A Request

Should you find this book helpful in building with concrete, we would consider it a favor to have you so inform us. Likewise, we would appreciate a description (and a photograph if possible) of whatever you have built in concrete.

In this way you will assist us in aiding others in the same way we hope we have helped you.

If you do not fully understand any part of this book, or if you desire further information, write us and we shall be glad to do anything else we can.

CONCRETE CONSTRUCTION
for the HOME and the FARM

“CONCRETE FOR PERMANENCE”

1916

THE ATLAS PORTLAND CEMENT COMPANY
30 Broad Street, New York 134 So. LaSalle Street, Chicago
Philadelphia Boston St. Louis Minneapolis Des Moines

INDEX

Special Index to Directions

General Index

Concrete in the Country

How the American Farmer is Solving
His Conservation Problem

Conservation is no new problem—it is as old as life itself. It becomes a highly important question to the person or the nation only when the resources scarcely supply the demands. Such is the situation in the United States to-day. In the early days the removal of the forests was necessary that much grain might be grown. The young Nation had to have money, and as farming was the only means at hand to furnish it, the natural fertility of the fields was reduced. But the money thus supplied was merely a long-time loan on the Bank of Natural Resources. To-day the vanishing forests and the failing fertility of the fields bear witness that the loan is now due. Hence the problem of conservation. Strange as it may seem, the farmer is using one material not only to replace lumber but also, in a way, to restore the fertility of his fields—that material is concrete.

The national and state governments and the railroads were the first to make extensive use of concrete. Not only did the beauty and mystery of this new construction naturally appeal to the farmer, but he concluded that the railroads did not use it, in preference to wood, steel and stone, merely to decorate the landscape. He knew too much about railroads. So strongly did the railroads’ idea of economy (the dollar argument) appeal to him that the farmer of the West is now building practically everything about the farm of concrete. At first, and quite naturally, land-owners in the rock and gravel regions began using this new form of construction; but, since its cheapness in first cost and value in lasting qualities have become generally known, a wave of enthusiasm for farm structures of concrete has swept the entire country. A gravel pit is now more valuable than many a gold mine.

With little help other than looking and listening, the farmer grasped the idea of a concrete walk, and being a natural inventor and jack-of-all-trades, improved on the method by adding a small curb next to his flower bed to keep the dirt from washing on the white walk. This walk was a blessing to the boy—all the time formerly given to scrubbing and weeding the old brick walk could now be devoted to fishing. The yard walk was extended to the barns and outlying buildings. Wading through seas of mud and resulting tracked-up kitchen floors became a thing of the past. By simply increasing the width of the walk, a cellar floor was provided and the farmer had a dry cellar. This was so clean and so odorless that he considered such a floor fit for that most immaculate of all places—the milk house. Concrete cellar hatchway and steps, safe under the heaviest barrel of vinegar, and water-tight, were made in a manner similar to walks.

Brick work had long been laid up in a mixture of Portland cement and sand. As this kept the water out, the farmer reasoned that it would keep the water in, and he started to build cistern floors, walls and cover of Portland cement concrete at one-third to one-half the cost of the old brick cistern.

After a little more observation, he quit digging deep cistern-pits, with the necessary annoyance of thawing out frozen pumps and carrying water—he built a concrete cistern on top of the ground and made the pumping and carrying of the water a mere matter of turning a faucet in the kitchen and the bath room.

Several years ago corn was so cheap that in some sections it was burned for fuel instead of coal. No consideration was then given to the bushels wasted in muddy feed lots. If the mud became too deep, the feeding was transferred to the blue grass pasture. To be sure, as the sod wore out, the feeding-place had to be changed; but somebody had advanced the idea that this particular method of feeding was good for the soil. Many farmers had tried wooden feeding floors and had found them a paying proposition as far as the saving of feed was concerned, in the general health of the animal, and in the shortened time of fattening. But two great drawbacks were the rats that infested them and the constant need of repairs. In concrete the thoughtful farmer saw the possibilities of an ideal floor—an easily cleaned, rat-proof, disease-proof surface upon which his hogs, sheep, cattle and poultry might consume the feed even to the smallest particle.

So satisfactory did the feeding floor prove that the same treatment suggested itself as a remedy for the fly-breeding, muddy holes in the earthen floors and the rat-infested wooden floors of the barns. But the careful horseman held up a bit: he was afraid that stamping at the flies, his valuable Percherons, Shires and Morgans might stiffen up their legs. He experimented by placing concrete floors in his open sheds, which were usually too muddy for the stock to lie down in stormy weather, just when the straw stacks afforded no protection and when he needed the sheds most, and found such floors satisfactory.

To-day the manure question is one of the most important considerations of the time. The virgin soil of the prairies, of the cleared woodlands and of the broken-up ranges, for a few years produced immense crops of cotton and grain. To build up the decreasing productiveness of the fields the farmer soon learned that barnyard manure was the best thing at hand. The passing of the cattle ranch and the resulting higher price of meats made stock raising very profitable even to the small farmer, especially since feeding floors made it possible for him to return to the soil, in the form of manure, all the fertility which had been removed in the growing of grain. Leaving out the matter of foods, the strength of manure is dependent directly upon its manner of storage. Manure piled on the bare ground or in wooden pens loses one-third to one-half of its fertilizing properties on account of leaching, due to heavy rains and tramping of the stock, and later because of fermentation or “firing” brought about by the lack of sufficient moisture. This fertilizer usually sells at from 75 cents to $1.00 per load.

The farmer of to-day builds a water-tight concrete cistern or pit in which he stores the manure and keeps it as moist as need be. He extended the concrete floors to the dairy barns with the result that they were so clean, so odorless and so sanitary that state inspection is now often insisting and will soon force careless dairymen to put in such floors as a means of protecting the public health from disease germs carried in unclean milk. The drop gutters carry all the liquids, the richest part of the manure, formerly wasted, to the manure pits. Consequently, one load of manure, thus properly preserved, is easily worth two loads as ordinarily stored. By confining the manure in pits and by paving the barn lot with concrete, the farm has been rid of the chief breeding-place of flies, gnats, mosquitos and disease. Moreover, such an interior court, surrounded by buildings and concrete wind walls, forms an excellent feed and winter exercise lot.

