PAVEMENT CRACK CLEANER

Abstract

Devices for cleaning and preparing pavement cracks for sealing are disclosed. An example device comprises a wire brush assembly for removal of mid and large-sized debris, an air blaster for removal of fine-grained particulate, a heat lance, and a vacuum for controlled removal of debris and particulates. The example device would also have means for attachment to an air compressor.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Application No. 61/470,547 entitled “Pavement crack cleaner for sealing,” filed Apr. 1, 2011, which is incorporated herein by reference in its entirety for all purposes.

FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

This invention was made with government support under National Academy of Sciences grant number NCHRP-159. The government has certain rights in the invention.

TECHNICAL FIELD

The present disclosure relates generally to cleaning and preparing cracks in pavement for sealing. More specifically, the present disclosure pertains to a device for efficiently and effectively cleaning pavement cracks of debris and de-icing chemicals in preparation for sealing of the pavement cracks.

BACKGROUND OF THE INVENTION

Flexible and rigid pavement joints and cracks are sealed or filled to mitigate further damage caused by the infiltration of water and foreign debris. Crack sealing is generally recommended for 5 to 19 mm size cracks, and can be utilized for cracks outside this range as well. The traditional procedures for preparing roadway joints and cracks for sealing and/or filling are either largely ineffective, labor intensive, or dangerous.

Air blasting is the most common means of pavement crack preparation. This method effectively expels voids of dust and relatively loose contaminants. Should the crack possess any level of moisture it is recommended that hot air blasting be utilized. However, air blasting is not an effective means of cleaning out vegetation and large debris, as well as the thin layer of de-icing chemicals that often coat the pavement of cold weather prone regions. Lastly, sealants and fillers require the surface of the pavement to be at least 40° F. for proper bonding; as cracks are more often sealed within the freeze-thaw period of winter, air blasting is not a recommended means of sole crack preparation.

Hot air blasting solves many of the cold weather drawbacks that are associated with the above procedure. Hot air blasting typically uses a compressed air heat lance that introduces gas and combustion to the compressed air to provide a hot jet of air to the treated area. However, hot air blasting introduces other problems. Extreme caution must be taken to ensure the pavement is not overheated, which will result in the asphalt binder becoming brittle and leading to premature failure. Care should also be taken to never allow for direct flame methods to be used as the charring effect will lead to a soot residue and cause poor initial bonding. It is not difficult to find such direct flame problems in the current practices. In addition, hot air blasting does not clean de-icing chemicals remaining in and out of the cracks. Furthermore, propane regulators are often frozen in cold weather, thus delaying the sealing process.

Sandblasting is noted as an efficient method of removing the de-icing chemicals often present in roadway cracks. However, there are several drawbacks to the sandblasting method of crack preparation. The first problem is that it includes two operators: one for the sand blasting, and one for cleaning out the sand left behind. Sandblasting also has a number of environmental and health concerns associated with it.

Although routing is a better approach than the methods above for cleaning cracks, it is not a solution for complete preparation for crack sealing. Routing only excavates narrow cracks and still leaves de-icing chemicals on both sides of the crack surface. The surface preparation is very important for better bonding between surface and sealing material. Also, routing which generally uses a ⅜″ carbide-tipped rotary impact bit is not effective for wider cracks to clean de-icing chemicals in cracks unless multiple routing paths are used. Furthermore, many groups hesitate to rout cracks because the routing equipment is very heavy and makes it difficult to follow cracks unless cracks are straight. It often results in creation of another crack while routing random cracks. Pulling such heavy equipment downhill or on a windy day often puts the operator in dangerous situations as well.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to a mechanical device used to effectively clean pavement cracks and the surrounding area, and thereby prepare pavement cracks and joints for sealing or filling. The device is capable of removing dirt, loose debris, and de-icing chemicals. The device is a highly customizable mechanism capable of being outfitted with a pneumatically driven rotary wire brush assembly, pavement routing assembly, vacuum, air blaster, or heat lance.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a pavement crack cleaner device with a router attachment and air blaster.

FIG. 2 is a schematic view of the wire brush assembly with an air blaster.

FIG. 3 is a schematic view with a masonry bit and an air blaster.

FIG. 4 is a schematic view of the router attachment and air blaster from the right side of the device.

FIG. 5 is a schematic view of the pavement crack cleaner device as in FIG. 1, with the addition of the heat lance.

FIG. 6 is a cross-sectional view of the heat lance attached to the pavement crack cleaner device.

