Design and evaluation of high-volume fly ash (HVFA) concrete mixes.
i


Design and evaluation of high-volume fly ash (HVFA) concrete mixes.

  • Published Date:

    2012-10-01

  • Language:
    English
Filetype[PDF-796.37 KB]


Details:
  • Resource Type:
  • Geographical Coverage:
  • Edition:
    Final report.
  • NTL Classification:
    NTL-HIGHWAY/ROAD TRANSPORTATION-Design ; NTL-HIGHWAY/ROAD TRANSPORTATION-Pavement Management and Performance ; NTL-HIGHWAY/ROAD TRANSPORTATION-Materials ;
  • Abstract:
    Concrete is the world’s most consumed man-made material. Unfortunately, the production of portland cement, the active ingredient in concrete, generates a significant amount of carbon dioxide. For each pound of cement produced, approximately one pound of carbon dioxide is released into the atmosphere. With cement production reaching nearly 6 billion tons per year worldwide, the sustainability of concrete is a very real concern. Since the 1930’s, fly ash – a pozzolanic material – has been used as a partial replacement of portland cement in concrete to improve the material’s strength and durability, while also limiting the amount of early heat generation. From an environmental perspective, replacing cement with fly ash reduces concrete’s overall carbon footprint and diverts an industrial by-product from the solid waste stream (currently, about 40 percent of fly ash is reclaimed for beneficial reuse and 60 percent is disposed of in landfills). Traditional specifications limit the amount of fly ash to 25 or 30 percent cement replacement. Recent studies, including those by the investigators, have shown that higher cement replacement percentages – even up to 75 percent – can result in excellent concrete in terms of both strength and durability. Referred to as high-volume fly ash (HVFA) concrete, this material offers a viable alternative to traditional portland cement concrete and is significantly more sustainable. By nearly doubling the use of reclaimed fly ash in concrete, HVFA concrete aligns well with MoDOT’s green initiative on recycling. However, HVFA concrete is not without its problems. At all replacement rates, fly ash generally slows down the setting time and hardening rates of concrete at early ages, especially under cold weather conditions, and when less reactive fly ashes are used. Furthermore, with industrial by-products, some variability in physical and chemical characteristics will normally occur, not only between power plants but also within the same plant. Consequently, to achieve the benefits of HVFA concrete, guidelines are needed for its proper application in bridges, roadways, culverts, retaining walls, and other transportation-related infrastructure components. The objective of this research was to design, test, and evaluate HVFA concrete mixtures. The study focused on the hardened properties of HVFA concrete containing aggregates and fly ash indigenous to the state of Missouri and developed guidelines on its use in infrastructure elements for MoDOT.
  • Format:
  • Main Document Checksum:
  • File Type:
  • Supporting Files:
    No Additional Files
No Related Documents.

You May Also Like:

Version 3.15