Analysis of Hardened Concrete for Admixture Content

摘要

An earlier Interim Report in 1978 by L. C. Muszynski and with the same title as this Report established a technique for the identification of organic admixtures present in hardened concrete by means of high pressure liquid chromatography (HPLC). Extension of the admixture from concrete was accomplished by use of a ternary azcotrop composed of 75 percent (by volume) of methylethyl ketone, 14 percent ethanol, and 11 percent water. Using HPLC conditions were found which provided a distinction among the various admixtures. With a LiChrosorb RP-18, 10 micron column operated in a reversal phase and a carrier solvent of 80 percent acetonitrile and 20 percent water by volume, HPLC use permitted qualitative identification of the admixture substances used. The amount of admixture used, however, was not determined. The purpose of this last phase of the study was to seek quantitative evaluation of the admixtures used. The purpose was not fulfilled.