Construction and demolition waste applications and maximum daily output in Spanish recycling plants

Abstract

The pursuit of construction sustainability has driven the use of partially or wholly waste-based eco-materials. New applications are being sought for recycled aggregate (RA) to further the use of this material and ensure the survival of the construction and demolition waste (C&DW) industry. RA, currently used in the construction of pavements, fills and embankments and only incipiently to manufacture structural or non-structural concrete, is a mere 8.99% of the total aggregate extracted in EU countries where RA is produced. Against this backdrop, the utility of this study lies in the overview afforded of RA typology, the application of the product in bound or unbound materials, the pursuit of new applications, structural or otherwise, and the assessment of daily maximum output by C&DW recycling facilities in Spain. The findings show that irrespective of its origin, RA most commonly adopts the form of wet mix macadam, gravel or sand used primarily in unbound applications with only dubious quality standards. Plant managers contend that RA from clean waste can feasibly be used in bound applications that require higher-performance materials. Maximum daily output varies widely, with capacity under 200 t d^-1 in 30% of the plants. One of the conclusions drawn is that the current business model is in need of revision, with an emphasis on aggregate quality control (certification) and the adoption of technology for separating out impurities, pollutants and undesirable materials to improve the quality of RA.