510 FILLING AND SEALING CRACKS AND JOINTS IN ASPHALT PAVEMENTS
From MDOT Policy Manual
- Clean then fill or seal cracks between 1/8 in. and of 1 in. wide. Repair cracks 1 in. or larger with asphalt repair mastic. Do not fill or seal cracks less than 1/8 in. wide. Repair distressed areas as specified and as directed.
- 510.03.01 EquipmentAll machinery, tools, and apparatus necessary for the proper construction and acceptable completion of the work, together with the necessary supplies for upkeep and maintenance.. All equipment shall be subject to approval. Ensure all equipment is maintained in satisfactory working condition at all times.
- (a) Air Compressor. Air compressors shall be portable, oil-free and capable of furnishing air a minimum of 100 cfm with a minimum blast flow of 150 cfm. The compressor shall have a 3/4 in. diameter nozzle.
- (b) Hot Air Lance. The Hot Air Lance shall produce a minimum temperature of 750 F at a minimum velocity of 650 fps. The Hot Air Lance shall be designed so that the flame does not come in contact with the pavement.
- (c) Melting Kettle. The Melting Kettle shall be a self-contained double boiler capable of heating the sealant to 400 F using oil as a heat transfer medium. The kettle shall be equipped with an automatic temperature control unit capable of achieving and maintaining a predetermined sealant temperature. The temperature control unit should not allow the heat transfer oil to exceed 525 F. The unit shall be capable of reading the temperature of the sealant within the melting vessel and within the discharge plumbing. The kettle shall also have a means to strongly and continuously agitate the sealant and apply the sealant to the pavement under pressure supplied by a gear pump with a direct connecting applicator tip. Do not use direct-fired kettles.
- (d) Hand Tools. Provide all hand tools such as brooms, shovels, metal bars with chisel shaped ends, tamping equipment and other miscellaneous tools necessary to complete the work.
- (e) Squeegee. Provide a metal industrial-type squeegee no more than 2-1/2 in. wide to shape the material into a feather-edge band.
- (f) Crack Router. The crack router shall be capable of following random cracks and be designed to adjust cutting widths. The router width shall touch both sides of the crack for proper cutting. The router shall remove 1/8 in. from each side of the crack and cut back to sound pavement.
- (g) Mastic Mixer. The Mastic Mixer shall be thermostatically controlled and capable of heating the mastic mixture using oil as a heat transfer medium. The Mastic mixer must be equipped with a full sweep horizontal agitator capable of gently lifting the material from the bottom of the reservoir and mixing the material thoroughly. The agitator shall be capable of mixing and suspending materials filled with aggregates with a specific gravity as high as 3.0.
- 510.03.02 Quality Control Plan (QCP). Submit a QCP for approval at least 30 days prior to the placement of any crack filler, sealer or asphalt repair mastic. The Plan shall document the proposed methods for controlling the equipment, materials, production, and operations to ensure conformance. The Plan shall also contain a list of technicians working on the project, their qualifications, and a list of all equipment to be used on the project. Discuss the Plan requirements with the AdministrationShall mean any one of the Administrations within the Maryland Department of Transportation, as listed in GP 1.02. prior to construction.
- 510.03.03 Training. Technicians working on the project must take a mandatory online course from National Highway Institute (NHI), Course No. FHWAFederal Highway Administration, U.S. Department of Transportation-NHI-131110C. The course is provided free of cost. An unofficial transcript of successful completion of the course can be downloaded from NHI’s website. Submit transcripts with the QCP.
- 510.03.04 Crack Identification.
- Wheel Path. Wheel path is defined as a distance of 16 in. to 56 in. (width of 40 in.) from the left or right of the center line of the roadway travel lane.
- Non-Working Cracks. Cracks with little annual horizontal or vertical movements that are less than 0.1 in.
- Working Cracks. Cracks with significant annual horizontal or vertical movements (≥ 0.1 in.).
- (a) Crack Filling. Identify non-working cracks within the wheel path 1/8 to 1 in. wide at the pavement joints including paving and patching construction joints and transverse cracks. Identify longitudinal cracks outside of wheel path areas.
