US2009984A - Method of leveling cellular concrete - Google Patents

Description

July 30, 1935. K. P. BILLNER.

METHOD 0? LEVELING CELLULAR CONCRETE Filed June 27, 1955 INVENTOR. w' I? 49% mation therein of a great number of small air or gas filled cells, as a result of which the Patented July 30, 1935 METHOD OF LEVELING CELLULAR CONCRETE Karl P. Billner, New

York, N. Y., assignor to The Aerocrcte Corporation of America, New York, N. Y., a corporation of Delaware Application June 27, 1933, Serial No. 677,858

1 Claim.

My invention relates to an improved method of leveling cellular concrete or in other words of producing Cellular a level top surface for the same. concrete is characterized by the forterial is light, sound-proof and fireproof. The cells in question may be formed chemically by the use of a water dissociating powder like aluminum as disclosed in U. S. Patent 1,087,098 to Aylsworth soap foam and Dyer or physically by the so the admixture of or in any other. suitable way.

The aerated nature of the material makes it possible to compress the top surface before the cellular concrete has set, thereby obtaining a dense compressed upper layer in the material, having but few gas or air bubbles therein. Such bubbles as remain are of reduced size, owing to the compression applied thereto.

Heretofore, the attempt has been made to secure a dense. upper layer of the material by pressing upon the top surface thereof, as by darbying it with a board. In practice this is not a satisfactory operation since the material tends to stick to the board and therefore the upper surface becomes uneven. As a result it has been found necessary to apply some kind of a filling coat if an even surface is required.

My improved method consists in applying pressure to the top surface of the cellular concrete by means of a roller similar to an ordinary garden roller.

Such a roller not only applies a very heavy pressure to the cellular concrete but also results in the formation of a smooth upper surface therein. By merely darbying the material but little pressure is applied so that the upper portion of the mass is not nearly so dense as when a roller is used. Furthermore as I have pointed out; a much more level surface is obtained by the use of a roller than can be secured by darbying.

In carrying my invention the cellular concrete in suitable forms of size result in the desired slab. The amount shape to of cellular cause the slightly higher than into effect I first pour and concrete thus poured is sufficient to top surface after expansion to rise the desired top level of the finished slab. Screeds are set at a convenient distance apart so that the tops of the screeds are in the the slab.

same plane as After the aeration of the concrete has been completed the'concre or substantially so and at least before te has obtained its final set and is still the finished surface of plastic the roller is rolled over the concrete resting upon the screeds above mentioned. This operation results in a compression of the upper portion of the cellular concrete, by causing the gas or air bubbles therein near the surface to be compressed in size, and at the same time much of the gas orair irom the cells adjacent the surface will escape therefrom. The resulting slab when it becomes hard will beformed with a dense upper portion substantially free from the gas or air cells and at the same time the upper surface will be smooth and level.

Preferably the roller is covered with a flexible sheet such as cloth or rubber fitted loosely thereto. In operation the loose fitting sheet forms a 15 sag at the back and the sheet therefore adheres to the compressed surface behind the advancing roller. The portion of the sheet behind the roller will therefore be successively ripped off from the surface of the compressed concrete in the operation. In this way there is less tendency of portions of the upper surface to be removed than if a plane roller were used or if the flexible sheet were tightly applied.

Ifind furthermore that it is possible to secure a perfect surface without any sticking of the material to the roller if suitable provision is made to keep the roller well greased with oil or lubricated with water during its operation.

In order that my invention maybe better understood attention is directed to the accompanying drawing forming a part hereof and in which Figure l is a longitudinal view showing the concrete in process of being levelled.

Figure 2, a transverse sectional view on the line 2-2 of Figure 1, and v Figure 3, a transverse sectional viewon the line 3-3 of Figure 1.

In these views like parts are represented by the same numerals.

The form or mold in which the concrete is poured is provided with sides l.-|.' Within this mold is poured a mass 2 of cellular concrete which upon expanding as shown in Figure 3 rises somewhat above the sides. A roller 3 supported by 45 the sides I rolls the concrete down from the level of Figure 3 to that of Figure 2 This roller is covered by a sheet of cloth"! sufliciently loose to form aloop behind the roller 3 as it moves from rightto left in Figure 1.

Having now described my invention what I claim is newtherein and desire to secure by Letters Patent isas follows: e I The method of producing slabs of cellular con-- crete which consists in permitting a ma s of face thereon and simultaneously with the application of such rolling pressure and in the rear of the area of application thereof, in continuously performing a ripping action on the compressed material, substantially as set forth.

KARL P. BILLNER.

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