"Three basic mortar formulae were used in this investigation, each mix having some different materials present and each having its own gelling characteristics. The study was directed along the theory that the dry materials used play an important part in the hardening. Certain admixtures were tested and several were found to improve the workability after storage. The presence of additional sodium ions in the mortar was found to be helpful in overcoming the gelation but these tended to lower the refractoriness of the mortar.
A study was made of the base exchange capacities of the dry materials and the material with the highest base exchange capacity was found to contribute more to the gelation than did one without so many exchangeable cations. The flame photometer was employed to analyze the concentration of the alkaline ions in the effluents obtained during the electrodialysis of a clay and the results indicated that the peaks in the time-current curve of the dialysis may be indicative of the relative amounts of the two valence-type ions removed.
The effect of the mineral constituents of the clays used in the mortars was discussed. One of the clays was found to contain considerably more free silica than did the other clay. This did not seem to have too great an effect on the hardening during the storage period. Opal was found to be present in one of the clays and differential thermal curves were given in an attempt to use this method to determine whether or not this mineral was present.
It was concluded that the gelation was not due to any one single factor but that the most predominant cause was the presence of polyvalent exchangeable cations adsorbed to the clay or other dry materials used in the mortars. The presence of free silica was found to cause some hardening, but this was deemed only a minor factor. The use of bentonite as a suspending medium in the mortar was found to be detrimental to the workability of the mortar as its high exchange capacity and high percentage of exchangeable magnesium was found to increase the gelation considerably"--Abstract, pages ix-x.
Herold, P. G.
Fuller, Harold Q., 1907-1996
Knapp, W. J. (William John), 1916-
Materials Science and Engineering
Ph. D. in Ceramic Engineering
Missouri School of Mines and Metallurgy
x, 95 pages
© 1949 James Irving Mueller, All rights reserved.
Dissertation - Open Access
Refractory materials -- Testing
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Electronic OCLC #
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Mueller, James Irving, "A study of the gelation of air-setting refractory mortars" (1949). Doctoral Dissertations. 506.