WO1988008055A1

WO1988008055A1 - Method and apparatus for removing concrete roadways

Info

Publication number: WO1988008055A1
Application number: PCT/US1987/000826
Authority: WO
Inventors: Leet E. Denton
Original assignee: Denton Leet E
Priority date: 1987-04-09
Filing date: 1987-04-09
Publication date: 1988-10-20

Abstract

Concrete roadways are removed by breaking them into narrow, longitudinally extending ribbons (110, 112, 114) which are then broken transversely into convenient lengths so that the resulting blocks or slabs may be readily transported to a crusher for reduction to aggregate for reuse or other disposition. The ribbons are formed by moving a wheel (BW) having a narrow, hard, peripheral road engaging rib (102) along the roadway while urging the rib (102) downwardly with sufficient continuous force to effect a vertical breaking of the concrete completely therethrough.

Description

METHOD AND APPARATUS FOR REMOVING CONCRETE ROADWAYS

Field of Invention

This invention relates to the removal of concrete roads or the like, as for example, in connection with the replacement thereof.

Background of the Invention

Heretofore the removal of concrete roads has been a relatively slow process entailing impacting the road with a drop hammer or explosive hammer or similar apparatus which operates to break a small area and is then moved to an adjacent area where the breaking is repeated. In addition to being .slow, such method results in pulverizing a good deal of the concrete thereby rendering it less useful for reuse in new road construction and the pounding endangers underground utilities in the vicinity of the road. More recently it has been suggested to break the roadway by high-frequency, low-amplitude impacts as shown in U.S. Patent 4,515,408 and others. In this case, it is my understanding that the size of the concrete pieces broken up cannot be readily controlled, and considerable waste may still result. In addition there is concern about the effect of the vibration on subjacent utilities in the vicinity of the roadway.

Summary of the Invention

My approach to removing concrete roadways is to break the road into parallel, relatively narrow, essentially continuous ribbons, running longitudinally of the road, such as between two and three feet in width.

The ribbons are then broken transversely into easily handled lengths and then loaded into trucks for removal to a crusher where they may be reduced to any suitable size for reuse with a minimum of pulverization. Preferably the ribbons are formed by urging a concrete breaking wheel having a narrow, hard, continuous periphery down against the concrete road with sufficient pressure to deflect the concrete beyond its elastic limit along the line of travel of the wheel, causing the concrete to break generally vertically therethrough.

A plurality of such wheels are provided, laterally spaced apart a distance to provide the desired width ribbon or ribbons. The concrete breaking wheels are carried by a vehicle having transport wheels for supporting the vehicle for travel between job sites. The vehicle is so constructed that its weight may be shifted from the transport wheels to the breaking wheels. If necessary to effect the breaking, weight may be added to the vehicle and then removed before transport to another job site. If desired, vibratory motion may be induced in the breaking wheels during the breaking operation.

Brief Description of the Drawings

Fig. 1 is a side view of a vehicle embodying my invention showing it in the transport mode;

Fig. 2 is similar to Fig. 1 but showing the vehicle in the road breaking mode?

Fig. 3 is a top view of the trailer portion of the vehicle of Figs. 1 and 2?

Fig. 4 is a side elevation of a typical concrete breaking wheel and related apparatus?

Fig. 5 is a cross-sectional view taken substantially on the line 5-5 of Fig. 4;

Fig. 6 is a cross-sectional view taken on the Line 6-6 of Fig. 5;

Fig. 7 is a plan view taken substantially along the line 7-7 of Fig. 4 and showing the breaking or fracture of the roadway by the breaking wheels as the vehicle moves along the road;

Fig. 8 is a cross-sectional view taken substantially on the line 8-8 of Fig. 4; and

Fig. 9 is a cross-sectional view taken on the line 9-9 of Fig. 1.

Brief Description of the Preferred Embodiment

In carrying out my method of removing concrete roadways, which, incidentally, may include airport runways, I crack or fracture the concrete vertically therethrough along parallel spaced apart lines . F running lengthwise of the road R to define a concrete ribbon 110 of indefinite length (see Figs. 7 and 8). This ribbon is then broken transversely at longitudinally spaced intervals therealong to form discrete blocks or slabs. This may be easily accomplished by lifting an end of the ribbon using a suitable front-end loader and the ribbon will break transversely into lengths from three to six feet more or less and the loader can lift the slab into a truck for removal along with other similar slabs. Desirably the blocks or slabs are taken to a crusher where they are reduced to a size suitable to use as aggregate in new concrete, fill or the like, and in fact may be used in making the concrete to be poured in replacement of that removed.

