US1985092A - Method of producing concrete structures - Google Patents

Description

Dec. 18, 1934. HAYDEN 1,985,092

METHOD OF PRODUCING CONCRETE STRUCTURES Filed March 5 1929 Arronwgy I Patented Dec. 18, 1934 f ra, a

, Application March 5, 1929, Serial No. 344,597 10mm. (Cris-4n tfo'concrete structures of the type which are produce'd by'the pouring of concrete into forms."

5 :Heretofore for the production of concrete structures such for example, as are produced by pouring concrete into forms, the forms being removed after the concrete has set or'reached a condition of required rigidity, substantial difli culty has been met within efiecting properycuring of the; concrete and the structures produced have been subjected to internal stresses and strains due to changes in the moisture content of the structure. Changes in'temperature also result in the development of certain types of stresses in concrete structures due to the expansionor contraction of an element the structure resulting from such change in temperature. Allowance tor the anticipated variation of dimensionsdue to temperature changesis made in the design of the structure; usually by the provision of expansion joints 'and variations'in the dimensions of conturesdue to changes in the moisture e 'lfstm .qn s e eo ma etsk ca of r y- Hqwever, in concrete structures; and more par ticularly where; for example, the concrete structure is reinforced with steel or the like," internal stresses develop within thest'ructure as a result of change in iirnensions oi the structure resultin rram'vanatmns inthe moisture content thereof and which'cannot be taken care of, as'can change indimerisi onsassuch, I I Heretof ore' the purines: concrete forming structures of the character produced by the pour- 11 g of concrete intoiorms has been more or less deduately accomplished by permitting theforms to remain on the-structure throughout thedura- ,tion of thestipuIatedcuring period, or at least until the structure *is isufliciently rigid-to permit the 'rmevar of the forms. However, where wooden forms are used, even though permitted to re'main in place 'until'fthe"-'concrete is cured, muchor the water necessary-to complete the hydrationofthe Portland "cement is lost by evaporation through the porous form "wall unless the forms"'are"ireduentlvwetted:during the curing period and incases where the forms are removed pri'orto the-end of the stipulated curing period, ithas been necessary'to frequently wet the-exposed 'suriace or the structure in an effort to 'inai'ntain-a'suflicient amount of water in the con- The; Barber Asphalt Company,

corporation of West Virginia v J assignor to Philadelphia,

structures I pouring of concrete intoforms which have increased strength and which" will be I free from the internal stresses incident to variations in the moisture content thereof throughout the "life of the structure, by ithe' encasement of thestructure in a water impervioussyste at-the time of pouring the concrete, into "the; form. Y It' I apparentthatitis unnecessary to makeprovi sion for dimensional changes" in the concrete. structure due to changes in'the moisture content thereof in structures so encased, as such dimensional changes will be obviated.

Now, it is'the object of my invention to provide a method of producing concrete structures, such as are produced by the pouring of concrete into forms, by which themixing water will be conserved within the structure for the complete hydration of the cement and themoisture content of the structure after the completion of such hydration will be permanently stabilized: with the result that a structure ofmaximum strength of the character produced by the will be templates provision-for the retention of the film on the concrete structure on removal of the forms, the film as originally applied, or asit'may be supplemented, acting,after removal' of the forms, to maintain the moisture contentof the concrete at a substantially 'constant percentage regardless of variations atmospheric. conditions or other conditions which would tend to infiuence the moisture contentzthereof. f

Inthe adaptation" of the method in accordance with my invention to practice from the broad standpoint, Iprovidetheior'ms, into which the concrete is to he poured, with a coating of a material capable of supporting'the water impervious film to be applied to the concrete. The coating serves'to support thefilm of water impervious material during the pouring of the concrete into the forms and is of such a character that after the concrete has been; poured and desirably puddled, the adherence-of the film to the concrete will be greater than its adherence to the coating material, or than the adherencegof the coating material to the forms, with c the result that on removal of the forms the water impervious film will remain adhered to the concrete. After removal of the forms any coating material adhering to the film is removed and if desired the film may be supplemented.

It will be understood that from the broad standpoint my invention contemplates the application of a water impervious "film to concrete as it is poured into forms and the retention of the film by the concrete after the forms are removed, the application of the film being effected through the medium of a film supporting coating initially applied to the forms. a

In carrying the method in accordance with my invention into practice, any type of forms for the formation of concrete structures may be used. However, the carrying out of the method will be facilitated where forms of the type which comprise sections composed of back and sides built in place and having a-separable front section adapted to; be secured .inplace when the concrete is to be poured-are used. As an illustration of the practicaladaptation of the method inaccordance with my invention in, for example, the construction of a. wall,the forms, for example, of the typehav r g b ck and sides .built in place anda .remova-blefront, having been constructed, the interior; of the forms,-; including the. separable front section if the form is of such type,

are coated with a' coating of, for example, clay slurry, whitewash, or the like,, the application being made, for example, by, brushing or by a spray gun, and there is formed upon the coating a waterimpervious film, for example, formed of a linseed oil paint, rubber latex, bitumen or bituminous material as, for example; asphalt, or of coal tar-pitch, or the'like. The water impervious film may be formed upon the .coating,

' c. for example,-by brushing or spraying upon the coating a water external phase bituminous emulsion, .heatedasphaltum, or asphaltum dissolved or cut back: by means of a suitable solvent. Where the waterimpervious film is formed through the use of heated asphalt, or asphalt solution, the clay slurry.- coating should be permitted to dry before application of the film forming material. However, where the film is formed by the use of a bituminous emulsion, drying of the clay slurry coating is not necessary prior to application of the film.

