US2039026A

US2039026A - Road making

Info

Publication number: US2039026A
Application number: US510937A
Authority: US
Inventors: Fred A Pease
Original assignee: Individual
Current assignee: Individual
Priority date: 1931-01-24
Filing date: 1931-01-24
Publication date: 1936-04-28
Anticipated expiration: 1953-04-28

Description

Palenle m3 ll Claim.

This invention relating, as indicated, to road making, has more particular reference to a method of resurfacing uneven road beds, either new or worn, or, in other words, applying to a road bed previously installed a so-called tread coating which will correct all of the imperfections in the contour of the original bed and, in addition thereto, will provide a wearing surface which shall be smooth and possess wearing properties equivalent to a new road bed.

After any type of road as now constructed either from brick, macadam, asphalt, or the like, has been in service for an appreciable length of time, it will be found that the passage of vehicles thereover has worn the road surface unequally in local areas so that some resurfacing method must be resorted to in order to place the same in condition for continuous use with the surface thereof restored to substantially its original smoothness and durability. When failures occurinwidely spaced local areas, it is common practice to suitably cleanse the upper surface of such failing areas and introduce thereto a sufficient amount of road surfacing material to repair such area and to bring the same to the level of the remaining portion of the road. This method is inexpensive, as heretofore employed, and is quite satisfactory where the failure of the road bed has occurred in only local areas relatively few in number as compared to the area of the road bed. When, however, the road has become worn so that the uneven portions extend substantially throughout the entire surface of the road bed, it has been found that the above described method of repair, as carried on in the past, has been unsatisfactory for numerous reasons, more particularly the cost of the operation which has been a manual one throughout each of its successive steps. I

When the road bed has become worn in the manner described, it has therefore been the practice to apply an entirely new layer of wearing material to the surface of the road, which layer is of substantial thickness and in reality amounts to superimposing a new road bed on to the old so as to provide the desired smooth surface of proper durability. This resurfacing or, in effect, rebuilding of the road has been accomplished by depositing a supply of previously mixed oil-bound aggregate on the surface of the road, smoothing the same to the proper level, and then rolling the resultant bed in order to compact the material, as is well known in the art.

A further method employed to resurface road beds in the manner described is the so-called sur face mix method which consists in depositing a quantity of unmixed aggregate and binding material upon the worn road bed and then by successively passing thereover a grading tool or mixing tool, the material is agitated sufiiciently to disperse the binding material throughout the body of the aggregate and simultaneously leveling and possibly inwardly packing the resurfacing material on the road bed.

Each of the above described methods of resurfacing worn roads are extremely unsatisfactory due to their cost and, further, due to the fact that traffic on the highway being repaired must be shunted around the area of operation.

Each of the above described methods has been excessively expensive due to the fact that no effort has been made to utilize, in effect, the old road bed which possesses properties of rigidity and durability by virtue of the duration of its installation which is not possessed by any new layer of material of substantial thickness, regardless of the foundation upon which the same may be placed.

It is among the objects of my invention to provide a method of resurfacing worn road beds or applying a tread coat to such worn road beds, or road beds which have imperfections in their surface due to any well known causes. My invention has particular advantages in the low cost thereof, the rapidity with which the same may be accomplished and, further, due to the fact that the traffic on the highway being prepared need not be materially interrupted. A further advantage of the method comprising my invention resides in the fact that such method utilizes all of the desirable characteristics such as rigidity and durability of the 'old road bed which can only be attained by any roadway by long and continued usage which compacts the material thereof and equalizes the same with respect to the underlying foundation. Other objects of my invention will appear in the course of the following description. To the accomplishment of the foregoing and related ends, said invention, then, consists of the steps hereinafter fully described and particularly pointed out in the claim.

The annexed drawings and the following description set forth in detail one approved mode of carrying out the invention, such disclosed mode however, constituting but one of the various ways in which the principle of the invention may be used.