- (b) Crack Sealing. Identify working cracks within the wheel path 1/8 to 1 in. wide at the pavement surface, including transverse reflective cracks. Identify longitudinal cracks outside of wheel path areas.
- (c) Asphalt Repair Mastic. Identify cracks of at least 1 in. width, potholes and other vertically uneven roadway elements as directed.
- 510.03.05 Cleaning and Preparation.
- Cleaning. All surfaces shall be dry and free of all dirt, dust, grease, and loose material prior to application of the filler. The cracks shall be cleaned by the use of compressed air produced from an air-compressor. The use of portable handheld or backpack blowers is not allowed. Direct the compressed air cleaning away from the passing traffic and do not blow debris into an already cleaned crack. Alternative methods of cleaning are subject to review and approval.
- Drying. Dry the crack using a hot air lance prior to filler placement. The use of direct flame dryers is not permitted. Do not overheat pavement surfaces.
- Crack Routing. For crack sealing, route cracks to be sealed by forming a reservoir with a width between 0.5 to 1.5 in and a depth of 3/4 in. Perform routing in such a way that the pavement does not spall. Do not perform routing on longitudinal joint cracks unless otherwise directed.
- Weather Restrictions. Perform crack filling or sealing when the ambient and pavement surface temperatures are least 45 F and rising, unless otherwise recommended by the manufacturer and as approved. Do not place sealant material if the pavement is wet. Should rain fall before the sealant has properly cured, remove and replace at no additional cost.
- 510.03.07 Installation. Heat the filler or sealant to recommended application temperature. Fill the crack using the flush fill method. Using the overband method is not permitted. Perform material handling and installation in accordance with the manufacturer’s instructions. Level and smooth the material to the desired level immediately after placement using a straight metal or rubber squeegee.
- Traffic Restrictions. Apply sand or the manufacturer's recommended blotter material to minimize tracking and remove excess material before opening to traffic.
- Acceptance. Filler that pulls loose within 96 hours after opening the pavement to traffic shall be repaired at no additional cost.
- 510.03.08 Asphalt Repair Mastic.
- Primer. Apply a surface conditioner or primer when recommended by the mastic manufacturer to the surfaces prior to placement of the asphalt repair mastic. Apply in accordance with manufacturer’s recommendations to promote increased surface adhesion to the existing pavement. The surface conditioner or primer must thoroughly cover all surface areas where the asphalt repair mastic will be placed. Do not install the asphalt repair mastic until the surface conditioner or primer has sufficiently cured per recommendations.
- Application Temperature. The minimum application temperature shall be per the manufacturer’s recommendations. The maximum application shall be 410 F, or per the manufacturer’s recommendations.
- Installation. The installer must be trained and approved by the mastic manufacturer.
- (a) Heat the asphalt repair mastic using the Mastic Mixer. Place the heated mastic onto the properly prepared pavement in layers if necessary.
- (b) Use a heated hand squeegee to level and smooth the mastic until the material has formed a durable, well-bonded, level repair. Keep the heated hand squeegee free of material buildup to ensure a smooth, quality finished product.
- (c) Apply the mastic to the surface area from the bottom up in lifts appropriate to the specific application. Due to the depths of some of the repair locations, multiple lifts may be required to obtain a level surface. In the event that multiple lifts are required, allow each lift to be properly cooled before any subsequent lifts are applied on top. The final lift shall fill the uppermost 0.5 to 1 in. of the work area. Remove and dispose of all excess material from the roadway.
510.04 MEASUREMENT AND PAYMENT.
- Payment will be full compensation for furnishing, hauling, and placing of all materials, crack routing, crack filling, crack sealing, asphalt repair mastic treatment, the removal and disposal of old filler and debris, and for all material, labor, equipment, tools, and incidentals necessary to complete the work. Payment will not be made for wasted material.
- 510.04.01 Crack Filler will be measured and paid for at the Contract unit price per linear foot or per lane mile or per pound as specified.
- 510.04.02 Crack Sealer will be measured and paid for at the Contract unit price per linear foot or per lane mile or per pound as specified.
- 510.04.03 Asphalt Repair Mastic will be measured and paid for at the Contract unit price per pound.