Development of sustainable recycled aggregate concrete in Croatia

With the aim to develop a sustainable structural engineering in Croatia, it is necessary to recover and reuse increased amounts of construction and demolition waste (C&D). Depending on its origin and composition, approximately 80% of construction waste, given certain recycling technologies, may be used as an economically valuable resource. But in Croatia, only 5% of waste is recycled. One of the recovery methods is recycling of crushed concrete waste and its reuse as an aggregate in new concrete. Characteristics of this recycled concrete aggregate are different in comparison with ordinary concrete and because of that it is necessary to investigate properties of recycled concrete aggregate. Results of the laboratory testing of concrete with different recycling aggregate amounts compared to control concrete with natural aggregate are presented in this paper. In accordance to obtained results, it is recommended to use maximum of 30 % recycled aggregate in concrete mixtures because, up to that amount, properties of concrete regarding the compressive strength, free shrinkage and water permeability would be satisfactory, or very near to the control concrete properties.