US829294A - Pavement. - Google Patents

Description

PATENTED AUG. 21, 1906.

P, G. REILLY PAVEMENT.

APPLICATION FILED MAR-30.1904.

w r x UNITED STATES PATENT OFFICE.

PETER C. REILLY, OF INDIANAPOLIS, INDIANA.

PAVEMENT.

To all whom it may concern:

Be it known that 1, PETER. O. REILLY, a citizen of the United States, residing at Indianapolis, Indiana, have invented a certain 5 new and useful Improvementin Pavements; and I do hereby declare the following to be a full, clear, and exact descri tionof the inven- V tion, such as will enable ot ers skilled in the art to which it appertains to make and use the same. I

This invention relates to pavements, and particularly to wearing-surfaces.

The obj ect of the invention is the provision of a wee; -surface having great stabilit anddui'abihty, afiording a secure foothol and requiring comparatively small tractive force.

v A difficulty encountered in the constructionipfp'avements exposed to the action, of the elements is. the liability to deterioration caused-by the absorption of water and uneven wear, due to. inequalities in density of the material in the structural composition. Bituminous pavements, Whether of asphalt or other kinds of bitumen or whether a combi nation of bitumen with other substances, must in order to produce the best results be compact and free from voids, and that pavement which is nearest free from voids is in that degree the best pavement. Bituminous pavements as heretofore laid contain a large percentage of voids, and this is true whether the bitumen be used in connection with sand or with broken stone or other material. The vresult of-this condition isthat the pavement is not at'all points stable and self-supporting but when it becomes heated by atmospheric influences or by the friction incident to trafiic it does not maintain its original position and creeps toward the lower points of the street and forms in waves transverse to the direction of traffic. A further result is that on account of the uneven distribution of the voids in the pavement the pavement is more easily compressed at some points than at others by the ressure of traflic, thus making an uneven surf cawhich after a time by the efiect of the trafiic forms waves, as above indicated. The defective condition of bituminous pavements above set out is the result of the unscientific method of construction heretofore practiced.

The bituminous pavement, commonly known as as halt pavement, is constructed with an asp altic cement, usually formed of asphaltum-- pitch and sand. This cement while in a heated condition is spread upon Specification of Letters Patent.

Application filed lllarch 80,1904. Serial No. 200.736

Patented Aug. 21, 1906.

the surface of the street and by a process of compression or rolling fixed in position, the compression being intended to so compact the cement as to make it one solid mass free from voids; but it has never been found possible by such a process to entirely eliminate the voids. e

Another method of constructing bituminous pavements hasbeen used whereby the wearingsurface of the pavement is constructed by taking predetermined proportions of broken stone of diflerent sizes so roportioned that when uncoated with pltch they may be settled into a mass having a small percentage of voids. This character of stone is then coated with bitumen, spread on in As a laboratory test it is ossible to ta e uncoated broken stone 0 predetermined proportions of different sizes and by a process of vibration settle them into amass whereby the percentage of voids will be small; but the same character of stone when coated with pitch and dumped and s read on a street and then compacted by roiling will not assume that perfectcondition that it can be placed in b laboratorymanipulation,and the result is t at the pavement is imperfect and not free from voids. It shows, therefore, the same defects after use as are found in the ordinary sheet-asphalt pavement, which are brought about in the same way.

It is impossible by the methods of compression above set out to take the materials above described and form them into a compact pavement free from voids. I have found that the only practical method by which a bituminous pavement can be laid so as to be free from voids is by taking a uarry run of stone, preferably from one iric down, and mixing it with suflicient proportions of sand and bitumen so as to make a dense mortar while in a heated state. If such a mortar be dumped and spread on a street, the bitumen and sand, being of a more fluid nature than Then by a rocess of tamping and rolling the particles 0 stone may be forced downward, and by a process of displacement the morta This mortary substance will not rise to the surface so long as there are any voids which mortar, and-therefore all voids will be filled before it will rise, so that if the tarnpmg and rolling process is-carried on to a time when substance will be brou ht to the surface.

it may seek toward the bottom of the coat of.

the stfeet, and compacted bya process of rollthestone, will flow at once to the bottom.

the mortary substance has risen to the top the whole will be free from voids. It may be suggested in criticism of my statements above that the same process of tam ing would produce a solid mass in an asp alt pavement or in the other bituminous pavement above described; but such is not the casev In the asphalt pavement as heretofore laid the substance when put upon the street is not a mortary substance, but is composed of as halturn-pitch and sand which is all practica y of the same size in its particles, and when the process of tampin and rolling is resorted to, themass being a l of a similar character and consistency, there isno fluid substance at the bottom to be displaced and forced to the top by the process of tamping and rolling; neither is there any mor tary substance in the other bituminous pavement above described which can flow to the top when a process of tamping and rolling is resorted to. More briefly stated, the producers of asphalt pavement rely upon the process of compression to produce a solid mass, the producers of the other bituminous pavement above described rely upon the intermixin of different sizes of stone in predetermine proportions, and I rely u on the mortary substance which flows to t io bottom of the pavement and is projected upward by a method of displacement caused by the process of tamping and, as above set out, cannot be forced upward so long as there may be any voids for it to seek in the lower part of the avement.

