Title: A STUDY OF COMPRESSIVE STRENGTH AND SULFURIC ACID AND MAGNESIUM SULFATE RESISTANCES OF GEOPOLYMER MORTAR MADE FROM LOW CALCIUM FLY ASH BLENDED WITH HIGH CALCIUM FLY ASH

Author(s): Kantiya Sothornchaiwit, Wirachat Tangjiraphat, Thiengchiwet, Chai Chaturaphithakkun

Publication: TCA

Volume: Vol. 6 No. 2 (2018): July 2018 - December 2018

Issue:

Appears on pages(s): 58-66

Keywords: Fly Ash, Geopolymer, Magnesium Sulfate, Sulfuric

DOI:

Date: 10/10/2018

Abstract:
This research studied the compressive strength, sulfuric acid resistance and loss of compressive strength due to magnesium sulfate attack of geopolymer mortar made from low calcium fly ash blended with high calcium fly ash at the rates of 15%, 25%, and 35% by weight of binder. Liquid to binder ratio of 0.60 by weight and NaOH concentration of 8 Molar were used. The compressive strength of geopolymer mortar was determined at the ages of 7, 28, 90, and 180 days. Weight loss of geopolymer mortar due to 3% of sulfuric acid solution (pH=0.5) was determined. Loss of compressive strength due to 5% magnesium sulfate solution was also investigated. The result showed that the compressive strength of geopolymer mortar increased with the increasing of high calcium fly ash content. Weight loss of geopolymer mortar due to sulfuric acid attack and loss of compressive strength due to magnesium sulfate attack also increased when high calcium fly ash increase. Therefore, the optimum replacement of low calcium fly ash by high calcium fly ash was 25% by weight of binder.