US2129769A - Method of constructing upright concrete walls - Google Patents

Description

Sept; 13, 1938. w. A. JENNINGS METHOD OF CONSTRUCTING UBRIGHT CONCRETE WALLS Filed July 27-, 1956 mm w ij lzlldfiifl 'ckzz/zz/z j I &y a Margy;

Patented Sept. 13, 1938 UNITED STATES PATENT OFFICE METHOD OF CONSTRUCTIN G UPR'IGHT v CONCRETE WALLS Application July 27, 1936, Serial No. 92,755

4 Claims,

'The object of my invention is to provide animproved'metho'd of constructing upright concrete walls'having a relatively great degree of strength and durability and at relatively low cost formaterial and workmanship.

' 'll/llore'specifically, it is my object to provide a method of this character in which the exposed surface of the finished wall will be relatively moistureresisting and of finished and ornamentalappearance and free from bubble holes or other depressions which are usually present in such walls, and which exposed surface may, if desired,'be ornamented in various colors or patterns;

My invention consists in the construction, arrangement and combination of the various parts of the device, whereby the objects contemplated are attained, as hereinafter more fully set'forth, pointed out in my claims, and-illustrated in th accompanying drawing, in which:

Figure 1 shows a vertical transverse sectional View throughtwomold forms-supported in spaced apart position and having the materialfor form.- ing a supporting concrete wall between-said mold forms;

Figure 2 shows a similar View of one of the mold forms moved to spaced apart position relative to the supporting wall; 7

Figure 3 shows a similar view with the concrete material for forming a supplemental wall poured into the space betweenthe supporting wall-and the said mold form;

Figure 4 shows a vertical transverse sectional view through a section of the supporting wall and the supplemental wall, and illustrating the tie wires for supporting the supplemental wall when in easily broken condition in upright position against the supporting wall; and

Figure 5 shows a similar view of the completed wall with the cement coating applied-to'theexposed surface of the supplemental wall.

Referring to the accompanying drawing, I have used the reference numeral 10 toindicate generally a sheet metal mold form of the kindnow in common use and which is customarily employed for forming upright walls and other concr'ete structures. These mold forms are usually provided with outwardly extended flanges formed A with perforations II, and they are usually supported by structural beams, such, for instance, as shown at l2, and the forms are supported on thesestructural beams by clamping devices indicated generally by the reference numeral 13 which connect the structural members l2 with the mold forms I and thereby support the mold forms in an upright position. I

In connection with the use of these mold'forms it is also customary toprovide spacingbars. The spacing bar is indicated generally by the reference numeral l4 and is provided with openings through which locking pins l are extended. These pins 'go through the openings II in a mold form, and also through the openings 16 in the spacing bars,-and these spacing'bar's perform. the function of holding the mold forms in properly spaced apart position.

Mold forms of this general character are in common use, and one example maybe found'in my co-pending'application No. 673,214 filed' May 2'7, 1933.

In practice with my improved method I "first erect two moldforms in spaced apart position and hold them in said position by "the structural members on the outer faces thereof and by the spacing rods extended through them. For the purpose of practicing'my improvedmethodI also place within the space "between the mold forms a series of tie wires I! which *are'supported at" one end by oneof the mold forms, and the other end is bent for a considerable distance in posi-' tion parallel with and against the adjacent inner surface of'the other moldform. I then pour'concrete of the usual kind into the space between the mold'forms and permit same to set and harden, thereby forming what I'have herein referred to as the supporting wall. After this supporting wall hasproperly set and hardened (in practice I usually let it set and harden for three or four days) I then remove the outer mold'form and straighten out the tie wires to theposition indicated in- Figure 2. I then replace thes'aid mold form to a position slightly sp'acedapart from the supporting Wall, as indicated in Fi'gure 2. In this position it may be supported-wholly by the spacing bars l4 and pins l5, althoughflfdesired, it may be supported also by-the structural members and fastening devices 12 and 13.

When the supporting'wall and mold forms are in the position shown in Figure2, I then fillthe space with concrete in the usual manner, and when this has'been done it will be noted that the tie wires are firmly imbedded inboththe supportingwall and in what I have termed the supplemental wall on the outer face of the'supporting wall. When the supplementalwall is in a fragile, easily broken or crumbled condition and/or before the supplemental wall "has fully set, I remove theadjacent mold form. When thus removed the supplemental wall is in such condition that the tie wires will support it in its upright position and, yet, it is wet, somewhat fragile and is being subjected to the chemical ac tion which causes it to firmly set.