Al the difficulties above noted are overcome and the desirable objects above noted are attained in the wearing-surface forming the subject of the present invention and the application for a patent thereon.

An embodiment of the invention is illustrated in the accompanying drawing, which represents a cross-section of apiece of pavement constructed in accordance therewith.

In this drawing, (1. represents the curb, b the foundation structure, and c the wearingsurface.

In producing a pavement of this character the concrete foundation 1) is laid in the usual manner, swe t, and a coating of cement (preferably hational brand bituminous cement N o. l) is applied thereto. The structure is then ready for the application of the wearin -surface, which is prepared as follows: he natural run of crushed granite or other suitable stone varying in size from one and three-fourths inches or any other selected size downward is mixed. with Sufficient clean, sharp, coarse sand and b tum nous cement (preferably National bituminous cement No. 2) to make the Whole a dense mortary substance. The crushed stone and sand before being mixed with the cement are heated to a temperature of approximately 250 Fahrenheit. The bituminous cementls heated a proximately tothe same temperature. T e resultant mass is mixed until each particle of stone and sand is thoroughly coated with the cement. This wearin -surface mixture is now added to the foum ation to a depth of approximatel three inches. It is thoroughly tamped an rolled in such manner as to .ring to the top the mortar forming the more fluid ortion of the mass.

roducing a uick-settlng smooth surface.

he do th of t e wearing-surface after tamping an rolling should be about two and onehalf inches. The pavement thus produced is ready for almost immediate use and has been found to be impervious to moisture, stable and fixed in character, of long life, and it requires a minimum of expenditure for repairs and renewals because of its firmness and fineness of texture.

By using a smaller proportion of the mortar substance it will not rise high enough to ma e the top of 'the pavement entirely smooth, but will leave the larger particles of the stone slightly protruding from the surface. thus forming a pavement with a rough surface very necessary and useful on inclines and where there is heavy drawin i \Vherefore, having thus fully disclosed my invention, what 1 claim as new, 'and desire to secure by letters Patent of the United States, is- V 1. A wearing-surface for pavements comprising a concrete mass, of which the larger com Jonent particles form the lower part, and the finer particles till the interstices between the larger particles and form a smooth upper surface, whereby is formed a wearing-surface containing stones decreasing in size from the bottom toward the top.

2. A wearing-surface for pavements, comprising a bituminous concrete mass of constituents decreasing in size from the bottom toward the top, the liner particles filling the voids between the larger particles and forming a smooth upper surface.

' 3. The method of producingawearing-surface for pavements which consists in ireparing a mortary mass, forcing the smaller particles into the interstices from the bottom toward the top and above the larger stone articles andallowing it to set, whereby is ormed a wearing-surface containing stones decreasing in size from the bottom toward the top. a

4. The method of producinga wearing-surface for pavements, which conrszstsin applying bituminous concrete as a o rt-ary mass, tamping or rolllng until the finer particles fill the voids and interstices of the larger articles and are largely brought above the finger particles to the top as a semiliquid mortar, and allowin it to set, whereby is formed a wearing-surfiice containing stones decreasing in size from the bottom toward the top.

5. The method of producinga wearing-sun face for pavements, which consists in adding to the natural run of broken stone, twenty Eer cent. of sand and ten tofifteen per cent. of ituminous cement, applying as a dense mor- 5 tar mass to the foundat1on,'and tanipi'ng or rol mg until the finer articles are forced into the voids and large y brought above the larger particles to the to i as a semiliquid mortar, and allowing it to arden, whereby is IO formed a Wearing-surface containing stones decreasing in size from the bottom toward the to t 6. 'l he method of producing a wearing-surface for pavements, which consists in prepar- I 5 ing a dense mortary mass of stone, sand and bituminous cement, applying the mass to a suitable foundation, tamping or rolling until the larger stone particles are forced to the bottom displacing toward the top the semiliquid portion to fill the interstices and form a smooth upper surface, and allowing to harden.

In testimony whereof I affixmy signature to this specification in the presence of two witnesses.

PETER O. REILLY.

Witnesses:

JAMES BRODEN, WILLIAM F. Moons.

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