US394126A - William - Google Patents

Description

UNITED STATES PATENT OFFICE.

ILLIAM C. MURDOCK, F \VASHING'ION, DISTRICT OF (OII M BIA, ASSIGNOR TOTHE NATIONAL YULUANITE COMPANY, OF NElV YORK, N. Y.

VULCANITE PAVING COMPOUND.

SPECIFICATION forming part of Letters Patent No. 394,126, dated December 4, 1888. Application filed May 16, 1888. Serial No. 274,093. (No specimens.)

To aZZ whom it may concern.-

Be it known that I, WILLIAM (J. MURDocK, of \Vashington, in the Districtot Columbia, have invented certain new and useful Improvemeuts in Vulcanite Paving Compounds; and I do hereby declare the following to be a full, clear, and exact description of the same.

This invention relates to thepreparation and combimttion of materials to form what is IO known as vulcanite pavement-a composition employedt'or paving streets, sidewalks, cellars, stables, &c.; and it consists in the novel and improved compositions and mode of treatment of the materials forming part I5 thereof, as hereinafter described, and pointed out in the claims.

In the preparation of asphalt pavements it has heretofore been customary to prepare the asphalt by subjectin crude Trinidad asphalt in kettles or retorts to a tire heat of from 700 to 1,000 I ahrenheit, for the purpose of melting the mass to precipitate the earthy and other matters containml therein and driving olt moisture. To the melted asphalt petro- 2 5 leum residuum is added in the proportion of about one part residuum to six parts asphalt, and the whole being subjected to heat and agitation produces what is known as petro leum-asphalt cement. By reason of the high 0 degree of heat heretofore deemed i'lecessary in carrying out this process the heavier essential oils are driven oil, to the detriment of the compound and injury of the pavement made therefrom, as the heavy hydrocarbons which 3 5 are necessarily expelled, instead of being detri mental, are exceedingly valuable in maintaining the lite and tenacity of the matrix, and their removal renders the residuum brittle, more liable to be injured by exposure to the atmospheric influences, as well as being more friable, and thus more readily destroyed and worn away when subjected to heavy or constant traffic, as in large cities. To counteract or in a measure compensate for the loss of the oils driven off in the preparation otthe asphalt, petroleum residuum is added; butthis again being subjected to the high heat is in turn deprived of a large portion of its more volatile oils hence it sometimes becomes nec- 5o essary 61' advisable to add in the subsequent treatment a certain proportion of petroleum residuum. As is well known, petroleum and petroleum residuum contain active solvents of bituminous matter, and its ettect upon the asphalt, especially when the former contains the lighter oils, is of such a nature as to render it extremely dit'ticult and practically impossible to thoroughly unite the asphalt cement with artificial asphalts made from coaltar or such as contain these artificial asphalts in large proportions. As the result of much experience and many trials, I have discovered that it is possible to avoid or counteract these defects both as to the manufacture and product by substituting coal-tar residuum for pe- 6 5 troleum residuum and subjectingthe crude asphalt to a temperature not exceeding 500" liahrenheit.

In practicing this part of my invention I place the crude natural asphalt in a retortor other vessel and add the coal-tar distil1ate i. 6., coal-tar deprived of the lighter oilsin about the proportion of seven parts of the former to one of the latter, and heat the mixture to a temperature of 450" Fahrenheit, re- 7 5 taining it at or about this temperature, but never exceeding 500" Fahrenheit, until the asphalt has been con'ipletely melted or amalgamated with the coal-tar distillate. In this way I manage to preserve all thedesirable 8o qualities and constituents of both the asphalt and coal-tar, while eliminatin the lighter oils,

or such as in practice have been found deleterious or destructive to the life of the pavement, at the same time eifecting a complete admixture of the two substances. The addition of the coal-tar distillate to the asphalt also assists materially in expediting the liquefaction and solution of the asphalt when subjected to the relatively low temperature em- 0 ployed.

The mixture is maintained at a practically uniform temperature of 450 Fahrenheit until evaporation ceases, and it is then in condition to readily and naturally combine with most, if not all, of the bituminous compounds, such as are employed for paving and similar purposes.

To form my improved pavingcompound or mixture, the asphalt thus produced is united 10o with distillate of coal -tar which has previously been subjected to a temperature not exceeding 450 Fahrenheit to drive off the more volatile oils, the proportions employed being approximately seventy parts of the distillate to thirty parts of the asphalt, forming 'an asphaltic cement possessing uniform properties and retaining all the heavier hydrocarbon oils and compounds not evaporatin at the temperature to which the materials have been subjected,i. 6., 450 Fahrenheit.

