US2124843A - Waterproofing composition and method - Google Patents

Description

July 26, 1938.

B. A. ANDERTON 2,124,843

WATERPROOFING COMPOSITION AND METHOD Filed June 3, 1935 INVENTOR Ben am/n A. finder fa/' ATTO R N EY Patented July 26, 1 938 UNITED STATES WATERPROOFING COMPOSITION MET HOD

Benjamin A. Anderton, Grantwood, N. J., assignor to The Barrett Company, New York,

N. Y., a

corporation of New Jersey Application June 3, 1935, Serial No. 24,713

11 Claims.

This invention relates to waterproofing, and more particularly to membrane waterproofing,

i. e., the waterproofing with layers of bitumen and fabric or felt of the vertical walls of buildings, particularly cellar walls, walls of fountains,

swimming pools, etc.; to the formation of Waterproof built-up roofs, especially steep roofs, constituted of alternate layers of roofing felt and waterproof coating material, and to bituminous waterproofing cements which may be used in membrane waterproofing.

The vertical walls of fountains and swimming pools have been waterproofed by coating the cement or concrete walls of the pool with bituminous material such as coal-tar pitch; frequently such coating has been supplemented with alternate layers of bitumen saturated felt and bi--- tuminous 'coating material, three layers of felt separated by coating layers and having coating layers on the third felt layer and also a coating layer between the wall and the first felt layer being commonly employed. Outdoor swimming pools, fountains, roofs and like structures are subjected to a wide range of temperatures, i. e., day and. night, summer and winter temperatures, and to the direct rays of the sun. A major difiiculty encountered in such waterproofing operations has been the selection of a bituminous waterproofing material of proper melting point and plasticity or ductility to permit it to remain coherent and intact at'the lowest temperatures encountered and over wide ranges of temperature change without bleeding or running at high summer temperatures.

Bituminous pitches heretofore employed in membrane waterproofing, when subjected to summer temperatures, particularly to the,direct sun rays during the summer, bled and ran along the vertical and inclined walls of the pool rendering the waterproofing defective. The use of a higher melting point pitch, such that it would not run when subjected to maximum summer temperatures, would result in a poor, if not totally defective, bonding or cementing of the felt layers to the vertical walls of the pool or fountain. Furthermore, such high melting point pitches, particularly when subjected to winter temperatures, tend to become brittle and hard, impairing the waterproofing and bonding prop- 0 erties of the pitch, especially when subjected to the stresses resulting from contraction and expansion of the wall or roof to which they are applied.

The defects hereinabove pointed out in connection with pitches employed in the waterproofing of swimming pools and fountains are also present in the pitches employed in the waterproofing of the vertical walls of buildings, such as cellars, and inclined construction masses or utilized in the formation of steep built-up roofs constituted of alternate layers of roofing felt and pitch coating material.

It is an object of the present invention to pro-- vide a process of waterproofing, and more particularly of membrane waterproofing in which a construction mass, such as the walls of cellars, pools, fountains, etc. and inclined roo'f decks of buildings, is coated with a so-called hot-application bituminous waterproof composition which when applied molten will bond firmly with wall or roof and when used with felt or woven fabric will result in a firm bond of the bitumen saturated sheets to each other and to the construction mass to which they are applied throughout the wide range of temperatures which may be encountered by the construction mass thus waterproofed and even though the waterproofed construction mass is subjected to the direct rays of the sun. Other objects and advantages of this invention will appear from the following detailed description.

The accompanying drawing is a perspective view illustrating, somewhat diagrammatically, the waterproofing of a steep roof deck or other construction mass in accordance with the invention.

I have found that by mixing a coal-digestion pitch of a melting point such that the pitch is flexible and not brittle throughout all temperatures which may be encountered in use with asbestos fibres in amount not more than 15 per cent based on the weight of the coal-digestionpitch and preferably from five (5%) to ten (10%) per cent by weight, an eminently satisfactory bonding and waterproofing cement for 3 membrane waterproofing is, produced. Preferably the pitch employed has a softening point of at least 40 C., a-penetration at 0 C. of at least 4 (as hereinafter explained) and is made by heating together bituminous coal and tar such. as coke-oven or water-gas tar or their distillation products to above about 270-300" C. so that the non-ash constituents of the mixture behave substantially as a uniform blend.

A coal-digestion pitch may be produced by heating, while agitating, bituminous coal, for example, New York steam coal, Pittsburgh Seam coking coal, or Ohio non-coking coal in intimate contact with tar, pitch or tar distillate under specific temperature conditions so that the coal is blended with the tar or tar products in which it is digested and the resultant mixture, when molten, behaves substantially as a homogeneous fiuid. The coal may be either a coking or a non-coking coal. Products containing, for example, from '7 per cent to' around 25 per cent of coal are satisfactory for use in the formation of membrane waterproofing cement. The proportion of coal necessary will vary, however, with the particular type of coal employed and also with the character of the pitch, tar or tar oil which is employed.

