Case Study #3 -- Severe Scaling of an Interstate Bridge Deck, and Potentially Reactive Carbonate Aggregates, Progress Report #6 (Partial): An Example of Bridge Deterioration Promoted by Alkali-Carbonate Reaction

Report No: 70-R42

Published in 1971

About the report:

The project designated "Concrete Durability Studies" comprises case studies of unusual durability, either in kind or extent. These case studies are directed toward situations in which appearances suggest materials or construction rather than structural causes. Included in this project as Case Study #3 is an occurrence of severe scaling and pattern cracking in bridge decks of an interstate project: one deck showed severe scaling after only one winter's exposure. Because the aggregate used in these decks was from a source known to contain potentially reactive carbonate rocks, the combination of scaling and chemical reaction was investigated as a likely dual cause. Concurrently with this case study, an extensive study of potentially reactive carbonate aggregates was in progress. One aspect of that study was an evaluation of field manifestations of the alkali-carbonate reaction based upon field surveys of bridge decks in the region of the severely scaled deck. Thus, this report, while primarily a case study of the Concrete Durability Study, is also considered to be a report of field performance for the project "Potentially Reactive Carbonate Rocks." The field survey for evidence of carbonate reactivity covers more decks than are treated in this report so that this report serves as a partial Progress Report #6 for that project.

Disclaimer Statement:The contents of this report reflect the views of the author(s), who is responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the Virginia Department of Transportation, the Commonwealth Transportation Board, or the Federal Highway Administration. This report does not constitute a standard, specification, or regulation. Any inclusion of manufacturer names, trade names, or trademarks is for identification purposes only and is not to be considered an endorsement.


  • Michael A. Ozol, Howard Newlon

Last updated: February 12, 2024

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