Cement

“ It should be used on the surface only and not for the entire tile or pottery. If used without any sand or gravel, it is termed “too fat,” and has the fault of cracking sooner or later. Therefore neat cement is always backed up with a concrete mixture.
CONCRETE is a mixture of sand and cement, gravel and cement, or rock and cement. In all instances where such a mixture is made, the two parts should be mixed dry before any water is added. Only enough should be mixed to meet immediate needs as it is not best to use cement that has stood so long that it has commenced to harden. ”

“ When people first make concrete, they often expect too much of their materials. A good rule for the strongest sort of cement, strong enough for floors on which heavy machines are to stand, is one fourth of a barrel of cement, half a barrel of sand, and one barrel of gravel or broken stone. ”

“ A cement recommended as something which can hardly be picked to pieces is made as follows:—Mix equal parts of lime and brown sugar with water, and be sure the lime is thoroughly air-slacked. This mortar is equal to Portland cement, and is of extraordinary strength. For a few weeks' preservation of organic objects in their original form, dimensions and color, Professor Grawitz recommends a mixture composed of two and a half ounces of chloride of sodium, two and three-quarters drachms of saltpetre, and one pint of water, to which is to be added three per cent. of boric acid. ”

“ The common cement used in building, which is called mortar, is made of sand and quicklime mixed with water. Roman and Portland cements consist of certain kinds of clay burnt and ground. Plaster of Paris forms a useful cement, it is to be mixed with water to the consistence of cream, and it hardens in a few minutes. Glue is an invaluable cement for wood and many other purposes, it also joins any kind of broken glass or china that will not have to be subjected to much wetting. Shellac dissolved in spirit is a useful cement ”

“ It must be remembered that cement and concrete is a process of creating stone and the stones can be formed in pleasing shapes and finishes and colors according to the wish of the worker. There is great opportunity for the worker with color cement to create garden ideas either for pleasure or for remuneration and any enthusiastic worker can plan and direct such work for neighboring needs or for those who are always anxious for the different but pleasing garden creation.
A TILE EFFECT for walks or courts in regular pattern can be made by pouring a color layer over a concrete solid layer. ”

“ THE FIRST MIXTURE OF CEMENT should be a thick mixture, just as thick as will run easily when the mold is rotated. The first mixture of cement should be of neat cement and may have color mixed with it. It is poured into the mold or placed in with a spoon, and the mold is rotated slowly until the mixture has covered all the inside surfaces. The surplus, if any remains, is poured out from one of the corners. ”

“ This last layer of neat cement is the part which is to be modeled and can be made into a color by the addition of color to it. This color should be added in the dry form to the dry cement, mulled or ground well into the cement and then mixed with water until it becomes a thick cement paste that will pour slowly onto the concrete mixture first placed in the mold, until it covers the entire surface. A gentle jarring of the mold will settle the color evenly and it should then be permitted to stand until of a good modeling consistency. ”

“ Good results cannot be obtained unless you use a good cement, nor will the work be at its best unless care is taken in the selection of clean sand and clean stone.
Among the uninitiated, there is an all too prevalent idea that anything is good enough for the making of concrete. Some will tell you that sawdust, shavings, mud, clay, etc., will do to complete the mixture, but the absurdity of this notion will very soon become evident to anyone who neglects the precautions which have been above pointed out. ”

“ This quality and the rapid setting, tenacity, and strength of brickwork in cement make it a most valuable material to use in those buildings or parts of a building where great steadiness and strength are wanted, and in sewage and dock work, where there is water to contend with. A good many cements made from natural stones used to be employed, such as Medina, Harwich, Atkinson's, or Roman cement. ”

“ Has there ever been an instance in which cement was used for a purpose other than to plaster over the Land? Whether it is made into buildings, fences, wharves, Hume pipe, or to make channels, its ultimate role is inevitably to block off the Land. So for every bag of cement that is produced, that much more of the Land will be covered over. ”

“ Where a very strong cement is needed for stone-work, it can be prepared by mixing a fine cement powder—e.g., Portland cement—with liquid silicate of soda. As it dries almost at once, it must be promptly applied. It is particularly well adapted for building under water, since it then becomes extremely hard. ”

“ This clinker is ground until it is reduced to a powder, and this is the Portland cement. Portland cement is generally mixed with an aggregate to produce strength and this aggregate is usually stone, gravel or sand. The third material needed to complete the combination is water.
SUCCESS IN THE USE OF CEMENT depends largely upon cement that is fresh. Cement is very sensitive to moisture and if kept where fogs, dew or moisture of any nature is absorbed into it, the first set or “hydration” takes place and destroys its use for fine handicraft. ”

“ Curing the Concrete.—The setting action of cement is a chemical process, not merely a drying out of the water introduced in mixing the concrete. The chemical action is progressive for a long time, but is more rapid during the first few hours than during the later periods, and the concrete reaches about three-fourths of its maximum strength at the end of seven days. ”

“ A similar cement is a mixture of dried fresh curd with 1/10th of its weight of quicklime and a little camphor; it is made into a paste with water when employed. A cement for Derbyshire spar and china, &c., is composed of 7 parts of rosin and 1 of wax, with a little plaster of Paris; a small quantity only should be applied to the surfaces to be united, for, as a general rule, the thinner the stratum of a cement, the more powerful its action. ”

“ The principal causes of scaling or crumbling surfaces are improper mixing, drying out before the cement has thoroughly hardened and the use of bad materials.
Cement needs water not only when mixed, but after being placed and tamped, and until it has entirely hardened. If concrete is not kept continually wet until hard, it is weakened, and the surface of such a walk scales or becomes soft and chalky. ”

