US2165437A - Floor and method of making the same - Google Patents

Description

Jilly 11, 1939. ADAM FLOOR AND METHOD OF MAKING THE SAME Filed March 12, 1937 gjvwewbyo R dine r2 .fldam/ Patented July 11,1939

UNITE STATES PATENTYOF'FICE Application March 12, 4 Claims;

This invention relates to improvements in floors andthe method of making the same, and its obs.

to prevent the concrete mixture from sticking to' any tamping or vibrating mechanism that may be used to compact the mass of concrete.

Third, to use the foregoing covering for the additional and ultimate purpose of materially speeding up the laying ofthefloor, the several details whereby this object'is attained and re-- sulting from the use of said covering being reserved for the description which follows.

Fourth, to construct a concrete floor made with a minimum amount of water, thus automatically producing a most superior quality of concrete, as any excess amount of water beyond the necessary amount to properly compact the floor and hydrate the cement produces an inferior quality of concrete.

Fifth, to construct a concrete floor Without the process of floating the surface of same after it has been tamped inorder to prevent any disturbance in the location of the aggregate in which it has been placed and compacted, and further to prevent any loosening or uncompacting of the mass which does take place in floating.

Other objects and advantages will appear in the following specification, reference being had to the accompanying drawing, in which:

The view is a. diagrammatic perspective which illustratesthe various steps in carrying out the method, the thickness of the resulting layers merely being illustrative.

In carrying out the invention a foundation concrete slab I is laid down or constructed according to known methods. Intermediate and upper toppings 2, 3, are applied to the base or foundation I. The intermediate topping 2 comprises a wet concrete mixture which is screeded ofi evenly, and contains a sufiicient amount of water for the hydration of the combined amounts of cement used in both toppings 2 and 3.

The topping 3 comprises a dry concrete mixture which is spread upon the intermediate topping 2 and is screeded evenly as well. By the term dry is meant that the materials in the topping 3 are only moist enough to barely hold together, or completely devoid of moisture, as distinguished from the nature of the layer 2 1937, Serial No". 130,596

ch s ctu y a wet mixture. The surface of. the dry mixture is slightly compacted by troweling. This assists in speeding up capillary attraction, by which the water travels from the wet layer 2 into the dry, or semi-dry, layer 3. Before undertaking the steps of tamping, a flexible, absorbent and porous covering. dis placedv upon the topping or uppermost layer 3.

Thisv covering may comprise burlap, cloth or any other suitable material of a similar naturehaving the qualities of flexibility, porosity and absorption. Mention has been made of the advantages of using'this covering. The purpose specifically set forth is that of interposinga guard, so tospeak, between the uppermost layer 3' and the tamping tool 5.

' In its capacity as a guard this covering 4 pre vents the concrete mixture from sticking to the tamping tool, whatever itsnature may be. The tamping is done upon the covering, and theforce of the blows is imparted to the concrete structure underneath. This function is readily accomplished because the flexible nature of the covering does not deaden the force of the blows to any appreciable extent.

But there are other advantages arising from the use of the flexible covering 4. Since the latter is porous, it permits the escape of air from the concrete mass while it is being compacted. The absorptive quality of the covering insures taking up any excess water that may not be absorbed by the upper dry layer 3, thereby leaving a minimum amount of water in the concrete mass for the hydration of the cement in the mass.

Further, the covering 4 being of a fine, porous nature Which permits the air to pass through it, prevents suction when said. covering is removed from the surface of the compacted concrete, thereby insuring a minimum amount of disturbance of the surface of the topping or layer 3.

After the covering 4 is removed, the condition of the concrete surface is such without there being any danger of any of the concrete mass adhering to the toolshould further tamping and compacting be found necessary. This step in the manufacture of the floor is illustrated at 6, the tamping tool 5a merely being a duplication of the tamping tool 5 already mentioned. The final act is to finish the surface at 1 with a hand trowel 8.

The use of the covering 4 in this method is not to be confused'with the more or less common practice of covering concerete roadways with a textile material for the purpose of keeping the concrete mass wet. It has been emphasized herein that one of the main purposes of the covering 4 is to enable compacting the concrete mass without the possibility of the tool picking up any of the surface cement. It has been found by actual practice that it is unnecessary to float the surface before the final troweling, as is common practice.

It has been demonstrated further that a floor laid according to this method may be troweled immediately without waiting for hydration or for evaporation, before finishing by troweling. From the first placing of the mass of concrete to the finish by troweling there is a time lapse of hardly more than ten minutes.

It has been found that foundation slab 1, intermediate layer 2, and top layer 3 may be constructed in one operation. The object of using layer 2, which may be composed of finer aggregate and cement than used in slab l, is to make a more even surface to receive top layer 3. This makes a more even division between layer 2 and 3. It has been found also that in some cases that intermediate layer 2 may be omitted. Such a case would occur wherein the foundation slab and the topping 3 are constructed in one operation. In this case topping 3 is applied directly to the foundation slab l and then compacted by means of the tool 5, the covering 4 being interposed and finally smoothed off with the trowel 8. In this case topping 3 is slightly compacted by troweling as previously described, before the tamping takes place.

I claim:

1. The herein described method consisting of laying a concrete foundation slab, spreading an intermediate topping of wet concrete mixture over said foundation slab, spreading an upper topping of dry concrete mixture over the intermediate topping, covering the upper topping with a flexible porous and absorbent covering and maintaining said covering in place for a predetermined period, and tamping upon said covering to induce the extraction of Water by percussion from the intermediate topping and promote its upward penetration into the upper topping.

2. The herein described method consisting of laying a concrete foundation slab, spreading an intermediate topping of wet concrete mixture over said foundation slab, spreading an upper topping of dry concrete mixture over the intermediate topping, covering the upper topping with a flexible porous and absorbent covering, and maintaining said covering in place for a protracted period, and traversing said covering with a percussion instrument to pound the superimposed layers therebeneath with a progressive step motion.

3. The herein described method consisting of laying a cementitious. concrete foundation slab, spreading a moist cementitious layer over said slab, covering said layer with a large, loose flexible porous and absorbent fabric sheet, and transversing the surface of said sheet with a percussion instrument to compact said layers into one solid mass.

4. The herein described method consisting of spreading a layer of wet concrete mixture upon a foundation, spreading a topping of dry concrete mixture over said layer, covering the topping With a flexible porous and absorbent covering and maintaining said covering in place for a protracted period, and tamping upon said covering to induce the extraction of water by percussion from said layer and promote its upward penetration into the topping.

ROBERT ADAM.

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