 Potholes are a major inconvenience, a safety hazard, and are damaging to vehicles. This program covers procedures for repair of potholes in asphalt concrete pavement. It focuses on the materials and equipment used in pothole repair and the procedures for making a permanent repair. Potholes must be repaired quickly because they are a hazard. They can cause serious accidents and they slow down the flow of traffic. It's important to follow the correct procedures for repairing potholes. You'll save money and you'll ensure that the repair will last longer. Potholes are caused when traffic breaks up a weak spot in the pavement. Several factors can contribute to weak spots, among them, overweight vehicles, construction flaws, or water. Another major cause is repairs not done right the first time. A poor repair job like this won't last more than a few days. On the job, you'll see many sizes and shapes of potholes. Some will be shallow, some deep, and some will be irregular. The repair procedures are basically the same no matter what the size or shape. Pothole repair involves nine steps. Placing traffic control devices, marking the defective area to be repaired, cutting out the defective material, cleaning out the hole, applying the tack material, placing the mix, compacting the mix, cleaning up the job site, and preparing to move to the next job site. Let's look at each work step in detail. The first step covers placing traffic control devices. You are responsible for the safety of the crew and motorists. Consider the work area and decide where to place control devices. Place signs, cones, and barricades so they can be seen by drivers in time for them to react. If required, position flagmen at appropriate sites. Follow your traffic control standards and procedures. The second step is to mark the defective area. First, sweep away loose material from the pothole. Turn the area carefully to see the extent of the weakened pavement. Then mark the area to be removed. Use chalk, crayon, or paint to mark the edges. Generally, you can use the width of an outstretched hand as a guide to be sure that you mark the area in good pavement. Anything more may result in the unnecessary removal of good pavement. Mark the repair area in a rectangular shape with straight sides and square corners. This is a step you should perform so your workers have clear instructions. And remember, you may have to enlarge the area once the cutting begins and you get a better look at subsurface conditions. Repair areas don't necessarily have to be square, but never use a round shape. Adapt the outline to the shape of the pothole. The third step involves cutting out the defective material. To do the cutting, you'll be using either a jackhammer with a spade bit or a pickaxe. The cutting action should always begin in the center and proceed toward the edges. This has two advantages. There is less resistance to cutting and you'll not weaken the good pavement outside of the marked edge. Also avoid rocking the spade bit because this will damage the good pavement. Vertical sides are essential for proper compaction of the patch. Always check the sides with something square to make sure that they are vertical. This along with compaction is one of the two most important steps for a permanent repair. Be sure to cut down to stable material. It will form a good foundation for the patch. Also make sure that the bottom is level. The fourth step is the removal of defective material. A patch adheres best to a clean surface. Using shovels, remove all loose materials and debris from the hole. Next blow out the fine materials using an air compressor or sweep it out using a stiff bristled broom. Dispose of debris properly. Do not leave materials in the roadway, on the shoulder or in a drainage ditch. Material left in the ditch will cause the water to pond and may result in another pothole. Next make a thorough inspection to see that no weakened material remains on the sides or bottom of the hole or in the corners. Once all loose material is removed, you're ready for tacking. Tacking the hole is step five. Tack serves as a kind of a glue to bond the patch in place. Apply tack to the sides of the hole first. Do not overlap onto the surrounding pavement. Use either a hand broom or a sprayer. Remember, tack should never be poured. It should form a thin film on the sides and the bottom of the hole, allowing the texture to show through. Poring results in excess tack, which will soften the patch and cause it to break up. The materials you'll use for tacking are either emulsions or cutbacks. Emulsion is preferred. Cutback requires only a little curing before putting premix in the pothole. Also you can apply it to damp surfaces. Cutback is less desirable as a tack, since it must cure at least 15 minutes. Also cutbacks may require additional heating for ease of handling. You can recognize cutback by its gasoline or kerosene smell. In some cases you'll have to cut out the damaged material down to the granular base. In this situation, apply a heavier coat of tack to the bottom of the hole. This is called priming. It acts as waterproofing. Properly cured tack is sticky to the touch. Remember, if you apply too much tack, the patching material will be weakened. But if you apply too little tack, the patch will not stick properly. Step six involves placing the premix material. If you're using hot mix or cold mix, make sure it's workable. Don't use it if it's hard to shovel or it's crusted. Begin placing the premix using a square pointed shovel. Begin in the corners and sides first. Then place material in the center. If the hole is deep, it may require several layers of material. Generally, the maximum depth to use for each layer is 8 centimeters in uncompacted layers. This is equivalent to the width of a hand. After placing each layer, spread it level with a rake. Make sure you keep all patch material in the hole. Mix left on the pavement around the hole will make the next step harder. Place additional layers only after compacting previous layers. Leave the uncompacted surface layer of the patch slightly higher than the surrounding pavement surface to allow for compaction. Step seven involves compacting the premix. Compaction, along with making the sides of the hole vertical, is one of the two most important steps. Good compaction makes the patch last a long time. To compact the patch, you can use several different types of equipment. The best type is the vibratory roller. It works better and faster. You can also use a vibratory plate. A tandem steel-wield roller. Or a hand tamp. A hand tamp is not the best tool to use. If it's the only compaction tool available, tamp especially thoroughly and use thinner layers, about one half the width of a hand. If you use a roller, make sure the area around the patch is clear of debris prior to compaction. Debris under the roller will cause poor compaction. Remember, if the hole is deep, it may require several layers. Compact each layer thoroughly prior to placing another layer. Whether you're placing one or two layers, the procedures are the same. Always start compacting in the corners and edges. Then work in toward the center of the patch. First, make one or two passes without vibration. Otherwise, the machine will push uncompacted pre-mix out of the patch. Then make a minimum of 10 to 15 passes with vibration. You can tell when the patch is thoroughly compacted because repeated applications of the compactor won't leave any impressions in the patch surface. Leave the final surface of the patch slightly rounded above the surrounding pavement. Check the rounding with a straight edge in the direction of traffic and across the roadway. The center of the patch should be about the thickness of a pencil above the pavement. This helps drain any water away from the patch. Next is step eight. You should make sure the crew cleans up the job site. Dispose of excess material properly. Once again, don't throw debris onto the shoulder in ditches or near catch basins. It will cause drainage problems. Load it onto the truck or dump it in a designated area. There's still one last step before the repair is complete. Step nine, preparing for the move to the next job site. First, count all the hand tools and equipment and make sure that tools and equipment are properly cleaned and nothing is broken. As the equipment is being loaded, make a final inspection of the job site. Make sure that nothing is being left behind and the work site is left in proper condition. Also, remove and load traffic control devices in the reverse order in which they were originally placed. Follow your standards for traffic control to make sure it is done correctly. As the crew loads the devices, make a final security check to see that all equipment is secured before moving on to the next job site. Before we finish, let's quickly review each of the nine steps of pothole repair. The nine steps include placing traffic control devices, marking the defective area to be repaired, cutting out the defective material, cleaning out the hole, applying the tack material, placing the mix, compacting the mix, cleaning up the job site and preparing to move to the next job site. Following the procedures presented in this program will result in professional, long-lasting repairs which will benefit you, your crew, and the driving public.