency of thermo-mechanic treatment was appreciated based on these results.

New concretes were prepared using the recycled concrete aggregates (before and after thermo-mechanic treatment) in order to assess the specific gravity and compressive strength. Thus, the compressive strength values, assessed on concrete prepared with recycled concrete aggregates subjected to thermo-mechanical treatment, are similar with those prepared with natural aggregate.

The thermo-mechanic process applied for the removal of cement paste/mortar adhered to natural aggregate grains is a possible solution for the improvement of recycled aggregates quality.