Roofing And Paving Process

Abstract

An improved paving process has been invented which employs a cold-mix asphaltic surfacing composition. This surfacing material does not require heat or mixing as a preliminary step before application on any area to be protected. The surfacing composition is very light in weight, adhesive, waterproof and has heat insulating properties being ideal for the resurfacing of any areas requiring these properties such as old worn roof decks and parking decks with areas of irregular contours in need of resurfacing. The paving material can be stored indefinitely in waterproof bags and when ready for application on a worn roof surface or parking deck this paving composition is easily spreadable and covers such worn surfaces which are irregular in depth to an even contour with a light weight, adhesive, waterproof covering.

Parent Case Text

This application is a continuation-in-part of U.S. application Ser. No. 664,867, filed Aug. 31, 1967 and now abandoned.

Description

This invention relates to the art of paving of worn roof surfaces and similar areas with a special bituminous composition having a perlite filler therein. More specifically the invention pertains to a method of resurfacing worn and irregular areas such as roof decks with certain cutback asphalt compositions having admixed therein an expanded siliceous volcanic rock, perlite.

The invention employs a well known bituminous material, asphalt, in a new and distinctive manner. This will be better understood by a consideration of this material.

Asphalt is a relatively high boiling, viscous or solid dark colored fraction or residue which may result from petroleum distillation or treatment or which may be natural in occurence. Asphalts include resins derived from mineral oils, e.g. by solvent extraction and also residues from mineral oil treating processes. Most asphalts are highly viscous, semisolid or solid materials at ordinary ambient temperatures. Accordingly, the art has developed liquid asphalt compositions by dissolving such asphalts in various organic solvents such as liquid petroleum distillates or naphtha.

Liquid asphalt compositions have been designated in terms of rate of cure or setting time. The RC series of liquid asphalts are rapid curing. They are designated by the symbol RC followed by a number indicating their viscosity in centistokes at 140.degree. F. For example, RC-250 is a liquid asphalt having a viscosity of 250 centistokes measured at 140.degree. F. It is a so-called cutback asphalt, since it is a solution of asphalt cutback with a naphtha solvent to yield this viscosity. The characteristics and identity of these liquid asphalts are more fully described in the "Asphalt Handbook," Manual Series No. 4 (MS-4) of the Asphalt Institute.

The art of paving and surfacing with such bituminous materials, e.g. asphalts, is old and well developed. Hard asphalts have long been softened and made suitable for such paving applications by mixing with solvents such as mineral spirits and oils. However, the art of paving and repairing worn roofs and other like surfaces has not known the use of a perlite filler which when mixed with such asphalts enhances its value as a paving repair and resurfacing composition.

The invention utilizes a cold light weight insulating paving material by the use of a manufactured aggregate, perlite, which is a siliceous volcanic rock expanded above 1,600.degree. F., weighing between 71/2 and 12 pounds per cubic foot dry-loose, and a binder, rapid curing cutback asphalt. Other cold-mix paving compositions may be made by the use of an asphalt emulsion or cutback asphalt with natural or light weight aggregates, but these produce material without the specific properties and light weight characteristics of the paving composition of the invention. Such other cold paving compositions normally weigh between 75 and 150 pounds per cubic foot when compressed to uniform thickness of one and one-half inches. The weight of the paving material according to this invention ranges from about 30 to about 40 pounds per cubic foot when compressed to a uniform thickness of 11/2 inches.

The process of this invention for the repair and leveling of worn, uneven roofs and other surfaces, for example, in the resurfacing of existing slag or gravel roof areas, has several steps to completion as shown in the drawing. The FIG. illustrates a section of a worn roof surface showing the complete process and is a perspective view of a repaired roof surface showing the several levels of the repaired roof partially cut away.

Referring to the drawing, the surface to be refinished (1) is first coated with an asphaltic binder 6 (2) for example, Durex Liquid Binder. "Durex" Liquid Binder is a cutback asphalt liquid primer composition available from Metropolitan Roofing Supplies Co., Inc., 355 Major Deegan Blvd., New York, New York. This primer is identified as having the following properties:

a. Specific gravity at 60.degree. F., 0.9260;

b. Furol viscosity at 122.degree. F., 119.4 sec.;

c. Flash point, .degree. F. 130;

d. Distillation, percentage by volume of total distillate:

(Initial Boiling Point <300.degree. F.)

