Structural recycled aggregate concrete made with precast wastes

• The recycled aggregate from wastes of precast structural concrete are clean and of high quality.
• A complete characterization of recycled aggregate and recycled concrete have been performance.
• Substitution of 20% coarse aggregate does not significantly affect the properties of concrete.
• Total replacement of coarse aggregate causes an increase in the amount of cement.

This paper presents the main results of the characterization of recycled aggregate concrete made with precast structural concrete wastes as a case study. The use of recycled aggregates presents two main benefits. On the one hand, there would be an economic and environmental saving because it would not need to deposit waste in landfills. On the other hand, there would be a further economic and environmental saving because it would reduce the need for natural aggregate. However, because of the need of a greater amount of cement not all degrees of substitution present advantages. The results were obtained from four degrees of substitution and different mixing proportions and methods using natural and recycled aggregates and superplasticizers. After obtaining the optimal mixing proportions, the concretes have been fully characterised performing mechanical and durability tests, the methods analysed and the results compared with the literature.