“ The cement is made from the slag-sand, common lime, and iron oxides. It is little inferior to Portland cement in strength, while it does not cost one-fourth as much. The concrete made from this cement, mixed with the "shingle," is an excellent conglomerate for use in monolithic structures. It is stated by Mr. Charles Wood, in a paper read before the British Iron and Steel Institute, that "it took two good men, with steel bars and sledge-hammers, as much as four days to cut through a wall of this concrete about twenty-six inches thick." ”

“ For glass, earthenware, porcelain, and all kinds of stoneware, these cements are excellent. A cement for glass and marble is prepared by rubbing together one part of fine pulverised glass, and two parts of pulverised fluorspar, and then adding enough waterglass solution to give it the consistency necessary in a cement.
Waterglass mixed with hydraulic cement to a thick dough makes a good cement for the edges and joints of stone and marble slabs. It is well to mix but little at a time, as it hardens very quickly. ”

“ These impurities that are inherent in the nature of the materials from which the natural cement is made and also in the process of manufacture that is of necessity followed, result in a cement that can be made and sold at a less price than Portland cement and that is inferior to it for many purposes, while, on the other hand, for a great many purposes natural cements have been found to answer every requirement and are made and used in enormous quantities. ”

“ We know that metal craftsmen{60} often roughen the surface of metal where enamels are to be placed and fired in, to insure more perfect attachment, and a similar treatment to the cement will do likewise for the cement color. When the cement tile has been removed from the water and surplus moisture shaken off a little plain neat cement is placed on the surfaces to be colored and to this the color in thin paste form is dripped from a brush. No back stroke is possible without injuring the finish. ”

“ One or two coats of cement having I then been laid over the centering, a stratum of the square tubes laid side by side, and breaking joint, is next embedded in fine cement, and the interstices between them also filled in with that material. One thin coating of cement is then laid over the whole stratum; and in a week, when this is dry, another stratum of tubes is laid over the first in a contrary direction, bedded and filled in with cement as before, and finished by a coating of the same material. ”

“ The diagrams and tables given have been compiled from results obtained in an extended course of cement tests now in progress in the Engineering Department of the State University of Iowa.
Cements, such as are used for constructive purposes, may be divided into two general classes, natural and artificial. The essential ingredients, carbonate of lime, silica, and alumina, are the same in both classes, the principal difference being the proportions in which they are present, and their purity. ”

“ Cement is more expensive than brick. The surface to be covered should, first, be levelled, then saturated with water; after which is laid a three-inch bed of cement concrete, made of gravel, sand, and cement in proper proportions. Upon this is placed a three-fourth-inch layer of cement mortar. Ordinary American, hydraulic cement may be used for concrete, but for the three-fourth-inch layer nothing but best Portland cement should be considered. Sometimes the cement work in the cellar is done by the plasterer. Outside cement work for walks requires special skill. ”

“ Concrete produces strength and the neat cement produces a smooth texture and surface. When concrete is used the cement and water will rise to the top and if the surface is worked{14} and pressed with a trowel the cement is “flowed” to the top, producing a smooth surface.
MOLDS ARE USED FOR FORMING CEMENT AND CONCRETE, and are made from wood, metal or plaster-of-Paris. The forms in all instances should be tied or braced together to prevent the moisture of the mixture from running out, as the water is essential to the successful hardening of the cement. ”

“ In making mortar the cement is mixed with the sand and the flour-like particles of the cement fit in between the grains of sand occupying a part or all of the voids. The amount of cement required in a mortar will naturally depend upon the amount of voids in the particular sand with which it is mixed and since a correct estimate of the number of barrels of cement per cubic yard of mortar is very important, and since it is not always possible to make actual mixtures before bidding, rules based on various theories have been formulated for determining these quantities. ”

“ KEENE’S PATENT MARBLE CEMENT.—This cement, which exceeds every other in hardness, is intended for interior uses, where strength and despatch in execution are required. From the smoothness of its surface, it is an advantageous substitute for wood in its application to skirtings, architrave, mouldings, &c., as it resists the action of fire, and keeps back vermin.
The coarse qualities form a paving not distinguishable from stone in colour and hardness, but of one-third the price. ”

“ When this{135} strata has partly set, it can be surfaced with trowel marks or a few twigs or weeds can be held in the hand and whipped over the cement surface, producing a roughened texture. The stone should then be covered so as to protect it from being walked upon and after the second day it should be sprayed with water to help its hardening process while drying. Do not permit the sun to prematurely dry the stones as the slower a cement dries the more durable it will be. ”

“ It is unquestionably true that quite as much depends upon the manner in which a cement is applied, as upon the cement itself. The best cement that was ever compounded would prove entirely worthless improperly applied. ”

“ A KNOWLEDGE IN MIXING CEMENT is the next step necessary in Color Cement Handicraft. The steps necessary toward mixing cement are simple, the main point being that the cement should be fresh. The student is cautioned to test the freshness of cement by seeing that no caked or hard lumps of cement are contained in the sack mixture. ”

“ II.—Mix finely powdered burned lime, 300 parts, with powdered starch, 250 parts, and moisten the mixture with a compound of equal parts of water and alcohol of 95 per cent until a paste results.
III.—Cement or plaster can be used if the surfaces are sufficiently large; cement is the better article when the object may be exposed to moisture or subjected to much pressure. A process which can be recommended consists in mingling equal weights of chalk, brickdust, clay, and Romain cement. ”