EFFECTS OF ALKALINE SOLUTION ON PROPERTIES OF THE HCFA GEOPOLYMER MORTARS

Document Type : Primary Research paper

Authors

Assistant Professor Department of civil Engineering Nehru Institute of Technology

Abstract

Geopolymers are novel binding materials produced by the alkaline activation of rich
aluminosilicate materials. Geopolymer
bindersareconsideredasgreenbuildingmaterialsthathaveincreasing
potentialtoreplacetheordinaryPortlandcementinthe concrete industry. This study
investigated the alkali solution effects on the physical and mechanical properties of the
high calcium fly ash based geopolymers. The parameters involved in this study were the
NaOH solution molarity and the
Na2SiO3/NaOHratio.ThreeNaOHconcentrations(8,10,and12molars)wereinvestigated.The
Na2SiO3/NaOHratiowasvaried between 1 and 2.5. The results showed that the studied
parameters significantly affected the properties of the produced geopolymer mortars. The
workability and setting time were found to decrease by increasing the NaOH
concentration or by increasing the Na2SiO3/NaOH ratio. The influence of the NaOH
concentration was higher on the workability and setting time while the Na2SiO3/NaOH
ratio highly affected the compressive strength. The initial setting time was in the range of
45-105 minuteswhilethefinalsettingoccurredquicklyafterthatwithin70-
115minutes.Ovencuringmethodresultedinhighstrengthat
earlyageswhereallofthemixeswereabletoachievemorethan75%ofthe28daysstrengthwithint
hefirst3days.The28-days compressivestrengthrangedbetween60-
85MPa,whichpromotestheuseofthehighcalciumflyashfortheproductionofearly high
strength geopolymerconcrete.

Keywords


Volume 11, Issue 1
International Virtual Conference on Materials, Manufacturing and Nanotechnology, December 2020
May 2020
Pages 513-525