US 3521528 A
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L. c. WANGEZROW 3,521,528
JOINT SEALING DEVICE OriginalFiled March 25, 1966 July 21,1970
IN-VENTOR LEROY C. WANGEROW BY T Togrggtv United States Patent Office 3,521,528 Patented July 21, 1970 3,521,528 JOINT SEALING DEVICE Leroy C. Wangerow, Oak Lawn, Ill., assignor to W. R. Grace & Co., Cambridge, Mass., a corporation of Connecticut Continuation of application Ser. No. 537,539, Mar. 25, 1966. This application Feb. 28, 1969, Ser. No. 806,003 Int. Cl. E01c 11/00; F16j 9/00 US. CI. 9418 3 Claims ABSTRACT OF THE DISCLOSURE This is a continuation of application, Ser. No. 537,539 filed Mar. 25, 1966, now abandoned.
This invention is concerned with sealing strips for joints in concrete structures.
The object of the invention is to provide a distortable, compressible joint strip which will maintain full wall contact with the opposing margins of the concrete slabs despite changes in the width of the joint caused by the expansion and contraction of the concrete with temperature change. i
As the specification proceeds, it will become apparent that the sealing strips of this invention are suitable for sealing transverse and longitudinal expansion and contraction joints in highways, airport runways, building floors, ramps, sidewalks, etc., and are useful also in construction joints. Changes which render the sealing strip suitable for these various uses are dimensional, and include principally the selection of the proper size of strip to fit the anticipated thermal movement of the joint. Since the strips for all types of joints are similar, one type a sealing strip for the expansion joint between concrete highway slabswill be set forth as the preferred example.
Because concrete does expand and contract to a limited degree, a concrete highway must be provided with expansion joints to allow for the dimensional change.
A common method of forming an expansion joint between highway slabs is to place a joint fillera slab of compressible material, often about /1 of an inch thick at the end of each specified slab length and transverse to the high-way. The joint filler extends vertically from at or slightly below the subgrade to approximately 1" below the road surface. The gap above the joint filler must be sealed to prevent the entrance of water and debris.
It has previously been the practice to seal the gap between the concrete slabs and above the joint filler with a plastic composition, usually bituminous, to prevent the entrance into the joint of water and debris. More recently, hollow rubber sealing elements called preformed sealing strips have been used and have proved to be desirable and long lasting. In particular, they are free from the cold-flow difficulties which are associated with joints sealed with plastic compositions and, generally speaking, better resist the up-thrust caused by ice and frost in the subgrade which pushes plastic seals above the highway surface. Preformed seals, preferably in continuous lengths which reach the full width of the slab, are forced into the gap either by hand or by machine.
In the development phase of this invention, numerous configurations of hollow rubber joint seals were made and were subjected to compression and expansion tests between concrete slabs in a compression-testing machine. It was found that when the walls of the seal which were intended to lie in contact with the transverse margins of the concrete slab were compressed towards each other, the central area folded downwards, and pulled the upper marginal portion of the seal with it away from contact with the concrete.
In FIG. 4, views a, b, and 0 illustrate the distorted shapes which are assumed by the joint seals not made in accord with this invention. View a illustrates the shape assumed by a joint seal 19 having parallel plane side walls and an X-braced internal structure. The crumpled condition is characteristic. View b shows a seal 21 having the same external shape. Forced between slabs 20 it formed two small gutters between the seal and the concrete slabs. It, too, has an X-shaped reinforcement in its bore. However, the X was in a different vertical position. View c shows the configuration assumed by a sealing strip 22 having parallel side walls, a centrally located vertical diaphragm, and a chevron-shaped but generally horizontal diaphragm located at the mid-point. The upper margin of this design pulled inwardly and away from the concrete walls and formed two small gutters.
Seals which pull away in a narrow line adjacent the concrete margin form a gutter which, with highway use, collects dirt and debris. Under traffic conditions, the debris continually is pounded downwards and between the wall of the rubber seal and the concrete slab. Ultimately the expansion joint fills with uncompressible matter.
I have discovered that these distortions and their deleterious effects will not occur if small projections extending beyond the normal side walls of the seal are formed at, or substantially at, the top margin of the seal. Instead, the projections or sealing tips press against the ends of the slab and have the effect of forcing the entire side wall of the sealing strip into contact with the slab walls.
When in position between the concrete slabs, my improved sealing strip assumes the configuration shown in FIG. 2. As a result, a tight, effective seal is formed.
Referring to the drawing:
FIG. 1 is a vertical cross-section of the presently preferred form of the sealing strip;
FIG. 2 is a vertical cross-section showing the strip when wedged between two opposing concrete highway slabs;
FIG. 3 is a vertical cross-section of an alternate form; and
FIG. 4 shows in dotted outline the various distorted shapes assumed by X and chevron type sealing strips with no marginal bead when the strips are under compression.
The sealing strip, 10, is a rubber or plastic tube extrusion, preferably having vertical side walls, 11, a chevron shaped top wall, 12, a chevron shaped bottom wall, 13, a mid partition, 14, and a bracing diaphragm, 15, also of chevron shape.
