Recycled aggregates from construction and demolition waste in the production of concrete blocks

Ferriz-Papi, JA; Thomas, S

Abstract

The construction industry generates large amounts of waste, usually mixed, which can be composed of
different origin materials, most of them catalogued as non-hazardous. The European Union targets for
this waste for 2020 have been already achieved by the UK, but it is mainly developed in downcycling
processes (backfilling) whereas upcycling (such as recycle in new concrete batches) still keeps at a low
percentage. The aim of this paper is to explore further in the use of recycled aggregates from
construction and demolition waste (CDW) in concrete mixes so as to improve upcycling. A review of
most recent research and legislation applied in the UK is developed regarding the production of
concrete blocks. As a case study, initial tests were developed with a CDW recycled aggregate sample
from a CDW plant in Swansea. Composition by visual inspection and sieving tests of two samples were
developed and compared to original aggregates. More than 70% was formed by soil waste from
excavation, and the rest was a mix of waste from mortar, concrete, and ceramics with small traces of
plaster, glass and organic matter. Two concrete mixes were made with 80% replacement of recycled
aggregates and different water/cement ratio. Tests were carried out for slump, absorption, density and
compression strength. The results were compared to a reference sample and showed a substantial
reduction of quality in both mixes. Despite that, the discussion brings to identify different aspects to
solve, such as heterogeneity or composition, and analyze them for the successful use of these recycled
aggregates in the production of concrete blocks. The conclusions obtained can help increase upcycling
processes ratio with mixed CDW as recycled aggregates in concrete mixes.

Citation

Ferriz-Papi, J., & Thomas, S. (2020). Recycled aggregates from construction and demolition waste in the production of concrete blocks. Journal of Construction Materials, 2(1), https://doi.org/10.36756/JCM.v2.1.6

• Journal Article Type: Article
• Acceptance Date: Oct 16, 2020
• Online Publication Date: Oct 25, 2020
• Publication Date: Oct 25, 2020
• Deposit Date: Dec 14, 2020
• Publicly Available Date: Dec 14, 2020
• Journal: Journal of Construction Materials
• Volume: 2
• Issue: 1
• DOI: https://doi.org/10.36756/JCM.v2.1.6
• Publisher URL: https://doi.org/10.36756/JCM.v2.1.6
• Related Public URLs: https://iconsmat.com.au/publication/
• Additional Information: Access Information : This article is a reprint of a conference paper originally presented in 2017 and can be accessed here: http://usir.salford.ac.uk/id/eprint/57312/ or https://doi.org/10.5281/zenodo.1132449