Up to 320.degree. F. -- 4.4

Up to 374.degree. F. -- 55.5

Up to 437.degree. F. -- 80.0

Up to 500.degree. F. -- 88.8

Up to 600.degree. F. -- 95.5

Residue over 360.degree. C. -- penetration at 77.degree. F.;

100 g., 5 sec.

e. Matter soluble in carbon disulfide--not less than 99 percent. After the binder has set the cold-mix light weight paving material (3) is spread evenly over the surface to be covered. Then a black back capsheet cover (4) is laid down and rolled over the entire surface area to be covered. If desired the capsheet may be lapped, e.g. about two inches, rather than butted.

The process of resurfacing and repaving of roofing according to the invention may be better understood by further reference to the drawing. All loose debris is removed from the roof (1). A spray coating (2) of Durex Liquid Binder, an asphalt primer, is spread over the prepared surface at a suitable rate, e.g. at a rate of 5 gallons per 100 square feet and allowed to set for a suitable time, e.g. 12 hours. This material penetrates and solidifies on the original surface material and acts as a primer for the resurface coating of the invention. Thereafter the composition of cold-mix light weight asphaltic-perlite material (3) is applied evenly over the primed surface to the desired thickness for example, to preferred thickness of about 1/2 inch. Any suitable thickness may be used but generally the asphaltic-perlite material will be from about 1/4 to about 11/2 inches in thickness. Then, there follows application of a layer of black back capsheet (4) butting or overlapping the edges thereof and compressing the material (3) evenly in the finished process using a suitable compressing means such as a roller of suitable weight, e.g. of about 150 pounds in weight. The FIG. shows butting capsheets (4a).

The filler and insulating material of the invention is perlite, a special volcanic rock which has been treated under high heat (temperatures of 1,600.degree. F. and higher) for a time sufficient to change its character to an expanded state. The perlite is preferably used in a finely divided state and sufficient perlite is mixed with asphalt to yield a paving composition whose density will be in the range of about 30 to about 40 pounds per cubic foot when compressed to a uniform thickness as described.

The cold-mix light weight asphaltic paving composition is made by mixing perlite (which is as described above a siliceous volcanic rock properly expanded at temperatures of 1,600.degree. F. and higher) together with a suitable rapid curing cutback asphalt in suitable proportions by weight. For example, the following percentages by weight illustrate a useful formula for a paving material according to the invention:

Filler: Perlite 50 percent

Asphalt: RC 250 cutback 25 percent

Asphalt: RC 70 cutback 25 percent

Any suitable asphalt for roofing and paving together with the usual cutback solvents may be employed in the invention. The exact type of asphalt-solvent system will depend to a certain extent on climatic conditions. This formula, for example, may be tempered for specific seasons of the year, using 50 percent perlite and 50 percent RC 70 cutback for winter climate; and 50 percent perlite and 25 percent RC 70 cutback with 25 percent RC 250 cutback for summer climate. The composition so made does not require the application of heat as a preliminary step before application on the desired area.

Generally, the preferred embodiment of the invention employs about equal parts by weight of perlite and asphaltic material. However, any suitable proportion yielding the desired density of paving composition can be used. Thus, a range of about 40 to 60 parts by weight of perlite may be used.

The cold-mix light weight asphaltic paving composition developed by the processing of perlite and rapid curing cutback asphalt as aforesaid, is suitable for vehicular and pedestrian traffic, ideal for areas such as roof decks and parking decks, waterproof in nature, absorbing not more than 3 percent of its weight of water after compression. This light weight asphaltic paving composition so developed is adhesive in nature, capable of adhering to base sheetcover used primarily in surfacing a roof and has thermal insulating properties, not exceeding .70 K factor, which protects the surfaced area from normal atmospheric conditions.

The asphalts used may vary from 60 to 40 parts by weight with reference to a 100 parts of total composition with the other component being perlite.

Various combinations of asphalts may be used to prepare the asphaltic component. Generally there is only one or at most two RC asphalts in the asphaltic component. These RC components may be in weight relationships of from zero to 99 parts and may be of the type RC 70 to RC 250 as characterized above. The preferred type is in the range RC 70 to RC 250. Thus said asphalt compositions are suitable for thermal and mechanical protection of pipes underground, having thermal insulation properties not exceeding .70 K factor.

In a preferred embodiment of the invention a cold-mix light weight asphaltic paving composition is used to repave worn surfaces as described herein, which composition weighs about 30 to 40 pounds per cubic foot after compression to one-half inch thickness upon the surface to be paved or covered. Other compositions having the desired properties may also be used in like manner.

