US842201A - Composite roadway and the process of constructing the same. - Google Patents

Description

No. 842,201. -PATENTED JAN. 29, 1907. *y S. G. HoWB. COMPOSITE ROADWAY AND THE PROCESS 0F SONSTRUSTING THB SAMSl APPLICATION FILED AUG.15. 1906.

INVENTDH fg/2 with a layer oi' foundation ii ililili @il SOLON G. HUWE, OF

narnnfr einden.)

DETROIT, MICHIGAN.

Specification of Letters Patent.

Patented.I Jan. 29, 1907.

Application filed August 15, 1906. Serial No. 330.693.

le it known that l, SoLoN G. Howe, a citizen of the United States, residing at Detroit, county Iof Wayne, State of Michigan, have invented a certain new and useful lmproveincnt in Composite Roadways and the Processes of Constructing the Same, of which the following is a speciiication, reference being had to the accompanying drawings, which form a part of this specification.

My invention has for its object an improved composite roadway and the process of constructing the saine, the invention being adapted for countryr roads and city streets, the roadway being of superior construction, economy, and utility; and it consists of the construction and the process of forming the same hereinafter described and claimed, and illustrated in the accompanying drawings, in which- Figure l. illustrates in Vertical cross-section my invention as applied to a city pavement. Fig. 2 is a similar view showing 'my invention as applied to aI country road. Fig. 2 is a fragmentary enlarged view.

My improved composite roadway consists, essentially, of two layers, formed and applied as hereinafter described.

F or a country road, for example, where no curb is required my invention contemplates' iirst digging a trench of suitablel depth-say a depth of ten inches-the trench being of any desired width for the roadway, giving the subgrade or bed a suiii cientA curvature or crown to insure a proper drainage. The subgrade or bed is then rolled with a heavy roller until -a d esired degree of compactness is attained. '.lhis compactness may readily be tested, as with a pointed steel prod, and should spots be y found not of a proper density or firmness my invention contemplates covering said spots composition, hereinafter set forth, then compressing the same by rolling or tamping until a proper iirinness is obtained. Next upon tins subgrade or bed my invention contemplates spreading a seepy foundation layer-z'. e.. a

layer through which wat-er will flow gently or slowlyin other words, a layer in which water will seep or ooze through said layercomposed of a mixture, hereinafterdescribed,

spread over the subgrade to a suitable depth-as, for example, a depth of six inches after being properly rolled and compacted. Upon this foundation layer I spread an upper surface course or layer formed of a different mixture, as herein set forth.

My foundation mixture or layer is come ,l posed of crushed stone, as of crushed cobblel stone, where the saine is obtainable,v although other kinds of crushed stone may be utilized, as crushed granite, trap-rock, or limestone, as they" may be more easily ob tained, i

The crushed stones are to be crushed to one to two and one-half inches in largest dimensions.

ing screened are then brought to the trench any suitable manner by hand or by machine with a su icient supply of sharp coarse sand low a half an inch in size, or thereabout, the gravel and sand being a little more than upper layer or wearing course.V

Tite top or wearing course ris composed of crushed gravel or other stone of irregular slapc of smaller dimensions than the crushed stone used in the lower or foundation course, the gravel-stoms bcingcrushed, preferably, to aboutonc-lialf to one inch' in largest size. Ground clay, preferably ferruginous clay, is mixed wi th a suii'ieient supply of water added to form a thick mortar,

sullicient quantity to coat the crushedgravel This top layer or body after being spread over the foundation layer is then subjected to heavy compression, as by a roller, whereby the clay mortar will be thoroughly com pressed intoall the spaces between the finely-crushed gravel or'stone,this upper course or layer constituting the wearing-surface ofthe roadway. The .clay mortar will also be forced in the operation of laying the roadway onto the exposed surfaces of the foundation layer, as upon -the exposed surfaces of the larger l give sizes varying, for example, from about' The crushed stones after b e-A enough to thoroughly fill the space or voidsv a rough'ened surface for the reception of the after wlieh tlie crusled stone is added to the .I clay mortar. l 'll'e clay mortar should be of or stone and thoroughly iill the intersizices.

where theroadway is to be laid and mixed in anzi gravel, the gravel being preferably be- IOO ies

broken stone at the 'top of the foundation layer, farming a Iirm bond between the top and the foundation vlayers or courses. The

top or wearing surface may be made of any desired'depth, a depth of four inches after compression beingv a very suitable depth. The road -bed below the foundation-layer may, if necessary, as already described have any spots found to be not of proper density or firmness provided with a lilling mixture similar to that of the foundation mixturefor example, the same being rolled or tamped down until all loose or Softspots are remedied, so as to obtain a thoroughly firm seepy bed. The rmness of the upper course or layer can be readily tested after rolling by a steel prod, as also the foundation layer, so as to make certain that each layer is of proper density vand firmness.4 For a street-pavement Athe process of construction is essentially the same, with the addition of a curb and a suitable base and back for the curb.

In the drawings, a represents the road-bed of earth below the foundation' course above described. b denotes the foundation layer, of coarser crushed stonepsand, and gravel, and c the top or wearing course ol' more finely crushed gravel or stone mixed with clay mortar. In the enlarged view Fig. 3, d represents the coarser crushed stone, e the particles of sand, and f the particles of gravel of the foundation layer, the sand and gravel being shown in the interstice between the broken particles of stone d. In Fig. 3 also the more finely crushed gravel or stone of the wearing surface or layer is indicated at g, the clay mortar being indicated at z filling the interstices between the particles of crushed stone g and coating said particles. In Fig. 1, 'i denotes a suitable curb of any desired construction, and j a concrete base and back for the curb. The construction of the roadway and the process of forming the same will now be clearly understood.

