PERFORMANCE AND DURABILITY OF CLASS C FLY ASH IN CONCRETE

In this study, seven Class C ashes and a Class F ash were blended with three different cements of variable tricalcium aluminate content to address the durability of Class C ashes in sulfate environment. Chemical and mineralogical analyses were conducted on all as-received materials and the durability of cement-fly ash blends was assessed through mortar cube strength, length expansion and hydrated phases identification at selected periods of exposure to a 5% sodium sulfate solution. It was found that the presence of sodalite phase and tricalcium aluminate in Class C ashes studied here resulted in rapid deterioration. In addition, the presence of 1.3% tricalcium aluminate (RIR method) in Class C ashes resulted in lowering the durability of cement/Class C ash blends if the cements contain 2% tricalcium aluminate (Bogue method). None of the Class C ashes studied in this investigation had better performance in the sulfate environment if compared to Class F ash. It is recommended that prior to using Class C ash in concrete mixes to be subjected to moderate or aggressive environment, a detailed mineralogical analysis is to be conducted to determine the presence of any detrimental phases in the as-received ash.

• 
• Corporate Authors:

  University of South Florida, Tampa

  Department of Civil and Environmental Engineering, 4202 East Fowler Avenue
  Tampa, FL  United States  33620

  Florida Department of Transportation

  Haydon Burns Building, 605 Suwanee Street
  Tallahassee, FL  United States  32301

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Zayed, A M
  • Toth, C
  • Garibaldi, M
• Publication Date: 1998-6

Language

• English

Media Info

• Features: Figures; References; Tables;
• Pagination: 62 p.

Subject/Index Terms

• TRT Terms: Chemical analysis; Concrete; Deterioration; Durability; Fly ash; Mineralogy; Sulfates; Tricalcium aluminate
• Subject Areas: Highways; Materials; I32: Concrete;

Filing Info

• Accession Number: 00755103
• Record Type: Publication
• Report/Paper Numbers: WPI 0510754,, Final Report,, USF 2104-235-LO
• Contract Numbers: B-9899
• Files: TRIS, ATRI, USDOT, STATEDOT
• Created Date: Oct 20 1998 12:00AM