Re-cycling of construction and demolition waste and steel slag: characterization of the durability

The main objective of the study was to evaluate the durability of a crushed concrete aggregate, processed from construction and demolition waste and an inert siderurgical aggregate for construction, processed from electric arc furnace steel slag, with a view to boosting their re-cycling, minimizing the consumption of non-renewable natural resources and preserving the capacity of landfills. Both recycled aggregates were selected based on their high availability worldwide and to be generally associated with suitable engineering properties. However, in many cases, their acceptance by the end-users continues to be very low. One reason for continuing this distrust is the lack of knowledge about the durability of both materials. In natural aggregates, durability has been considered as an important mechanical property in the evaluation of their performance, but it has not been studied in recycled aggregates; so, slake durability tests were carried out. Their durability was compared with the behaviour of two reference natural aggregates, a basalt and a limestone. To complement the durability results obtained, macropetrographic and micropetrographic examinations as well as physical characterizations were performed. The results of the tests showed that, under the test conditions adopted, both recycled aggregates present durability which foresees their use in civil engineering applications.