Effect of Recycled Aggregate and Steel Fibers on the Mechanical Properties of Alkali-Activated Slag/Fly Ash Blended Concrete

Research output: Chapter in Book/Report/Conference proceedingConference contribution

6 Citations (Scopus)

Abstract

This paper focuses on developing ambient-cured alkali-activated concrete incorporating recycled concrete aggregates (RA). The binder was either slag or a blend of slag and fly ash (3:1, by mass). Hook-ended steel fibers were added, in 2% volumetric fraction, to improve the properties of concrete made with RA. The alkaline activator solution was a blend of sodium silicate and sodium hydroxide. Concrete mixtures were proportioned to achieve three target compressive strengths, namely 30, 45, and 60 MPa. The performance of concrete mixtures was assessed based on 1, 7, and 28-day compressive strengths. Experimental results showed that full replacement of natural aggregates by RA caused up to 28% reduction in compressive strength of plain alkali-activated slag concretes, with greater reductions being reported in mixtures with higher target strength and tested at 28 days. The incorporation of 2% steel fibers enhanced the strength and caused limited strength reductions of up to 7%. Compared to alkali-activated slag RA concretes, mixtures with 25% fly ash replacement exhibited lower strengths at 1 and 7 days, but their 28-day strength was superior. Analytical multi-linear regression models were developed to identify statistical significance of concrete components and examine their impact on the compressive strength.

Original languageEnglish
Title of host publication11th ACI/RILEM International Conference on Cementitious Materials and Alternative Binders for Sustainable Concrete, ICCM 2021
EditorsArezki Tagnit-Hamou
PublisherAmerican Concrete Institute
Pages210-223
Number of pages14
ISBN (Electronic)9781641951395
Publication statusPublished - Apr 28 2021
Event11th ACI/RILEM International Conference on Cementitious Materials and Alternative Binders for Sustainable Concrete, ICCM 2021 - Virtual, Online
Duration: Jun 7 2021Jun 10 2021

Publication series

NameAmerican Concrete Institute, ACI Special Publication
VolumeSP-349
ISSN (Print)0193-2527

Conference

Conference11th ACI/RILEM International Conference on Cementitious Materials and Alternative Binders for Sustainable Concrete, ICCM 2021
CityVirtual, Online
Period6/7/216/10/21

Keywords

  • alkali-activated concrete
  • compressive strength
  • recycled aggregates
  • regression models
  • steel fibers

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Building and Construction
  • General Materials Science

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