The sealing tips, 16, are formed as a continuous, preferably pyramidal, bead located at the junction of the top wall, 12, and each side wall, 11, and extend outwardly from the walls, 11.
The seal, 10, may be formed of plastic, rubber or of any of the age and oil resistant so-called rubber polymers such as chlorobutadiene, butadiene-acrylonitrile, polyisoprene blends, or polyurethane, polybutene with isoprene or butadiene, ethylene-propylene, polyvinyl chloride, etc. All of these materials give satisfactory performance.
The actual dimensions of the seal will be those as set by the highway specifications, but a dimension which gives satisfactory performance has been found to meet a majority of highway specifications as follows:
Width between side walls when expanded Thickness of side walls and central web% Thickness of top Wall% Overall depth1" Dip of chevron in the top wall Dip of chevron in the bottom wall Projection of tip beyond side wall- A It should be understood that the above dimensions are illustrative only; seals embodying the invention may also be considerably larger.
After the gap in the pavement has been formed by lifting the installing cap and finishing the margins, and the gap has been brushed out and cleaned, a continuous length of sealing strip of FIG. 1 is laid across the highway and forced into the opening between the adjacent concrete slabs. Forcing the strip into the gap between the slabs may be done by hand by pressing the strip from above with any implement which is no wider than the gap. Care must be taken to prevent the strip from twisting as it is being forced downwards. Somewhat better and quicker results are secured when a mechanical strip inserter is used, since the strip is held from twisting by the nose of the machine, and a disc or wheel which fits between the concrete slabs, pressing down on the seal, forces it into position.
Such sealing strips possess all of the well-recognized advantages of rubber preformed highway seals which, in contrast to an asphalt seal, do not have to be chiseled down to the road surface to remove the winters upthrust. When necessary, they can be quickly removed, the joint area cleaned out, and the seal can be either reinserted or replaced with simple tools. No hot tar pot is required, but seals, when improved with the top marginal bead herein disclosed, will remain in service for considerably longer times than previously has been possible, since do dirt or debris is forced down between the sealing strip and the concrete to accumulate and force the strip out of position.
Although the sealing strip with vertical side Walls and generally of chevron shape has been set forth as the preferred example, it has been found that other shapes, e.g., circular (see FIG. 3), make effective seals, provided that longitudinal sealing beads, 17, projecting beyond the normal outside wall, 18, of the seal are formed at the intended junction of the top surface and the side walls.
The sealing tip, 16, may have any cross-section which concentrates the maximum side thrust of the sealing element against the concrete in a narrow band adjacent the top longitudinal margin of the element. A pyramid, which concentrates the maximum thrust along a line, performs ideally, but other shapes, e.g., a single small rectangle, form satisfactory seals, and greatly reduce the distortion of the sealing element over that of a seal having an extensive wall contact.
It is claimed:
1. A preformed element adapted to form the flexible sealing member in an expansion joint of a concrete structure comprising a rubber tube, the periphery of which exhibits a chevron-shaped top and bottom wall and two 7 parallel side walls joining said top and bottom walls, said side walls having upper marginal portions and smooth exterior surfaces, said tube having a vertically extending diaphragm connecting said top and bottom walls, and said tube bearing means to prevent said upper marginal portions of said side walls from pulling away from the vertical face of a concrete slab consisting of two continuous beads, one each of said beads being formed at the junction of each side wall with said top wall, said beads being substantially normal to and extending outwardly from said side walls, whereby continuous contact of said element with said vertical face is maintained and inward distortion of said side walls is prevented when said element is compressed between opposed slabs.
2. A preformed joint sealing element adapted to form the flexible sealing member in an expansion joint of a concrete structure comprising a rubber tube, the periphery of which exhibits chevron-shaped top and bottom walls and two parallel side walls joining said top and bottom walls, said side walls having upper marginal portions and smooth exterior surfaces, said walls being interiorally reinforced by a horizontal chevron-shaped diaphragm connecting said side walls and a vertical diaphragm connecting said chevron-shaped top, said horizontal chevronshaped diaphragm and said chevron-shaped bottom wall at the crests of said chevron, said tube bearing means to prevent said upper marginal portions of said side walls from pulling away from the vertical face of a'concrete slab consisting of two continuous beads, one each of said beads being formed at the junction of each side wall with said top wall, said beads extending substantially normal to and outwardly from said side walls, whereby continuous contact of said element with said vertical face is maintained and inward distortion of said side walls is prevented when said element is compressed between opposed slabs.
3. The element of claim 2 wherein said beads have a pyramidal configuration comprising a base and a conical portion extending therefrom, said base being adjacent said top wall.
References Cited UNITED STATES PATENTS OTHER REFERENCES Acme Highway Products Corp. (Trade Publication), Received July 17, 1963, 4 pages (note page 3), Class 94, sub 18.2.
SAMUEL ROTHBERG, Primary Examiner US. Cl. X.R. 277-207