Thus, one object of my invention is to break the concrete in straight parallel lines to provide straight ribbons which can then be broken transversely in pieces which can be loaded as discrete blocks into trucks for removal to a crusher and there reduced to aggregate without the waste accompanying the prior methods of roadway removal. In addition, it is an object of my invention that the breaks in the concrete be reasonably vertical so that essentially square-sided slabs are provided. According to my method, because larger pieces are being broken than in the past, there will be less fines or waste and thus more of the removed concrete will be useable in making aggregate for the new.

Preferably the ribbons of concrete extend longitudinally of the roadway and may be of any desired width depending on the size of the handling equipment available. According to one embodiment, the concrete may be broken along parallel lines at between two and three feet apart whereby ribbons of a corresponding width are created. The ribbons can, however, be of a width to suit the handling equipment and thus wider or narrower ribbons may be created as desired. In a preferred embodiment, the parallel breaks through the concrete proceed continuously and are followed by front-end type loaders which lift the ends of the ribbons causing them to break as aforesaid and then the blocks or slabs are lifted into trucks for removal to the crusher. The method may thus be essentially continuous with the parallel breaks in the concrete proceeding down the highway followed by the loaders breaking the ribbons into slabs and loading the slabs into transporting trucks for removal to the crusher.

The concrete is broken into parallel, spaced-apart lines F, as shown in Figs. 7 and 8, by applying sufficient vertical downward pressure at a localized point on the surface of the roadway to cause the concrete to fracture vertically therethrough. As this pressure is being applied the pressure point is moved along the roadway in a straight line extending longitudinally along the road. I believe the breakage may occur for various reasons or for a combination of reasons. For example, though the concrete is theoretically supported therebelow by the sub-base S, there are sometimes voids between the sub-base and the concrete layer overlying it, so applying localized pressure on the upper surface of the road will cause the concrete to flex into the void and when the flexure exceeds the elastic limit of the concrete, it fractures vertically. The fracturing of the concrete may also occur simply because, even though there is no space or void between the sub-base and the overlying concrete layer, the sub-base cannot resist the pressure applied in a localized area to the overlying concrete and gives way allowing the concrete layer to flex beyond its elastic limit. I have found, for example, that when the sub-base is frozen, the concrete will not break with the same pressure that it will break with unfrozen ground.

There is also the theory that the concrete may be fractured beneath the point of locally applied pressure simply by a shearing action down through the concrete, i.e., the pressure applied at the localized point on the upper surface of the road exceeds the total of the shear strength of the concrete and the underlying sub-base.

An examination of a concrete roadway fractured according to my method shows, as in Fig. 8, fractures F of inverted V-shaped configuration that might be expected to accompany a downward flexure of the concrete roadway exceeding the elastic limit of the concrete structure.

Apparatus for carrying out the method is shown in the drawings as including a self-propelled vehicle 10 comprising a tractor 12 pulling a trailer 14, both being supported on conventional dual transporting wheels 16, 18, 20, 22, 24, 26. A greater or fewer number of wheels may be provided as desired. This tractor-trailer rig is of conventional construction. The trailer is of the low boy" type and includes a bed portion 28 connected to a tongue portion 30 through a hydraulically operated joint 32 which may be operated to raise or lower the front end 34 of the trailer. Mounted on the trailer is means for increasing or decreasing the vehicle weight. In the particular embodiment shown, this comprises a water tank 36 having a fill pipe 38 for connection at 40 to a source of water for filling the tank. The tank is supported on a suitable framework 42 underlying the tank. Hold-down devices 44 extend between the frame 42 and a peripheral flange 46 welded to the tank. The top of the tank is preferably closed as at 48 and an overflow or vent may be provided at 50. Water within the tank is illustrated at the breakout in Fig. 4 at 52. The framework 42 includes vertical supports 54 and 55 at opposite ends of the tank, main vertical supports 56 and angled supports 58, 60, 62. The lower ends of the supports 54, 56, 58, 60 rest on the trailer bed members 62, 66, 68, 70 and on overlying supplementary frame members 71 and 73. The members 71 and 73 (see Fig. 5) are secured by bolts 72 and underlying plate 74, as shown in Fig. 6, to the trailer bed members 66 and 68. The weight of the tank is thus transmitted by the vertical supports to the frame of the bed 28 and the supplemental frame members 71 and 73.