Government statistics show that the human death-rate on the farm, in spite of the fresh food and pure air, is greater than the death-rate in the city. State University tests of drinking-water have shown beyond a doubt that the waters of many ordinary shallow and unprotected wells contain the germs of such dangerous diseases as typhoid fever. To prevent the polluted surface waters from seeping into the well, many people are covering their wells and walling them up with water-tight concrete. Others are sinking “driven” wells and protecting them with concrete housings. The principle of deep wells for pure water, among other things, has made gasoline engines a necessity on the farm. These engines and hydraulic rams at springs, firmly set and housed in concrete, supply an abundance of water for the concrete reservoirs or elevated, reinforced pressure tanks. From these places of storage water is distributed to float-controlled, rot-proof watering tanks and troughs of the same material. With such a water supply animals never suffer for water. Even springs and mouths of drain tile are improved and the water made clean and wholesome by the use of concrete.

Thus the conservative farmer of the present time gives careful attention to the health, comfort and convenience of his family. Moreover, the care of the animals is not neglected. A concrete dipping vat holds the liquids which free horses, cattle, sheep and hogs of mange, lice, mites, ticks and fleas. The Department of Agriculture is stamping out the Texas fever and sheep scab by insisting on the use of dipping tanks throughout all quarantined districts. A hog wallow with concrete sides and bottoms gives the hog the pleasure afforded by running streams and at the same time protects him from the cholera often carried down from animals affected further up stream.

The continual rotting off of wooden fence posts, the constantly increasing cost of new ones, and the annual expense of fence repairs, called for the introduction of some substitute. Land is entirely too valuable and life too short to attempt growing wooden posts. Even before the telephone and telegraph companies had thought of the possibilities of concrete in this line, a few venturesome farmers had given reinforced concrete posts a trial and found their use not only advisable from the standpoint of cheapness in first cost, but more profitable on account of their everlasting qualities. The Department of Agriculture at Washington has thoroughly investigated the use and methods of making concrete posts and is furnishing a free bulletin describing the process. Such posts are also valuable in the culture of grapes and hops.[1]

The use of concrete in farm buildings has gradually developed from the ground upward. The drip soon rots out timber near the ground and eventually crumbles away the brick foundation. At first, uselessly making the walls as heavy as those of brick, the farmer gave concrete a trial in foundations. Concrete is stronger than brick. As a wall it kept the basement and back barn dry. The height of the foundation wall increased until it supported the joists of the hay loft. Finally, after a study of methods, of reinforcing, the entire barn—basement, walls, floors, mangers, troughs, gutters, beams and even the shingles—became concrete. Matches or lanterns accidentally dropped on concrete floors in concrete barns do not cause the terror of former times. The oil will burn until smothered out with a horse blanket, but no further damage will be done.

Poultry raising on many farms has become well-nigh impossible on account of rats. To free the farm of these destructive animals, as a last resort and in spite of the assertions that the grain would spoil, the thoroughly provoked farmer put concrete floors under his cribs and granaries. Corn matured enough not to spoil on other floors kept perfectly on concrete. The rats had to go; they could not get through such floors. And so we might continue, describing how farmers have successfully used concrete in building every class of structure from a stepping stone to the entire group of farm buildings.

Just as there are right and wrong methods of farming, so, too, are there right and wrong ways of using concrete. It is the aim of this book to give such directions and information as will enable the reader to build with concrete surely and successfully.

“CONCRETE IN THE COUNTRY” does not pretend to fully cover the subject—the field is too large to be exhausted in one such volume. But the publishers have attempted to deal with as wide a variety of types of concrete construction as is possible in the space available.

Fuller details are given in other pamphlets, which will be furnished free to anyone who will write to the address given on the first page of this book.

Publications issued by the Association of American
Portland Cement Manufacturers,
Philadelphia, Pa.

At the office of the above Association there are available books dealing with concrete construction of all classes. These books describe the construction of silos, fence posts, tanks, troughs, concrete roads, and many other works. Upon request there will be sent a list of the publications in print. The books, with one or two exceptions, are sent free of cost.

What is “Concrete”?

Concrete—a manufactured stone—is made by mixing together Portland cement, sand and stone (or gravel). Various proportions of each are used, depending upon the use to which the concrete is put. About half an hour after mixing these materials together, the mass begins to stiffen, until, in from half-a-day to a day, it becomes so hard that you cannot dent it with the hand. By a month the mass is hard like stone—indeed, harder than most stones.

Materials

Before attempting to describe the actual process of mixing and placing concrete, it will be well for us to have a pretty clear understanding as to the nature of the materials with which we are to work, and how best these may be selected.

Portland Cement

For domestic use, Portland Cement is furnished in cloth sacks and paper bags. When furnished in cloth sacks, the price per barrel includes the cost of the sacks (four sacks making a barrel). When the sacks are returned in good condition, the amount charged is rebated to the customer. Where cement is furnished in paper bags, the price also includes the cost of the paper bags which, however, are not returnable.

Many cement users prefer their cement furnished in paper bags, as it does away with the bother of keeping account of the cloth sacks and sending them bade to the dealer for credit.

The paper bag or cloth sack of cement weighs 94 pounds, and four such make a barrel of 376 pounds.

The storage of cement is very important. It must be kept in a dry place. Once wet, it becomes hard and lumpy, and in such condition is useless. If, however, the lumps are caused by pressure in the store house, the cement may be used with safety. Lumps thus formed can be easily broken by a blow from the back of a shovel.

In storing cement, throw wooden blocks on the floor. Place boards over them and pile the cement on the boards, covering the pile with a canvas or a piece of roofing paper. Never, under any circumstances, keep cement on the bare ground, or pile it directly against the outside walls of buildings.

Sand

Do not use very fine sand. If there is a large quantity of fine sand handy, obtain a coarse sand and mix the two sands together in equal parts; this mixture is as good as coarse sand alone.