Fig. 1 is a perspective view of a worn or uneven road bed to be conditioned by the method comprising my invention; Fig. 2 is a transverse sectional view of the road bed illustrated in Fig. 1;

til

Figs. 3, 4, 5 and 6 are respectively transverse sectional views similar to Fig. 2, illustrating successive steps in the carrying forth of the method comprising my invention; Fig. '7 is a longitudinal sectional view of the road-way illustrated in the previous figures showing associated therewith a form of apparatus for accomplishing one of the steps of my method; and Fig. 8 is a transverse sectional View of the roadway illustrated in the previous figures, showing in association with such roadway, diagrammatic representations of successive stages in the accomplishment of one of the steps comprising my method.

Referring more specifically to the drawings and more especially to Fig. 1, the road bed herein illustrated for purposes of convenience, consists of a central portion I which may be made of any suitable road material, such as macadam, brick, asphalt, or the like. The principles of my invention are applicable to the reconditioning of any type of worn or irregular road surface. The road bed I is shown laterally bounded by

curbs

2 and 3, although it will be understood that such curbs may be omitted and the surface of the road I continued adjacent the berm or shoulder of the road without the employment of such curbs. The road bed I here illustrated consists of a plurality of surfaces such as 4 which are at least somewhat lower than the surfaces such as 5, this variation in the roadway having been occasioned either by wear due to the passage thereover of vehicles or erosion, or any other action such as settlement of the bed-supporting means having a tendency to produce an uneven road bed.

As illustrated in Fig. 2, and as is well known to those familiar with the art, a road bed in condition as illustrated in Figs. 1 and 2 will usually have a superficial layer of loose, foreign material, such as 6, thereon, which will be found to have localized itself in the depressed areas wherein the road bed has become most worn. The first step in the method comprising my invention is to clean the surface of the road bed by brushing such loose material therefrom, or by washing, if a suitable source of water may be found convenient. This cleansing of the road bed preparatory to resurfacing by the method comprising my invention, may be dispensed with if it is found that the material on such bed consists almost entirely of the material such as stone, and the like, from which the original road bed was constructed. Best results will, however, be achieved if such loose material is removed as the first step in the method of my invention. After the loose material, such as 6, illustrated in Fig. 2, is removed from the surface of the road bed, the bed will be sprayed or coated with a thin layer of penetrating oily material such as viscous bitumen, and the like, which will penetrate, as illustrated in Fig. 4, sufficiently so that any material placed on such road bed in a subsequent operation will be securely united thereto.

With the worn or uneven roadway prepared in the manner described, i. e., cleaned and sprayed with a layer of penetrating oily material, the roadway is leveled off by applying a layer of oil-bound aggregate of variant thickness determined by the difference in elevation of the high and low spots of the worn bed I. This layer of oil-bound aggregate will preferably consist of new material supplemented by material derived by striking off to a certain extent the high spots in the roadway. The method in which this is accomplished is most clearly illustrated in Fig. 7 in which a drag, such as l, is pulled across the surface of the roadway. This drag will be of particular construction in that the transversely extending elements, such as 8, 9 and ID will be of sufiicient weight so that the high portions of the road bed are struck off to form smooth areas. Only sufiicient new material such as is indicated at l i will be placed on the roadway ahead of the drag, so that when such new material is supplemented by the material struck off from the high portions of the roadway, the resultant quantity will be just sufficient to provide the layer of varying thickness which is determined by the difference in elevation between the struck-01f high spots and the low spots of the worn bed.

The road bed i, after the drag. has passed thereover, somewhat relieving the high spots and filling in the low spots thereof, is illustrated in Fig. 5.

By placing just the proper amount of material on the road bed I ahead of the drag 1 as the drag passes thereover, such material supplemented by the material struck off from the high spots in the road will just fill the depressions in the road bed and bring the level thereof up to the line defined by the upper surfaces of such high spots. The drag will then be prevented from discharging streams of such material laterally therefrom in the passage over the road, so that an even surface will result from the dragging operation. In order to insure that every portion of the roadway is properly and fully treated in the manner hereinbefore described, the drag 'l, which proceeds longitudinally of the roadway in successive laterally spaced stages, may be so moved across the road bed as to slightly overlap with the previous path, as most clearly illustrated in Fig. 8. In this last-named figure, the portion included in the bracket at E2 will be the portion covered by the drag in its first passage down the road and the areas included in the brackets l3, M and [5 will be the areas covered by the drag in the successive stages of its travel longitudinally of the road bed. It will be noted, however, the sequence of the areas such as I2, [3 and I4, need not occur in the manner indicated, but the central portion of the road may first be dragged and then the edges.

