Recycled Aggregates from Construction and Demolition Waste in the Manufacture of Urban Pavements

Manuel Contreras-Llanes; Maximina Romero; Manuel Jesús Gázquez; Juan Pedro Bolívar

doi:10.3390/ma14216605

Recycled Aggregates from Construction and Demolition Waste in the Manufacture of Urban Pavements

Materials (Basel). 2021 Nov 2;14(21):6605. doi: 10.3390/ma14216605.

Authors

Manuel Contreras-Llanes^{1

2}, Maximina Romero³, Manuel Jesús Gázquez⁴, Juan Pedro Bolívar²

Affiliations

¹ Research Centre for Natural Resources, Health and Environment (RENSMA), Department of Sociology, Social Work and Public Health, University of Huelva, 21007 Huelva, Spain.
² Research Centre for Natural Resources, Health and Environment (RENSMA), Department of Integrated Sciences, University of Huelva, 21007 Huelva, Spain.
³ Department of Materials, Instituto de Ciencias de la Construcción Eduardo Torroja (IETcc-CSIC), 28033 Madrid, Spain.
⁴ Department of Applied Physics, Marine Research Institute (INMAR), University of Cádiz, 11510 Cádiz, Spain.

Abstract

Construction and Demolition Waste (CDW) is among the largest waste streams in the world. Therefore, within the Circular Economy concept, there is a growing interest in its reuse. The purpose of this work was to study the use of recycled aggregates (RAs) obtained by a specific separation method from CDW, replacing natural aggregates (NAs) in the manufacture of precast concrete elements, such as kerbstones and paver blocks. The physical and technological properties of precast products formulated with RAs were analysed in accordance with current regulations, comparing them with those of commercial products manufactured with NAs. The results indicated that partial or total substitution of NAs by RAs increased the water absorption and apparent porosity values of the precast elements while reducing the bulk density and compressive strength. However, all units manufactured with RAs showed breaking load values higher than the minimum required by EN 1338 and, in some cases, slightly higher average tensile strength values than the reference material. In addition, some of the compositions including RAs gave rise to pieces that, according to their flexural strength, were classified as class 1 and marked S in accordance with EN 1340. According to abrasion resistance, in most cases, the precast elements are classified as Class 4 and I (≤20 mm). Finally, precast concrete produced from RAs satisfies the tolerance requirements for classification as class 3 (≤1.5 kg m^-2). Therefore, it could be suitable for use in high pedestrian or traffic areas.

Keywords: construction and demolition waste; eco-efficient materials; environmental impact; recycled mixed aggregates; treatments improvement; urban pavements.