Sometimes fine sand must be used, because no other can be obtained; but in such an event an additional amount of cement must be used—sometimes as much as double the amount ordinarily required. For example, in such a case, instead of using a concrete 1 part cement, 2 parts sand, and 4 parts stone, use a concrete 1 part cement, I part sand, and 2 parts stone.

Besides being coarse, the sand should be clean, i. e., free from vegetable matter. “But,” you say, “how shall I tell whether the sand is what you call clean?”

The presence of dirt in the sand is easily ascertained by rubbing a little in the palm of the hand. If a little is emptied into a pail of water, the presence of dirt will be shown by the discoloration of the water. This can be discovered also by filling a fruit jar to the depth of 4 inches with sand and then adding water until it is within an inch of the top. After the jar has been well shaken, the contents should be allowed to settle for a couple of hours. The sand will sink to the bottom, but the mud, which can be easily recognized by its color, will form a distinct layer on top of the sand, and above both will be a clear depth of water. If the layer of mud is more than one-half inch in thickness, the sand should not be used unless it is first washed.

Having discovered that the sand you contemplate using is not clean, and provided you cannot readily obtain any that is clean, you may use what you have, provided you wash it in the following manner:—

Build a loose board platform from 10 to 15 feet long, with one end a foot higher than the other. On the lower end and on the sides, nail a board 2 by 6 inches on edge, to hold the sand. Spread the sand over this platform in a layer three or four inches thick, and wash it with a hose. The washing should be started at the high end, and the water allowed to run through the sand and over the 2 by 6-inch piece at the bottom. A small quantity of clay or loam does not injure the sand, but any amount over 5 per cent. does.

Stone or Gravel

This is known as the “coarse aggregate” of concrete. Great care should be used in its selection. The pebbles should be closely inspected to see that there is no clay on their surface. A layer of such clay prevents the “binding” of the cement. If necessary stone or gravel may be washed in the same way as above described for sand. Indeed, it is more easily done than sand, as the water flows through the larger voids in the gravel more readily than through the voids in the sand. Dust may be left in the crushed stone without fear of its interfering with the strength of the cement, but care should be taken to see that such dust is distributed evenly through the whole mass, and when dust is found in stone, slightly less sand should be used than ordinarily.

As to the size of stone or gravel, this must be determined by the form of construction contemplated. For foundations or any large thick structure, use anything from ½ to 2½ inches in diameter. For thin walls use ¼ to 1-inch stone.

The best results are obtained by the use of a mixture of sizes graded from small to large. By this means the spaces or voids between the stones or pebbles are reduced and a more compact concrete is obtained. Moreover, this method makes it possible to get along with less sand and less cement.

Pure Water Necessary in Mixing

Water for concrete should be clean and free from strong acids and alkalies. It may be readily stored in a barrel beside the mixing board and placed on the concrete with a bucket. If you are at all in doubt about the purity of the water that you contemplate using, it would be well to make up a block of concrete as a test, and see whether the cement “sets” properly.

Proportioning the Mixture

That mixture in which all the spaces (called “voids”) between the stone or gravel are filled with sand, and all the spaces between the sand are filled with cement, is the ideal mixture. This mixture is rarely attained, as the voids in each load of gravel and sand vary slightly, and in order to be absolutely safe, it is well to use a little more cement than will just fill the voids.

Fig. 1.—Quantities of cement, sand, and gravel in 1: 2: 4 concrete mixture, which means 1 part cement, 2 parts sand, 4 parts crushed stone or gravel, and the resulting quantity of concrete, which is only slightly greater in size than the gravel, the sand and cement filling the voids in the gravel.

TABLE I.

Showing the Quantities of Materials and the Resulting
Amount of Concrete for Two-bag Batch.

As above explained, concrete is composed of a certain amount of cement, a larger amount of sand, and a still larger amount of stone (or gravel). To determine how much of each of these materials to use, we must first consider the type of work we wish to undertake. For ordinary work about the farm (silos, tanks, cisterns, fence posts, well curbs, etc., etc.) use twice as much stone as sand, and twice as much sand as cement. This is called a 1: 2: 4 mixture—meaning that there are in that mixture:

• 1 part of cement,
• 2 parts of sand,
• 4 parts of stone or gravel.

For sidewalks, gutters, etc., a “weaker” mixture is sometimes used, consisting of:

• 1 part of cement,
• 2½ parts of sand,
• 5 parts of stone or gravel.

The proportions should always be measured by volume, and the best way to do the measuring is by the use of a home-made “measuring box,” of any kind of rough boards having straight sides, but with no top or bottom. The size of these measuring boxes is determined by the proportion desired for your mixture. For such boxes you need the following sized lumber:

• 4 pieces 1 inch by 11½ inches by 2 feet rough (ends of sand and stone boxes).
• 2 pieces 1 inch by 11½ inches by 4 feet rough (sides of sand box).
• 2 pieces 1 inch by 11½ inches by 6 feet rough (sides of stone box).

Note: The two pieces 4 feet long and the two pieces 6 feet long have an extra foot in length at each end to be made into a handle, as shown in [Fig. 3.]

For a 1: 2½: 5 mixture, you require the following sized lumber:

• 4 pieces 1 inch by 11½ inches by 2 feet (ends of sand and stone boxes).
• 2 pieces 1 inch by 11½ inches by 4 feet 6 inches (sides of sand box).
• 2 pieces 1 inch by 11½ inches by 7 feet (sides of stone box).

Note: The two pieces 4 feet 6 inches long and the two pieces 7 feet long have an extra foot in length at each end to be made into a handle, as shown in [Fig. 3.]

To illustrate the use of the measuring box, let us once more assume that a 1: 2: 4 mixture is required, and that the amount of finished concrete needed is 8½ cubic feet. By referring to the [table on page 11] it will be noted that two bags of cement are required, also 3¾ cubic feet of sand and 7½ cubic feet of stone or gravel. Under “size of measuring box” it is found that the sand should just fill a box 2 feet by 2 feet by 11½ inches, and that the stone should fill a box 2 feet by 4 feet by 11½ inches. Lay the sand box, or frame, on the mixing platform and fill it. Then raise the box. Empty two bags of cement on the sand and mix as described under “[Mixing],” see pages 14-22. Even off the mixture thus obtained with your shovel, place the stone measuring box on top of the mixture and fill it. Raise the measuring box—and you have the correct amount of stone all ready to be mixed with the cement and sand. It is important to measure both the sand and stone loose in the box—never “pack” them.

