US2061098A - Waterproofing masonry structure - Google Patents

Description

IN VENTOR Arf/7W A. Johnson. BY #Za/ ATTORNEYS A. A. JOHNSON WATERPROOFING MASONRY STRUCTURE Flled May 24, 1953 Nl mi MwCOb Nov. 17, 1936.

atented Nov. 17, 1936 iTED STATES PATENT FC'E Arthur A. Johnson, Great Neck, N. Y., assignor to Johnson-March Corporation, a corporation of Delaware Application May 24, 1933, Serial No. 672,568

2 Claims. (Cl. 61-45) This invention relates to waterproofing masonry structures, and particularly structures such as subways, cellars, vaults, tunnels, etc., which are of such size and structural character- 8 istics that there is likelihood of cracks occurring between different parts of the construction. It is particularly applicable to the waterproofing of subterranean structures of concrete, incorporating'steel framework or re-enforcements.

It is necessary in structures of the character described to carefully waterproof the work so as to prevent, as far as possible, the leakage of ground water into the interior of the structure. Frequently where the work is at some depth below the surface of the ground, the ground water exerts considerable pressure upon the bottom and sides of the structure and, if there are any openings or cracks whatever, the leakage will be substantial. It is well known that concrete walls and floors are not in themselves sufciently waterproof to prevent this leakage, and it is accordingly customary to apply waterproof coatings of bituminous materials such as asphalt with or without layers of fabric, felt, paper or the like. Such asphaltic and bituminous coatings have not proved fully efficacious in practice for the reason that such materials do not possess any true elasticity, but are really viscous uids. If bituminous or asphaltic compounds are used which are quite soft they may eventually flow out entirely from their intended location. On the other hand, if compounds-are used which are sufficiently hard not to flow excessively, they will harden further and tend to become brittle when cold and will crack. 'I'hls is particularly true where there is expansion and contraction of the structure, or movement of the parts thereof due to settling of the earth, vibration, etc. As structures of any size are always subject to these influences, some leakage invariably occurs where known methods of waterproong are utilized. A

great deal of difficulty has been experienced from these causes, and large sums are constantly being expended in attempting to repair waterproofing which has failed, in pumping out seepage, and in other ways. These diificulties with the use of bituminous or asphaltic waterproofing coatings are not overcome by the use of fabric re-enforcements in the coating. The fabric may tear if the movement of the parts is considerable, but, even if the movement is slight, the bituminous coating will be cracked or disrupted to such an extent as to permit leakage even if the fabric is not torn. Furthermore, if the asphaltic coating is cracked to such an extent as to permit Water to reach the fabric, the latter will rot.

In accordance with my invention, I have overcome these defects in previous waterproofing coatings by providing a waterproofing coating or 5 layer which possesses true elasticity as distinguished from mere fluidity, and which will yield, stretch and contract in accordance with the expansion and contraction or settling of the elements of the structure, and thereby retain its 10 continuity and effective waterproofing qualities under the varying conditions of use.

Another disadvantage of the ordinary bituminous or asphaltic waterprooiings is that they have to be applied hot. This is an expense due to 'i5 the necessity for heating apparatus at the job, and requires expert supervision in carrying out the heating at the proper temperature so as to avoid danger of overheating or burning the waterproofing material which destroys th'e use- 2o fulness. The heating of the asphaltic materials is particularly objectionable in underground work as the fumes endanger the health of the workmen. In accordance with my invention I provide a waterproofing process which, in its pre- 215 ferred embodiment, does not require the heating of the waterproofing materials, as the preferred materials which I employ may be applied cold.

As an illustration of a particular application of the invention, the same Will be described as 30 applied to the waterproofing of a subway incorporating a steel frame-work and having a iioor, walls and roof of concrete.

In the drawing Figure 1 shows a View in perspective, partly broken away, oi' a subway con- 35 struction showing various stages in the building thereof.

Figure 2 is a vertical diagrammatic sectional view through the floor of the subway construction showing the different layers embodied in a 40 preferred example thereof.

