Preliminary Study of Recycled Aggregate Mortar for Electric Arc Furnace Dust Encapsulation

Enrique F Ledesma,Ruan L S Ferreira,José María Fernández-Rodríguez,Angélica Lozano-Lunar,José Ramón Jiménez

doi:10.3390/app11209525

Abstract

This article shows the preliminary results of a study carried out to determine the technical feasibility of encapsulating a high percentage of EAFD in cement-based mortars manufactured with the fine fraction of recycled concrete aggregates (RCA). Two families of mortars, with natural aggregate as a reference and with RCA, were studied. An incorporation rate by weight of two parts mortar to one part EAFD was tested. The mechanical strengths (compressive strength and tensile strength) before and after immersion in water, the rate of delitescence and the leaching behavior were studied. Mortars made with RCA showed similar mechanical strengths to the reference mortars made with natural aggregates; however, the incorporation of EAFD decreased the mechanical strengths. Encapsulation considerably reduced the leaching of heavy metals, although the Pb concentration remained above the hazardous waste limit. With this preliminary study, two wastes are managed together, and the results have shown that the use of RCA instead of natural aggregate is a viable alternative since it does not significantly impair the mechanical or leaching properties of the cement-based matrices used to encapsulate EAFD.

Highlights

The “Europe 2020” strategy aims to generate smart, sustainable and inclusive growth by opting for an efficient economy in the use of natural resources
The dry bulk density decreased slightly when NA was replaced by recycled concrete aggregates (RCA), attributed to the lower density of the RCA particles and the higher w/c ratio used [9]
The incorporation of Electric Arc Furnace Dust (EAFD) causes a higher porosity of cement-based mortars [32] due to the interaction of the heavy metals contained in the EAFD with the cement hydration products, which explains the lower dry bulk density of this type of

Summary

Introduction

The “Europe 2020” strategy aims to generate smart, sustainable and inclusive growth by opting for an efficient economy in the use of natural resources. The new paradigm of the “circular economy” has as its main objective the sustainable use of resources through the principle of “closing the lifecycle loop” of materials—that is, to reintroduce into the production process materials classified as “waste” whose destination was the landfill [1]. This practice reduces the volume of waste managed in landfills and reduces the amount of raw materials consumed [2]. Construction and demolition waste (CDW) is one of the major waste streams globally; the use of recycled aggregates from CDW as raw materials in mortars and concretes is a practice to be promoted and is in line with the new paradigm of the “circular economy”

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Results

Conclusion