After the layer of oil-bound aggregate of variant thickness determined by the diiference in elevation of the. struck-off high and low spots of the worn bed has been deposited thereon in the manner hereinbefore described, then, the entire road bed will be coated with a superficial layer of surfacing aggregate which will preferably be dry so as to prevent the tires of the vehicles passing over the road bed from coming in contact with the oil forming the binder in the body of such bed. After the layer of surfacing aggregate has been placed on the road bed, the entire bed will be rolled with a suitable roller so as to thoroughly compact the layer of variant thickness and compress the same into intimate contact with the upper surface of the original bed, so that a firm bond will be established therebetween.

It will be noted from the foregoing description that I have indicated the surfacing material to be employed by the method comprising my invention as oil-bound aggregate. It will be found for certain types of installation that it may be advisable to spread dry mineral aggregate over the precoated road bed and then spray such dry aggregate with a suitable binder, preferably an oily material. This spraying of the aggregate in place on the road bed as one of the steps in the method comprising my invention, has been found to reduce the cost for certain types of operation.

The hereinbefore described manner of accomplishing the method comprising my invention, it will be noted, is particularly applicable to the resurfacing or repairing of a macadam or asphalt road bed wherein the action of the drag i may be relied upon to strike-01f to a certain extent the high spots in the original bed. However, should the original bed to be coated, resurfaced or repaired, consist of a material such as brick or concrete, the action of the drag will not be effective to reduce or remove the high spots in the road, but such drag will then deposit a layer of the oil-bound aggregate over the worn surface of the road to the thickness defined by the difference in the elevation between the high and low spots of the bed.

It has been found, in the practice of the method. comprising my invention, that the character of the material comprising the original road bed to be prepared covers to a large extent the quantity and quality of the binding material employed in connection with the new material added to furnish the layer of material occurring between the high and low spots of the roadway. It has been found, for certain localities in which high temperatures occur, that a road bed consisting of a material having an oil binder to begin with, the priming coat of penetrating oil might be. omitted if sufficient binder is employed in connection with the new material added to the roadway. However, the employment of the priming coat is believed to be warranted in all installments unless circumstances of an unusual character occur which make it possible to dispense with such coating.

It will be noted that by carrying forth the method comprising my invention, only so much new material need be used as is required to produce a layer over the road bed of variant thickness defined by the difference in elevation of the high and low spots of the road. Therefore, by employing only a minimum amount of material,

the first cost, i. e., the cost of materials, is reduced to a very low minimum for the production of the desired results. The employment of the drag for the purpose of distributing, equalizing, depositing and superficially packing the added material and, further, to strike-01f to a certain extent the high spots of the road bed and to intermingle the same with the new material to form a homogeneous layer, is a further advantage of my invention, inasmuch as this operation may be accomplished by a single passage of the drag over the road surface. For roads which have become severely worn, it may be necessary to pass the drag over such road bed several times before the same is sufiiciently leveled to present a smooth finished surface. The employment of the method comprising my invention has a further advantage as hereinbefore indicated, in that the durability and rigidity of the original road bed, which has been attained by its being positioned on its foundation through long and continued usage under the impact of the vehicle wheels passing thereover, is retained and fully utilized in the roadway resulting from my repairing or resurfacing method. Other advantages of my invention are believed to be so well known to those familiar with the art of road building, that a more detailed description thereof will be unnecessary at this point.

I claim:

The method of providing a tread surface for an uneven roadbed including the steps of coating the protuberant portions of such surface with an oily material to such an extent that it will penetrate the protuberances sumciently to be softened throughout, levelling the roadbed by striking off the tops of high portions and supplementing the struck-off material with oil bound aggregate sufficient to form a layer of variant thickness defined by the difference in elevation of the low portions of the bed and the struck-01f higher portions, applying a superficial layer of dry surfacing aggregate, and then rolling the resultant bed.

FRED A. PEASE.