Referring to the drawing, a suitable excavation or trench is rst dug, the ground surface at the bottom of the excavation being indicated at l, the side wells ef the trench er excavation if 45 necessary being protected by suitable temporary sheathing 2 which is supported by wooden framing 3. If the subway is located under a street a wooden iiooring 4 may be laid on the framing 1f desired. on the bottom ef thetrenen e 1eyer 50 of concrete I0 is laid which is referred to as the invert protection concrete. This layer of concrete is also carried up the side walls ofthe excavation for a distance, as indicated at Il. A coat of waterproofing material is then applied to 55 the concrete and carried up the side walls far enough to protect the joint between the bottom f and side wall protective concrete, and on this layer of waterproofing one or more layers of fabric are laid such as burlap or coarse muslin. A further coating of waterproofing material is preferably applied over the fabric, so that the fabric and waterproofing compound combine to form a waterproofing layer I2. As the waterproong material, I do not use a hot applied bitumen or asphalt such as is commonly employed, but in place thereof I use a mix/ture containing rubber latex or other dispersed rubber. This is preferably incorporated with an asphalt or bitumen and the mixture is of such a nature that it can be applied cold. I prefer to use a mixture cornprising`a water emulsion of asphalt, rubber latex and a ller. As an example of such a mixture and the method of preparing the same the following may be given;

A bituminous emulsion (mixture A) is first prepared as follows: l

Parts Native asphalt and/or gilsonite 50 Water 50 Protective colloid may now be Parts Latex (38% rubber) 96 Sulphur (in colloidal form) 1 to 3 Shellac (powdered) 2 Sodium benzoate 2 In place of the sodium benzoate other preservatives to prevent destructive fermentation of the latex may be employed such for instance as ammonia, formaldehyde, phenol, or phenol derivatives, urea, etc. The shellac may be omitted altogether or in place of it some other gum or resin may be utilized such as rosin, manila copal etc. The sulphur is not always necessary, but acts to vulcanize the rubber and thereby renders the coating tougher and more permanent. Any of the usual accelerators and activators may be added if desired. The sulphur by bringing about vulcanization of the rubber also acts as a preservative and where it is used, the use of other preservatives for the latex-may in some cases be dispensed with.

A mixture is now made comprising about 75 parts more or less of the asphalt emulsion (mixture A) and about 25 parts more or less of the latex compound (mixture B). A suitable quantity of ller is now added usually in an amount about equal to the amount of the above mentioned compound. Also a small amount of sodium silicate is preferably added. For example the following proportions may be utilized:

, Parts Compound having the formula above given- 100 Powdered feldspar or other ller 100 Sodium silicate 1 to 3 The amount of sodium silicate will vary depending upon the amount of ller used. The filler is preferably wetted with water prior to incorporating in the compound.

Instead of using a water emulsion of asphalt with the latex incorporated therein I may use a, compound comprising asphalt dissolved in a volatile solvent and having a coagulated latex or dispersed rubber incorporated therein. An example of a formula for such compound is as follows:

As an example of a coating compound which I may employ which does not have' an aqueous vehicle, the following may be given: A solution or dispersion of asphalt in a. volatile petroleum oil is prepared in any suitable manner. This may be an ordinary solution or dispersion 'of petroleum asphalt or native asphalt or it may be a liquid asphaltic preparation prepared as described in the United States patent to McRae No. 1,684,593. To this may be added a solution or dispersion of rubber in a volatile solvent. Preferably this solution or dispersion is prepared as follows:

Natural latex derived from Hevea Braziliensis or other rubber bearing plant is treated with a coagulating agent, preferably acetic acid, in order to obtain the solid material. Other coagulables that may be used are salts, acids, alcohol, etc. Aiter treating the latex with the coagulant the aqueous layer is lteredvor drained off and the rubber residue obtained is dispersed or dissolved in petroleum spirits to a concentration of approximately rubber. The latex prior to precipitation or solution in the petroleum spirits may have added sulphur up to 3% of the rubber content and rosin, manila gum, shellac or other resins soluble in the mixture.

