Mechanical properties of brick aggregate concrete

This paper presents the results of a research program carried out at University of Aveiro, Portugal to evaluate the properties of concrete made with crushed bricks replacing natural aggregates. Two types of brick were investigated. The bricks were crushed in order to obtain a usable aggregate. The properties investigated were the workability and the density of fresh concrete, and the compressive strength, tensile splitting strength, modulus of elasticity and stress-strain behaviour of hardened concrete. Replacement ratios of natural aggregates by 15% and 30% were investigated as well as water/cement ratios of 0.45 and 0.5. Strength indexes were used to assess the effectiveness of aggregate replacement. The results of concrete produced with recycled aggregates were compared with a reference concrete produced with natural limestone aggregates currently used in Portugal. Observed results indicate that ceramic residuals could be used as partial replacement of natural aggregates in concrete without reduction of concrete properties for 15% replacement and with reductions tip to 20% for 30% replacement. The type and the manufacturing process of bricks seem to influence the properties of the resulting concrete. The properties and aesthetics of concrete with bricks indicate the possibility of using this type of concrete in precast applications. (C) 2008 Elsevier Ltd. All rights reserved.