Effect of Type of Sand on the Flowability and Compressive Strength of Slag-Fly Ash Blended Geopolymer Mortar

Joud Hwalla, Hilal El-Hassan, Joseph J. Assaad, Tamer El-Maaddawy, Jad Bawab

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

2 Citations (Scopus)

Abstract

This paper investigates the influence of the type of fine aggregates on the properties of slag-fly ash blended geopolymer mortar. Twelve mixes were prepared with two types of sand: desert dune sand (DS) and crushed dolomitic limestone sand (CS). Different alkaline activator solution-to-binder (0.50, 0.60, and 0.65) and binder-to-sand ratios (1:2, 1:3, and 1:4) were considered to analyze their effect on the performance of the geopolymer mortar. The properties under investigation included the amount of additional water needed to maintain a flow of 150 ± 2 mm and the 7-and 14-day compressive strengths. Experimental test results showed that an increase in fine aggregates content resulted in a higher additional water demand, regardless of the type of sand used. As a result, the mortar compressive strength decreased by up to 29% compared to mixes with the lowest binder-to-sand ratios (1:2 for DS mixes and 1:3 for CS mixes). An increase in the alkaline activator solution-to-binder ratio reduced the additional water needed to satisfy the target flowability but increased the overall liquid-to-binder ratio. Meanwhile, for optimum compressive strength, DS-based mixes comprised B:S and AAS/B ratios of 1:2 and 0.60, respectively, while those of CS-based mixes were 1:3 and 0.65, respectively. Compared to mixes made with CS, those incorporating DS required the addition of more water to maintain the flowability and experienced up to 81% loss in compressive strength; still, DS-based mixes achieved 14-day compressive strengths exceeding 28 MPa. The experimental findings advocate the use of DS as fine aggregates in the production of slag-fly ash blended geopolymer mortar to be utilized in various construction applications.

Original languageEnglish
Title of host publicationProceedings of the 8th International Conference on Civil, Structural and Transportation Engineering, ICCSTE 2023
PublisherAvestia Publishing
ISBN (Print)9781990800221
DOIs
Publication statusPublished - 2023
Event8th International Conference on Civil, Structural and Transportation Engineering, ICCSTE 2023 - Ottawa, Canada
Duration: Jun 4 2023Jun 6 2023

Publication series

NameInternational Conference on Civil, Structural and Transportation Engineering
ISSN (Electronic)2369-3002

Conference

Conference8th International Conference on Civil, Structural and Transportation Engineering, ICCSTE 2023
Country/TerritoryCanada
CityOttawa
Period6/4/236/6/23

Keywords

  • compressive strength
  • dune sand
  • flow
  • fly ash
  • geopolymer
  • limestone
  • mortar
  • slag

ASJC Scopus subject areas

  • Transportation
  • Materials Chemistry

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