Abstract
The aim of this critical review is to show the applicability of recycled fine aggregates (RFA) in concrete regarding technical performance, environmental impact, energy consumption and cost. It is not possible to judge the performance of concrete by considering one dimension. Thus, this study focussed on the fresh and hardened (e.g., mechanical and durability) properties and environmental and economic life cycle assessment of concrete. Most literature investigated showed that any addition of recycled fine aggregates from construction and demolition waste as a replacement for natural fine aggregates proves detrimental to the functional properties (quality) of the resulting concrete. However, the incorporation of recycled fine aggregates in concrete was proven to enhance the environmental and economic performance. In this study, an extensive literature review based multi criteria decision making analysis framework was made to evaluate the effect of RFA on functional, environmental, and economic parameters of concrete. The results show that sustainability of RFA based concrete is very sensitive to transportation distances. Several scenarios for the transportation distances of natural and recycled fine aggregates and their results show that only if the transportation distance of the natural aggregates is more than double that of RFA, e the RFA based concrete alternatives would be considered as more sustainable.
Highlights
Due to the rising need for urbanization, concrete usage is expected to be doubled by 2050 [1].Given the fact that aggregates comprise around 70% by volume of concrete, alarming depletion rates of non-renewable natural resources such as river sand and limestone are expected [2]
Regression models were developed based on data obtained from the literature, and a multi criteria decision making analysis framework was used to combine the results for the mentioned parameters and to find the optimum incorporation level of recycled fine aggregates (RFA) in concrete
The process by which construction and demolition waste (CDW) is turned into aggregates, whether coarse or fine, suitable for reintegration in concrete can be divided in several stages, namely separation by metal detectors, initial screening, crushing, secondary screening, secondary crushing and sieving and separating [40]
Summary
Hisham Hafez 1, *, Reben Kurda 2 , Rawaz Kurda 3, * , Botan Al-Hadad 4 , Rasheed Mustafa 5 and Barham Ali 6. Received: 30 December 2019; Accepted: 27 January 2020; Published: 4 February 2020
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