US188645A - Improvement in concrete pavements - Google Patents

Description

I06. COMPOSITIONS, COATING OR PLASTIC.

A. K. LEE. CONCRETE PAVEMENT.

No.188,645. -1 a.t'e nt.ed III {arch 20, 1877.

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PATENT QFFIGE.

UNITED STATES AROHIBALD K. LEE, OF PHILADELPHIA, PENNSYLVANIA.

" IMPROVEMENT IN C ONCRETE PAVEMENTS.

Specification forming part of Letters Patent No. 188,645, dated March 20, 1877 application filed February 11, 1877.

To all whom it may concern:

Be it known that I, AROHI'BALD K. LEE, of the city and' county of Philadelphia, in the State of Pennsylvania, have invented a certain new and useful Concrete Pavement, of which the following is specification:

The object of my invention is to provide a pavement which shall possess the qualifications of economy in first cost, durability in use, imperviousness to moisture, efi'ectual resistance to variations of temperature, and the presentation of a desirable surface; to which ends my improvement consists in the combination of a bed or lower layer of broken stone,

an intermediate layer of concrete, and an upper layer or facing of an asphaltic concrete, all as hereinafter fully set forth. Various mixtures or conglomerates have been heretofore proposed for paving and roofing purposes, and a large number have been made the subject of Letters Patent both in the United States and Europe. So far as my knowledge extends these compounds have consisted of substances such as sand, wood, and coal-ashes, cinders, charcoal,-iron slag, road-dust, clay, rubber, &c., the binding or cementing ingredients being coal-tar, deadoil, rosin-oil, pine-tar, pitch, or like material. Many so-called asphalt pavements have been experimented with in this and other countries as substitutes for the natural asphalt, and most of them will be found to embody some of the ingredients above specified. In some, asphalt is used in combinationwith coal tar; Richie mineral, Albertite pitch, rosin, rosin-oil, petroleum, dead-oil, or like materials, but in none, so far as'I am aware, is asphalt, per 80, recommended or prescribed. None of these pavements, however, have gone into very general use, and, while a certain degree of success has been attained in some of them, nearly all fail to satisfactorily stand the test of time and wear, showing evidences of disintegration and periodically requiring repair or refacing, and hence opposition and prejudice against concrete pavements have arisen which tend materially to impede the progress of improvement in this direction.

Among the causes which have operated to produce such failure may be stated the following: First, the natural principle that no loose, hard material can remain long distributed among substances of a' softer nature. Every tread upon a pavement of this composition tends to force away the soft substance, j and the effect. of this is to leave the .hard

little aflinity between silicious matter andbitumen that their parts separate from one another by a very small disruptive force. Again, it is well known that gas-tar or pitch, generated by the action of fire at a high temperatnre, becomes soft at 115 Fahrenheit, while the natural asphalt sustain a heat of 170 Fahrenheit without injury. Goncrete composed of gas-tar or pitch has also the property of decomposition by the joint agency of air and water, whereas the natural asphalt is known to remain for ages without alteration. Bituminous coal, from which the coaltar and pitch are made, has in itself but little, cohesive power, and it is well known that upon exposure to the air, and by the attrition of handling, a large percentage is lost in line dust. Nor is there anything in the operation of coking the coal to obtain illuminating-gas, or in the subsequent process of distillation by'fire of the coal-tar, which overcomes the inherent tendency to crack and crumble when in concrete. In oint of fact, such process,

instead of dimin Suing only increases this action toward disintegration.

It is by these characteristics that we account for the disappointments so commonly experienced in pavements, which at first appear firm and beautiful, but which soon become disintegrated and unsatisfactory. The admixtures and distillations from coal-tar have hitherto been relied upon as the base for an artificial asphalt, on account of a sup- O6. COMPOSITIONS,

COATING OR PLASTIC.

posed resemblance to the true asphalt. This idea is not sustained by scientific tests. Seen ,ble. Goal-tar concrete, upon exposure to the cold, cracks and bulges up in unsightly lumps, while asphalt-concrete pavements are known to have stood all the various destructive agencies and vicissitudes of climate from Bomba to St. Petersburg.

