Properties of concrete prepared with low-grade recycled aggregates

This paper presents the properties of concrete prepared with the sorted construction waste (low grade recycled aggregates) and a commercial recycled aggregate for concrete production. Three Series of concrete mixes were prepared by using the low grade or commercial recycled aggregates at 0%, 25%, 50% and 100% replacement levels of natural crushed granite. The concrete mixes were kept constant cement content and a free water to cement ratio of 410 kg/m(3) and 0.55, respectively. The test results on properties such as compressive and splitting tensile strength, E values, resistance to chloride-ion penetration and ultrasonic pulse velocity (UPV) are presented. The results showed that the strengths, E values and UPV of the concrete were decreased with an increase in the recycled aggregate content. The relationship between UPV and compressive strength was exponential for recycled aggregate concrete. Moreover, the recycled aggregate decreased the resistance to chloride ion penetration of the concrete. The results gathered would form a part of useful information for recycling the low grade recycled aggregates. (C) 2012 Elsevier Ltd. All rights reserved.