In one embodiment the tank 36 is designed to hold approximately 4,000 U«S. gallons of water to provide a weight of approximately 28,000 pounds. This weight, together with the weight of the trailer, may be transmitted to the concrete breaking wheels BW which are supported on the ends of arms 76, 78 which are pivotably supported at the opposite ends on pivots 80, 82 carried by the frame members, 62, 66, 68, 70, 71, 73. The ends of arms 76 and 78 just above the wheels BW are connected to the lower ends of piston rods 84, 86 of hydraulic cylinders 88, 90 which are connected at their upper ends to frame members 92, 94 underlying the tank 36. The hydraulic cylinders are connected to a suitable source of hydraulic pressure (not shown) carried either on the trailer 14 or the tractor 12 and upon pressurization, the piston rods may be either extended or retracted. Upon extension, the hydraulic cylinders are capable of forcing the wheels BW downwardly against the roadway to transfer the weight of the trailer from the transport wheels 22, 24, 26, to the concrete breaking wheels BW. In fact the hydraulic cylinders are capable of lifting the transport wheels completely off the roadway to transfer substantially the entire weight of the trailer to the breaking wheels BW as shown in Fig. 2. Of course, during transport between job sites the hydraulic cylinders are pressurized to retract the piston rods and thus raise the concrete breaking wheels BW to a position of nonengagement with the roadway such as shown in Fig. 1.

My initial experimentation has involved the use of breaking wheels BW as shown in Figs. 8 and 9. Each wheel has a shaft 101 mounted in journal bearings 104 on the arm such as on the arm 76 in Fig. 9. A heavy sleeve 105 is carried by sealed roller or sleeve bearings 107 and 109, being supported thereon by annular spacers 111 and 113 welded to the sleeve. A circumferential, narrow, hard, continuous ^' eripherial rib 102 is welded to the surface 100 of the sleeve 105. In one embodiment, the sleeve is substantially 11^ inches wide and 15 inches in diameter. The rib 102 is substantially 1/2 inch wide and projects radially substantially 11* inches from the cylindrical surface 100. As presently contemplated, the breaking wheels BW should have a steel cylindrical surface 100 of from between 12 to 16 inches in diameter and 9 to 14 inches wide. This cylindrical surface will limit penetration of the rib 102 into the concrete and will prevent uncontrolled settlement should the wheel encounter soft spots in the road. The rib 102 may be of different widths and depths, but at present is contemplated to be on the order of k to 2 inches wide and project from 3/4 to 4 inches ^: radially outwardly from the cylindrical surface 100. Abrasion of the rib by the concrete may be reduced by wetting it with a small stream of water either from tank 36 or another supply (not shown) through a drip nozzle 103 shown in Fig. 4 mounted on the arm 76.

When the weight of the trailer and the filled tank 36 is transfered from the transport support wheels to the concrete breaking wheels BW by the extension of the piston rods 84, 86, substantially the entire weight of the trailer may be transmitted to the concrete roadway through the narrow ribs 102 and a pressure of 30,000 psi may be imposed by each wheel BW upon the roadway. More or less pressure may be necessary depending upon the various factors confronted. If additional weight is needed, scrap iron can be added to the trailer. While I have shown a water tank 36, it is within the purview of my invention to substitute the use of any heavy weight such as scrap iron. While desirably the weight needed to effect proper fracturing of the concrete may be carried between job sites on the trailer 14 through the use of the transport wheels, in the event some jobs require greater weight than may be legally transported, it may be necessary to have a supplementary trailer bring additional weight to the job site for tranfer to the trailer 14. In the embodiment shown, tractor 12 serves to • move the trailer 14 not only between job sites riding on the transport wheels, but when the weight of the trailer is taken on the breaking wheels BW, the tractor 12 serves to pull the trailer to move the breaking wheels along or over the concrete roadway.

As shown in Figs. 7 and 8, parallel fractures F are being created as the wheels BW are pulled along the surface of the roadway R. In Fig. 8, I have exaggerated the deflection of the roadway under the weight of the breaking wheels to illustrate the fracture occurring. Of course, the ribbon 110 is defined by the fractures F and it is such ribbon that would be broken transversely by the front-end loader picking up an end of the ribbon. Adjacent ribbons 112, 114 may similarly be broken by the front-end loader and transported to the crusher. Thus, if the space between fractures F are proportioned in accordance with the width of the roadway R, it is possible that with but a few parallel fractures an entire strip of roadway may be removed.

The speed.at which the roadway may be broken will depend upon several factors, but it is my expectation that the method should enable the breaking of substantial lengths of roadway in a 24-hour period, certainly far more than the prior art methods utilizing the drop hammer method of concrete breakage.

In a modification of the apparatus, I provide a pair of vibrators 120, 122 which are mounted on the top of arms 76, 78 substantially above the- breaking wheels BW. The vibrators should be arranged so that they impart vibration in a vertical plane to the breaking wheels. The use of the vibrators may be desirable in some instances where, for various reasons, the concrete is particularly difficult to break.

