Specifications and Protocols for Acceptance Tests of Fly Ash Used in Highway Concrete

Fly ash--a byproduct of coal combustion--is widely used as a cementitious and pozzolanic ingredient in hydraulic cement concrete. The use of fly ash in concrete is increasing because it improves some properties of concrete and often results in lower cost of concrete. However, the chemical and physical compositions of fly ash influence constructability, performance, and durability and may contribute to problems, such as cracking and alkali-silica reactivity in concrete pavements, bridge decks, and other highway structures. Regulatory requirements have also contributed to changes in fly ash properties that may adversely affect concrete performance. In addition, current specifications and test methods do not adequately characterize fly ash properties, address the effects of fly ash characteristics on fresh and hardened concrete properties, or consider the alkali content of the cement. For example, carbon content of fly ash is not usually determined directly, but is often assumed to be approximately equal to the loss on ignition (LOI). Such inadequate characterization may lead to unwarranted restrictions on the use of suitable materials. Although a great deal of research has been performed on the effects of fly ash characteristics on concrete properties, the research has not dealt with the applicability of current specifications to the fly ashes that currently are produced. In addition, existing test methods for sampling and testing fly ash used in concrete do not adequately address the characterization of fly ash or the performance aspects of highway concrete. Further research is needed to develop recommendations for improving fly ash specifications and test protocols and thus help highway agencies better evaluate and use fly ash that will provide acceptable structural performance and durability. The objective of this research is to recommend potential improvements to specifications and test protocols to determine the acceptability of fly ash for use in highway concrete.

• Record URL:
  http://www.trb.org/TRBNet/ProjectDisplay.asp?ProjectID=479

Language

• English

Project

• Status: Completed
• Funding: $749125.00
• Contract Numbers:

  Project 18-13

• Sponsor Organizations:

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590

  American Association of State Highway and Transportation Officials (AASHTO)

  444 North Capitol Street, NW
  Washington, DC  United States  20001

  National Cooperative Highway Research Program

  Transportation Research Board
  500 Fifth Street, NW
  Washington, DC  United States  20001
• Project Managers:

  Hanna, Amir

• Performing Organizations:

  Michigan Technological University, Houghton

  University Transportation Center for Materials in Sustainable Transportation Infrastructure (UTC-MiSTI)
  1400 Townsend Drive, 301 Dillman Hall
  Houghton, MI  United States  49931
• Principal Investigators:

  Sutter, Lawrence

• Start Date: 20070716
• Expected Completion Date: 0
• Actual Completion Date: 20120914
• Source Data: RiP Project 11824

Subject/Index Terms

• TRT Terms: Chemical reactions; Concrete; Concrete pavements; Concrete structures; Cracking of concrete pavements; Durability; Fly ash; Properties of materials; Research projects
• Identifier Terms: National Cooperative Highway Research Program
• Subject Areas: Bridges and other structures; Highways; Pavements; I30: Materials;

Filing Info

• Accession Number: 01464872
• Record Type: Research project
• Source Agency: National Cooperative Highway Research Program
• Contract Numbers: Project 18-13
• Files: UTC, RIP, USDOT
• Created Date: Jan 3 2013 2:51PM