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|Title:||Investigation of accelerated methods for the determination of available alkali in pozzolans|
|Authors:||United States. Army. Office of the Chief of Engineers.|
Miller, William G.
|Publisher:||Concrete Laboratory (U.S.)|
Engineer Research and Development Center (U.S.)
|Series/Report no.:||Miscellaneous paper (U.S. Army Engineer Waterways Experiment Station) ; C-74-1.|
Abstract: The procedure specified in acceptance testing of pozzolan for tne determination of the available alkali released by a pozzolan requires the lime-pozzolan paste to be stored for a period of 28 days prior to test. In order to investigate the possibility of reducing the storage time of the paste prior to test, six pozzolans were tested for available alkali release rate by subjecting the paste to three conditions of storage time and/or temperature. The three conditions were as follows: a. Condition 1, Standard Condition, 28 days at 38 c-; b. Condition 2, seven days at 38 G; c. Condition 3, seven days at 65.5 C. The results of these tests are as follows: a. The highest available alkali values for all pozzolans were obtained under Storage Condition 1. b. All pozzolans, except calcined tuf'f, produced higher values for Condition 3 than for Condition 2. c. All pozzolans, except calcined tuff, produce available alkali values far Condition 3 that were in excess of two-thirds of the values produced for Condition 1. Results of this study indicate that if the available alkali value of a pozzolan is 1.0 percent or less when the paste is stored at 65.5 C for seven days, the maximum specification limit of 1.5 percent will not be exceeded when the pozzolan is evaluated by the present Standard Condition, 28 days at 38 C. In order to reduce the storage tine of th1 lime-pozzolan paste to seven days, storage Condition 3 with a maximum limit of 1.0 percent available alkali is recommended as an optional method for the acceptance testing of pozzolan.
|Rights:||Approved for public release; distribution is unlimited.|
|Appears in Collections:||Miscellaneous Paper|
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