How To Fill Cracks In Pavement

[Boleslao Drinker]

Iloved the transformation of this ugly hole into a tiny color celebration. I also noticed how happy they made people as they stumbled upon them. Next, a friend of mine bought her first house in Fairmount and I wanted to give her a housewarming present, so I made one of my biggest ones, the big red flower.

Sidewalk: I do not really understand why I take such pleasure in doing it. I think it is the element of surprise that color-filled cracks provide, little gifts to the downwardly focused. It is one thing to transform a blank canvas or even a street wall but another to fill an ugly hole or crack with something fun. Besides, if you hate it, it is over in a split second.

Sidewalk: Now that I think about it, the movement from my very big mosaic murals to the street cracks might be a kind of a relief from the grandiosity of my taking on too big walls as a rank beginner. Who knows.

We used melt-in 1/2-in.-diameter Latex-ite Pli-Stix Crack and Joint Filler and the best asphalt patch, Latex-ite Trowel Patch, for this project. Our driveway had several 25-ft.- long cracks. So we bought four 30-ft. packages of the crack filler and four 2-gallon pails of the trowel patch. We already had a propane torch. But we bought a 5-foot extension hose to eliminate the flame-outs that occur when you tip a propane cylinder upside down (WH0159 Bernzomatic Universal Torch Extension Hose).

Sweep the torch flame side to side slowly over a 12-in. section until the filler begins to melt. Then move on to the next section. Return to the previous section and heat again until the filler levels out and seeps into the crack.

After the filler has cooled, scoop up the trowel asphalt driveway patch and tap it onto the crack filler to create a small mound. Smooth it with a trowel and let dry overnight. If a depression remains the next day, apply a second coat.

Allow the filler to cool to the touch (at least 20 minutes) before covering it with the trowel patch material. Then lay down a bead of trowel patch and smooth it (Photo 5). Let the trowel patch dry overnight. Apply a second coat if you see a depression where the crack was filled.

Asphalt driveways can develop pitted areas from motor oil and coolant contamination and repeated freeze/thaw cycles. If the pits are 1/2 in. or less, you can fill them with a spreadable filler product for asphalt repair. (We used Latex-ite Trowel Patch again.)

Clean oil stains and prime with oil stain primer. Then coat the entire pitted area with asphalt driveway patch material and let dry overnight (Photo 1). Apply a second coat to top off any partially filled pits (Photo 2) and smooth the surface. Let dry to complete your asphalt repair.

A good time to do crack sealing is when an asphalt road or street is in fair to good condition. Along with proper drainage, crack sealing is probably the single most important maintenance activity. Most pavement distresses can be related to the intrusion of water into the pavement structure. If water is kept out of the pavement, the majority of distresses can be stopped or delayed.

Crack sealing where cracks are subject to expansion and contraction is done using a specially prepared hot-poured sealant. Depending on the climate, the materials used, the pavement conditions and the technique used, crack sealing will last three to eight years.

Cracks that are 1/8 inches (3 millimeters) or less in width are too small to seal effectively. If there are numerous hairline cracks over a large area, then a surface seal such as fog seal, chip seal, slurry seal or sand seal should be used. The particular surface seal must be fluid enough to flow into the all the hairline cracks.

Cracks that are 1/8 inch or slightly larger are usually routed to a width of inch or greater to provide a reservoir for the sealant. The crack is then cleaned and sealed. If the cracks are more than 2 inches deep, a backer rod should be installed to conserve sealant.

Cracks that are inch to inch wide usually need only cleaning and sealing. Install a backer rod if cracks are more than 2 inches deep. Cracks that are larger than 3/4-inches wide should be filled with an asphalt emulsion slurry seal, a hot mix asphalt sand mix, or a hot-poured sealant.

The time of year when the crack filling is done will affect the performance of the sealant. Most cracks will open and close, depending on the season of the year. Crack sealing should be carried out when the cracks are in the middle of their opening range, which usually equates to spring or fall. Cracks filled in summer, when they are at minimum width, will be under-filled in the winter. Cracks filled in the winter, when they are at maximum width, will be over-filled in the summer and traffic may pull the crack filling material out of the crack.

Asphalt crack sealing materials must have good adhesion or bonding. They must be elastic yet resist softening. They must be easy to apply yet resist cracking, aging and weathering. Also, they must be compatible with asphalt pavement.

