Recycled Concrete Aggregate from Construction and Demolition Waste: Characterization and Use in Sustainable Concretes
Beatrice Malchiodi, Virginia Barbieri, Luca Lanzoni, Paolo Pozzi, Cristina Siligardi
Appears on pages(s):
construction and demolition waste; recycled concrete aggregate; structural concrete; sustainable concrete
The use of recycled concrete aggregate (RCA) from construction and demolition waste (CDW) in new concrete production is a promising solution to reduce the exploitation of non-renewable resources and landfill waste. Nowadays, only a small part of RCA is recycled due to severe regulatory restrictions in this field. Specifically, Italian Standards enable the use of solely coarse RCA and limit by 30% its substitution ratio to natural aggregate for structural concrete >C20/25 and ≤C30/37. In the present paper, concrete waste resulting from selective demolition was fully characterized and the high potential to develop green structural concrete using high RCA content was outlined. Substitution ratios of 30, 60, and 90vol% of natural aggregates were evaluated. Special attention was paid to the concrete mix design depending on the peculiar properties of RCA. Compressive strength tests at 3, 7, and 28 days of curing outlined the possibility to develop highly sustainable concrete of strength class C25/30. Thus, a viable and sustainable valorization of all particle size fractions was suggested, as well as the necessity of more permissive regulations based on the quality of the RCA used.