BACKGROUND ON CARBONATE AGGREGATE BEHAVIOR IN CONCRETE

CARBONATE AGGREGATE BEHAVIOR IN CONCRETE IS REVIEWED. COARSE CARBONATE AGGREGATES ARE WIDELY USED IN CONCRETE WITH GREAT SUCCESS. TWO TYPES OF CARBONATE AGGREGATE BEHAVIOR RELATED TO DISTRESS IN CONCRETE HAVE BEEN IDENTIFIED ON THE BASIS OF SERVICE RECORDS. THE PROBLEM AGGREGATES WHICH HAVE RECEIVED MOST ATTENTION ARE THOSE WHICH EXPAND IN ALKALINE ENVIRONMENTS. A DIRECT RELATIONSHIP BETWEEN THE EXPANSIVITY OF CYLINDERS OF AGGREGATES SOAKED IN SODIUM HYDROXIDE SOLUTIONS TO EXPANSION OF CONCRETE CAUSING DETERIORATION HAS BEEN ESTABLISHED IN CANADA AND VIRGINIA. THE EXPANSION OF AGGREGATE IS CONSIDERED TO BE CLOSELY ASSOCIATED WITH THE CHEMICAL REACTION CALLED 'DEDOLOMITIZATION.' THE CHEMISTRY OF THIS REACTION IS PRESENTED AND DESCRIBED. DOLOMITIC LIMESTONES OR CALCITIC LIMESTONES HAVE BEEN RECOGNIZED IN IOWA AS PROBLEM AGGREGATES. REACTION RIMS WHICH OCCUR PERIPHERALLY ON THE COARSE CARBONATE AGGREGATES ARE DISCUSSED. IT IS CONCLUDED THAT CARBONATE AGGREGATES REACT IN ORDER TO ADJUST TO THE ALKALINE CONCRETE ENVIRONMENT. AN EXPANSION TEST HAS BEEN DEVISED WHICH CAN EFFICIENTLY RECOGNIZE POTENTIALLY EXPANSIVE AGGREGATES.

• Authors:
  • Lemish, J
• Conference:
  • Highway Geology Symposium, Iowa State U
• Publication Date: 1968-7

Subject/Index Terms

• TRT Terms: Alkali aggregate reactions; Carbonates; Chemical reactions; Coarse aggregates; Concrete; Concrete aggregates; Deterioration; Dolomite; Expansion; Sodium hydroxide
• Uncontrolled Terms: Deteriorated concrete
• Old TRIS Terms: Dedolomitization
• Subject Areas: Geotechnology; Highways; Materials;

Filing Info

• Accession Number: 00213343
• Record Type: Publication
• Report/Paper Numbers: pp 128-129
• Files: TRIS
• Created Date: Jul 7 1994 12:00AM