After the-formation of the water impervious film, as described above, the concrete is poured into the form and the surface thereof, at the open top of the form, coated directly with a material which will form'a water impervious film, for example, amaterial similar tothat used in forming the waterimpervious film on the coated forms as, for example, a bituminous emulsion or an :asphalt solution, heated asphalt, coal tar pitch, or the like. The concrete is then permitted to set and when it has set or hardened sufiiciently, the forms are removed. On removal of the'forms the water impervious film will remain adhered to the, concrete, since the adherence of the film to'the concrete, as will be hereinafter described, may be made greater than to the clay coating; in any event the adherence of the water impervious film to the concrete will be greater than the adherence of the claycoating to the forms so that on removal of the forms the film will remain with theconcrete structure formed. If desired, and'more'especially where the water impervious filmis formed with heated asphalt or asphalt solution, theadherence of the film to the concrete may be insured by the addition to the film after its formation and before it has set of a sharp mineral aggregate, as relatively finely crushed stone, slate, or the like, which will provide the film with a toothfor engagement with the concrete.

After the forms are removed from the concrete, if it be that the water impervious adhering to the structure carries with itfin whole "or in part,

the coating initially applied to the forms as a basis for the formation of the film, the coating is removed as, for example, by washing it off, and

the water impervious film, if it were damaged,

for example, bythe tools used in puddling the 'concrete, is repaired with material of the same character as 'thatused in forming the film, in

emulsion, by meansfof brushing or through the use of a spray gun'. "The film may be supplemerited by a coating of any desired weight and may be supplemented'by more than one coating if desired. Under circumstances where the concrete structure is .so placedas to be subjected to:

the direct action of the elements, .theinitial film may be supplemented by the application of weather resistant material, as 'for example, by the application of bituminously impregnated fabric, for example, such as asphalt impregnated felt, the

application of which may be effected, for example, by firstcoating the film with a mopping of hot asphalt, or of asphalt solution, or the'like, then applying the saturated fabric in sheet form While the asphalt coating is in an adhesive condition and finally coating the-fabric and sealing the joints, between the strips thereof with, for example, heated asphalt or asphalt solution. It may also be desirable to embed a granularaggrer gate such as slag, crushed stone or slate in the surface of the supplementary coating in order that a layer of Portland cement or magnesite stucco, or the like, may be. adhered theretofor th'e purpose of more permanently protecting thev surface of the structure and also forthe purposeof decoration thereof. I V v While it will be understood that the method embodying my, invention maybe carried out without the use of any special apparatus, i haveillustrated in-the accompanying drawingthe application of the method embodyingmy inventionto the production of a.- concrete block, I

In the accompanying drawing: Y l ,a mould composed the reception of a Fig. 1 is a sectional view of of form members ready for charge of concrete. V r

Fig. 2 is a sectional view of the mould shown in .Figure 1, the concrete having beenpoured.

Fig. 3 is a perspective view, partly broken away, showing a block produced in the mouldof Figures 1' and 2, the form members removed from the block being indicated.

In the several figures :1 indicates form members, comprising in the present case sides and ends arranged together toform a mould for. the production of a block. b indicates a coating of, for example, clay slurry, applied to the interior surface of the members forming the mould and- 0 indicates a coating of bituminous material, as asphalt appliedover the coating of clay. -slurry. d indicates a mass of concrete poured into the mould, while c indicates a coating or him of asphalt applied over the surface of the concrete ai'ter pouring into the mould. e indicates the finished concrete block, the form members a composing the mould having been removed. The block, it will be noted, is entirely encased with asphalt due to adherence to it of the asphalt coating 0 applied interiorly of. the mould and the asphalt coating 0' applied to the top of the concrete after pouring into the mould. The asphalt coating c is prevented from adhering to the interior of the mould rather than to the outside or the block owing to the coat of clay slurry which is applied directly to the mould and which, as shown in Figure 3, remains on the form members on their removal from the block.

It will now be observed that as a result of my invention provision is made for the application to concrete as it is poured into forms of a water impervious film, which coats the entire surface of the concrete and which serves to prevent evaporation of water from the concrete after pouring and during the curing period, when the maintenance of requisite water is essential to the sufflcient hydration of the cement content for adequate curing and, at the same time, provision is made for insuring the retention of the film by the concrete structure after the removal of the forms with the result that the moisture content of the concrete will be stabilized during the life 01' the concrete structure by the fact that the water impervious film will protect the body of the concrete from the effect of variations in the moisture content of the atmosphere or other variable conditions which would tend to affect the moisture content of the concrete structure. .As has been described, the film may be supplemented to a greater or less degree after the removal 01 the stresses and strains arising from variations in the a moisture content thereof through change in the moisture content of contiguous bodies or atmospheric humidity.

It will be understood that I do not intend that my invention shall be limited to the precise procedure described herein by way of illustration, nor to the use of any particular material for the formation of the water impervious film or for supplementing it, the use or any material capable of producing the results herein described being contemplated by me, though the method will be economically and effectively carried out through the use of bituminous material, as for example, asphaltum, which may be used, as has been indicated, in a heated condition, in solution in a suitable solvent, or, and which is perhaps preferable, in the form of an emulsion.

Having now fully described my invention, what I claim and desire to protect by Letters Patent is:

A parting medium adapted for the coating or a a mold for concrete and for the support of a flexible, water-impervious film to be adhered to concrete formed in the mold, comprising a coating of clay formed by the application of an aqueous clay slurry to the mold.

a HAROLD P. HAYDEN.

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