As will be appreciated from the foregoing, the apparatus is so designed that substantially the entire weight of the trailer and water tank may be taken on the breaking wheels so that the maximum weight is applied thereto. At the same time, when it is desired to transport the apparatus to another job site, this trailer weight may be transferred from the breaking wheels to the transport wheels. In addition, the tractor 12 is utilized not only to drag the trailer for transport between work sites, but is also utilized to move the trailer during the concrete breaking operation. It will also be noted that the design of the structure is such that the weight of the water tank is located substantially directly above the breaking wheels BW thereby simplifying the construction of- the trailer. Furthermore, substantially the entire weight of the water tank is transferred to the pavement breaking wheels.

Claims

Clai s

1. The method of removing concrete roadways comprising the steps of: cracking the concrete roadway vertically therethrough along parallel spaced apart lines defining a concrete ribbon by moving a wheel having a narrow, hard, peripheral road engaging rib along the roadway while urging the rib downwardly into the concrete with sufficient continuous force to effect said breaking; breaking the ribbon transversly at longitudinally spaced intervals therealong to form discrete blocks; and removing the discrete concrete blocks as whole pieces.

2. The invention defined by claim 1 characterized in that the ribbon extends longitudinally of the roadwa .

3. The method of removing concrete roadways comprising the steps ofs applying sufficient continuous vertical downward pressure at a localized point on the surface of a concrete roadway to crack the roadway vertically; moving such point along the roadway while continuing such pressure thereon to form an elongated generally vertical fissure completely through the roadway; and removing the concrete from the roadway adjacent the fissure.

4. The invention defined by claim 3 characterized by applying said vertical downward pressure at a plurality of points spaced apart laterally at the surface of the roadway . to crack the roadway vertically at each point and moving said points along parallel paths to form at least one elongated ribbon of roadway cracked from adjacent portions of the roadway.

5. The invention defined by claim 4 characterized in that said parallel paths extend longitudinally of the roadway.

6. The invention defined by claim 4 or 5 characterized by breaking the ribbon transversly at longitudinally spaced apart lines to form blocks and removing the blocks from the roadway.

7. The method of breaking concrete roads comprising the steps of: providing a wheel having a circumferential radially outwardly projecting, hardened rib; positioning said wheel with the rib in contact with the concrete road surface; applying a vertical loading on said wheel sufficient to urge the rib downwardly into the surface of the road causing the concrete to fracture vertically below the rib from the upper surface to the lower surface of the concrete; and rolling said wheel along the road while continuing to apply said vertical loading to fracture the concrete along the -line of travel of the wheel.

8. The invention defined by claim 7 wherein said wheel has a cylindrical surface and said rib projects radially from said cylindrical surface, and said wheel is urged toward the concrete roadway to bring said cylindrical surface into contact with the surface of the roadway to limit penetration by said rib.

9. The invention defined by claim 8 wherein said cylindrical surface is between 12 and 16 inches in diameter and from 9 to 14 inches wide.

10. The invention defined by claim 9 wherein said rib is approximately h inch to 2 inches wide and from between 3/4 and 4 inches deep.

11. The invention defined by claim 7 wherein water is applied to the wheel to lubricate the contact between said rib and the concrete roadway.

12. Apparatus for breaking concrete roadway comprising: a vehicle for movement over the roadway to be broken and for transport between job sites; a roadway breaking wheel on said vehicle for engaging the roadway to be broken; transport wheels on the vehicle for supporting the same with the breaking wheel out of contact with the roadway for movement between job sites; said breaking wheel having a narrow continuous hard peripheral surface for engaging the concrete roadway to be broken; means for transferring sufficient vehicle weight from the transport wheels to said breaking wheel to cause said narrow continuous hard peripheral surface to crack the roadway generally vertically therethough in the line of travel of such wheel as the vehile is propelled along the roadway; and means for propelling the vehicle along the roadway for breaking and for transport between job sites.

13. The invention defined by claim 12 characterized by a plurality of roadway breaking wheels on said vehicle disposed in laterally spaced apart relation to break a ribbon of concrete beneath the vehicle.

14. The invention defined by claim 12 or 13 characterized by tank means disposed on the vehicle for receiving a liquid to add weight to the vehicle for application to said roadway breaking wheel.

15. The invention defined by claim 12 wherein said vehicle comprises a trailer and the means for propelling the vehicle comprises a tractor removeably coupled to the trailer.

16. The invention defined by claim 12 or 13 characterized by means for inducing vibration in the breaking wheel to facilitate breaking the concrete.

17. The invention defined by claim 16 wherein the direction of vibratory motion as applied to the breaking wheel is generally vertical.

18. The invention defined by claim 12 or 13 characterized in that the breaking wheel comprises a continuous cylindrical surface for engaging the surface of the roadway and limiting penetration, thereof, and a continuous, narrow peripherial rib encircling the cylindrical surface and projecting radially outwardly therefrom for contacting the road and having a width and angular length providing a concentrated unit loading when the vehicle weight is applied thereto sufficient to fracture completely therethrough the concrete therebeneath.