The temperature to which the coal and tar or pitch, which may be water gas tar,coal tar or their distillation products, are heated varies with the particular type of coal employed but in general the temperature is around 300 C., say from about 270 C. to 340 C.

The heating period in practice will vary depending upon the quantity of material in the heating vessel, the efficiency of the stirring apparatus, the amount of heating surface, etc. For small amounts of the material the period of heating to raise the temperature to around 300 C. may be only a couple of hours or less; with larger amounts in batch operation, especially where the agitation is less rapid, 8 or 10 hours or more may be required in order to avoid overheating portions of the charge. 4

Products especially adapted for the practice of this invention should contain in general from seven (7%) to fifteen (15%) per cent up to 25 per cent of coal and should have a penetration at C. of at least 4 and a softening point of at least 40 C. Softening points and penetrations are determined in accordance with procedure and using standard apparatus prescribed by the. America Society for Testing Materials. Softening points referred to herein are determined by the ring and ball method. Penetration is given in tenth millimeters; in the case of penetration at 0 C., 200 grams are applied for 60 seconds; for penetration at 25 C., 100 grams are applied for 5 seconds; and for penetration at 46.1 C., 50 grams are applied for 5 seconds.

Preferred products for the practice of this invention may have a softening point of, say, between 40 C. and 85 C. and a penetration at 0 C. of from 4 to 25 with a penetration at 25 C. of not more than 50 above these values.

The following examples will illustrate the general characteristics of coal tar pitch products suitable for the formation of membrane waterproofing cements as hereinabove described Example 1.-Into a suitable vessel were charged about 3,200 gallons (30,700 pounds) of dehydrated coke oven tar and 5,000 pounds of pulverized bituminous coal. While the charge was agitated, the temperature was raised slowly to 320-340 C. This temperature was attained in a seven hour heating period. When the material had reached the required temperature, it was permitted to cool somewhat. The final product so'obtained had the following characteristics:

Softening po 62 C. Penetration at 0 C 6 Penetration at 25 C Penetration at 46.1 C 7 Example 2.A product prepared from 85 parts of heavy water gas tar and parts of coal exhibited the following characteristics:

Softening point 83 C, Penetration at 0 C 6 Penetration at 25 C Penetration at 46.1" C 49 Example 3.--A coal-digestion pitch particularly suitable for waterproofing the walls of a fountain without the use of a felt membrane had Penetration at 46.1 C

Example 4.-Another suitable product made from coal-digestion pitch had the following characteristics Softening point 69 C.

Penetration at 0 C 13.5 Penetration at C 31 Penetration at 46.1 C 91 I have found that the addition of asbestos fibres to such coal-digestion pitch, when introduced in amount from 5 to 15 per cent by weight of the pitch, does not have a deleterious effect on the waterproofing and binding properties of the pitch as would an inert filler such as infusorial earth, silica, etc. I have further found that asbestos fibres give body and strength to coal-digestion pitch and reduce the flow tendencies thereof when subjected to elevated temperatures. Furthermore, asbestos fibres are not subject to decay.

A coal-digestion pitch of a softening point of from 50 C. to 75 C., when mixed with asbestos fibres in the proportions stated, I have found is sufficiently flexible throughout conditions of use encountered to result in an efficient waterproof construction with or without the use of membranes of felt or fabric. Instead of coaldigestion pitch other pitch such as coal tar or water gas tar pitch of a softening point from 40 C. to 75 C. may be employed, although coaldigestion pitch hereinabove disclosed is preferred.

In waterproofing a fountain, a mixture of 93 per cent by weight of coal-digestion pitch of Example 3 above and 7 per cent by weight of asbestos fibres was employed. The pitch was melted in a kettle and the asbestos fibres added to the molten pitch while agitating the same to produce a substantially uniform mixture. This mixture,

while hot, was mopped on the vertical walls of the fountain. The coat thus applied had a glossy appearance. Upon cooling and setting of the waterproof composition a firm bond of the pitchasbestos composition to the walls of the fountain resulted. The waterproof construction thus produced, in spite of the absence of felt or fabric layers, has withstood severe summer temperatures and has resulted in a satisfactory waterproof structure.

The coal-digestion-pitch-asbestos 'composition may be used advantageously in the construction of steep built-up roofs, or other vertical or steeply inclined construction masses, involving the application of layers of roofing felt or woven fabric such as muslin alternating with layers of the coating composition. As illustrated in the accompanying drawing, a layer of the coal-digestion pitch-asbestos-composition l0 may be applied to a steep roof deck or other construction mass II, and alternate layers of sheet material such as bitumen-saturated felt I! and coal-digestion pitch-asbestos-composition applied to the initial coating layer; an additional layer of coal-digestion pitch-asbestos-composition I3 may then be applied to the upper surface of the felt. Such roof construction will be firmly bonded to the roof deck and the layers thereof will be firmly bonded to each other.

