US 2151420 A
Description (OCR text may contain errors)
March 21 1939. cARvEL 2,151,420
CONCRETE WALL SECTI ON Filed May 3, 1935 2 SheetsSheet l g 2 INVENOR March 21, 1939. R; CARVEL 2,151,420
CONCRETE WALL SECTION Eild May 3, 1935 2 Sheets-Sheet 2 Fi .2 1 1,3 ,12 9 1s 9 Z 7 2 lNv NToR I BY 2.12 V A;
Patented Mar. 21, 1939 PATENT OFFICE CONCRETE WALL SECTION Richard Carvel,
New York, N. Y.
Application May 3, 1935, Serial No. 19,592
This invention relates to building construction and pertains more particularly to a method of forming concrete wall. sections having the external appearance of masonry or brick walls of 5 the usual character, and capable of supporting loads to which such walls are ordinarily subjected, but formed in such manner as toreduce the expense which is usually incidental tothe making of masonry and brick walls of usual methods.
It is an object of the present invention to provide a concrete wall section, and a method of forming the same, which shall provide two connected concrete slabs separated by an air space intended to prevent penetration of moisture through the wall section. By thus constructing the said wall sections, the outer slab serves as the usual outer wall of the building, while the inner'slab takes the place of the usual lath and plaster, so that the entire wall of the building may be precast in one operation, instead of being put together piece by piece by several operations according to usual methods.
Other objects and advantages of the invention will appear hereinafter.
A preferred embodiment of the invention selected for purposes of illustration is shown in the accompanying drawings, in which,
Figure l is a top plan View showing the wall section in the process of formation, certain parts being broken away.
Figure 2 is a section. on the line 2--2 of Figure 1.
Figure 3 is a section on the line 33 of Figure 1.
Figure 4 is an enlarged detail sectional view illustrating the method of making dowel holes.
Figure 5 is a section through one of the spacing blocks.
Figure 6 is a section through a'modified form 40 of spacing block, and
Figure 7 is an enlarged sectional view showing the method of forming the air space.
In previous patents issued to me No. 1,809,504, dated June 9, 1931 and No. 1,856,906, dated May 3, 1932, methods of forming wall sections have been described in which wall sections of substantial size are formed on the ground or on any level surface which may be provided for the purpose, which said sections, after being allowed to set and harden, may be hoisted into place, either by hand or by suitable machinery, to form an integral part of the wall under construction. The outer surface of said sections may be decorated to present the external appearance of masonry or brick work, or a combinationv of the two, or may be decorated with other suitable material, and the said sections may be designed as regards thickness and reinforcement to have the reqllisite strength to support the stresses to which they may be subjected. The said patents also 5 describe methods of treating abutting edges of adjacent wall sections so as to conceal the lines where sections are joined so that the external surface of the finished Wall may present an unbroken surface similar in appearance to a 10 masonry or brick wall constructed by usual methods.
According to the present invention, the principles described in my issued patents are utilized, but the wall sections are so formed that an air 15 space is provided between the front and rear slabs of these sections, the said air space being useful to provide insulation and to prevent penetration of moisture through the wall section. Accordingly, the inner slabs of the wall sections may 20 be used as the interior walls of the rooms of the building, thereby eliminating the necessity of lath and plaster.
Referring to the drawings, a form I may be provided of any desired length and width, and 25 of a depth suflicient to provide a wall section of the desired thickness. For purposes of illustration, stone has been selected as the decorative facing material, although it will be understood that brick or other facing material may be employed as described in said patents. When using stone, a layer of sand 2 is spread over the bottom of the form, and a layer of stone 3 is laid on the sand. At intervals sufficient to provide sections of suitable size for convenient handling are placed separating strips 4 of rubber or other suitable flexible material, the said strips being preferably sufliciently flexible so that they may conform readily to the shape of the individual stones or units as illustrated in Figures 1 and 3. Preferably thesaid rubber strips are provided with a longitudinally extending rib 5 for purposes hereinafter described.
After these rubber separating strips are placed,
a layer of concrete 6 is poured into the mold to a 4 depth suflicient to provide an outer wall of the desired thickness, all as described in said prior patents. Preferably, the width of the rubber separating strips 4 should be substantially equal to the combined thickness of the stone and concrete layers 3 and 6 and should not protrude substantially above the upper surface of the concrete layer.
Next, it is desirable to provide for the formation of the air space between the slab previously described which constitutes the outer wall, and the slab hereinafter described which constitutes the inner wall. It has been proposed heretofore to form concrete wall sections having inner and outer walls separated by an air space by pouring a layer of concrete, laying a layer of sand thereon, then pouring a. second layer of concrete, and then, after the concrete was set and hardened, washing the sand from between the concrete layers, thus leaving an airspace between, the inner and. outer Walls being tied together by metal reinforcing rods. This method has not been entirely satisfactory because of the fact that it was difficult to make the air space of uniform thickness, and
. consequently both the air space and the inner wall had to be made somewhat thicker than would otherwise have been necessary.
