Innovative technologies for recycling End-of-Life concrete waste in the built environment

Abraham T Gebremariam,Francesco Di Maio,Ali Vahidi,Peter Rem

doi:10.1016/j.resconrec.2020.104911

Abraham T Gebremariam, Francesco Di Maio + Show 2 more

Open Access

https://doi.org/10.1016/j.resconrec.2020.104911

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Abstract

Currently, natural resources are consumed at an alarming rate than their production (United Nations Environment Programme, 2014). This imposes unprecedented pressure on the environment. The problem seems to get worse with the present increase in population and demand for infrastructures. To alleviate these and other related problems, a circular approach to construction material flow is crucial. Recycling construction and demolition wastes (C&DW) to generate high-quality materials is essential to ensure materials circularity in the construction sector.This article, therefore, describes the development of two large-scale technologies called Advanced Dry Recovery (ADR) and Heating Air classification System (HAS). ADR and HAS are industrial-scale technologies aimed to recycle End-of-Life (EoL) concrete into coarse, fine and ultrafine particles. While ADR is used to sort out clean coarse aggregates, HAS is used to produce clean fine aggregates by heating and separating the ultrafine hydrated cement components. The process parameters and the quality of aggregates are briefly described. Accordingly, concrete made of recycled coarse and fine aggregates displays comparable mechanical properties as the reference concrete which is made of natural aggregates. Both technologies are designed to be mobile so that EoL concrete wastes are processed at the site of demolition or close to ready-mix concrete plants, reducing the heavy traffic related to construction activities. These technologies, in general, have a potential in increasing sustainability and thereby greening the construction sector. This is by far a convenient contribution towards sustainable development and a big step towards closing the recycling loop in the construction sector.

Highlights

The primary sources of concrete wastes originate from construction, maintenance and refurbishment, deconstruction and demolition of buildings and civil works
The performance of Advanced Dry Recovery (ADR) coarse and Heating Air classification System (HAS) fine products has been investigated by totally replacing natural coarse aggregates (NCA) and natural fine aggregates (NFA) with recycled coarse aggregates (RCA) and recycled fine aggregates (RFA)
It is shown that the amount of ultrafines passing 63 μm sieve is below 1.5% of coarse aggregate weight, which ensures the suitability of the coarse aggregates (4–12 mm) for concrete production

Summary

Introduction

The primary sources of concrete wastes originate from construction, maintenance and refurbishment, deconstruction and demolition of buildings and civil works. Such activities are diverse in nature and the waste composition varies from place to place. In the EU, construction and demolition activities include a wide range of materials such as, excavation materials, construction and maintenance materials, concrete and other stony materials, out of which concrete is the major component after excavated soil (European commision, 2017). The amount of recycled concrete aggregates produced in the EU is about 9.4% compared to the total aggregate demand (European commision, 2017). In the Netherlands, for instance, the production of recycled aggregates comprises about 25% of the total aggregate production

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