All concrete crack repair equipment operation must be inspected before, during, and after the crack repair project to ensure proper operation of the equipment, safety of the personnel involved in the project, and potential damage to the pavement due to equipment problems.
Proper safety procedures in accordance with OSHA guidelines and common sense practices must be followed for the protection of all project personnel. Hand tools should always be available for working in areas where machinery is not practical or allowed.
All sealant equipment must be equipped with nozzles designed to fill the concrete cracks from the bottom up. The equipment must be inspected daily prior to application of the sealant and during the operation to ensure safe operation and that the sealant is being applied properly. If a two-component sealant is used, the metering ratio must be checked daily.
Types of Concrete Crack Repair Equipment:Following are the types of concrete crack repair equipment:
Random Crack SawSawing is the preferred method for preparing concrete cracks for sealing. This device is essentially a concrete saw but has a smaller rear-mounted blade approximately 5 inches (130 millimeters) in diameter. Random Crack Saws are generally self-propelled machines with caster wheels that allow more freedom of movement than an ordinary concrete saw for following the path of cracks. Diamond blades are typically employed and should be thick enough to saw the crack to the desired width and prevent warping of the blade during operation.
Vertical Spindle RouterCracks may be routed out if a saw is not available. The vertical spindle router has a vertically mounted router bit and is constructed such that the device can caster and easily follow the contours of a crack . The bit must be the proper size for the sealant reservoir and be belt-driven for safety considerations arising from jamming of the bit if the router are forced along the crack. The bits must yield the proper shape for the sealant reservoir and not cause spalling or ravelling along the crack path.
Sandblasting EquipmentThe necessary sandblasting equipment for concrete crack repair includes an air compressor, air hose, and a 1/4-inch- (6-millimeter-) diameter venturi-type nozzle. The compressor must be capable of delivering 150-cubic feet/minute (4.25-cubic meters/minute) at 90 pounds/square inch (620 kPa) and be equipped with operating in-line traps to keep the air hoses and the sandblasted surface free of oil and water. This device must be capable of removing all sawed slurry, dirt, and old sealant that may be present in cracks that are being resealed. Ceramic and tungsten carbide nozzles are available for sandblasting, but the tungsten nozzles last longer. A guide that keeps the nozzle a constant height from the pavement surface promotes consistency to the sandblasting technique and reduces operator fatigue. The nozzle should have an adjustable guide that will hold the nozzle aligned with the joint approximately 1 inch (2.5 centimetres) above the pavement surface. Safety must always be a primary concern. Sandblasting operators are required to follow OSHA guidelines. A helmet with separate air source and air purification equipment reduces the possibility of inhalation of silica dust. Protective clothing may also be required.
Compressed Air EquipmentCompressed air can be employed for the final cleaning phase of the project. The air source must produce sufficient pressure and contain no oil that may foul the surface prior to sealing. Some compressors have in-line sources for the constant lubrication of air tools. These devices must be removed along with the oil-coated pressure hoses, and in-line oil and water traps must be installed to provide a clean air source for the air blasting operation.
Hot-Air LanceA hot-air lance is sometimes employed to dry the surface of the pavement immediately prior to sealing. Strict safety precautions that must be employed to reduce operator hazard may include protective clothing as well as eye and ear protection. The operator must take special precaution not to overheat the pavement which may cause cracks and chalking of the concrete surface. Direct flame devices must not be used.
Water blasting EquipmentWater blasting is an excellent technique for cleaning joint faces. This technique is sometimes employed as an alternative to sandblasting due to local air regulations or where the sand and debris might create additional problems. Water blasting equipment should consist of a trailer-mounted water tank, pumps, high-pressure hoses, an auxiliary water supply, a wand with a safety cut off if the operator should lose control, and a proper size nozzle for the crack width. After water blasting is completed, the entire joint must be dried.
Power BroomA vacuum-type power broom should be present to remove debris from the pavement surface and reduce the potential for .
Backer Rod Installation EquipmentBacker rod may be placed by hand and many contractors have constructed their own hand-held equipment for this operation. However, there are manufacturers of installation equipment. These devices place the rod at a consistent depth without undue stretching or tearing of the backer materials
Hot-Applied Sealant EquipmentThere are two basic types of hot-applied sealant equipment for concrete crack repair:
- one for heating sealants that are solids or liquids at room temperature and
- one for sealants that are liquids only.