-Asphalt concrete pavements, in their smooth, seamless face, not aflbrding any escape to the terrestrial heat through joints, are kept warm and open from below in most cases, while block pavements present an icy. surface. They are clean and fit for traffic a few hours after being laid, while stone pavements, either new or repaired, must always be covered for months with a heavy coat of sand, to be drifted by every. breeze in dry weather, and add to the mud in rainy spells. Another important consideration in their favor is that repairs upon them can be made in dry cold days in winter, while the defects in stone pavements must be endured till spring.

In my improved pavement, a section of which is shown in the accompanying drawing, I have sought to render available at as low a cost as is practicable, the valuable properties of natural asphalt, and to avoid impairing its usefulness by the admixture of elements which have been demonstrated by experiment and practice to be detrimental.

My improved pavement is constructed as follows: The roadway is first to be excavated to a ,depth of about twelve inches, graded, and wellrolled, in order to present a proper surface for the bed or lower layer A of stone or rock, which consists preferably of broken rock of irregular form, of the average size of a hens egg. This layer should be, say, four inches thick, and, after being spread evenly, is to be well rolled with heavy rollers, and its upper surface thoroughly coated with fluid asphalt.

3 The asphalt which I prefer to use for this purpose, and elsewhere when required, in my pavement, as hereinafter .to be specified, is that which has been reduced to 'theli nid form without the aid of heat, as describe in Letters Patent of the United States, No. 162,394, granted and issued to me under date of April 20, 1875; but I do not wish to limit myself thereto.

Upon the prepared bed A 1 next place an intermediate layer, B, of concrete, having the following composition, to wit: Twenty-five Cross Reference feet sand two barrels cement! .four hundred pounds hydrate of lime; ten pounds powdered alum. ese ingredients are to be well mixed with a suflicient quantity of water or oil, to form a plastic mass, a layer of which, to the thickness of, say, six inches,-is to be spread upon the bedA and well rolled. -After sufficient time has been allowed to permit the concrete layer B to dry thoroughly it is to be well coated with fluid asphalt, and, while this coating is still wet, an upper layer facing, O, of asphaltic concrete is to be spread over it, tb a thickness of, say, two inches or more.

The compositionof the asphaltic concrete is as follows: Nine cubic feet clean grawel nine cubic feet plulverized stone: pre era y limestone six 011'l0 ee ne san wo ari'eIs cementone barrel huimu e preparation of the concrete'last above stated the ingredients are to be thoroughly incorporated in a suitable machine or mixer, and to be heated to expel carbonic acid and moisture. The composition thus constituted is in a dry pulverulent state, and is applicable to use as a facing for my improved pavement, or for other purposes, by being converted into a plastic mass, which, upon'hardening, is firm, durable, water-proof, and pO S- sessed of ample power of resistance to changes of temperature.

7 When used to form an artificial stone' the requisite plasticity to enable it to be made into the shape required is imparted by adding a proper quantity of liquid silicate of soda, oil, or water. Other cementing ingredients might likewise be employed under certain circumstauces, but I consider those that I have named as best adapted for the purpose.

For use as a facing for my improved pavement the composition is .to be heated, and,

while the mass is hot, liquid asphalt is to be added to and mixed with it, in the proportion of about forty-five gallons, more or less, "o each cubic yard, and it is'to be stirred unti it forms a homogeneous mass. 'For this pu. pose I prefer asphalt which has been liquefic without the aid of heat, as, for example, th -t described in my Patent No. 162,394, dated April 20, 1875. In this condition it is to 'be placed upon the layer of concrete-B, to the thickness of two inches or more, as before stated, and to be well rolled down and allowed to dry, when the pavement will be complete.

The mixed ingredients, in their pulverulent state, may be barreled and transported, and the liquid asphalt subsequently added, if such procedure should be found more convenient than the preparation of the complete concrete at one operation. I

I claim as my invention, anddesire to secure yards broken stone, broken small; nine cubic by Letters Patent- 1. A concrete composition, I consisting of layer of concrete, and an upper layer or facnlverized stone fine sand, cement ing of concrete compositiomals above set forth, ra e of h'me ul'v'er me'n cemented with liquid asphaltnm.

. AROHIBALD K. LEE.

Witnesses J. Snowman BELL,

2. The combination, in a pavement, of a D. L. (JoLLmn,

lower layer of stone, with-an intermediate

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