Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 32601
Effect of Na2O Content on Durability of Geopolymer Mortars in Sulphuric Acid

Authors: Suresh Thokchom, Partha Ghosh, Somnath Ghosh


This paper presents the findings of an experimental investigation to study the effect of alkali content in geopolymer mortar specimens exposed to sulphuric acid. Geopolymer mortar specimens were manufactured from Class F fly ash by activation with a mixture of sodium hydroxide and sodium silicate solution containing 5% to 8% Na2O. Durability of specimens were assessed by immersing them in 10% sulphuric acid solution and periodically monitoring surface deterioration and depth of dealkalization, changes in weight and residual compressive strength over a period of 24 weeks. Microstructural changes in the specimens were studied with Scanning electron microscopy (SEM) and EDAX. Alkali content in the activator solution significantly affects the durability of fly ash based geopolymer mortars in sulphuric acid. Specimens manufactured with higher alkali content performed better than those manufactured with lower alkali content. After 24 weeks in sulphuric acid, specimen with 8% alkali still recorded a residual strength as high as 55%.

Keywords: Alkali content, acid attack, compressive strength, geopolymer

Digital Object Identifier (DOI):

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 2530


[1] J. Davidovits, "Properties of geopolymer cements",Proc.First International conference on Alkaline Cements and Concretes,vol. 1, SRIBM, Kiev, Ukraine, 1994, pp. -131 - 149.
[2] T. Bakharev, "Resistance of geopolymer materials to acid attack", Cement & Concrete Research 35, 2005 pp.658 - 670.
[3] X. J. Song, M. Marosszeky, M. Brungs, R. Munn, "Durability of fly ash based Geopolymer concrete against sulphuric acid attack", presented at 10 DBMC Int. Conference on Durability of Building Materials and Components, Lyon, France, 2005
[4] S.E. Wallah, B.V. Rangan, "Low calcium fly ash based geopolymer concrete: Long term properties, Research report GC2, Curtin University of Technology, Australia, 2006.
[5] S. Thokchom, P. Ghosh, S. Ghosh, "Resistance of fly ash based geopolymer mortars in sulfuric acid" J. of Engg. and Applied sciences", 4(1), 2009 pp. 65-70
[6] S. Thokchom, P. Ghosh, S. Ghosh, " Acid resistance of fly ash based geopolymer mortars" Int. Journal of recent trends in Engg."1(6),2009 pp.36-40.
[7] A. Allahverdi, F. Skavara, "Sulfuric acid attack on hardened paste of Geopolymer cements, Part 1. Mechanism of corrosion at relatively high concentrations", Ceramics - Silikaty 45 (3)2001 pp.81 - 88.
[8] A. Allahverdi, F. Skavara, "Sulfuric acid attack on hardened paste of geopolymer cements, Part 2 Corrosion mechanism at mild and relatively low concentrations, Ceramics-Silikaty 50 (1),2006 pp.1 - 4
[9] A. Allahverdi, F. Skavara, "Nitric acid attack on hardened paste of geopolymeric cements, Part 1, Ceramics-Silikaty 45 (3),2001 pp.81 -88.
[10] A. Allahverdi, F. Skavara, "Nitric acid attack on hardened paste of geopolymeric cements, Part 2, Ceramics-Silikaty 45 (4),2001 pp.143-149.
[11] R. N. Thakur, S. Ghosh, "Fly ash based geopolymer composites" in Proc. 10th NCB International seminar on cement and building materials, New Delhi,Vol.3,2007,pp.442 - 451.
[12] F. Rendell, R. Jauberthie, "The deterioration of mortar in sulphate environments" Construction and building materials, 13, 1999, pp.321-327.