5-26 Section 502. HMA Crack Treatment
502.01. Description This work consists of treating cracks in HMA surfaces using both a saw or rout and seal process and an overband process.
A.Definitions Primary Crack . Crack ⅛ inch to 1¼ inch wid e with less than 25% of its length having secondary cracking. Secondary Crack. Series of parallel cracks with no or few interconnecting cracks to the primary crack. 502.02. Materials Provide materials in accordance with the following section : Joint and Crack Sealants for Construction ............................................... 914
A.Saw or Rout and Seal. Provide a hot -poured, extra low -modulus, joint-and-crack sealant product from the Qualified Products List. Follow manufacturer ’s recommendation for material installation.
B.Overband. Provide an overband crack fill asphalt rubber product from the Qualified Products List. Follow manufacturer ’s recommendation for material installation. 502.03. Construction
A.Equipment. Provide equipment capable of meeting the requirements of this subsection.
1.Compressed Air System . Provide and use a compressed air system that produces a continuous, high-volume, high-pressure stream of clean, dry air to prepare cracks. Equip the air compressor with a moisture separator to remove oil and water from the air supply. Provide a compressor capable of producing at least 100 psi at a continuous air flow of 150 cfm.
2.Melter Applicator . Provide a melter applicator consisting of a boiler kettle equipped with press ure pump, hose, and applicator wand. Equip the unit with the following:
a.Shutoff control on the applicator hose;
b.Mechanical agitator in the kettle to provide continuous blending;
c.Thermometers to monitor the material temperature and the heating oil temperature ; and MDOT Standard Specifications for Construction Section 502
5-27 d. Thermostatic controls that allow the operator to regulate material
temperature up to 425°F .
3.Application Wand . Apply the material using either a wand followed by a V-shaped or U -shaped squeegee or a round application head with a concave underside.
B.Pre-Production Meeting. Before beginning work, conduct an on-site pre-production meeting with the Engineer to discuss the following:
1.Contractor ’s detailed work schedule;
2.Traffic control plan;
3.Required project documentation;
4.Review crack treatment methods criteria;
5.Inspection of the condition of equipment ;
6.The Contractor ’s QC Plan ; and
7.The Contractor ’s designated Authorized Representative.
C.Crack Preparation. Clean and dry cracks using compressed air and other tools to remove loose dirt, vegetation, and deleterious material. Clean cracks no more than 10 minutes before filling. Any debris or vegetation removed from cracks in a curb and gutter section will be removed and disposed at no additional cost to the Department.
D.Crack Treatment Methods
1.Saw or Ro ut and Seal . Treat primary transverse cracks in the pavement surface using the saw or rout and seal process. Treat primary transverse cracks in the shoulders unless otherwise directed. Saw or rout, clean, and fill all primary transverse cracks. The Depart ment defines a transverse crack as a crack less than 10 degrees off of perpendicular to the centerline. The following cracks should not be sealed:
a.Secondary cracks;
b.Multiple nearby cracks that have raveled; and
c.Multiple cracks that include broken asphalt. Saw or rout all primary transverse cracks as defined above by creating a reservoir along the crack. Create the reservoir to a volume of at least 7.5 cubic inches per foot of crack and with a 1:1 width -to-depth ratio. Ensure that the finished reser voir walls are vertical and the reservoir bottom is flat. Fill the reservoir such that the final level is MDOT Standard Specifications for Construction Section 502
5-28 flush with the pavement surface and spread uniformly over the entire
length of the crack. The width of the overband, including the routed reservoir, must be no more than 2½ inches wide with a thickness of ⅛ inch.
2.Overband . The Contractor will treat all other primary and secondary cracks with material placed in an overband configuration. Apply overband material to clean, dry cracks. Apply overband 4 inches wide, ±½ inch and from ⅛ inch to 3/16 inch thick. The Contractor may increase the maximum application width to 6 inches for coverage of multiple cracks, with Engineer approval. Place temporary pavement markings before opening the road to traffic if overband material obliterates existing pavement markings. Apply overband as follows unless otherwise required:
a.Stand Alone Overband Crack Fill . If no other surface treatment is require d on the pavement, fill visible cracks in the road less than 1¼ inch wide.
b.Micro -Surfacing Preparation . If preparing the pavement for a micro -surface overlay, fill visible cracks in the road less than 1¼ inch wide. Allow to cure for a minimum of 3 days pri or to placement of micro -surface.