Having thus produced my asphaltic cement, I proceed to prepare the ingredients which, when combined therewith in the manner and proportions specified, constitute the paving material. These materials or ingredients are clean, fine, and sharp sand, carbonate of lime, sulphur, sulphate of calcium, mineral wool or asbestus, l1 "dlL1lllG cement, calcareous gravel, and stone dust in proportions varying with the climate and service to which. the pavement is to be subjected, the proportions also varying somewhat according to the relative coarseness or fineness of the materials used. Thus, to form the wearing-surface I may employ seventy parts sand, one part hydraulic cement, ten

parts calcareous gravel, one part sulphur, six

parts carbonate of lime, six parts sulphate of calcium, two parts mineral wool or asbestus, and six parts stone dust. These ingredients are thoroughly mixed and heated to a temperature not exceeding 250 Fahrenheit, but pref rably at 230 Fahrenheit, and to this heated mixture I add at the same temperature a sufficient quantity of the asphaltic cement, prepared as described, to 'form the required wearingsurface.

The quantity of asphaltic cement will necessarily vary somewhat with the climate and thickness of the wearing-surface of the pavement; but it is usually within a margin of from five to eight per cent. of asphaltic cement to one hundred per cent. of the metal described. The materialsasphaltic cement and metalare placed in an amalgamator and thoroughly mixed, after which, and while still hot and plastic, they are taken to the locality where the pavement is'to be laid and spread upon a prepared surface, raked to the proper degree of thickness and tramped and rolled into a solid homogeneous mass or coating. The surface is then covered with hydraulic cement, or, preferably, a mixture of hydraulic cement and sulphate of calcium in about equal proportions, after which it is rolled again until cold and fit for use.

For street-work I prepare the base or substratum by first leveling off the surface to the proper grade and placing thereon a layer of broken stone, the larger stone being placed at the bottom and the smaller on top. This mass of stone is then covered and the interstices filled with coal-tar distillate and rolled into a solid mass or layer of the required thickness. Upon the base thus formed is spread the binder-course, consisting of small stone previously heated to about 150 Fahrenheit and mixed with the prepared asphaltic cement hereinbefore described, in the proportion of about one gallon of asphaltic cement to one cubic foot of metal. This mixture is laid evenly upon the prepared substratum and rolled to the required thickness, after which the wearing-surface is applied in the manner previously explained.

By preparing the binder-con rse with the asphaltic cement and interposing it between the coal-tar distillate of the substratum and the asphalt cement of the upper or wearing face a more perfect amalgamation. of the several courses is effected and the life and endurance of the wearing-surface-the part most subject to decay-is increased and prolonged.

I do not claim herein the method of laying the pavement, nor the pavement itself, as con: tradistinguished from the method of preparing the ingredients as herein described and claimed, said subject-matter being reserved in a divisional application, No. 290,038, filed November 5, 1888.

Having thus described my invention, what I claim as new is 1. The hereinbefore-described improvement in the art of manufacturing asphaltic cement for use in paving compounds, which consists in distilling coal-tar and asphalt together at a temperature of 450 Fahrenheit and not exceeding 500 Fahrenheit, and subsequently adding thereto coal-tar which has been heated to 450 Fahrenheit, substantially as described.

2. The hereinbeforedescribed improve ment in the art of manufacturing asphaltic pavements, which consists in heating coal-tar and crude asphalt, in about the proportions named, to a temperature of about 450 Fahrenheit and not exceeding 500 Fahrenheit, until the vapors arising at said temperature are eliminated, adding to said mixture a further quantity of coal-tar which has been deprived of its lighter constituents by being subjected to a temperature of between 450 and 500 Fahrenheit, and subsequently adding to the asphaltic cement thus formed mineral substances at a temperature not exceeding 250 Fahrenheit, substantially as described.

3. The hereinbefore described improved process of forming vulcanite paving compounds, which consists in mixing comminuted mineral substances, of which sulphur forms one ingredient, heated to a temperature not exceeding 250 Fahrenheit, with an asphaltic cement composed of coal-tar distillate and native asphalt refined at a temperature not exceeding 500 Fahrenheit, substantially as described.

4. The hereinbefore described improvement in the art of manufacturing avulcanite paving composition, which consists, essentially, in refining native asphalt by heating it, together with distillate of coal-tar, at a temperature of about 450 Fahrenheit and not exceeding 500 Fahrenheit, adding, in about cium, stone dust, and mineral wool 01' asbesthe proportions named, distillate 0f coal-tar tus, suljmtantially as described.

which has been subjected to about the same 7 Y Y 7 temperature as the asphalt, and-subsequently ILLIAM RDOCIX' mixing with the asphaltic cement thus formed \Vitnesses:

sand, hydraulic cement, calcareous gravel, THOMAS DURANT,

sulphur, carbonate of lime, sulphate of call MELVILLE CHURCH.