While the supplemental wall is in said condition I apply a coating of neat cement and water to the exposed surface thereof. In applying this coating I preferably employ pressure. In many instances I have taken the neat cement and water in what might be termed plastic condition, and by hand rubbed and pressed it against the supplemental wall. This, however, may be done with trowels or other implements. 7

Immediately after applying this neat cement coating l8 there occurs a chemical reaction and a physical bonding between the coating and the supplemental wall when both are in the condition described.

The essential constituents of Portland cement are three in number; lime, silica, and alumina. These compounds combine during the manufacturing process to form tricalcic aluminate, tricalcic silicate, and dicalcic silicate. All of these compounds are unstable and upon being wetted they rearrangeat diiferent speeds.

Tricalcic silicate reacts first with the water, forming gelatinous calcium hydrate and gelatinous silica. This reaction constitutes the initial set of the cement, taking place in about three hours time. As the hydration (combination with water) continues, the gelatinous materials form a strong bond between the particles of sand and crushed rock. The tricalcic aluminate reacts at the same speed as the tricalcic silicate but does not produce a strong bond. The dicalcic silicate acts only after several months time, therefore, all cement gets stronger as time passes.

The neat cement plastic coating will adhere perfectly to the fresh, barely set supplemental wall while it is in its said condition, because the gelatinous substances of the neat cement and the wall will intermingle and, upon hardening, form a tough and perfect bond exactly similar'to the bond between said particles of the wall itself. This type of attraction is infinitely stronger and better than any possible sort of physical bond.

During the application of the neat cement coating to the wall I preferably applypressure for the purpose of forcing the coating into air holes, pits or cracks in the exposed surface of the supplemental wall, thereby applying in addition to the chemical bonding, a physical bond due to the clinching of the coating into said air holes,

etc.

The application of the neat cement coating before described produces another advantageous result, in that it makes the exposed surface more moisture resistant because said air holes, etc., have become filled with neat cement which presents amore moisture resistant surface than that of the concrete wall.

In practice I have found that withthismethod a wall of this character may be constructed of highly ornamentalcharacter, and this is done by using ordinary dyes or coloring matter in the neat cement coating, thereby giving to the exposed surface of the wall any desired color. Furthermore, while this cement coatingv is in its plastic condition during or after its application to the supplemental wall, various patterns may be formed'in it, and it may be rough and irregular in outline simulating Various classes of natural stone.

In practice with my improved method I have demonstrated that an upright wall constructed in substance.

accordance with my improved method is relatively strong and durable. More particularly, I have demonstrated that it can be constructed at a minimum of cost because the outer mold form may be replaced by simply hanging it upon the spacing bars supported in the set and hardened supporting wall, and the amount of labor and expense required in applying the coating of plastic neat cement to the surface is not appreciably greater than that which would be required in filling up the holes in said surface left upon removal of the spacing bars.

I have found in actual practice that the proper time for the removal of the mold form from the exposed surface of the supplemental wall may be determined in a practical Way by permitting the supplemental wall to commence its process of setting and hardening for a period of about three hours. I then move a portion of the mold form away from the supplemental wall. If the cement sticks to the surface of the metal form, then I immediately replace the metal form. This operation is repeated after fifteen or twenty minutes, and when the mold form can be removed without having the concrete adhere to it, the proper time has arrived for removing the metal form bodily and at once applying the neat cement coating.

Almost immediately after the concrete is poured and permitted to come to rest, the chemical action of setting and hardening commences. At the early stages of this initial setting there is formed between thegrains of sand a gelatinous At first this gelatinous substance is in such condition that it has almost no binding effect. It, however, continues to become thicker and harder, and after about three hours it has become thick and hard enough to give to the concrete what is commonly known as the initial set, and when this initial set takes place, the mass of cement is in condition where it may be easily crumbled or broken 01f. At this stage in the setting and hardening of the cement and upright wall, unsupportedwould crumble and fall. It is, however, at this stage of the setting and hardening process that the neat cement coating must be applied in order to produce the desired result.