c.Chip Seal Preparation . If preparing the pavement surface for a single or double chip seal, fill cracks with widths from ¼ inch to 1¼ inch or 3 feet or longer. Allow to cure for a minimum of 7 days prior to placement of chi p seal.
d.Paver -Placed Surface Seal (PPSS). If preparing the pavement for a paver -placed surface seal, fill cracks with widths from ¼ inch to 1¼ inch or 3 feet or longer. Allow to cure for a minimum of 14 days prior to placement of PPSS.
e.HMA Ultra -Thin Overl ay. If preparing the pavement for an HMA ultra-thin overlay, fill visible cracks less than 1¼ inch wide. Allow to cure for a minimum of 14 days prior to placement of the HMA ultra-thin overlay. Do not seal the following cracks when preparing the pavement for micro -surfacing, chip seals, paver -placed surface seals , or HMA ultra-thin overlays: Multiple nearby cracks that have raveled; Multiple cracks that include broken asphalt ; and MDOT Standard Specifications for Construction Section 502 5-29 Multiple longitudinal cracks in each wheel path.
E.Weather Limitation s. Place material at air temperatures from 45°F to 85°F. Do not place material if moisture is present in the crack.
F.Cure Time and Repair. Allow the material to cool before opening the road to traffic. Apply detackifying solution, if required, to protect the uncured crack treatment material from tracking. Do not use blotting materials, including sand, aggregate, sawdust, or paper. Repair treated pavement areas, damaged by traffic at no additional cost to the Department.
G.Quality Control . Provide and follow a QC plan for production and construction processes. Provide the Engineer with a copy of the QC plan for review and approval, prior to the pre-production meeting. Maintain QC measures until the Engineer accepts the work. Comply with the approved QC plan thro ughout the project and allow the Engineer access to work in progress for assurance review and testing. If the Engineer identifies a condition causing unsatisfactory crack treatment, immediately stop production and correct the work at no additional cost to the Department. Ensure that the QC plan addresses the following:
1.A detailed description explaining how field crews will determine primary transverse and all other primary and secondary cracks. Separately detail projects with multiple pavement sections ;
2.The sealant material and equipment used to heat, handle, and apply sealant material in accordance with the manufacturer ’s specifications. Provide the material manufacturer ’s specifications to the Engineer upon request ;
3.Saw or rout and seal operation reservoir configuration;
4.Procedures for crack cleaning ;
5.Replacement criteria for cutting tools ;
6.Controls implemented to ensure that flying dust and debris are not directed toward adjacent traveled lanes, pedestrians, parked v ehicles, or buildings ;
7.An action plan for adjusting crack sealing operations to address actual environmental conditions if adverse environmental conditions occur ; and
8.Proposed procedure for monitoring the work to ensure that acceptance requirements are met . MDOT Standard Specifications for Construction Section 502
5-30 H. Acceptance. Upon completion of work, schedule an inspection with the
Engineer. The Engineer will note deficiencies, including areas exhibiting adhesion failure, cohesion failure, missed cracks, or other factors the Engineer determines unacceptable. Correct the unacceptable work. Notify the Engineer upon completion of corrective work. 502.04. Measurement and Payment Pay Item Pay Unit Overband Crack Fill, Lane ........................................................ Lane Mile Overband Crack Fill, Ramp ....................................................... Lane Mile HMA Crack Treatment, Lane ..................................................... Lane Mile HMA C rack Treatment, Ramp ................................................... Lane Mile
A.Overband Crack Fill . The Engineer will measure Overband Crack Fill, Lane along the centerline of each lane. This measurement includes traffic lanes, as defined in the Lane Mile Inventory, and any adjacent paved shoulders. The Engineer will measure Overband Crack Fill, Ramp along the ramp centerline beginning at the 2-foot gore point including shoulders. The unit prices for Overband Crack Fill , of the type required, include the cost of preparing and filling cracks using the overband method, providing the required documentation, corrective work, and temporary traffic markings.
B.HMA Crack Treatment . The Engineer will measure HMA Crack Treatment, Lane along the centerline of each lane. This measurement includes traffic lanes, as defined in the Lane Mile Inventory, and adjacent paved shoulders. The Engineer will measure HMA Crack Treatment, Ramp along the ramp centerline beginning at the 2-foot gore point including shoulders. The unit price for HMA Crack Treatment, of the type required, includes the cost of preparing, filling, and sealing the cracks, including treating primary transverse cracks with the saw or rout and seal method, and treating all other primary and secondary cracks with the overband method.
Source: Michigan Standard Specifications for Construction, 2020 Edition. Pages 285–289 of 1,146.