Cement - Concrete
||25% blast furnace slag or
10% cenospheres or
0-40% fly ash or
5% silica fume
||Each region of the country will be different
concerning availability of concrete/cement with these
additives, dependent on the respective industries in the
region--be it fly ash from coal-fired power plants, cenospheres
from fly ash, silica fume from electric arc furnace stacks,
etc. Cement in small quantities (bags) is not generally
available with these additives.
Bagged cement with recycled content is also available. Two brands that contain recycled content are Basalite and Quikrete IF produced in an area where the specified recycled material is available. Quikrete is developing a map to denote if we purchase bags of Quikrete in areas a, b, c we know they contain fly ash and can claim credit for that purchase. If we purchase bags of Quikrete in areas x, y, z we know they do not contain fly ash and should then denote those purchases not available. To date the Quikrete production areas we know are producing bags of cement with fly ash are Fremont, CA; Charlotte, NC; Nashville, TN; Pounding Mill, VA; and Martinsville, VA. In addition, Quikrete has a ?Green Concrete Mix? which contains 50% or more recycled aggregate such as recycled concrete. Basalite production codes that denote fly ash and/or blast furnace slag is in the product begin either with 1406 or 1409. The production codes are printed on the bag in front of the date. A third brand (FA-S10, FA-S-6, MS-S10, MS-S6) contains either fly ash (the FA brand) or silica fume (the MS brand). However, this brand is sold in bagged form only in the Chicago area.
||Price for concrete/cement with
the additives is typically similar to the price without
the additives. Should that not be the case in your region,
please let us know.
The additives not only make use of a material that
would otherwise be wasted but they increase the strength,
endurance, thermal stability (in the case of cenospheres),
electrical resistivity (in the case of silica fume)
of concrete and decrease shrinkage and weight (in the
case of cenospheres) and fluid permeability (in the
case of silica fume), thereby reducing damage from thaw/freeze
The additives do increase curing time and so a lower
percent of the additive should be requested when pouring
concrete in cold temperatures. The U.S. Environmental
Protection Agency has recommendations
that address materials, state, and contract specifications;
performance standards; mix design; and quality control.
||Cast-in-Place Concrete (Spec 03300)
National Energy Technology Lab
Sandia National Lab
Pertinent Language from Sandia Nationlal Lab
B. American Society for Testing and Materials (ASTM)
C618 Specification for Fly Ash and Raw or Calcined
Natural Pozzolan for Use as a Mineral Admixture
in Portland Cement Concrete
2.04 CONCRETE MATERIALS
A. Portland Cement: ASTM C150 Types I-II and III, "Low-Alkali"
cement, unless otherwise specified. Use one brand of cement
throughout project unless otherwise acceptable to the SDR
D. Fly Ash: ASTM C618, Class F; use one brand of fly ash
throughout project unless otherwise acceptable to the
2.06 CONCRETE MIX DESIGN
4. Fly Ash: Fly ash shall be used in all concrete mixes.
Class F fly ash shall be proportioned by weight of
cement to provide fly ash to Portland cement ratio not
less than 20%, or greater than 25% of the sum of total
weight of fly ash and cement.
||Concerns have been expressed
about hazardous materials leaching out of concrete with
additives. The fly ash used in concrete is a byproduct
from coal fired power plants, for example, and not a hazardous
waste. Fly ash from municipal solid waste combustors would
be a hazardous waste, but that is not the fly ash used
||According to the Western Region Ash Group,
each ton of fly ash used to replace a ton of cement saves
the equivalent of one barrel of oil required to produce
the cement. See the King County "Fly
Ash in Concrete" bulletin for more information.
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