Article In: cienciavitae, orcid, scopus

Performance Enhancement of Alkali-Activated Electric Arc Furnace Slag Mortars through an Accelerated CO2 Curing Process

Applied Sciences - Basel

Dany Kassim; Ghandy Lamaa; de Brito, J — 2022 — MDPI

Key information

Authors:

Dany Kassim; Ghandy Lamaa (Ghandy Lamaa); Rui Silva (Rui Vasco Pacheco Santos da Silva); de Brito, J (Jorge Manuel Caliço Lopes de Brito)

Published in

02/05/2022

Abstract

The use of electric arc furnace slag (EAFS) as sole precursor to produce alkali-activated mortars has been experimentally investigated. EAFS, a by-product of the steel recycling industry, is a coarse material with unevenly distributed and size-extensive particles. Milling of EAFS was required to achieve a cement-like sized powder before it could be used as precursor. Different combinations of sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) were used, by varying the Na2O/binder concentration (4%, 6%, 8%, 10%, 12%) and SiO2/Na2O ratio (0, 0.5, 1.0, 1.5, 2.0, 2.5) to maximize the mechanical performance. The alkaline solutions were prepared 24 h prior to mixing to unify temperatures for all mixes. The results showed that the SiO2/Na2O ratio and strength development are directly proportional. The maximum 28-day compressive strength obtained, after being subjected to an initial 24 h thermal curing at 80 ◦C, was 9.1 MPa in mixes with 4% Na2O/binder and 2.5 SiO2/Na2O. However, after an additional 28 days of accelerated carbonation, the maximum compressive strength (i.e., 31 MPa compared to 3.9 MPa in uncarbonated mixes, corresponding to an 800% increase) was obtained in mixes with 12% and 1.0 for Na2O/binder and SiO2/Na2O, respectively, thus showing an alteration in the optimal alkaline activator contents.

Publication details

Authors in the community:

Publication version

EVoR - Enhanced Version of Record

Publisher

MDPI

Title of the publication container

Applied Sciences - Basel

First page or article number

1

Last page

18

Volume

12

Issue

3

ISSN

2076-3417

DOI

10.3390/app12031662

Fields of Science and Technology (FOS)

civil-engineering - Civil engineering

Keywords

  • alkali-activated materials
  • electric arc furnace slag
  • mechanical performance
  • carbonation
  • mortars

Publication language (ISO code)

eng - English

Alternative identifier (URI)

http://dx.doi.org/10.3390/app12031662

Rights type:

Open access

Creative Commons license

CC-BY - CC-BY