Recycling Concrete to Aggregates. Implications on CO2 Footprint

Over the last decades, the needs of the contemporary way of life and the ongoing population growth have affected the construction industry by causing rapid development of the sector. This accretion combined with the challenging management of construction and demolition waste (CDW) resulted in an increasing amount of waste being produced as well as an associated impact on the environment. Those impacts render their management necessary, in order to contribute to the concepts of sustainable development and Circular economy. The present paper discusses the usage of recycled aggregates (RAs) from CDW, in correlation with natural aggregates (NA) in the manufacture of concrete, both from quality and environmental perspectives. Upon analysis of the physical–chemical and mechanical properties, a replacement ratio of RAs of 50% was suggested, considering two factors: (1) the highest acceptable decrease in aggregate properties; and (2) the higher contribution to the environment, which is also accepted by the EN-12620 standard. Furthermore, it was calculated that the net carbon balance of aggregate utilization, based on the above scenario, is approximately 20% lower compared to NA.