FIG. 7 is the pavement crack cleaner device of FIG. 5 with the addition of a vacuum component.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a schematic view showing one of the embodiments of the invention. The lever near the handle at the top of the device allows the user to control the air flow rate to the air blaster. The control switch just below the handle acts to split the air flow between the air blaster and the pneumatically powered motor. The motor is located within the housing just above the guard cover. The guard cover is the semi-circle in the drawing above the pavement router which acts to prevent debris from flying up or to the left of the device as it operates. The primary air blaster nozzle is positioned behind the pavement router.

FIG. 2 is a close-up view of an embodiment showing the wire brush assembly instead of the pavement router. All other aspects of this embodiment are identical to the embodiment in FIG. 1.

FIG. 3 is a close-up view of an embodiment showing a masonry bit instead of the pavement router. All other aspects of this embodiment are identical to the embodiment in FIG. 1.

FIG. 4 is a schematic view of the embodiment in FIG. 1, from the opposite side of the device.

FIG. 5 is a schematic view of the embodiment in FIG. 1 with the addition of an electrically-powered heat lance. The heat lance is positioned just above the guard cover and has an electrical power cord that is attached to the shaft of the device.

FIG. 6 is contains a cross-sectional view of the heat lance, displaying the heat coils internal to the heat lance.

FIG. 7 is a schematic view of the embodiment in FIG. 5 with the addition of a vacuum component. The vacuum intake is directly behind the router and air nozzle, and acts to suck in particles and debris cleaned from the pavement crack.

One contemplated embodiment of this device consists of a pneumatically driven wire brush assembly and air blaster. The wire brush assembly is used to clean the mid- to large-sized debris, old sealed material, and vegetation from the pavement cracks, with the air blaster following the wire brush assembly to further expel fine grained particulate. The wire brush assembly ideally is made from steel and/or aluminum, but other materials could work just as well. Different sizes of steel wire brushes can be used depending on the diameter or width of the crack needing to be cleaned. The compressed air blaster should ideally have a minimum pressure of 100 lb/in², but the device would still be functional at lower pressures. The minimum ideal flow rate of the compressor should be 150 ft³/min, but the device would still function at lower flow rates. A secondary air nozzle either with a direction-adjustable air hose or a straight air wand may also be attached to the device. This can be used when cleaning debris created on the pavement surface.

The device could additionally comprise a heat lance, and the ability to retrofit the device with a single router bit which is interchangeable with the wire brush assembly. The ability to add an optional heat lance is important as pavement cracking typically occurs in moist or cold climates. The heat lance will allow pavement crews to adequately heat the pavement crack to the recommended 40° F. while removing any additional moisture in the crack, both of which are critical to obtaining proper material adhesion. The temperature of the heat lance must not exceed 930° F. to prevent overheating of the pavement. Heat lances that run on propane gas are the only option currently available for pavement crack cleaning. The present invention could comprise a heat lance powered by propane gas, or alternatively by electricity. Many street maintenance trucks already have electrical generators, which could be used to supply the electricity for the heat lance. Alternatively, a separate electrical generator could be used to power the heat lance.

Many pavement cracks will not sufficiently allow for the penetration of a stiff bristled wire brush, and routing must take place. The present device can allow for the ability to interchange the wire brush assembly with pavement routing bits. In order to interchange the wire brush assembly with the pavement routing bit, the guard cover is removed and the nut holding the wire brush assembly to the device is removed. The wire brush assembly can then be removed. The router bit can then be installed by inserting a bushing in the router bit since the size of the router bit is different from that of the wire brush assembly. The nut is then placed back on to hold the router bit in place, and finally the guard cover is replaced. The routing bit should be capable of routing widths of 12 mm to 38 mm, and routing to a depth of 19 mm. The device could additionally comprise a vacuum component for control and disposal of the debris and particulates being cleaned from the pavement crack. The vacuum component is positioned behind the air blaster to catch the expelled particulates and debris. The vacuum suction should be powerful enough to capture an adequate amount of the particulates and debris. An industrial vacuum with an 110V power supply and suction rate of 18 ft³/min at 100 lb/in² would be powerful enough to accomplish this task.

Another embodiment would involve using a masonry blade unit in place of the wire brush assembly or pavement router. The masonry blade unit can be used for many applications, including pothole repair. The masonry blade unit is attached to the device in the same manner as the wire brush assembly and pavement router.

The affordability of this device is a benefit over the currently existing options for pavement crack cleaning. Purchasing a new commercially available gas-powered pavement router, gas combustion heat lance, and crack cleaning vacuum system will cost maintenance agencies $10,000, $3500, and $60,000 respectively. On the other hand, this invention could conceivably incorporate all three of the previously mentioned units at a small fraction of their total costs. This is accomplished by using pneumatically powered components, which has considerable cost savings and safety benefits over gas-powered components. The combination of the wire brush assembly and air blaster should act to remove deicing chemicals, which is imperative to the sealed cracks lasting as long as possible. The combination of multiple devices into a single device also means less labor power required to clean the pavement crack, turning a three or four person job into something that can be accomplished by a single person.

