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Effect of Clay Content on Alkali-Carbonate Reactive (ACR) Dolomitic Limestone

Project Details
STATE

FHWA

SOURCE

TRID

START DATE

11/01/16

END DATE

07/01/21

RESEARCHERS

Jose Mila, Tyson Rupnow, William Saunders

SPONSORS

Louisiana Department of Transportation and Development

KEYWORDS

Alkali aggregate reactions, Alkali carbonate reactions, Clay, Limestone, Portland cement concrete

LINKS

Project webpage

Product

Project description

This study aimed to evaluate whether an aggregate’s clay content plays an overarching role in Alkali-Carbonate Reactive (ACR) expansion and deterioration within the limestone sources that have been approved for use in portland cement concrete in Louisiana. A total of 29 aggregate sources from the Louisiana Department of Transportation and Development (DOTD) approved materials list were screened for chemical analysis to determine whether the aggregates were potentially expansive based on their calcium oxide, magnesium oxide, and alumina contents. Twelve out of 29 aggregates were found to be potentially reactive and therefore were selected for concrete prism tests per ASTM C1105 to verify their expansive potential. The results showed that none of the aggregates tested exhibited deleterious expansion after 12 months. In addition, the clay content (based on the aggregate’s alumina composition) did not directly affect the selected group of aggregates’ reactivity.
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