Effects of Coarse Aggregate on the Physical Properties of Florida Concrete Mixes

Portland cement concrete is a heterogeneous, composite material composed of coarse and fine granular material embedded in a matrix of hardened paste. The coarse material is aggregate, which is primarily used as inexpensive filler and comprises the majority of the volume of concrete and can be obtained from a variety of different sources. The physical properties of concrete are heavily influenced by the aggregate properties. Most of the coarse aggregate produced in Florida is a limestone material that is more porous, less dense, and softer than limestone produced from other areas of the U.S. To differentiate between limestone produced in Florida and limestone produced elsewhere, limestone from the geologic formations in Florida is typically referred to as “limerock.” The coarse aggregate produced in Florida and used in structural concrete require special consideration with regard to relative strength, thermal, and physical properties. The structural design of concrete is based on service limit states and utilizes modulus of elasticity as a design parameter. However, the modulus of elasticity of concrete used for the design of structures is typically determined by relationships which utilize compressive strength. Due to the assumption that structural concrete made with weaker Florida limerock would have lower strength than concrete made with other aggregates, an aggregate correction factor of 0.9 is used in the calculation of elastic modulus from compressive strength testing for structural design equations. The use of an aggregate correction factor of less than 1.0 requires the use of more concrete to meet structural requirements. The primary goal of the research was to study the effects of different coarse aggregate types on the physical properties and design of portland cement concrete, with the emphasis on coarse aggregate from Florida for use in structural concrete. Concrete specimens were made and tested to acquire the information necessary for use in the design equations used to predict the physical properties of the concrete. A value of 1.0, rather than the currently used value of 0.9, was found to be appropriate for the aggregate correction factor for Florida limerock.

• Record URL:
  https://fdotwww.blob.core.windows.net/sitefinity/docs/default-source/research/reports/fdot-bdv31-977-08-rpt.pdf
• 
• Summary URL:
  https://fdotwww.blob.core.windows.net/sitefinity/docs/default-source/research/reports/fdot-bdv31-977-08-sum.pdf
• Summary URL:
  https://rosap.ntl.bts.gov/view/dot/29647
• Record URL:
  https://rosap.ntl.bts.gov/view/dot/29646
• Corporate Authors:

  University of Florida, Gainesville

  Department of Civil and Costal Engineering
  365 Weil Hall, P.O. Box 116580
  Gainesville, FL  United States  32611

  Florida Department of Transportation

  Research Center, 605 Suwannee Street, MS 30
  Tallahassee, FL  United States  32399-0450

  Department of Transportation

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Ferraro, Christopher C
  • Tibbetts, Caitlin M
  • Perry, Michael C
  • Watts, Benjamin E
  • Paris, Jerry M
• Publication Date: 2015-10

Language

• English

Media Info

• Media Type: Digital/other
• Edition: Final Report
• Features: Appendices; Figures; Photos; References; Tables;
• Pagination: 172p

Subject/Index Terms

• TRT Terms: Admixtures; Coarse aggregates; Limestone; Mix design; Modulus of elasticity; Physical properties; Portland cement concrete
• Geographic Terms: Florida
• Subject Areas: Highways; Materials; I32: Concrete; I36: Aggregates;

Filing Info

• Accession Number: 01583640
• Record Type: Publication
• Report/Paper Numbers: 00114669/00114670
• Contract Numbers: BDV31-977-08
• Files: NTL, TRIS, ATRI, USDOT, STATEDOT
• Created Date: Dec 23 2015 8:11AM