SECTION 406 - COLD MILLING
406.01 Description. This work consists of removal of pavement materials on the
roadway and shoulders by cold milling to the designated depth and, loading, hauling, and disposal of the milled materials by the Contractor in accordan ce with the plans and specifications, or as directed by the Engi neer. The milled su rface shall provide a desirable surface free from go uges, continuous grooves, ridges, oil film, and other imperfections of workmanship and shall have a uniform appearance. This work also consists of the removal of portions of existing pavement using a cold fine milling process to a nominal depth using grade control as specified on the plans or as directed by the Engineer. It shall also include the loading, hauling, and disposal of the milled materials by the Contr actor in accordance with the pl ans and specifications. The planed surface shall provide a textured surface suitable for repairs, paving, or as a temporary riding surface, whichever is specified.
406.02 Blank.
406.03 Construction Requirements.
406.03.1 Equipment. The equipment to be used for this work shall be a self-propelled
milling machine capable of removing a minimum width of four feet. The equipment shall have sufficient power, traction, and stability to remove material and maintain an accurate grade and cross slope. The equi pment shall accurately and automatically establishing profile grades along each edge of the machine by referencing from the existing pavement with means of an approved profile averaging device with extreme contact points with surface at least 30 feet apart, or from an independent grade line and shall have an automatic system for controlling cross slope. The machine shall be equipped with an integral loading and reclaiming means to immediately remove material being cut from the surface and discharge the cu ttings into a truck or windrow, all in one operation. When fine milling is required, the milling machine shall, in addition to the above, be designed specifically for grinding surfaces to close tolerances and shall be operated at a rate recommended by the manufacturer so as to avoid tearing and gouging of the pavement surface. The fine milling machine shall be equipped with a fine milling drum of the size and shape necessary to produce an ultrafine te xture to the milled surface and meet the requirements of this specification. The bit or teeth spacing on the drum shall have a maximum spacing of six millimeters (6 mm). The equipment shall have a positive means for limiting any dust resulting from the operation from escaping into the air. Adequate back-up equipment, such as mechan ical sweepers, loaders, water truck, etc., and personnel shall be provided to ensure that all cuttings are removed immediately behind the milling machine.
406.03.2 Construction Methods . When asphalt will be required on the milled area,
milling operations shall not begin until the Contractor has an approved job-mix formula and is prepared to begin paving operations. The pavement and shoulder materials shall be removed to the depth, width, grade, and cross section shown on the plans, or as directed by the Engineer. The number of passes necessary to accomplish the work required herein and on the plans shall be determined by the Contractor. The surface of the pavement and shoulders, after milling, shall be reasonably smooth and true to the established line, grade and cross section. Areas damaged by the Contractor's operations shall be corrected and/or repaired as directed by the Engineer at no additional costs to the State. The Contractor shall take necessary action to prevent or minimize the ponding of water on the milled roadway and shoulder. Where traffic is required to be maintained adjacent to the milled area, no more than a 2¼- inch differential in grade between the milled area and the adjacent surface will be allowed, unless a positive separation in accor dance with the plans and specifications is established between the traffic and milled area. A longitudinal pavement edge that traffic is expected to move across should have an elevation difference of not more than 2¼ inches. Uneven pavement signs, as shown in the plans or contract documents, will be required if the pavement edge is more than1½ inches and less than or equal to 2¼ inches. If the pavement edge is less than or equal to 1½ inches, no uneven pavement signs will be re quired. Transverse pavement joints shall be sufficiently tapered to allow for the safe movement of traffic. When traffic is required to be maintained adjacent to milled shoulders, traffic control devices shall be placed in accordance with the requirements of the detail sheet for shoulder closures, or as directed by the Engineer. It is understood that the milled shoulder shall be covered with the next required course as soon as possible but in no case later than 30 calendar days after milling.
406.03.3 Fine Milling. Unless otherwise noted or advised by the Engineer, the fine
milling operation shall be conducted using an automatic grade control device, as referenced in Subsection 406.03.1, to establish accurate grade control and cross slope. The milled surface shall be textured, substantially free from waves or irregularities. Prior to beginning a fine milling operation, the Engineer may require the Contractor to construct a 500-foot test section. The texture and consistency of profile and cross slope of this test section will be evaluated by the Engineer to verify the above straight-edge requirement can be met. If the tolerance is exceeded in the test sectio n, the Contractor shall cease work and take corrective actions to improv e the process. Once correc tive actions are taken, the Contractor will construct another test section. This designated section shall be fine milled to conform to the same requirements as those required in the initial test section. The Contractor shall not be allowed to star t continuous fine milling until an acceptable test section is obtained. Fine milling shall produce a uniform finished surface and maintain a constant cross slope between extremities in each lane. The surface tolerance of the fine milling sha ll be checked to assure a uniform pavement texture that is true to line, grade, and cross section. Fine milled pavement surfaces are subject to visual and straightedge inspections by the Engineer at any time during the milling operation. The final fine milled surface shall be a uniform finish on the grade and slope shown to be required on the plans. The finished surface shall also not vary more than ¼” from a 10-foot straightedge placed anywhere on the surface of the milled area. The cross slope shall be checked to assure uniformity and that no depressions or slope misalignments exist when the sl ope is tested with a straight edge placed perpendicular to the center line. Dust, residue, and loose milled material shall be removed from the fine milled surface. Traffic shall not be allowed on the milled su rface nor any tack coat applied and asphalt lift placed on the milled surface until removal is complete.
406.04 Method of Measurement. Cold milling of pavement and shoulders, all depths,
will be measured by the square yard, cubic yard (LVM), or ton as indicated in the contract. Fine milling of pavement and shoulders will be measured by the square yard, cubic yard (LVM), or ton as indicated in the contract. Fine milling to repair failed areas in Open Graded Friction Courses will not be measured for payment unless authorized by the Engineer.
Cold Milling in other states
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