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Title: Fly Ash Iodine Number for Measuring Adsorption Capacity of Coal Fly Ash

Author(s): Zeyad T. Ahmed, David W. Hand, Lawrence L. Sutter, and Melanie Kueber Watkins

Publication: Materials Journal

Volume: 111

Issue: 4

Appears on pages(s): 383-390

Keywords: adsorption; air-entraining admixtures; fly ash; foam index; iodine number; isotherms

DOI: 10.14359/51686582

Date: 7/1/2014

Abstract:
Fly ash is used as partial replacement of cement in concrete. The residual carbon in fly ash adsorbs some of the organic concrete admixtures, altering the concrete properties. The use of fly ash in concrete is limited by the lack of adequate fly ash adsorption capacity quantification tools. This paper presents the fly ash iodine number test for the direct measurement of the adsorption capacity of coal fly ash. This test can be used to determine suitability of fly ash for concrete. The developed test was evaluated by comparing the results obtained with the loss on ignition (LOI) and foam index test results for the same fly ash samples. Results show that the fly ash iodine number test can replace current qualitative indicators of adsorption capacity and can be directly used for the characterization and specification of fly ash for the use in concrete.