US 2277203 A
Description (OCR text may contain errors)
March 24, 1942. L. cs. BOULT METHOD OF CONSTRUCTING CONCRETE FLOORING AND LIKE SURFACES Filed Dec. 2, 1938 FIG.\.
Patented Mar. 24, 1942 METHOD OF CON STRUCTING CONCRETE FLOORING AND LIKE SURFACES Louise Gertrude Boult, Olton, Birmingham, England Application December 2, 1938, Serial No. 243,661 In Great Britain July 1,1938
This invention relates to methods of constructing concrete floorings and like surfaces and has particular reference to the construction of nonskid and like road surfaces.
It has been the practice to construct a concrete flooring by laying a fairly thick foundation layer of a suitable concrete mix, with a topping layer, usually of a. different mix, to give the desired surface to the flooring.
Such topping layer, including granite chips or the like to give a dustless or other desired surface to the finished flooring, has been applied in dry or non-hydrated form before drying or hardening of the foundation layer, in which case the gauging water from the foundation layer was relied upon tohydrate and fix the dry topping layer. In certain cases a hardening agent in dry or powder form has been incorporated in the dry topping mix to harden the topping layer and improve the wearing or other desirable qualities of the flooring.
Liquid hardening agents have also been used in the construction of a floor comprising a single concrete layer, such hardening agents being embodied in the wet concrete mix as part of the liquid content thereof, by mixing the desired constituents, including the necessary liquid content, before application of such mix to form the flooring. This method has, however, a limited application owing to the cost of the hardening agent required for the construction of surfaces involving substantial thicknesses of concrete such as are necessary for road surfaces.
The object of the present invention is to provide an improved method of forming flooring and in particular road surfaces, to enable the construction of a surface or floor with greater uniformity and consistency and with better wearing and non-skid properties than has hitherto been possible.
One method according to this invention for the construction of a granolithic flooring or road surface is illustrated in the accompanying drawing, wherein Figure 1 is a view in section of a flooring as laid according to an initial step in the method, Figure 2 is a similar view illustrating the next step, and Figure 3 is a similar view illustrating the finished flooring. This method includes the formation over the desired surface of a concrete foundation layer 5 of substantial thickness say from six to eight inches in thickness.
This foundation layer is applied to a suitably prepared bedding 6 which, in the case of a road surface, may include the usual graded rock and/or other tamped road material of suitable gauge with or without a layer of waterproof paper, felt or like material between the bedding and the foundation layer.
The foundation layer may be formed from the normal 1.2.4 structural concrete mix and suitable reinforcement of metal bars or strips or Wire mesh or rods may be incorporated.
Ballast in the form of pieces or chippings of stone or other material may be embodied.
To this foundation layer prior to the completion of the drying or hardening thereof is applied a liquid hardener i such as is obtainable in the open market for use with concrete structures or surfaces, this hardener being added in quantities sufficient to cover the surface of the foundation layer to a degree which will hereinafter he referred to.
One example of a liquid hardener for this purpose is that known by the trade name of C. C. Premix manufactured by Concrete Casehardening Co. Ltd. of Crescent Wharf, Birmingham 1, England, the liquid for use being obtained by diluting this liquid hardener in the proportions of three parts of water to one part of liquid hardener, this mixture being liberally applied to the surface of the concrete foundation layer.
To this treated surface is then applied in mixed but dry form the ingredients to form a good granolithic topping 8, namely, suitable proportions of cement and granite or like chips with or without other ingredients.
One example of a suitable topping mix is as follows:
Granite chips from 6 to 9 lbs. by weight per yard super.
Dry cement from 4 to 6 lbs. by weight per yard super.
These dry materials after intimate mixing are applied in sufficient quantities to form a topping of the desired thickness and this mix may be spread over the surface of the foundation layer by hand or by suitable mechanical means, or alternatively, may be sprinkled or suitably projected over the surface.
This topping mix is .then tamped to compact the materials and to cause the topping mix to unite with, and penetrate the surface of the foundation layer, as shown in Figure 3, to give a monolithic flooring with a granolithic finished surface 9. The topping mix may be forced to penetrate the surface of the foundation layer.
The liquid hardener partially penetrates the upper surface of the foundation layer and com.
blues with the gauging water or liquid of this foundation layer, whilst in addition the liquid hardener penetrates the dry topping layer thus hydrating and fixing the materials of the topping layer.
The combination of the liquid hardener with the gauging water of the foundation layer provides a partial hardening of the foundation layer, such hardening being graduated from the upper surface of such layer through the thickness of the layer to a depth depending upon the degree of penetration of the layer by the hardening agent.