The advantages of this composite roadway are many ,and will be evident, as follows: For' a country roadway where no curbing is desired gutters it' may readily be formed, as by a supplementary roller attached to the side of the compression-roller. A vspecial advantage of such a composite roadway is that it is comparatively inexpensive in construction and is easily and cheaply maintained. Should any soft spots or depressions develop under heavy traffic, repairs could readily be made by simply first. cleaning such depressions, so as to make as `good a y bond as possible, and then filling the depression with a mixture such as above described, constituting the top or wearing course, and rollino Qrtamping the same firmly into'place. The lhng in the interstices of the crushed stone in the foundation layer inak'es a cushioned foundation for the upper layer or wearing-surface, while the clay mortar in the upfilling the interstic-es with sharp sandand gravel to form -a lower seepy foundation course and filling the interstices of the upper course with clay mortar the tendency of the mixture to slip or move out of position is practically eliminated, and without such movement there would be but 'little chance for Wear and creatiqn of dust. The general uniformity ofvsizes of the crushed stones in the two courses, respectively, while insuring a compactness will not, however,^develop a rigidity in one place and a softness or springy condition in another, but the construction will insure a body likely to remain firmly and continuously intact.. The construction Aof the lower or foundation layer of such a roadway being pervious to water will allow a perfect seepage which will tend to keep the lbody in good condition and with proper subdrainage where the soil'underneath the roadway will not properly absorb the moisture will insure a perfect condition at all times.

The clay mortar used as a binder if of a proper consistency will bond the small irregular-shaped pieces or particles of crushed stone constituting the upper or wearing surface of the roadway, the only requisite being a suitable degree of moisture, which when not had by rainfalls can vbe had by sprinkling. This clay binder and crushed stone body forming the upper layer after a hot day will absorb water readily, so that by passing a sprinkling-cart over it at Sundown the tendency would be to Very materially cool the atmosphere, and the body would absorb sufficient water over night to maintain a certain degree of dampness and eliminate the formation of dust on the surface during the following day. Such a seepage of Water as I provide 1n my foundation layer in other kinds of pavement are detrimental, and therefore other forms ofpavement must be made impervious to water in a well-known manner. Other kinds of pavement laid upon a customary concrete foundation are supposed to be mipervious to water, thereby lexcluding; the allowance of water and air needed for shadetrees on the sides of the streets.

l/Vhat I claim as my invention-is 1. A composite roadway comprising a foundation seepy layer composed of a mixturel of coarsely-crushed stone gravel and substantially as described.

2. A composite roadway comprising a foundation. seepy layer composed of a mixture pf coarsely-crushed stone gravel and sand spread o ver and compressedl upon 'the bed of the roadway, and a seepy wearing- -body or uppersurface layer composed of a mixture of more finely crushed stonev and clay mortar spread over and compressed,

upon the foundation body or layer, vthe gravel and sand of the foundation layerv filling the interstices between the crushed stone,

and the clay mortar coating the crushed stone of the upper layer and filling the interstices therebetween, whereby water will seep through the entire roadway, substantially as described.

3. A composite roadway comprising a foundation layer composed of a mixture of coarsely-crushed stone. gravel anda sand s read over and compressed upon the bed of t ie roadway in a dry condition, and a wearing-body or upper surface layer composed of a mixture of more finely'crushed stone and clay mortar vspread ovenand compressed upon the foundation layenthe layers of said roadway being pervious to moisture, the

lgravel and sand of the foundation layer forming a seepy cushion, and the clay mortar of the uplper layer forming a bond, whereby wa 4terwil seep through the entire roadway, sub# stantially as described.

4. The process of constructing a composite roadway consisting of first mixing coarsel crushed stone gravel and sand 1n a dry con ition, spreading the mixture over and compressing the same upon the road-bed to form a seepy foundation layer, and then spreading upon the foundation layer amixture of more finely cru shed stone and clay mortar and compressing the same upon the foundation layer to form an u per seepy course or wearing-surface, whereiiy water will seep through the entire roadway, substantially as described. 1

roadway consisting of first excavating a trench, compressin the soil and filling soft places therein wit a previously-prepared mixtureA of crushed 'stone gravel and sand compressed thereinto, thenv spreading thereupon a seepy found ation layer consisting of a previously-preparedmixture of crushed stone gravel and sand, and compressing the same in place, and then spreading upon the foun-y dation layer an upper seepy layer consisting of a previously-prepared mixture of more finely crushed stone and clay mortar and compressing the saine in place upon the found ation layer, whereby water will seep through the entire roadway, substantially as described. l

. 6. A two -course composite roadwa or pavement comprising a foundation ayer composed of 'a previously-prepared mixture of coarsely-crushed stone gravel and sand -spread over and compressed upon the bed of the roadway, and a wearing-body orupper surface layer composed of a previously-prepared mixture of crushed stone and clay morfoundation body or layer, the said layers be ing pervious to moisture whereby water will seep through the entire roadway.

n' In testimony whereof I have signed this ing witnesses. SOLON G. HOWE.

Witnesses:

JAMES F. HILL,

N. S. WRIGHT.

5. The process of constructing a composite l tar spread over and .compressed upon theV specification in the presence of two subscrib-

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