Since certain changes in carrying out the above process, and certain modifications in the article which embody the invention may be made without departing from its scope, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. 'The membrane waterproofing process which comprises applying a coating of coal-digestion pitch of a softening point such that the pitch is flexible and ductile under service conditions throughout alltemperatures which may be encountered in use and asbestos fibres in amount not more than fifteen 15%) per cent, based on the weight of the pitch, to a vertical or inclined construction mass to be waterproofed, applying a layer of bitumen-saturated felt to this coating and applying a second coating of like composition to the felt.

2. The membrane waterproofing process which comprises applying in heat liquefied condition a waterproofing composition constituted of bitumen material which is flexible and ductile under service conditions throughout all temperatures which may be encountered in use, mixed with asbestos fibres in amount not more than fifteen (15%) per cent, based on weight of bituminous material and not less than five (5%) per cent of the weight of the bituminous material, to a vertical or inclined construction mass, applying bitumen-saturated material to the coating layer and applying asecond layer of coating material of like composition to the bitumen saturated material.

3. The process of forming a steep built up roof which comprises applying to a steep roof deck alternate layers of waterproofing composition in heat liquefied condition and bitumen saturated felt, the waterproof composition being constituted of bitumen which is flexible and ductile under service conditions throughout'all temperatures which may be encountered in use and being mixed with asbestos fibres in an amount not more than fifteen (15%) per cent, based on the weight of the bituminous material and not less than five (5%) per cent of the weight of the bituminous material and the waterproofing composition being applied in heat liquefied condition.

4. The membrane waterproofing process for waterproofing the vertical walls of swimming pools, fountains and the like, which comprises coating the said walls with a composition constituted of a coal-digestion pitch having a softening point of from 40 to 85C. and a penetration of at least 4 at C. and from five to fifteen (15%) per cent by weight of asbestos fibres, said composition being applied while in heat liquefied condition, covering said coating "layer with sheet material and causing the said composition to set to firmly bond said sheet material with said vertical walls.

5. The membrane waterproofing process for waterproofing vertical or steep construction masses which comprises coating the said construction masses with a composition of matter comprising a product obtainable by heating together bituminous coaland a material of the group consisting of coal tar and water gas tar and their distillation products to a temperature such that the non-ash constituents of the mixture behave substantially as a homogeneous blend,

said product having a softening point of at least 5.

40 C. and a penetration at 0 C. of at least 4 and being admixed with asbestos fibres in amount of from 5 to 15 per cent by weight of the said product, covering said coating with bitumen-saturated felt and applying a second coating of like composition to the bitumen saturated felt.

6. A waterproof cement adapted for application in heat liquefied condition, comprising coaldigestion pitch having a softening point of from 40 to 85 C. and from 57 to per cent by weight 15 of asbestos fibres.

7. A waterproof cement comprising coal digestion pitch having a softening point of from 40 to 85 C. and a penetration of at least 4 at 0 C.

and from 5 to 15 per cent by weight of asbestos 8. A bituminous waterproof cement consisting of a coal digestion pitch having a softening point of about 64 C., a penetration at 0 C. of about 4,

at C. of about 15, at 461 C. of about 73 and 25 from 5 to 8 percent by weight of asbestos fibres.

9. A composition of mattercomprising a product obtainable by heating together bituminous coal and a material of the group consisting of coal tar and water gas tar to a temperature such .that the non-ash constituents in the mixture behave substantially as a homogeneous blend, said product having a softening point of at least 50 0., a penetration at 0 C. of at least 4, and containing from 5 to 15 per cent by weight of asbestos fibres.

10. A composition of matter comprising a product obtainable by heating bituminous coal and a member of the group consisting of water gas tar,

coke-oven tar and their distillationproducts, to

above about 300 C. so that the non-ash constituents of the mixture behave substantially as a homogeneous blend, said product having a softening point of at least C., a penetration at 0 C. of at least 4, and containing from 5 to 15 per cent 45 by weight of asbestos fibres.

11. The waterproofing process which comprises liquefying by heat a composition constituted of a coal-digestion pitch obtainable by heating together bituminous coal and tar at a temperature such that their non-ash constitutents behave as a substantially homogeneous blend, said pitch having a softening point of from 40 to C.. and a penetration of at least 4 at 0 C. admixed with from 5 to 15% asbestos fibers based on the weight of the coal-digestion pitch, applying said coal-digestion pitch-asbestos-composition in heat liquefied condition to a vertical or steep construction mass and permitting the heat liquefied composition to set.

- BENJAMIN A. ANDERTON.

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