For purposes of explanation, size of mixture will be referred to as a “batch” of so many bags of cement. Thus, a “two-bag batch of concrete” would mean one requiring two bags of cement, with the sand and stone proportioned accordingly, as shown above.

For a “four-bag batch of concrete” it would be necessary to multiply the amount of stone and gravel by 2, also multiplying the cubic contents of the measuring box by 2, and using four bags of cement instead of two.

The [table previously referred to] also shows the amount of water for different sized batches, but it is to be noted that the quantity of this ingredient is only approximated. Use the amount indicated in the table for the first batch, and if it proves too wet for the use desired, reduce the amount of water; if too dry, increase the amount of water. Always use a bucket in measuring the amount of water, as this secures uniform results.

Natural Mixture of Bank Sand and Gravel

Naturally mixed bank sand and gravel are sometimes found in the right proportions for making concrete. Generally, however, there is far too much sand for the gravel, and great care should be exercised in using this class of material. Unless the mixture runs very even throughout the bank, and is found to be made up of one part sand to two parts gravel, it is better to screen the sand out of the gravel and prepare the materials in the usual way.

Herewith is a table showing the quantities for a natural mixture of bank sand and gravel. The quantities can be found in the same way as in [Table I, on page 11].

TABLE II.

Showing the Quantities of Materials and the Resulting Amount of Concrete for Two-bag Batch, Using Natural Mixture of Bank Sand and Gravel.

There are three kinds of mixtures, in general, on concrete work:—

1st.—Very Wet Mixture.—Concrete wet enough to be mushy and run off the shovel when handling, used for thin walls or for thin sections, etc.

2d.—Medium Mixture.—Concrete just wet enough to make it jelly-like, used for foundations, floors, etc. To better describe this mixture it may be said that a man should sink ankle deep if he were to step on top of the pile.

3d.—Dry Mixture.—Concrete like damp earth, used for foundations, etc., where it is important to have the concrete “set” up as quickly as possible.

The difference between the mixtures is, that the dryer the mixture the quicker will the concrete “set up”—but in the long run, when carefully mixed and “placed,” the results from any of the above mixtures will be identical. It may be said, however, that a dry mixture is the harder to handle, must be protected with greater care from the sun or from drying too quickly; and lastly, is likely—unless used by most experienced hands—to show voids or stone pockets in the face of the work when the “Forms” are removed. The less the voids in the stone or gravel, the greater will be the volume of the concrete. In general, the amount of concrete will be greater in each instance than is shown in the table—especially when gravel is used.

Fig. 2.—Concrete Mixing Plant, showing Concrete Board,
Tools, etc., Necessary for Mixing Concrete by Hand.

Tools

One great advantage of concrete, so far as the farmer is concerned, lies in the fact that, generally speaking, it necessitates no outlay for tools, for it so happens that most of the tools needed for forms of concrete construction are the very ones every farmer uses—

Shovels—One for each man on the job.

Wheelbarrows—At least two, preferably those with sheet iron bodies.

Rake.

Water Barrel.

Several Water Buckets.

A Tamper or Rammer—This is made of wood with handles nailed to it, as shown in [Fig. 2]. The measurement is 4 inches by 2 inches by 2 feet 6 inches.

A Garden Spade.

A Sand Screen, made by nailing a piece of ¼-inch mesh wire screen, 2½ feet by 5 feet in size, to a frame made of 2-inch by 4-inch scantling.

In addition to the above tools you will require a Mixing Board. This is simply a water-tight platform. It should be (for a two batch mixture and for two men to work on) about 10 feet square. Make it out of 1-inch boards 10 feet long, surfaced on one side, using 5 cleats to hold the boards together. The cleats should measure 2 inches by 4 inches by 9 feet. If 1-inch by 6-inch tongued and grooved roofers can be obtained, these will answer very nicely, provided they are fairly free from knots. The object of having surfaced boards is to make the shoveling or turning easy. The boards should be so laid as to enable the shoveling to be done with and not against the cracks between the boards. The boards must be drawn up close in nailing, so that no cement “grout” will run through while mixing.

For a larger job, a slightly larger mixing board will be needed.

In setting up your mixing board, choose a place giving plenty of room near the storage piles of sand and stone. Block up your concrete board level, so that the cement grout will not run off on one side, and so that the board will not sag in the middle under the weight of the concrete.

Wheelbarrow “Runs”

You will also have to make wheelbarrow “runs” leading from your mixing board to the spot where the concrete is to be placed. Do not use, for these runs, any old boards that are handy. Make a good run—smooth, and, if much above the ground, at least 20 inches wide. This one feature will lighten and quicken the work to a remarkable extent.

How to Mix Concrete

Having selected the proper materials and arranged the mixing board and runs, the next step is the actual process of mixing.

The proportions of materials and the nature of same for various types of work have already been [described on pages 11-13]. In following the mixing instructions here given, considerable assistance will be obtained by referring to the illustrations with which instructions are interspersed.

Fig. 3.—Lifting off the Sand Measuring Box and Getting Cement Ready.

Fig. 4.—Spreading the Cement Over the Sand.

The Hand Mixing Method

There are many ways of “hand mixing,” all having the same good results. The way described here we believe to be the one best calculated to obtain good results with a minimum of labor. In this description, and the accompanying illustrations, we have taken as a basis a “Two-Bag Batch” of 1: 2: 4 concrete.

