The Diaphragm Method for the Measurement of Water in Open Channels of Uniform Cross-Section Volume 8, No. 1 (Paperback)

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1917 edition. Excerpt: ...6. The tendency to shrink or expand was not found to bear any direct relation to the chemical constitution of the cement. 7. Maximum strength and hardness were obtained with about that amount of magnesium chloride solution necessary to give a good working consistency, ---that is, about 85 c. c. of solution per 100 g. of solid material. The use of much more or much less resulted in a decrease of strength and hardness. This amount of solution corresponds fairly closely to the amount required, according to the assumed formula for the composition of magnesia cement, for perfect combination between the magnesium oxide and the magnesium chloride. 8. In a dry atmosphere the per cent expansion of the specimens was found to increase with the amount of solution used; in a moist atmosphere the per cent expansion was found to decrease with the amount of the solution used. 9. In dry air the per cent loss in weight of the specimen was found to increase with the amount of solution used; in moist air the per cent gain in weight was found to increase with the amount of solution used. 10. The strength, stiffness, and hardness were found to increase with the density of the magnesium chloride solution used. Mixes made with a solution having a density less than 1.15 were found to have very little strength. A density of 1.15 would seem to be the least that should be employed in any case. 11. In a dry atmosphere the per cent expansion of the specimens was found to increase with the density of the solution; in a moist atmosphere, it was found that the per cent expansion at first varied inversely, and later directly, as the density of the solution. The relation between per cent expansion and density of solution did not, however, appear to be very clearly defined...