Bulletin of the New York State Museum, Issue 44

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The University, 1901 - Cement - 968 pages
 

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Page 726 - One of these cakes, when hard enough, should be put in water, and examined from day to day to see if it becomes contorted, or if cracks show themselves at the edges, such contortions or cracks indicating that the cement is unfit for use at that time. In some cases the tendency to crack, if caused by the presence of too much unslacked lime, will disappear with age.
Page 734 - If cracks do appear, the cement is not to be condemned, but the results of the decisive test with the cakes hardening on glass plates under water must be waited for. It must, however, be noticed that the heat test does not admit of a final conclusion as to the constancy of volume of those cements which contain more than 3$ of calcium sulfate (gypsum) or other sulfur combinations.
Page 865 - ... this that an argillaceous limestone (cement rock) mixed with a comparatively small quantity of purer limestone, as in the Lehigh plants, requires less thorough mixing and less fine grinding than when a mixture of limestone and clay (or marl and clay) is used, for even the coarser particles of the argillaceous limestone will vary so little in chemical composition from the proper mixture as to affect the quality of the resulting cement but little should either mixing or grinding be incompletely...
Page 730 - In selecting cement for experimental purposes, take the samples from the interior of the original packages, at sufficient depth to insure a fair exponent of the quality, and store the same in tightly closed receptacles impervious to light or dampness until required for manipulation, when each sample of cement should be so thoroughly mixed, by sifting or otherwise, that it shall be uniform in character throughout its mass.
Page 727 - If satisfactory results are obtained with a full dose of sand, the trials need go ' no further. If not, the coarser particles should first be excluded by using a No. 100 sieve, in order to determine approximately the grade the cement would take if ground fine; for fineness is always attainable, while inherent merit may not be.
Page 730 - Of the regular grade, from 15# to 37# of crushed quartz, no. 3 passes a no. 30 sieve, and none of it passes a no. 50 sieve. As at present furnished, it would need resifting to bring it to the standard size; but, if there were sufficient demand to warrant it, it could undoubtedly be furnished of the size of grain required at little, if any, extra expense. A bed of uniform, clean sand of the proper size of grain has not been found...
Page 730 - Wire Gauge. The object is to determine by weight the percentage of each sample that is rejected by these sieves, with a view not only of furnishing the means of comparison between tests made of different cements by different observers, but indicating to the manufacturer the capacity of his cement for improvement in a direction always and easily within his reach.
Page 651 - ... longer, is more elastic and consequently tougher, will stand higher temperature, resists better the action of water and chemical agents, and is much more cheaply produced. On account of the slight difference in specific gravity of the two substances composing it, lime glass is also less liable to striation. In the manufacture of plate glass, which is ground and polished, it is found that glass which is rich in lime is harder to polish than that poor in lime, but holds its polish better and longer...
Page 770 - While there are outcrops of the limestone at a number of points in the valley followed by the Harlem railroad, only two large openings have been made. These are at Dover Plains and South Dover. At Dover Plains, G. & JH Ketcham have operated a quarry along the highroad one half mile southeast of the town. The rock is a soft, fine grained dolomite of gray or white color. The opening is about 200 feet long, 20 to 30 feet wide and 10 feet deep. No analysis was made of the stone but several samples were...
Page 731 - MACHINES No special machine has been recommended, as those in common use are of good form for accurate work, if properly used, though in some cases, they are needlessly strong and expensive. Machines with spring balances are to be avoided as more liable to error than others. It is by no means certain that there exists any great difference in well made machines of the standard forms given. AMOUNT OF MATERIAL The amount of material needed for making five...

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