First load your sand in wheelbarrows from the sand pile, wheel on to the “Board,” and fill the sand measuring box, which is placed about two feet from one of the 10-foot sides of the board, as shown by the diagram in [Fig. 3]. When the sand box is filled, lift it off and spread the sand over the board in a layer 3 or 4 inches thick, as shown in [Fig. 4]. Take the two bags of cement and place the contents as evenly as possible over the sand ([see Fig. 4]). With the two men at points marked “x” and “xx” on the sketch below [Fig. 4], start mixing the sand and cement, each man turning over the half on his side of the line AA. Starting at his feet and shoveling away from him, each man takes a full shovel load, turning the shovel over at the points marked 1 and 2 respectively in [Fig. 4]. In turning the shovel, do not simply dump the sand and cement at the points marked 1 and 2 in the diagram under the cut, but shake the materials off the end and sides of the shovel, so that the sand and cement are mixed as they fall. This is a great assistance in mixing these materials. In this way the material is shoveled from one side of the board to the other, as shown in Figs. 5 and 6. [Fig. 5] shows the first turning, and [Fig. 6] the second turning.

The sand and cement should now be well mixed and ready for the stone and water. After the last turning, spread the sand and cement out carefully, place the gravel or stone measuring box beside it as shown in [Fig. 7], and fill from the gravel pile. Lift off the box and shovel the gravel on top of the sand and cement, spreading it as evenly as possible. With some experience, equally good results can be obtained by placing the gravel measuring box on top of the carefully leveled sand and cement mixture, and filling it, thus placing the gravel on top without an extra shoveling. This method is shown in [Fig. 8]. Add about three-fourths the required amount of water, using a bucket and dashing the water over the gravel on top of the pile as evenly as possible. ([See Fig. 9]). Be careful not to let too much water get near the edges of the pile, as it will run off, taking some cement with it. This caution, however, does not apply to a properly constructed mixing board, as the cement and water cannot get away. Starting the same as with the sand and cement, turn the materials over in much the same way, except that instead of shaking the materials off the end of the shovel, the whole shovel load is dumped as at points 1 or 2 in the diagram under [Fig. 4] and dragged back toward the mixer with the square point of the shovel. This mixes the gravel with the sand and cement, the wet gravel picking up the sand and cement as it rolls over when dragged back by the shovel. ([See Fig. 10]). Add water to the dry spots as the mixing goes on until all the required water has been used. Turn the mass bade again, as was done with the sand and cement. With experienced laborers, the concrete should be well mixed after three such turnings; but if it shows streaky or dry spots, it must be turned again. After the final turning, shovel into a compact pile. The concrete is now ready for placing.

Fig. 5.—First Turning, Sand and Cement.

Fig. 6.—Second Turning, Sand and Cement.

Fig. 7.—Filling the Stone (or Gravel) Measuring Box—First Method.

Fig. 8.—Filling the Stone (or Gravel) Measuring Box When
on Top of Mixed Sand and Cement—Second Method.

Fig. 9—Placing the Water on the Stone (or Gravel)
which is on Top of the Mixed Sand and Cement.

Mixing Natural Mixture of Bank Sand and Gravel

Spread out the mixture of sand and gravel as much as the board will readily permit, add enough water to wet the gravel and sand thoroughly, spread the cement evenly in a thin layer over the sand and gravel, and turn over, as described previously, at least three times, adding the rest of the water necessary to get the required consistency while the materials are being turned. It requires some experience to work up a natural mixture of bank sand and gravel, and if at all doubtful about the concrete made from it, first screen the sand from the gravel, and then mix in the regular way.

Fig. 10.—Mixing the Stone (or Gravel) with the Sand and Cement.

Number of Men

For the above operation only two men are required, although more can be used to advantage. If three men are available, let two of them mix as described above and the third man supply the water, help mix the concrete by raking over the dry or unmixed spots as the two mixers turn the concrete, help load the wheelbarrows with sand and stone or gravel, etc. [Fig. 5] shows a third man on the board. In this illustration, he is helping mix the sand and cement by raking it—a most effective practice.

If four men are available, it is best to increase the size of the batch mixed to a four-bag batch, doubling the quantities of all materials used. The cement board should also be increased to 10 by 12 feet as shown under “Tools.” In this case start the mixing in the middle of the board, and each pair of men mixing exactly as if for a two-bag batch, except that the concrete is shoveled into one big mass each time it is turned back on to the center of the board. When more than four men are available, the rest may place the concrete, make new runs, load wheelbarrows, etc., taking the concrete away from the board as fast as it is mixed. In this case another small concrete board should be placed next to the big “board,” so that in the last turning the batch can be shoveled over on to the small board for placing, making room on the big board to mix the next batch. The small platform need be only just big enough to hold the pile of mixed concrete.

How to Determine Quantities of Materials Needed

First figure the number of cubic feet of concrete that will be required for the work in question. Then by multiplying this number by the number under the proper column and required mixture shown in [Table III], the amounts of cement, sand, and stone or gravel can be found.

TABLE III.

Example

Suppose the work consists of a concrete silo requiring in all 935 cubic feet of concrete, of which 750 cubic feet is to be 1: 2: 4 concrete, and 185 cubic feet is to be 1: 2½: 5 concrete. Also enough sand and cement is needed to paint the silo inside and outside, in all 400 square yards of surface, with a 1: 1 mixture of sand and cement. One cubic foot of 1: 1 mortar will paint about 15 square yards of surface and requires 0.1856 barrels of cement and 0.0263 cubic yards of sand.

Solution, Etc.

Thus the necessary quantities of materials are:—

• 57½ barrels of Portland cement.
• 16½ cubic yards of sand.
• 31 cubic yards of stone or gravel.

It is always wise to order two or three extra barrels of cement, if the dealer is at considerable distance, as this avoids any possible trouble that a shortage might cause. Besides, any cement left over always comes in handy for repair work around the house or barn.

Forms for Concrete

Concrete is a plastic material and before hardening, takes the shape of anything against which or in which it is placed.

Naturally, the building of the Form is a most important item in the success of the work.

These Forms hold the concrete in place, support it until it has hardened and give it its shape, as well as its original surface finish.

Kinds of Forms

Almost any material which will hold the concrete in place will do for a Form. Concrete foundations for farm buildings require shallow trenches, and usually the earth walls are firm enough to act as a Form.

Molds of wet sand are used for ornamental work. Frequently colored sands are used for this purpose, providing both the finished surface and color to the concrete ornament.