Asphalt emulsions, asphalt cements and fiberized asphalt are used for crack filling. Asphalt rubber, rubberized asphalt, low-modulus rubberized asphalt and self-leveling silicone are used for crack sealing.

If the cracks need to be routed or sawed to remove extraneous material, it should be done before cleaning the cracks. The routing or sawing is best accomplished using a vertical-spindle router, rotary-impact router, or a random-crack saw. After doing the routing or sawing, clean the cracks using high-pressure air, sandblasting, wire brushing, hot air blasting or high-pressure water.

Cleaning the cracks is an essential step to ensure that the sealant will adhere to the sides of the crack. After cleaning, check the cracks for depth. A backer rod should be placed in large deep cracks to conserve sealant. The backer rod should be a compressible, non-shrinking, non-absorbent material with a melting point higher than the temperature of the sealant. The backer rod should be about 25 percent wider than the crack, to prevent slipping or floating out after placing the sealant.

After the cracks are prepared, they are sealed with liquid asphalt. Equipment used for crack sealing or filling varies from truck-mounted pressure applicators with hand wands to pour pots. Each type of equipment can heat and maintain the temperature of the sealant in the 450F range.

Patching is the process of filling potholes or excavated areas in the asphalt pavement. Quick repair of potholes or other pavement disintegration helps control further deterioration and expensive repair of the pavement. Without timely patching, water can enter the subgrade and cause larger and more serious pavement failures.

Full-depth patching is the removal of the entire pavement surface layer, regardless of its thickness, over the patching area. Deep patching is the removal of four inches or more of the pavement surface course. Full-depth patching applies to either asphalt or concrete pavements, but deep patching applies only to asphalt pavements.

In full-depth patching, the material in the repair area is removed to the depth necessary for reaching firm support. This means oftentimes removing some of the sub-grade. A full-depth patch may even require some additional drainage.

The excavation should extend at least one foot into the good pavement surrounding the patching area. Patches should be square-edged and the cuts rectangular in shape without having varying lengths or widths within the patch area. If the width of the patch is near the width of the lane, a full lane patch may be best because the contractor can use standard paving equipment rather than handwork and eliminate extraneous longitudinal joints. A pavement saw makes a fast and clean cut. When large and numerous patches are necessary, a medium-sized milling machine works well. When small and numerous patches are needed, use a small milling machine. After the material is removed and the patch area cleaned, apply an asphalt tack coat to the vertical faces of the patch.

A full-depth patch should be backfilled with a dense-graded hot mix asphalt. If hot mix asphalt is not available, an appropriate cold mix, specialty mix or proprietary mix can be used. If the patch is more than six inches deep, place the patching material in 4-inch layers, and compact each layer as it is placed.

Proper compaction is a critical factor in producing a permanent patch. A vibratory-plate compactor is excellent for small patches and mandatory for compacting corners. A medium-sized roller may be more practical for large patch areas. A properly compacted patch should be overfilled in anticipation of traffic compaction. A straightedge or string-line should be used to check the evenness of the surface. A patcher truck is useful if numerous patches are involved. The truck can contain a bin for hot mix asphalt or store liquid asphalt and aggregate to mix and dispense into the patch. Vibrating compactors can be part of or attached to the patching truck.

Surface patches are usually temporary patches. They are constructed by milling a portion of the pavement to a depth that removes all deteriorated material. The patch area should be milled to a minimum depth of at least three times the nominal maximum size of the aggregate used in the patch. Using a 3/8 inch size aggregate or inch size aggregate will minimize the necessary milling depth, help tie the patch to the existing pavement, and provide adequate hot mix thickness to reduce the possibility of raveling.

Spray-injection patching is a method of repairing small pavement defects with semi-permanent repairs, particularly during wet or cold weather. This method requires a truck or trailer-mounted unit that contains an emulsion tank, aggregate tank, heating components, high-volume blower, telescoping boom with injection head and the necessary controls. The operation consists of cleaning the patch area with compressed air to remove loose material and debris, applying a tack coat of hot asphalt emulsion, blowing the combined aggregate and hot emulsion into the patch with forced air, and then placing a dry coat of aggregate on top of the patch to prevent tracking.

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