The hardening agent together with surplus gauging water from the foundation layer completes the fixing or hardening of the topping layer in a uniform manner and due to the graduated hardening of the foundation layer as above referred to, the hardening action of the liquid agent is distributed through the thickness'of the toppinglayer and into the adjacent portions of the foundation layer.
The general effect is to obtain a graduated hardening which decreases substantially uniformly from the exposed surface of the topping layer downwardly through this layer and into the upper portions of the foundation layer due to the graduated dilution of the hardening agent by the grading water or liquid of the foundation layer.
It may be necessary under certain circumstances to tamp the foundation layer to facilitate passage of the gauging water of this layer to the v surface thereof but in general the normal application and smoothing operations on the foundation layer are sufficient to bring to the surface thereof sufficient gauging water to combine with the liquid hardener to produce the effect above referred to.
fter application of the materials as above referred to the layers are allowed to harden completely and the topping layer sets with the foundation layer to give a monolithic construction.
Where used, the granite chips in the topping layer give a dustless and good non-skid surface particularly suitable for road surfaces and the hard topping with the graduated hardening throughout the thickness of the surface gives good wearing and rupture-resisting properties to the surface.
By applying the hardeningagent to the surface of the foundation layer the desired hardening of the exposed surface can be obtained in .a relatively inexpensive manner since the hardening agent, which is fairly expensive, is concentrated adjacent the surface to be hardened, It would be a relatively expensive matter to construct a thick road surface by mixing with the materials for the entire surface, an amount of hardening agent sufficient to give the desired hardening at the exposed surface but with the method according to the present invention the desired hardening can be obtained with a relatively small body of liquid hardener concentrated in or adjacent the exposed surface to be hardened.
Further, the degree of hardeningcan. readily be regulated with the method according to the present invention by regulating the amount of liquid hardener applied to the surface of the foundation layer and if necessary by adding liquidto the surface of the topping layer after the latter has been applied to the foundation layer.
-In some cases an improvement of the finished surface can beeffected by treating the flooring-or other surface with suitably diluted liquid har' dener after final setting of the surface.
The proportions hereinbefore specified for the various parts of the structure are only given by way of example and may be varied without departing from the essence of the invention. the constituents and proportions depending upon the use to which the flooring or like structure is to be put.
Further, the strength of the liquid hardener applied to or incorporated in the structure may be varied to alter the hardening effect. The strength of the hardening liquid specifically mentioned hereinabove is given only as an example of one suitable strength of the particular hardening liquid referred to and other proportions may be adopted or necessary with liquid hardeners other than that mentioned.
In any of the above alternatives the topping layer may include any or any combination of any usual ingredients for the construction of concrete surfaces or flooring as, for example, granite, stone or other chippings, grit sand or well-washed gravel, the grading and proportions of such materials depending upon the surface desired, or the loading to be applied to the flooring or road being constructed.
What I claim then is:
l. A method of constructing concrete floorings and like surfaces involving the steps of constructing a foundation layer, applying to said layer prior to the completion of the drying thereof a liquid hardening agent comprising three parts water and one part commercial liquid hardener and a dry mixture of aggregate in the proportion of from six to nine pounds by weight per yard super and dry cement in the proportion of from four to six pounds by weight per yard super, said dry mixture being forced into the surface of the foundation layer to form a monolithic structure, the liquid hardener being relied on to hydrate and to fix said materials to form a topping layer and treating the finished surface of the topping layerwith :a liquid hardening agent.
2. A methodiof constructing concrete fioorings and like'surfaces'involving the steps of constructing a foundation layer, applying to the surface of said layer a :liquid hardening agent and applying thereon a'dryimixture of aggregate. particles and cement withoutipremixingsaid dry mixture withse'tting liquid, the liquidihardener being relied on to 'hydraterand to fix said materials to form a cement toppinglayer and said topping layer being applied before completion of the setting of the foundation layer so that the two Iayersunite togetherto form a monolithicstructure with a hardened top surface.
'3. A method of constructing concretefloorings and like surfaces involving the steps ofconstructing a foundation layer, applying to' saidlayer prior-to the completion of the setting thereof a liquidhardening agent and a dry mixture of granite chips in the proportion ofiifrom six to nine pounds by weight per yard super and dry cement in the proportion of from four to six pounds by weight per yard super and working said dry mixture into the surface of said unset foundation layer to form a monolithic structure the surface stratum of which is hardened by said liquid'harden'er.
4. A method of constructing concrete floorings and like surfaces involving the steps of constructing .a foundation layer, applying to said layer prior tothe completion of the setting'thereof a to fix said materials to form a hardened topping layer and working said dry mixture into the surface of said unset foundation layer to form a monolithic structure the surface stratum of which is hardened by said liquid hardener.
LOUISE GERTRUDE BOULT.