Cast, wrought or galvanized iron is used, where an extremely smooth finish is desired, without further treatment upon the removal of the Forms. Forms made of iron are more easily cleaned, and can be used a greater number of times than those of wood. Rusty iron, however, should not be used.

By far the greatest number of Forms are made of wood, owing to the fact that lumber in small quantities can always be obtained.

Requirements of a Good Form

Plan your Forms so there will be no difficult measurements to understand. Make as few pieces of lumber do the work as you can, and do not drive the Forms full of nails. If you do the Forms will be difficult to take apart without splitting.

Forms must be strong enough to hold the weight of the concrete without bulging out of shape. When they bulge, cracks open between the planks and the water in the concrete, with some cement and sand, will leak out. This weakens the concrete, and causes hollows in the surface which look badly after the Forms are removed.

Forms which lose their shape after being used once can hardly be used a second time. A part of the erection cost of Forms is saved if the Forms are built in as large a section as is convenient to handle. This saving applies to their removal, as well as to their setting. Consequently, the lightest Forms possible, with the largest surface area, are the most economical.

How to Plan Forms

Wiring Forms Prevents Bulging.

The first consideration in planning Forms is the use to which they are to be put. Neglect of this point means waste of money and time. If they are for work afterward to be covered with a veneer coat, the finish of the surface is of small consideration, while the alignment of the Form is all-important.

If a tank or retaining wall is to be built, the fact that the Forms are not in exact alignment will hardly be noticed.

In planning Forms for large structures, the oftener each section is used, the less the cost. You save money if they are rigid in alignment, and well surfaced. In other words, if you count on using your Forms over and over again, the more nearly perfect they are, the more often they can be used, and the cheaper they become.

If Forms are to be used only once, as is generally the case on the farm, they should not be nailed so securely as to prevent their being readily taken apart, and the lumber used for something else. If often pays to put them together with screws. If nails are used, do not drive them home.

Care Needed in Selecting Lumber for Forms

The selection of lumber is of importance. If the Forms are to be used over many times, surfaced lumber, matched, tongued, and grooved stuff, free from loose knots, is an economy. If, however, they are to be used only once, almost any old plank will do. By nailing a board on the outside of the cracks or over the bad knot, and filling with a little clay, the Form is made tight.

Green lumber is preferable to kiln-dried or seasoned stuff. Seasoned stuff, when wet (either by throwing water on the form before placing the concrete or by absorbing the water from the concrete) warps, and the shape and tightness of the Form are damaged.

Originally only surfaced lumber was used for Forms, dependence being placed on it for giving a finish to the work. While to-day other than smooth surfaces for concrete are the fashion, surfaced lumber has some advantages. The Forms fit together better and are easier to erect. They are more easily cleaned. They are easier to remove. All these items reduce the cost of the work. The saving effected will of course depend on the difference in local price between finished and rough lumber.

How to Clean

Particles of concrete stick to the Forms. In order to prevent this, give the surface next the concrete a coat of oil or soft soap. Linseed, black or cylinder oil may be used. Never use kerosene.

Before erecting, paint the Forms with the oil or soap. Then carefully protect them from dust or dirt until erected. Upon removal, immediately clean off all the particles of concrete sticking to the surface. A short-handled hoe will take off the worst, while a wire brush is most effective for finishing. Be careful not to gouge the wood in cleaning, as it will spoil the surface of your next section of concrete. It will not be found necessary to repaint after each time of use. Watch the surface and repaint if it appears dry in spots.

If chips or blocks of wood fall inside the Forms while erecting, carefully remove them. The space inside the Forms is intended for the concrete; and care should be taken to see that only concrete is placed there.

The necessity of Forms presents a problem calling for the use of that ingenuity for which the farmer is justly famed. Forms can be economically placed in so many ways that only one example will be given. A foundation Form in place is [shown in the photograph]. Note the simple and easy method of bracing. Also note how lumber is saved from cutting by allowing the sides to project, as well as the studding.

For this building, 18 by 24 feet, trench 18 inches wide and 2 feet deep—total cost of setting forms $4.00. The lumber was all on hand and can be used again.

How to Place Concrete

No time should elapse between the “mixing” and the “placing.” Directions for placing must of necessity be general, and the farmer must use his own judgment as to how to handle this part of the concrete work, in connection with whatever particular job he has on hand. The important thing to remember is, that the materials should not separate in placing.

You may shovel the concrete off the board directly into the work; you may shovel it into wheelbarrows, wheel it to position and dump, or you may carry it to the proper place by buckets and hoisting apparatus.

Directions for Placing

Ordinarily speaking, concrete should be deposited in layers about 6 inches thick.

After placing concrete in the Form, it should be “tamped” lightly with a wooden or iron tamper (or rammer) until the water shows on the top and no stones are left uncovered by mortar.

In order to obtain a smooth face on the concrete, the mixture should be carefully “spaded” immediately after “placing”—on the side next to the Form where the finished concrete will be exposed to view. By “spading” is meant the working of a spade or a beveled board between the concrete and the side of the Form, moving it to and fro, and up and down. This forces the large stones away from the boarding, or Form, and brings a coating of mortar next thereto, thus making the face of the work present an even, smooth appearance.

The Necessary Tools

On certain jobs—as, for instance, in the case of a 6-inch silo wall—a spade cannot very well be used, on account of the narrowness of the concrete section. In this event, use for surfacing, a thin wooden paddle, made from a board 1 inch by 4 inches, and gradually sharpened to a chisel edge at the end. The sharpening should be on one side only, and in using this paddle place the flat side against the Form, as shown in illustration.

When the mixture is a dry one, great care must be used in this “spading” or surfacing, in order to obtain uniform results, but in the case of a wet mixture, spading is only required as an added precaution against the possibility of voids in the face of the work, and in many cases it is not necessary at all.

Protection of Concrete after Placing

Green concrete should not be exposed to the sun until after it has been allowed to set for five or six days. Each day during that period the concrete should be wet down by sprinkling water on it, both in the morning and afternoon. This is done so that the concrete on the outside will not dry out much faster than the concrete in the center of the mass, and should be carried out carefully, especially during the hot summer months. Old canvas, sheeting, burlap, etc., placed so as to hang an inch or so away from the face of the concrete will do very well as a protection. Wet this, as well as the concrete. Often the concrete Forms can be left in place a week or ten days; this protects the concrete during the setting-up period and the above precautions are then unnecessary.

