Nature of the thaumasite sulfate attack mechanism in field concrete

Citation
Dw. Hobbs et Mg. Taylor, Nature of the thaumasite sulfate attack mechanism in field concrete, CEM CONCR R, 30(4), 2000, pp. 529-533
Citations number
18
Categorie Soggetti
Material Science & Engineering
Journal title
CEMENT AND CONCRETE RESEARCH
ISSN journal
00088846 → ACNP
Volume
30
Issue
4
Year of publication
2000
Pages
529 - 533
Database
ISI
SICI code
0008-8846(200004)30:4<529:NOTTSA>2.0.ZU;2-8
Abstract
In the United Kingdom a number of cases of chemical attack on buried concre te bridge foundations have occurred, involving the sulfate-bearing mineral thaumasite. All of the affected concretes were in contact with a large volu me of clay backfill. It is postulated that oxidation of pyrites within the backfill led to the formation of sulfuric acid, reducing the pH of the grou ndwater and resulting in attack on the foundations and in reactions that ra ised the groundwater sulfate level. It is shown that the observations made on thin sections taken from the affected bridge foundations are in accordan ce with sulfuric acid attack being the probable primary cause of deteriorat ion. (C) 2000 Elsevier Science Ltd. All rights reserved.