When the supplemental wall is in said condition I apply the coating containing neat cement and water in the proportions of about one part of cement and one part of Water, and when this is pressed against the exposed surface of the supplemental wall, it'then commences its process of setting and theformationof gelatinous substances. Thereupon the gelatinous substances contained in the coating and which are just commencing their process of setting and hardening, produce the result that the comparatively soft and fluid gelatinous substances of the coating will chemically combine with the comparatively thicker and stiffer gelatinous substances of the supplemental wall and thereby cause the coating to become an integral part of the supplemental wall. I have demonstrated that if the setting and hardening act of the gelatinous substances of the supplemental Wall is permitted to continue for a period of live or six hours, or until the gelatinous substances in the supplemental wall have become sufiiciently set so that the gelatinous substances of the coating will not penetrate and chemically unite with it, then the coating will adhere to the supplemental wall only by physical entanglement or clinching and may be easily brokenaway or removed from the supplimental wall.

By the term neat cement as herein employed I mean any mixture of cement and water, including such additions thereto as may be desirable, such, for instance, as color or other ingredients which will not alter the chemical reactions which necessarily take place in the practice of my improved method.

I claim as my invention:

1. The method of constructing an upright concrete wall, which consists in erecting two mold forms spaced apart, extending spacing bars through the mold forms, placing tie wires between the mold forms, pouring Portland cement concrete between the forms for forming an upright supporting concrete wall, permitting it to set and harden, moving one of the mold forms outwardly from the supporting wall, bending the tie wires out into the space between the wall and mold form, then pouring Portland cement concrete into the space between the supporting wall and the latter mold form, then removing the latter mold form while the cement is in easily broken or crumbled condition and its gelatinous substances have not fully hardened, the supplemental wall being supported in its upright position by said tie wires and spacing bars, removing any portion of the spacing bars that may project a substantial distance beyond the exposed surface of the supplemental wall and then applying a coating of Portland cement in plastic condition to said exposed surface while said wall is in said condition, to therebyform a chemical and physical bond or union between said wall and coating.

2. The method of constructing upright concrete walls, which consists in providing mold forms spaced apart, in upright position, placing tie devices in said space, pouring Portland cement concrete between the mold forms and permitting it to set and harden, then moving one of the mold forms to position spaced apart from the concrete and supporting it in said position and causing said tie devices to extend across the space between the concrete and the said form that has been moved, then pouring Portland cement concrete into said space and permitting the concrete to remain in said space until the gelatinous substances formed therein have become sufficiently hardened to serve as a binder to hold the particles of the concrete together in a mass which is easily broken or crumbled and which would not support its own weight in the form of an upright wall of substan:

3. The method of constructing upright concrete walls, which consists in providing mold forms spaced apart, in upright position, placing supporting devices in said space, pouring Portland cement concrete between the mold forms and permitting it to set and harden, then moving one of the mold forms to position spaced apart from the concrete and supporting it in said position and causing said supporting devices to extend across the space between the concrete and the said form that has been moved, then pouring Portland cement concrete into said space and permitting the concrete to remain in said position until the gelatinous substances formed therein have become sufiiciently hardened to serve as a binder to hold the particles of the concrete together in a mass which is easily broken or crumbled, but which will be thus supported by the previously formed concrete wall and the supporting devices, then removing one of the mold forms and supporting the concrete in upright position from the side of the concrete opposite from the exposed surface, then applying to said exposed surface a coating of Portland cement in thin plastic condition and thereby causing the gelatinous substances in the coating in their initial process of formation, to chemically combine with the partially hardened gelatinous substances of the concrete.

4. The method of constructing upright concrete walls, which consists in providing mold forms spaced apart, in upright position, placing supporting devices in said space, pouring Portland cement concrete between the mold forms and permitting it to set and harden, then moving one of the mold forms to position spaced apart from the concrete and supporting it in said position and causing said supporting devices to extend across the space between the concrete and the said form that has been moved, then pouring Portland cement concrete into said space and permitting the concrete to remain in said position 'until' the gelatinous substances formed therein have become sufficiently hardened to serve as a binder to hold the particles of the concrete together in a mass which is easily broken or crumbled, but which will be thus supported by the previously formed concrete wall and the supporting devices, then removing one of the mold forms and supporting the concrete in upright position from-the side of the concrete opposite from the exposed surface, then applying to said exposed surface a coating of Portland cement in thin plastic condition and thereby causing the gelatinous substances in the coating in their initial process of formation, to chemically combine with the partially hardened gelatinous substances of the concrete, then applying pressure to said coating while being applied to the concrete for causing a physical union of the coating and wall.

WILLIAM ALLEN JENNINGS.

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