Points to Remember

It may be well, in summing up, to emphasize the following points:—

• 1st. The materials must be perfectly clean.
• 2d. The mixing must be in proportions carefully determined.
• 3d. The mixture must be used while absolutely fresh.

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.

Reinforcement

Principles involved

Concrete and steel render valuable assistance to each other in the support of heavy burdens. On a solid foundation, loaded from above and thus under direct pressure, a concrete column will withstand the strain of an enormous load. A much smaller load so placed as to cause stretching or bending toward one side of the same column may cause it to snap off, for concrete is strong, but brittle. On the other hand, steel is tough and elastic. In the form of rods or wire, steel withstands massive loads that tend to stretch it, and thus displays a kind of strength directly opposite to that of the plain concrete column. In modern construction these two valuable properties of concrete and steel are utilized by combining them in what is called reinforced concrete. With steel properly buried in the concrete, the column withstands not only the load which might otherwise snap it, but one many times larger, and even though it is applied at any place along its length.

Reinforcement, therefore, is steel in the form of rods, bars or wires, buried in concrete to take up and to withstand the strains which tend to stretch or to bend the concrete. A concrete fence post is merely a small concrete column. Reinforced, it easily stands the strain from usage in a fence line.

The value of reinforcing concrete posts properly may readily be seen in the figure. If a load (L) is raised so that its weight is supported on one side by a wooden post, the post will bend. The fibre in the wood on the side away from the load may be tough and elastic enough to prevent the post from breaking, and when released the post will spring back into its former position. In the third figure a No. 9 wire (W) is fastened securely to the wooden post at the top and at the ground surface, and is supported along its length by the struts (S). If the same load is applied, the post will not bend, because the wire takes up the bending or stretching strain. This is precisely the case with the reinforcement in a concrete post. Supported along its length by the concrete, the wire (W) or steel in other shapes takes up the bending or stretching strains. Since the load which causes bending or stretching may come from any direction, concrete posts are reinforced on every side; otherwise they might break in a manner somewhat similar to that in which the wooden post bends when the reinforcement is not on the proper side of the post.

In the effort to be safe it is a common fault to insert more reinforcement than is absolutely necessary. This adds needlessly to the cost, for concrete becomes stronger as it grows older.

Kinds of Reinforcement

With regard to the roughness of the outside, metallic reinforcing materials are divided into two classes, smooth and corrugated or deformed. The general result of the many tests carried on in testing laboratories seems to indicate that in strength of bond, if the concrete is sufficiently rich and well mixed, smooth surfaces give satisfactory results. Two kinds of reinforcement are much used—bars and wire.

Bars.—Round bars three-sixteenths or one-fourth of an inch in diameter are the size and kind most used on the farm. The stock on hand at blacksmith shops and hardware stores is generally from steel that stretches too easily and therefore is not the best for reinforcement. Companies which make a specialty of reinforcing materials can furnish both rods and bars which stretch only under very large loads.

Wire.—The development of the wire fence has produced a material well suited for reinforcing purposes. Of equal size, such wire will produce a stronger reinforcement than the material above described. In order to obtain straight wire of the necessary length, the coils ordinarily placed on the market should not be straightened out. Straight wire can be obtained from dealers in the same manner as baling wire; that is, either single or twisted into two or three-ply cables, and of the length desired. The plain, ungalvanized fencing wire is the proper kind, for galvanization adds nothing to the strength, and the metal will not rust when incased in the concrete.

Concrete Sidewalks and Floors

Concrete floors are nothing more than sidewalks of large size, and are formed by casting slabs in place.

The description given is an economical and practical method of laying sidewalks or floors, easily adapted to any use where concrete is found advantageous. This description will therefore apply not only to the building of sidewalks, but to all flat surfaces of concrete resting on the ground.

Lasting Qualities

Concrete floors must remain hard and in position to be permanent. To accomplish this, good materials must be used, and proper methods of mixing and placing must be followed. Only in this way can settlement cracks, upheaval by frost or roots of trees, contraction cracks, crumbling, and general failure be avoided.

Settlement Cracks

To avoid settlement cracks, thoroughly ram the ground after excavating for the foundation. This gives a solid bearing to the concrete slab.

Upheaval by Frost

To prevent upheaval by frost a foundation formed of crushed stone, hard furnace cinders, brick bats broken to about a 2-inch size, broken tile or any other hard porous material, should be laid in such a way as to obtain perfect drainage. Never use ashes.

If freezing occurs, room is in this way provided between the pieces of stone for the expansion of the ice.

If this foundation is placed in clay soil, side outlets or blind drains of tile should be provided at points along the walk where they are necessary, leading into holes filled with cinders or crushed stone, which will allow the surrounding earth to soak up the accumulated water. Clay soil holds the water collected in the drainage foundation, and if it becomes entirely full of water, the ice formed during freezing weather will upheave the walk.

Upheaval by Tree Roots

Upheaval by tree roots can be easily avoided by cutting out all roots which run under the pavement at a less depth than 18 inches below the surface of the ground.

Contraction Cracks

Cement concrete expands and contracts by changes of temperature in the same way as steel. It is, therefore, necessary to cut joints which will allow for this expansion and contraction. The concrete must be cut entirely through to the bottom of the slab with a trowel, cleaver or other instrument, the joint formed being from ⅛ to ¼ of an inch wide. Blocks formed in this way should not be greater than 6 feet square (36 square feet).

Scaling or Crumbling of the Surface

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.

Specifications

Drainage Foundation

Stake out the lines of the walk, or dimensions of the floor. Excavate to a depth of 16 inches, ram and tamp the ground thoroughly and evenly and fill in 12 inches with clean large cinders, broken stone, pebbles, brick bats, broken tile or other material selected. Place in position wooden forms made of 2 by 4’s, these 2 by 4’s to be set on edge and held in position by stakes firmly driven in the ground, the top edge to be located so as to accurately outline the established grade or slope of the walk or floor.