The composition containing perlite is prepared in such a way as to be capable of being stored for indefinite periods of time in waterproof bags ready for application without mixing or heating. As described hereinabove this paving composition is composed essentially of (a) the filler component, perlite, or other like siliceous expanded rock, and (b) the asphaltic component, a bituminous composition made liquid by cutting back with a suitable solvent as is well known in the art. In preparing the asphaltic component it may be advantageous to add certain auxiliary agent such as dispersing agents. The silicones are particularly useful such as dispersing agents. For example, a silicone dispersing agent may be added in an amount ranging from about 1 to about 50 parts per million parts by weight of the weight of asphaltic component containing asphalt cutback with solvent. Examples of suitable dispersing agents are Dow Corning Silicone DC-200 and Humble Oil Company's Corexit 7669. One such silicone dispersing agent useful in the invention is characterized as having average properties as follows: specific gravity of 0.97, surface tension of 21.1, flash point of 600.degree. F. refractive index of 1.403, and viscosity of 350 centistokes at 77.degree. F.

From the foregoing the many advantages of the invention can be seen in the process of its application for the leveling of uneven roof surfaces and for the resurfacing of existing slag or gravel roof areas eliminating the need for scraping and removal of all the slag or gravel, providing a level surface, and eliminating the use of an adhesive in the application of the dry base sheet cover rolled over the invented composition. The invention is ideal for areas such as roof decks and parking decks, because it can be used as a combination vapor barrier and roofing insulation for new roof decks. Further, the invention is also useful in making parking decks, because it can be used as an excellent waterproofing protecting course before application of quarry title or paving blocks.

Claims

We claim:

1. The process of repairing a worn roof which comprises:

a. forming a paving composition by mixing together (i) from about 40 to about 60 parts by weight of a filler component, and (ii) from about 60 to about 40 parts by weight of asphalt component, said filler component consisting essentially of a finely divided siliceous volcanic rock expanded by heating at a temperature of at least 1,600.degree. F. for a time sufficient to irreversibly expand said rock, said asphalt component comprising at least one cutback asphalt having a viscosity at 140.degree. F. of from about 70 to about 250 centistokes;

b. preparing the worn roof surface for repair without removal of the old roof materials except for loose debris, by coating the old roof after removal of debris with a primer coating composition over the entire worn roof surface at a rate of about 5 gallons of primer per 100 square feet of worn roof surface, said primer being a cutback asphalt having properties substantially as follows:

i. Specific gravity at 60.degree. F., 0.9260,

ii. Furol viscosity at 122.degree. F., 119.4 sec.,

iii. Flash point, .degree.F. 130,

iv. Distillation, percentage by volume of total distillate:

(Initial Boiling Point 300.degree. F.)

Up to 320.degree. F. -- 4.4

Up to 374.degree. F. -- 55.5

Up to 437.degree. F. -- 80.0

Up to 500.degree. F. -- 88.8

Up to 600.degree. F. -- 95.5

Residue over 680.degree. F. -- penetration at 77.degree. F.,

100 g., 5 sec. -- 12

v. Matter soluble in carbon disulfide -- not less than 99 percent;

c. spreading the aforesaid paving composition over the worn roof surface coated with said primer, placing a capsheet over the paving composition and then compressing the capsheet and paving composition which is applied to the worn roof, in such quantities that when compressed together with the capsheet to from about 1/4 to 1/2 inch thickness the resulting paving composition has a density of not more than 40 pounds per cubic foot.

2. The process of claim 1 wherein said paving composition after forming is placed in bags and stored until used for spreading on the worn roof surface.

3. The process of claim 1 wherein said paving composition comprises about 50 percent by weight of perlite and about 50 percent by weight of asphalt component comprising at least one cutback asphalt having a viscosity of from about 70 to about 250 centistokes at 140.degree.F.

4. The process of claim 3 wherein said asphalt component comprises a cutback asphalt having a viscosity of 70 centistokes at 140.degree. F.

5. The process of claim 3 wherein said asphalt component comprises about equal parts by weight of two cutback asphalts having viscosities at 140.degree. F. of 70 and of 250 centistokes, each respectively.

6. The process of claim 3 wherein said asphalt component contains from about 1 to about 99 parts per million by volume of a dispersing agent, based on volume of said asphalt.