The safety benefits of this device cannot be overlooked. The new device will have the ability to largely replace the use of sandblasting and compressed gas heat lancing. The abrasion by wire brush or simply using the router bit to open up existing cracks will eliminate the health and environmental concerns associated with sandblasting. Additionally, the use of an electrically powered heat lance as a means of warming pavement cracks will eliminate the many safety considerations that must be addressed when utilizing flammable gas. The cover guard also acts to protect the operator from flying particulates and debris, and either guides the debris into the vacuum in certain embodiments, or else down or to the side away from the device and operator in other embodiments.

There is a clear benefit in regard to mechanical simplicity. The proposed device is powered by pneumatic means. A person of ordinary skill in the art will understand pneumatically powered to mean using compressed air to power a device. This allows for a decrease in maintenance cost due to the simplicity of air driven motors, rather than the traditional gasoline engines used to power the portable rotary brushes and routers. Additionally, the need for hauling combustible fuel is eliminated. The device will be easily attached to current air blasting devices, or maintenance trucks equipped with air compressors, making the upgrade costs as minimal as possible. Most maintenance trucks currently have a one-inch Chicago fitting for air hose connection. A hose can be connected to an air compressor on a maintenance truck, and then be run to the device. The air supply would be split, with some air being used for the air blaster component, and some air being used to operate the pneumatically powered motor of the device.

In addition, it is expected that this device will be used on a higher percentage of cracks, yielding an increase in preventative maintenance and a decrease in new construction costs by formulating a more efficient way of cleaning joints and cracks, including removal of de-icing chemicals. The current state of the art does not effectively remove de-icing chemicals. The combination of the wire brush assembly with the air blaster allows the present device to remove the chemicals, resulting in significantly more effective crack seals. Preventative maintenance is generally considered to be much more cost effective than rehabilitation and reconstruction. Furthermore, utilizing versatile effective means of crack and joint preparation will undoubtedly lead to an increase in overall quality. This upgrade in quality will promote an increase in the useful life of pavements, and postpone the allocation of valuable tax revenue towards the rehabilitation or new construction of existing roadways.

The device includes a heavy-duty pneumatic motor to power the various components of the device. The motor could be 1.25 hp (950 W) with a maximum of 7,500 rpm. Motors with similar or more powerful specifications would also work. Also an electrical heat lance working with either 110V or 220V can be attached to the device to generate hot air. Another configuration of the device will include an attachable vacuum system. The suction compartment will be attached behind the wire brushing/routing mechanism in this configuration, as can be seen in FIG. 7. The device has the correct air pressure and supply to ensure the various working components are appropriately powered. The air pressure and supply can be adjusted depending on the requirements of a specific pavement crack.

The heat lance attached to the device can be either gas powered or electrically powered. In either case, the heat lance should be capable of heating the pavement crack to 40° F. The heat will be delivered to the crack pneumatically.

The addition of a vacuum component is very important to meet a number of state's environmental protocols, and to make it safer for the pavement crew and surrounding traffic. The vacuum component should be powerful enough to capture large-sized debris in addition to fine particulate created from brushing and routing processes.

The present device maintains a high level of innovation for three key reasons: 1) the device can be completely powered by pneumatic power, a power source standard on most maintenance trucks and already used within the typical joint and crack sealing process; 2) the device can customize up to four tasks in one pass: routing and brushing, air blasting, vacuuming, and warming the pavement; and 3) the proposed device is not only lower-cost, but also lighter and easier to maneuver on cracks and joints compared to pushing and rotating a heavy walk-behind device.

Claims

1. A device for cleaning pavement cracks comprising a wire brush assembly and an air blaster.

2. The device of claim 1, further comprising a heat lance.

3. The device of claim 2, wherein said heat lance is electrically powered.

4. The device of claim 1, further comprising a single router bit capable of being interchanged with the wire brush assembly.

5. The device of claim 1, further comprising a vacuum component.

6. The device of claim 1, further comprising a pneumatic motor.

7. The device of claim 1, further comprising a means of attachment to an external pneumatic power source.

8. A device for cleaning pavement cracks comprising a single router bit and an air blaster.

9. The device of claim 8, further comprising a heat lance.

10. The device of claim 9, wherein said heat lance is electrically powered.

11. The device of claim 8 further comprising a wire brush assembly capable of being interchanged with the single router bit.

12. The device of claim 8, further comprising a vacuum component.

13. The device of claim 8, further comprising a pneumatic motor.

14. The device of claim 8, further comprising a means of attachment to an external pneumatic power source.