| Description |
v, 61 leaves : illustrations ; 29 cm |
| Summary |
"In many industries whose product or products contain alkalies, the determination of the amount present is very essential from a control standpoint. This present investigation is concerned with a method for quantitative determination of sodium and potassium as accurately as by customary chemical methods and which will require less time in its operation. Portland cement is a product in which the amount of sodium and potassium present is of prime importance. This importance of the alkalies upon the behavior of concrete was first noticed in California where, after numerous tests, it was definitely shown that with certain aggregates there was a reaction between the aggregates and with cements having comparatively high alkali contents. In the summary of the above paper, the failure of the artificial stone in Los Angeles was attributed to the use of an unsuitable aggregate, and altered lime-soda feldspar. It was shown that the altered feldspar (plagiolase) contained a large quantity of the zeolite, laumontite, which was primarily responsible for the disintegration; also kaolin, which tended to hasten the process of disintegration after it had started; also calcite, which, though relatively stable, tends to dissolve rapidly when finely divided and in contact with water. However, feldspar aggregate free from serious alteration when quarried, will, under any conditions, undoubtedly outlast any cement matrix which binds it together in the form on concrete"--Introduction, leaf 1. |
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