Fine aggregate determination
C1777, Methylene Blue Value WK36906, Ground Limestone Fines
ASTM International Committee C09 on Concrete and Concrete Aggregates has recently approved a new test method for evaluating the suitability of fine aggregates and other fillers for use in concrete. The standard provides a rapid test for laboratory and field use to determine the amount of methylene blue adsorbed by a specimen of fine aggregate or mineral filler. The new standard is under the jurisdiction of Subcommittee C09.20 on Normal Weight Aggregates, which is currently developing a proposed new standard for ground limestone fines and other finely divided materials for use in concrete.
C1777, Test Method for Rapid Determination of the Methylene Blue Value for Fine Aggregate or Mineral Filler Using a Colorimeter, was developed by Subcommittee C09.20 on Normal Weight Aggregates, part of ASTM International Committee C09 on Concrete and Concrete Aggregates.
“The test in C1777 will be used to distinguish between harmful and non-harmful fines in concrete aggregate,” says Eric Koehler, vice president, Verifi LLC, and a C09 member. In addition, Koehler notes, C1777 will enable the qualification of new material sources, as well as production quality control.
“C1777 will enable increased use of ground limestone filler and a wider range of fine aggregates in concrete,” says Koehler. “Previously, some of these materials could not be used because no test method was available to identify the potential presence of clay minerals, resulting in a broad range of materials being prohibited.”
Quality control personnel at aggregate producers and ready mix concrete producers are the most likely users of C1777.
Koehler says single operator precision for C1777 has already been determined, but C09.20 is planning to perform an interlaboratory study for reproducibility. Interested laboratories are encouraged to participate.
A proposed new standard will reference C1777. WK36906, Specification for Ground Limestone Fines and Other Finely Divided Materials for Use in Concrete, is also being developed by C09.20. Once approved, WK36906 will allow concrete producers to use such products approved as sources of materials to be used in concrete mix specified by architects/engineers and departments of transportation.
“Due to the implementation of government regulations and policies for the sustainable development of green technologies in the construction industry, engineers, architects, concrete producers and contractors are increasingly required to adhere to these new sustainable building regulations by specifying appropriate mix designs,” says Caroline Talbot, director, key account management and tunneling division, The Euclid Chemical Company, and a C09.20 member. “As a consequence, the use of minimum cement content in concrete mixtures without compromising the performance is highly recommended.”
Talbot notes that the industry could adhere to such regulations by increasing the proportion of supplementary cementing materials such as fly ash and slag, and mineral filler such as ground limestone.
All interested parties are invited to participate in the standards developing activities of C09.20.
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Originally published in Masonry magazine.
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This article appears in the May/June 2014 issue of Standardization News.