 We have all seen cracks in asphalt pavement many many times, but we know very little about them. This videotape will focus on medium-sized cracks which are 3 to 12 millimeters wide or about the thickness of your finger. These cracks can be linear or area in nature. You will see their causes and how to properly repair them. Linear cracks can appear several ways. They can be line breaks along the edge of the pavement, cracks along joints in the pavement, or line breaks just about anywhere throughout the pavement. Area cracks are recognized as a network of random cracks in the pavement. This is often called alligator cracks. The pattern formed in the pavement resembles the pattern of an alligator hide. They are caused by a heavy flow of traffic on the pavement above a weak place in the road base. The pavement surface must be repaired as soon as the cracks can easily be seen because water can pass through the cracks causing more damage to the road base. If the work is delayed, the pavement will become badly broken up and will require major repair. Pavement with cracks wider than the thickness of your finger require more extensive repair than we are covering in this videotape. These wide cracks indicate serious damage of the road base that you should schedule to be repaired. For repair information, refer to the IRF videotape base and sub-base repair. To repair linear and area cracks, you will need hand tools and equipment designed to do the job best. The proper hand tools include narrow and wide squeegees, a sharp pointed rod, a rake, stiff brooms, shovels, and a pouring pot for the asphalt mixture. You will also need an asphalt sprayer to apply the asphalt to seal the cracks. An air compressor to remove debris from the surface and cracks. Be sure to take along the blowpipe attachment. A dump truck will be needed to transport the materials, equipment, and crew to the work site. The proper equipment alone will not make a good repair. You will also need the proper materials which include an asphalt slurry mixture for filling the cracks. This mixture can be made before you go to the work site. It consists of 10 liters of asphalt emulsion to every 35 kilograms of sand with water added as needed. The mixture has reached the desired consistency when it is thick, smooth, and free of lumps. You will also need asphalt emulsion or asphalt cutback to fill and seal the cracks and clean medium sand, approximately one to two millimeters in size for cover aggregate. We will look at the eight steps for repairing linear and area cracks in asphalt pavement. Step one, place the traffic control devices. Step two, clean the surface area and cracks. Step three, fill the cracks with asphalt mixture. Step four, apply the liquid asphalt over the cracked area. Step five, spread the cover aggregate. Step six, roll the aggregate. Step seven, clean the work site. Step eight, remove the traffic control devices. Now that we have briefly covered the eight steps, we will look at each step in detail. Step one, place the traffic control devices at the work site. Proper placement of these signs, cones, and barricades is important to the safety of your crew and the passing vehicles. Place these devices so that drivers have adequate time to respond. For further information, refer to the IRF videotape, traffic control during maintenance. Step two, clean the surface area and cracks. A broom will do the job adequately, but compressed air is more effective. After the pavement surface area and cracks have been cleaned, you must inspect them for damage. Identify the cracks that need more cleaning to your crew. A sharp pointed rod may be necessary to remove any material stuck in the cracks. Remove any loose material from the area to be repaired. Step three, fill the cracks with asphalt mixture. The asphalt mixture must be smoothed immediately after it is poured. Run the squeegee over the cracks and along both sides. Any excess asphalt mixture must be removed. Step four, apply the liquid asphalt over the cracked area. Before you begin, make sure the asphalt mixture in the cracks has cured. The liquid asphalt should be sprayed over the area in a light coat. You can use a wide squeegee if a sprayer is not available. Make sure the light coat extends beyond the cracked area about 30 centimeters or the distance equal to the length of your foot. This step is not done for linear cracks. Step five, spread the cover aggregate. The aggregate must be spread immediately after the liquid asphalt has been applied. Be sure that the cover aggregate is cast evenly over the liquid asphalt in a single layer. Do not dump the aggregate in piles. The aggregate will protect the surface of the repair. It will prevent the tires from picking up the asphalt mixture or sealer. The aggregate also provides good friction for vehicles. Step six, roll the aggregate using the truck. It must be driven several times across the aggregate to make the aggregate particles fit tightly together. Step seven, clean the worksite. All unused material must be loaded on the truck. Do not leave any unused material at the worksite. Also the tools used to make the repair must be cleaned at the end of the day and loaded back on the truck. Loose aggregate should be swept up and properly disposed of away from the road and drainage ditches. Check for anything left behind and be sure it gets loaded on the truck. Step eight, remove the traffic control devices. Pick them up in the reverse order of their placement. This road crew is now ready to proceed to the next worksite. Remember there are eight steps necessary to repair linear and area cracks. Step one, place the traffic control devices. Be sure the signs, cones and barricades are placed correctly. Step two, clean the surface area and cracks. Remove all debris from the cracks. Step three, fill the cracks with asphalt mixture. Be sure you fill all the cracks. Step four, apply the liquid asphalt over the cracked area. The asphalt should cover the repair surface in a light coat. Step five, spread the cover aggregate. Cast it evenly over the entire repair surface in a single layer. Step six, roll the aggregate. This will make the aggregate particles stay in place. Step seven, clean the worksite. Sweep and properly dispose of any loose aggregate. Step eight, remove the traffic control devices. Pick them up in the reverse order of their placement. Crack repair is very important because it prevents further deterioration of the pavement surface and protects the base from water damage. Proper repair of linear and area cracks will prolong the life of the pavement. Your efforts will keep the road in good condition and safe for everyone.