A walk should be higher in the center, or at one edge, to insure the water running off. This slope should be ¼ of an inch to the foot.

Selection of Materials

Particular attention must be paid to the selection of the materials and their mixing.

The concrete should be composed of gravel or crushed stone all of which will pass through a ¾-inch mesh screen, and be collected on a ¼-inch mesh; sand, free from loam and preferably coarse, and a grade of Portland cement guaranteed to meet all the requirements of the Standard Specifications as adopted by the American Society for Testing Materials and the American Society of Civil Engineers.

Proportions

The strength of the slab is not always governed by its thickness. The greater strength is obtained by properly proportioning the gravel or crushed stone, sand and Portland cement, so that all the spaces between the stone are filled with sand and cement.

The Portland cement, sand and gravel or crushed stone should be mixed in proportions, if the sand is not very coarse, of 1: 2: 4—which means, 1 part Portland cement, 2 parts sand, 4 parts gravel or crushed stone, all passing a ¾-inch mesh and all collected on a ¼-inch mesh. If the sand is coarse and the crushed stone or gravel well graded in size of particles, it may be mixed in proportions of 1 part Portland cement, 2½ parts sand, 5 parts gravel or broken stone. All proportions are measured by volume.

Bank run gravel is often used for sidewalk work, particularly where a good bank can be found on the farm. It is safer, if this material be used, to screen out the pebbles, using them as stone, measuring the quantities of stone and sand as described above. Concrete should not be laid in freezing weather.

Consistency of Concrete

Mix the concrete as described on [page 15] to a consistency that when tamped, it will not quake, but it should be sufficiently wet so that some moisture will rise to the surface under tamping.

Placing

Divide the walk by setting forms at right angles to the side forms. The cross forms can be made of 2 by 4’s. These provide for expansion and contraction joints. Hold these forms in place by driving stakes through the foundation into the ground on the opposite side from where the concrete is to be placed. Spread the concrete over the drainage foundation to the thickness of the walk or floor, and in slabs not over 6 feet square. The thickness of a walk should be 4 inches, a driveway 6 inches, a floor over which a wagon may be driven 6 inches, and all other floors 4 inches.

Fill in every other slab, placing enough forms to use up all the concrete mixed in one batch. No batch should stand longer than one half hour before being placed.

Tamp the concrete thoroughly. Use a template, with ends resting on the side forms, and cut to a curve to give the walk the necessary crown. The concrete should be tamped so as to conform to the curve of the template. If one edge of the walk is made higher than the other, use a straight edge resting on the side forms. Tamp the concrete to conform to the straight edge.

Mix another batch of concrete, remove the cross forms and place the concrete between each slab, forming a continuous walk. Use the template or straight edge and tamp as before. Immediately after placing the closing slab, work a straight trowel or knife down through the entire depth of the concrete between each slab, thus insuring a perfect contraction joint. Smooth the surface with a wooden float.

A neat appearance may be given the contraction joints by running a jointer along the top, thus smoothing the edges. Do this before the concrete gets too hard. The sides of the walk may be smoothed in the same way by use of an edger.

When the concrete is nearly hard go over the surface with a piece of oakum or a stiff brush, removing the marks of the float and giving a good even wearing surface which will not be slippery. In using oakum or a brush be careful not to remove the larger pieces of stone. If surfacing in this manner disturbs the particles of stone and roughens the walk to too great an extent, allow the walk to harden a little more before finishing in this way. At the end of each day’s work see that the last slab is entirely filled and finished.

All interior floors, such as floors of cellar, barns and stables require no contraction joints. They are made by laying a solid continuous sheet of concrete. All outside floors should have contraction joints forming slabs not over 6 feet square. These are provided the same as in sidewalks. A feeding floor is formed merely by sidewalk pavements set side by side. Instead of using a template for crowning the surface, use a straight edge, each end resting on the extreme outside forms to give a slope to the feeding floor. Contraction joints for exterior floors are formed in the same way as for sidewalks. The concrete is also placed in alternate slabs and finished in the same way as sidewalks. When completed the walk or floor must be continuously protected from the rays of the sun and from the wind for at least three days, so that it will not dry out at any time. This can be easily done by covering the concrete when it is hard with hay, straw, or old carpet. This covering should be thoroughly soaked with water, and kept wet for three or four days or longer if economy will permit.

While the walk or floor is hardening it should be so protected as to prevent persons or animals from disfiguring the surface by walking on it.

A Foundation Gutter and Walk

Foundation gutters catch the water from off the rain-beaten side of the building, quickly carry it away, and, by preventing “seepage,” keep the cellar, basement, or ground-floor dry. In sloppy, muddy weather, they also serve as convenient walks around the out-buildings.

Determine the grading or sloping of the gutter bottom from observation of direction of the flow of surface water during rain storms, or from local conditions, such as location of outlet into underground drain. Excavate a trench 1 foot 6 inches in width, 10 inches deep on each side, and hollowed out to 13 inches deep in the middle. Use a straight edge or a grade cord, together with a spirit level, to give the bottom of the trench the desired slope or “fall.” For each foot of length a slope of one-eighth inch will be sufficient.

Clean the dirt off the foundation wall with a stiff broom or brush.

In the bottom of the trench place a 6-inch foundation of well-“tamped” gravel, brickbats or crushed stone.

Make a one-bag batch of concrete in proportions, 1: 2½: 5. Have the mixture just wet enough to tamp well.

Place a 4-inch thickness of concrete to form a dish-shaped gutter 3 inches deep in the middle. Every five feet, make an expansion joint ⅛ of an inch wide by inserting a metal strip not less than 7 inches wide and 18 inches long, or by cutting a joint entirely through the concrete with a straight spade. Smooth the surface with a wooden float.

Repairs to Farm Buildings

Since wood always fails first at the ground, the use of concrete on the farm has developed from the ground up. After a farmer has had to replace several sills or blocks of wood, he begins to look about him for a new material which will not rot or will not have to be replaced. Concrete is his natural selection.