415Milling of Asphalt Pavement Surfaces

415.1-DESCRIPTION: This item shall govern for the milling of existing and/or new asphalt pavement at locations shown on the plans or as directed by the engineer in accordance with the requirements herein and MP 401.07.24. The work shall provide a skid resistant surface that meets smoothness requirements and provides a constant cross slope, or be used as surface preparation prior to placement of a final surface course. 415.1.1-Standard Milling: Item 415005-* shall be used as the default milling of asphalt pavements. It should be used when the Division plans to remove existing asphalt pavement in preparation for an asphalt overlay or other process. This method of removal is most common and possesses a minor level of profile and slope control, or as otherwise shown in the plans. 415.1.2-Fine Milling: Item 415006-* shall be used when the Division intends to overlay the milled surface with a thin lift asphalt course, or as otherwise shown in the plans. This removal method shall be considered a detailed surface preparation, therefore requiring a high level of profile and slope control, or as otherwise shown in the plans. 415.1.3-Micromilling: Item 415007 -* shall be used for in an effort to recover skid resistance on existing pavement or smoothness correction, bump and/or grade corrections on existing or newly paved surfaces where called for in the plans. This removal method shall be considered specialized and is not intended to be used when standard overlays are to be used. 415.2-CONSTRUCTION: 415.2.1-General: The plans will designate the area of pavement surfaces to be milled. Milling of roadway shoulders will not be required unless indicated on the plans or required to provide drainage. 415.2.2-Equipment: The equipment for removing the existing pavement shall be a power operated planing machine or grinder. The equipment shall be capable of accurately establishing profile grades along each edge of the machine within plus or minus 1/4 inch by referencing from the existing pavement and able to maintain acc urate depth of cut and cross - slope. The machine shall have a control system providing for uniformly varying the depth of cut while the machine is in motion to prevent cutting of or damage to drainage works, manholes or other appurtenances within the paved area. At the end of each working day, all equipment shall be removed to a location where it does not present a hazard to traffic, the pavement shall be cleaned by sweeping or flushing. 415.2.3-Milling Residue: The Contractor shall establish a positive and immediate means for removal of milling residue. The machine shall have adequate loading equipment to remove solid residue from the surface and discharge them into a truck or as directed. Residue shall not be permitted to flow across lanes us ed by the traveling public or into gutters or drainage facilities. 218 415.2.4-Millings: The removed pavement material shall become the property of the Contractor. Excess waste material resulting from the operation shall be removed and disposed of in a manner approved by the Engineer. 415.2.5-Milled Surface Opened to Traffic: If the ground area is opened to traffic the following shall apply; 1) Any transverse vertical face shall be sloped so as not to present a hazard to traffic; 2) Any longitudinal vertical face shall not exceed two (2) inches; 3) The pavement surface shall be cleaned by sweeping or flushing. 415.2.6-Cross Slope: Milling will be accomplished in a manner that eliminates crack or joint faults while providing positive lateral drainage by maintaining a constant cross -slope between grinding extremities in each lane. Auxiliary or ramp lane grinding shall transition as required from the mainline edge to provide positive drainage and an acceptable riding surface. The operation shall result i n pavement that conforms to the typical cross -section and the requirements specified for the final surface finish. However, it is the intention of this specification that the faulting at joints and cracks be eliminated and the overall riding characteristics be restored within the limits specified. To accomplish the smoothness required, milling may not be required on 100 percent (100%) of the pavement surface. If directed by the Engineer, any spalling or dislodged unsound pavement due to milling shall be corrected by the Contractor via section 109.4. 415.2.7-Surface Finish: The milling process shall produce a smooth riding pavement surface that is true to the established line, grade and cross section with the milled area consisting of a longitudinal co rduroy-type texture. The milling operation shall be capable of efficiently and accurately establishing profile grades along each edge of the machine within the tolerance listed below: 415005-* Standard Milling 1/4 inch 415006-* Fine Milling 1/8 inch 415007-* Micromilling 1/8 inch Transverse joints and cracks shall be made flush with adjacent surfaces. Transverse joints and cracks shall be visually inspected to ensure that adjacent surfaces are in the same plane. Alignment of adjacent sides of the joints or cracks shall be within 1/8 inch of each other to be considered flush. The transverse slope of the pavement shall be uniform to a degree that no depressions of misalignment of slope greater 1/4 inch in twelve ( 12) feet are present when tested with a straightedge placed perpendicular to the centerline. Straightedge requirements do not apply outside of the milled area. The peaks of the ridges shall be approximately 1/8 inch higher than the grooves. The finished, milled pavement surface shall be evaluated using MP 401.07.24 except that the volume of glass beads to be used for each test shall be 200 ml (12 in3), and only one such test shall be required at each individual test location. The measured diameter for each test shall be equal to or greater than the values shown below: 219 415005-* Standard Milling NA 415006-* Fine Milling 9 inch Dia. 415007-* Micromilling 12 inch Dia. Testing shall be performed as soon as practical behind the milling operation in order to not allow gaps to occur between sections being milled and sections being evaluated. Three tests shall be performed within the first 3,000 square yards of milling, and then at a minimum frequency of one test for every 7,500 square yards of milled surface thereafter. If the minimum diameter is not maintained, cease operations until necessary adjustments to the equipment and/or the process are made to meet this requirement. Do not resume milling operations until the Engineer is satisfied with the corrective actions. Upon resuming operations after any adjustments are made, the first 3,000 square yards shall be evaluated as stated above. Additionally, if the equipment is replaced for any reason, or if mobilization back to the project site occurs at a later date for any reason, the first 3,000 square yards shall be evaluated as stated above. The Engineer may reduce the testing frequency provided that a uniform texture is consistently maintained meeting the requirements shown above. 415.3-METHOD OF MEASUREMENT: Pavement milling will be measured by the square yard of pavement milled and accepted. The quantity of pavement milling will be determined by multiplying the width specified on the plans by the total length of the finished pavement surface. 415.4-BASIS OF PAYMENT: The contract price per square yard for Standard, Fine Milling, or Micromilling shall be full compensation for furnishing all labor, materials, tool, equipment and incidentals and for doing all work involved in milling the existing pavement, removing residue, cleaning the pavement, and testing per MP 401.07.24 in accordance with these specifications and as shown on the plans. 415.5-PAY ITEMS: ITEM DESCRIPTION UNIT 415005-* Standard Milling Square Yard 415006-* Fine Milling Square Yard 415007-* Micromilling Square Yard * Sequence number 220