US1473134A - Road construction - Google Patents

Description

Nov. 6, 1923.

J. B. WATTS ROAD CONSTRUCTION Filed June 18 l/VVE TOR Jbhrzfi. Wa its.

ATTORNEYS JIM/588,58 Wm Patented Nov. 6, 1923.

JOHN BRYANT WATTS, OF CON GORDIA, KANSAS.

ROAD CONSTRUCTION.

Application filed June 18, 1920.

To all whom it may concern:

Be it known that I, J OHN BRYANT Name,

a citizen of the United States, and a resident of Concordia, in the county of Cloud and 6 State of Kansas, have invented certain new and useful Improvements in Road Construction, of which the following is a specification.

My invention is an improvement in road 10 construction, and has for its object to provide a construction of the character specified, wherein there is provided means for permitting'the top of the roadway to respond to temperature changes in expansion and contraction, without interference from that portion which is below and not so subject to temperature changes, and for permitting the surface of the roadway to be renewed or repaired Without affecting the foundation or base of the roadway.

In the drawings:

Figure 1 is a perspective View of a portion of the roadway, with a part in section, and with a part broken away;

Figure 2 is a transverse vertical section.

In the present embodiment of the invention the improved roadway is composed of a base or foundation 1 of suitable material, as, for instance, cement, concrete or the like, and a surface or top layer 2 of similar material, but of different texture and density. These portions are separated by a layer, indicated at 3, of heat insulating material, as, for instance bitumen, asphaltum, tar paper or any other material that would separate the upper course 2 from the lower course 1 and which will not bind the said courses together.

In the present instance the roadway is crowned, as shown, the upper faces of both layers being convex and it is finished by curbing 4 which is shaped to form drains at each side of the road. Preferably, the layer 2 of the roadway will'be divided into rectangles, as shown, by transversely extending expansion joints, these joints being cut through with a tool and emphasized by a marker. There are also expansion joints be tween the curbing and the three layers. The central layer 3 is of a material that will Serial No. 389,902.

not bind the two courses or layers together, and it will be obvious that when any section of the upper layer becomes worn or broken it may be removed and replaced without disturbing the remainder of the course and I25nd without disturbing the foundation or ase.

As is known, since the top or surface of a roadway must be made rich with cement to withstand traffic, the lower portion is richer than is necessary. Hence the roadway is more expensive than it should be. If the top coat or course is made richer, because of the fact that it is laid before the lower course sets, the top; course adheres to and becomes a part of the base or bottom course, thus making a solid pavement, with no cleavage between the two courses. Vhen a crack appears in the soil beneath, this crack will follow up through the pavement and appear on the surface. Repairs are difficult because of the fact that concrete does not readily lend itself to patching, and a complete block must be cut out from the ground level to the top.

lVith the improved roadway, a layer of concrete of 'a thickness of four or more inches is laid. After this course has set and hardened the central layer is spread, of bitumen, asphaltum, paper roofing or the like. Thislayer or course should be about one-fourth inch in thickness and upon the said course will be laid the wearing or top course, of rich concrete, spread two to four inches in thickness. This arrangement permits a block to be cut out from the upper course without disturbing in any way the base or adjacent topblocks. The central layer will allow a crack formed in the sub grade or sub-soil to spend its energy on the base, and the top layer will not crack. In addition, the central layer acts as a cushion for the top course, absorbing a portion of the shock, thus giving longer life to the top course. o

I claim: 1. A roadway composed of upper and lower layers of concrete having different densities and different coefficients of expansion-and contract-ion the upper course being the richer, and a substantially thick layer being of substantial thickness and of bituminous cushioning separator between such consistency as to be incapable of bind- 1 said upper and lower layers, whereby the ing, and a wearing surface richer in concrete upper and lower layers are isolated and than the base layer laid on the cushioning 5 independent of each other. I and spacing layer, whereby said top layer is 2. A roadway composed of a concrete independent of the base and separator layer.

base, a bituminous cushioning and spacing I layer superposed thereon, said cushioning JOHN BRYANT WATTS.

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