According to the present invention, in order to overcome these difiiculties, I provide spacer blocks 9 preferably of concrete, having embedded therein metal tie rods ID. If desired, the ends of these rodsmay be bent over as at I! in order to form a better bond with the concrete. As soon as the concrete layer 6 is poured, I place a plurality of these spacer blocks thereon with the lower face of the blocks resting on the concrete, and with the lower ends of the tie rods embedded in the concrete, and with the other ends of the tie rods projecting upwardly. These spacer blocks form a permanent part of the finished wall sections.
Preferably these spacer blocks. are arranged in rows as illustrated in Figure 1, and between the rows of spacer blocks, I place temporary spacer members l2, preferably in the form of wooden boards having a thickness approximately equal to or slightly less than the thickness of the spacer blocks 9. Boards having a thickness of approximately 1" are sufficient for this purpose. In the form illustrated in the drawings, the said boards extend lengthwise of the form from one end to the other, although it will be understood that the said boards can be arranged crosswise if preferred. The boards should be of a width to substantially fill the space between adjacent rows of spacer blocks 9, and the remaining space between the boards and between the spacer blocks 9 is filled with sand l2.
In order to permit convenient removal of the boards l2 after the section is completed, each board is preferably wrapped in a sheet of rubber l3, one edge of which is secured to a metal key M extending lengthwise of the rubber sheet for a purpose hereinafter described.
After the spacer members 9 and i2 are in place, and the remaining space has been filled with sand, a second relatively thin layer of concrete I is poured which forms the inner wall of the section. It is also desirable to break the inner wall along lines which correspond generally to the divisions established by theseparators 4, and accordingly separators l6, preferably of rubber, may be placed in the upper layer of concrete, extending across the layer in the same direction as the separators 4.
After the block thus formed has been permitted to set and harden, the form is removed, and the boards l2 are withdrawn lengthwise through their rubber coverings. After the boards are withdrawn, the rubber sheets l3 may be wound up on the keys M and also withdrawn. The sections of the completed block may then be separated and' the rubber separators 4 and W are removed. The sand is then washed outof the air space and the sections are ready to be erected in the building.
If desired, a modified form of permanent spacer blocks may be employed which provide additional protection against transmission of moisture from the outer wall to the inner wall. The said modified form is illustrated in Figure 6 and comprises a plurality of layers of concrete 28, 2| and 22, each layer being separated from the next layer by a layer of Waterproof material such as waterproof paper 23. The provision of such separating layers of waterproof paper prevents penetration of moisture through the concrete, but it has been found in some instances that moisture penetrates along the metal tie rods. Accordingly, as. an additional means of protection, two tie'rods 24 and 25 are used in each block, the rod 2 extending through the concrete layers 20 and 2| and the rod 25 extending through the layers 2| and 22.
In some cases, it is desirable to provide longitudinally extending passages 26, sometimes called dowel holes, through the wall sections in order to permit the sections to be tied together with metal reinforcing rods as they are erected. Such passages may be conveniently formed by placing a temporary form member, such as a pipe 21, in the form above the layer of stone at whatever level it is desired to have the passage. Preferably the pipe 21 is wrapped with a sheet of rubber 28 to one edge of which is affixed a longitudinal extending key 29, so that after the concrete is set and hardened, the pipe 2'! may be withdrawn, and the rubber sheet may then be rolled up on the key 29 and also withdrawn.
When sections thus formed are set in place in the building, the adjacent sections fit snugly one against the other and may be permanently joined by pouring grout (a mixture of cement, water and sand without any gravel or stone) into the dowel holes, with or without previous insertion of metal reinforcing rods, from which it spreads laterally through the ke-yways formed by the ribs 5. In this manner, the adjoining sections are easily fitted together in such manner that it is impossible to detect the joint from the exterior except upon closest examination.
It will be understood that the invention may be variously modified and embodied within the inner and outer walls being spaced by a plurality V of relatively small concrete blocks having a layer of waterproof material "extending transversely thereof and tending to prevent transmission of moisture from one wall to another, and having embedded therein metal. tie rods extending into and embedded in said inner and outer walls, each of said blocks being bonded to'both said inner and outer walls.
3. A concrete wall section comprising inner and outer walls separated byan air space, said inner and outer walls being spaced by a plurality of relatively small concrete blocks comprising at least three layers of concrete separated by layers 7' 1 of waterproof material extending transversely thereof and tending to prevent transmission of moisture from one wall to another, and having embedded therein metal tie rods extending into and embedded in said inner and outer walls, each of said tie rods extending only part way through the block in which it is, embedded, and being separated from one of'said walls by at least one layer of said waterproof material.
4. A concrete wall spacing block comprising at least three layers of concrete separated by layers of waterproof material, a metal tie rod entering one face of said block and extending through two layers of concrete but through only one layer of waterproof material, and a second metal tie rod entering the opposite face of said block and extending through two layers of concrete but through only one layer of waterproof material, both of said rods extending through one common layer of concrete.
5. A concrete wall section comprising inner and outer walls separated by an air space, said section being broken transversely into a plurality of smaller sections having matched surfaces which fit together, said surfaces having a keyway formed therein, said sections having longitudinal passages therethrough communicating with said keyways and affording access for the introduction of grout to bond the sections together.