Recycled concrete and mixed rubble as aggregates:
influence of variations in composition on the concrete properties
Cathleen Hoffmann a, Andreas Leemann a
a
Swiss Federal Laboratories for Materials Testing and Research (Empa), Überlandstr. 129,
CH-8600 Dübendorf, Switzerland
Abstract
The recycling of concrete, bricks and masonry rubble as concrete aggregates is an important
way to contribute to a sustainable material flow. However, there are still various uncertainties
limiting the widespread use of recycled aggregate concrete (RC). The fluctuations in the
composition of commercial grade recycled aggregates (RA) and their influence on the
properties of fresh and hardened concrete are of particular concern regarding the use of RC.
In this project, variations in the composition of RA were studied over a period of several
weeks. Concrete mixtures were then produced with these aggregates in order to evaluate the
resulting variations in concrete properties. Although the high variability in aggregate
composition causes corresponding variations in concrete properties, the results obtained
demonstrate that RA is suited for a wide variety of applications in the building industry.
Keywords: Petrography, Recycling concrete; Mixed recycled aggregate, Durability