The rubber solution described is then added to the asphalt solution in the desired proportion up to a maximum of approximately 50% of the total volume. Suitable fillers are now added such as clay, talc, gypsum, feldspar, bentonite, carbon or lamp black, wood flour, asbestos or ground cork. Generally speaking, an amount of ller may be utilized approximately equal to the amount of the liquid compound.

The above examples are merely illustrative as particular vingredients and the proportions thereof may be varied. The important characteristic of the waterproofing material is that after it sets or cures it shall possess a degree of elasticity so that in the event of cracks forming in the masonry the imperviousness of the waterproofing will not be destroyed.

Upon the waterproofing layer I2, in the example of subway construction illustrated, a course of brick and mastic is applied which retains the waterproofing layer in place during the further construction. Upon the layer of brick and mastic the main concrete floor I4 of the subway is laid. Supported on the floor I4, or upon suitable piers, are footings I5 on which rest the steel columns I6 which support the roof girders I1, each pair of columns land transverse girder I1 constituting a steel bent. Between these steel bents are formed the concrete side wall arches I8 and roof arches I9.v The side walls and roof are waterproofed by means of the application of alternate coats of the waterproofing material described and of fabric, a coating of waterproofing compound being rst applied then a ply of fabric and then another coat of waterproofing compound and a ply of 'fabric until three or four plies of fabric are in place. A waterproofing layer 20 is thus formed covering the side walls, and a similar layer 2l covering the roof. The side wall protective concrete II is carried up over the side wall waterproofing layer and a roof protective layer of concrete 22 is laid over the waterproofing on the roof.

The subway is thus seen to comprise a complete box or tube comprising a, bottom Il of concrete, side walls comprising concrete arches I8 and steel columns I6, and a roof comprising steel girders I1 and concrete arches I 9. This construction is completely encased in a waterprooiing layer comprising an elastic waterproofing compound such as the asphaltic and rubber latex compound described, which waterproong compound is reenforced with one or more layers of fabric incorporated therein. The waterproofing layers are held in place and protected by a complete layer of protective concrete comprising the invert protection concrete I0, side Wall protection concrete H and roof protection concrete 22. In a large construction of the character described there is certain to be settling of the earth in places, expansion and contraction due to temperature changes, and severe vibration due to the running of the trains through the subway. These causes are sure to cause cracks in the concrete in pla-ces, particularly where the steel bents are located. This will result from the unequal settlement, ex-

pansion or contraction, or vibration oi the bents.

With ordinary asphaltic or bituminous waterproong materials the cracks in the concrete will result in many instances in the formation of cracks in the waterproofing layer, but in my improved method of waterproong the permanent elasticity of the waterproofing layer will permit such layer to stretch and contract so as to cover the cracks in the masonry without the formation of corresponding cracks in the Waterproofing, and leakage is thereby efectually prevented.

As will be understood, the example of my invention given is merely illustrative of one preferred embodiment thereof, and my method of waterproofing may be applied in a similar manner to the waterproofing of cellars, or other masonry structures.

I claim:

1. The method of waterproofing masonry structures which consists in applying cold to the surface of the masonry to be Waterproofed, a permanently elastic waterproong layer comprising a water emulsion of asphalt having rubber latex incorporated therein, applying fabric over said waterproong layer, applying a further waterproong coating over the fabric and laying a protective wall of concrete over said waterproofing.

2. The method of waterproofing subterranean structures during the construction thereof which consists in laying a protective body of concrete on the bottom of the excavation, applying a permanently elastic waterproong layer thereon comprising asphalt, rubber latex and a vulcanizing agent and one or more plies of re-enforcing fabric, laying a masonry floor on said waterproofing layer, constructing side walls and a roof above said floor, said side wvi/alls and roof being constructed of concrete having steel frames therein, applying a permanently elastic waterproong layer over said side walls and roof, said layer comprising asphalt, rubber latex and a vulcanizing agent and one or more plies of re-enforcing fab- Y ric, and covering said Waterproofing layer with a protective layer of concrete extending over the side walls and roof of the structure.

ARTHUR A. JOHNSON.

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