Comparison of chloride permeability methods for Alkali-Activated concrete. (20th March 2018)

• Record Type: Journal Article
• Authors: Thomas, R.J.; Ariyachandra, Erandi; Lezama, Diego; Peethamparan, Sulapha
• Is Part Of: Construction & building materials. Volume 165(2018)
• Page Start: 104
• Page End: 111
• Publication Date: 2018-03-20
• Subjects: Alkali-activated concrete -- Chloride permeability -- Diffusion coefficient -- Salt ponding; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2018.01.016
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: We compare chloride permeability tests for alkali-activated concrete. High pore solution conductivity causes problems with electrical methods. Resistivity and RCPT work but classifications should be changed. Abstract: This paper presents the results of an experimental study of chloride permeability in alkali-activated fly ash, alkali-activated slag, and Portland cement concrete. Test methods include the rapid chloride permeability test (RCPT), AC and DC electrical resistivity, and the 90-day salt ponding test. We hypothesize that differences in pore solution chemistry between alkali-activated and Portland cement binders render electrical methods unable to accurately estimate chloride permeability in alkali-activated concrete. The present study seeks to evaluate this hypothesis by comparing results from electrical tests with diffusion coefficients from salt ponding tests. Contrary to previous claims, the RCPT provided a good estimate of chloride permeability in both alkali-activated slag and alkali-activated fly ash concrete. RCPT results showed excellent correlation with diffusion coefficients determined from salt ponding tests. Resistivity-measurements exhibited poor correlation to diffusion coefficients and overestimated the resistance to chloride ion penetration. Furthermore, AC and DC resistivity measurements showed significant disagreement for alkali-activated concrete. Finally, evidence form salt ponding tests suggests differences in chloride binding potential between alkali-activated and Portland cement concretes.