American CementsRogers & Manson, 1898 - 299 páginas |
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Términos y frases comunes
50 sieve alumina American rock cements amount artificial cements average barrels of cement beam Binnewater brand of cement brick briquettes brittle Building calcination carbonate of lime carbonic acid CEMENT COMPANY cement mortar cement rock CEMENT TESTING MACHINE cent clay color column combination compression concrete crushed crushers CUMMINGS day in air days in water Eddystone Lighthouse engineer evaporation exposed frost grinding hardening hydrated hydraulic cement hydraulic lime kilns laboratory layers lime and alumina limestone load magnesia masonry material meshes mills mixed mixture molds months natural cement natural rock cement neat cement neat tests obtained percentage Portland cement pounds pozzuolana practically produced proportions River Rock cement Roman cement Rosendale sample of cement Silicate of lime silicic acid specimens square inch stone temperature tensile strain tensile strength tensile test testers Ulster County uniform week weight wire writer
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Página 108 - 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 unslaked lime, will disappear with age.
Página 44 - Now, all the pottery belonging to the mound-builders, age, which I have seen, is composed of alluvial clay and sand or a mixture of the former with pulverized fresh-water shells. A paste made of such a mixture...
Página 108 - The determination of this question requires that the tests should also be applied to the cement as found in the market. Its quality may be so high that it will stand the tests even if very coarse and granular, and on the other hand, it may be so low that no amount of pulverization can redeem it. In other words, fineness is no sure indication of the value of a cement, although all cements are improved by fine grinding. Cement of the better grades is now usually ground so fine that only from 5 to 10...
Página 109 - 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.
Página 109 - ... off level; the molds in each instance, while being charged and manipulated, to be laid directly on glass, slate or some other non-absorbent material. The molding must be completed before incipient setting begins. As soon as the briquettes are hard enough to bear it, they should be taken from the molds and be kept covered with a damp cloth until they are immersed.
Página 12 - ... go to pieces, and those exposed to air and weather only are comparatively of inferior strength. By this memorable discovery Smeaton overset the prejudices of more than . two thousand years, adopted by all former writers, from Vitruvius in ancient Rome to Belidor in France and Semple in this country, who agreed in maintaining that the superiority of lime consisted in the hardness and whiteness of the stone, the former of which may or may not be accompanied by water-setting or powerful cementing...
Página 104 - The cake used for setting test will be preserved, and when examined from day to day must be of uniform color, exhibiting no blotches or discolorations. 30. Fineness. — The cement must be evenly ground, and when tested with the following standard sieves, must pass at least the following percentages. No. 50 sieve, having 50 meshes per lineal inch, 98 per cent; No. 74 sieve, having 74 meshes per lineal inch, 94 per cent; No. 100 sieve, having 100 meshes...
Página 113 - The material that seems likely to give the best results is the crushed quartz used in the manufacture of sand-paper. It is a commercial product, made in large quantities and of standard grades, and can be furnished of a fairly uniform quality. It is clean and sharp, and although the present price is somewhat excessive (3 cents per pound), it is believed that it can be furnished in quantity for about $5.00 per barrel of 300 Ibs.
Página 107 - It cannot be said that a new and untried cement will by the same tests be proved to be satisfactory; only a series of tests for a considerable period, and with a full dose of sand, will show the full value of any cement; and it would be safer to use a trustworthy brand without applying any tests whatever than to accept a new article which had been tested only as neat cement and for but one day only. The test for compressive strength is a very valuable one in point of fact, but the appliances for...
Página 114 - The molds furnished are usually of iron or brass, the price of the former being $2, and of the latter $3 each. Wooden molds, if well oiled to prevent their absorbing water, answer a good purpose for temporary use, but speedily become unfit for accurate work. A cheap, durable, accurate, and noncorrodible mold is much to be desired.