508 MILLING ASPHALT PAVEMENT

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508.01 DESCRIPTION
Mill asphalt pavement.
508.02 MATERIALS
Not Applicable.
508.03 CONSTRUCTION
Perform roadway patching as specified in Section 505 prior to milling. Additional roadway patching may be required after milling.
Quality Control Plan (QCP). Submit a Quality Control Plan for Milling to the District Engineer for approval at least 30 days prior to milling according to the Field Quality Control Plan (QCP) in 504.03. The QCP shall show methods proposed to control and maintain the milling equipment, materials, and daily milling operations. Discuss the Milling QCP requirements in the pre-construction, pre-pave, and progress meetings.
508.03.01 Equipment
(a) Milling Machine. Provide all equipment necessary for approval prior to beginning work. Use a power operated milling machine capable of removing asphalt pavement to the specified depth in one pass and at least half the lane width. The machine shall be equipped with automatic control devices capable of controlling grade, elevation, and cross slope at a given rate. The machine shall be capable of establishing profile grades along each edge of the machine, within plus or minus 1/4 in., by referencing from the existing pavement or independent grade control. The milling machine shall have a system capable of side, rear or front offloading of the milled material into a transfer vehicle for off-site disposal. The machine shall meet NIOSH standards for emission control. Continuously monitor the cutting head to ensure and maintain a uniform textured surface after milling. Provide supplemental equipment as necessary to remove material in areas that the milling machine cannot reached.
(b) Measurement Devices. An approved 10 ft straightedge for testing the transverse and longitudinal surface during and after milling. Use MSMT 413 for Volumetric Pavement Macrotexture Depth (Sand Patch) Testing.
(c) Street Sweeper. Provide a vacuum equipped or mechanical street sweeper to follow behind the milling machine. The sweeper shall be capable of removing all loose material from the roadway to minimize dust escaping into the atmosphere.
508.03.02 Control Strip. Mill a control strip at least 500 ft in length with a uniformly textured surface and cross section as approved. The resulting surface shall be true to the established grade and verified every 50 ft. with a 10 ft straightedge to test the transverse and longitudinal surface tolerance at ±1/4 in. The Contractor has the option to choose either Sand Patch Test (MSMT 413) or the Straightedge Test as shown in Table 1 - Texture Requirements.
TABLE 1 - Texture Requirements
Milling type Minimum Average Diameter

Per Sand Patch Option (in.)

Maximum Ridge to Ridge Distance
and Ridge to Bottom Height
Per Straightedge Option (in.)
Standard 9 5/8
Fine 11 3/8
Micro 14 1/4
Do not perform pavement macrotexture measurements in areas where there is rutting, exposed delamination, within several feet of any structure, in areas that will not hold the pattern, or where the previously milled surface texture is exposed.
508.03.03 Pavement Milling. Mill one lane at a time using all automatic control devices. If the milling depth exceeds 2.5 in., mill the abutting lane or shoulder on roadways carrying traffic on the same day. Mill the abutting lanes and shoulder prior to weekends or temporary shutdowns, regardless of depth. The abutting lane or shoulder may be milled on alternate days if the milling depth is 2.5 in. or less. Provide adequate advance warning devices where uneven pavement joints exist as specified. Provide positive drainage to prevent accumulation of water on the milled pavement as directed.
Straightedge Testing. Verify surface tolerances with a 10 ft straightedge at a minimum of five random locations daily. The variation of the top of two ridges from the testing edge of the straightedge, between two ridge contact points, shall not exceed values in Table 1. The variation from the top of the ridge to the bottom of the groove adjacent to that ridge shall not exceed values in Table 1. Correct unsatisfactory surfaces at no additional cost. Report test information per the QCP.
Sand Patch Testing. Verify surface texture requirements in Table 1 by performing random daily visual checks. Ensure the milling continues to exhibit a uniformly textured surface and cross section as produced in the Control Strip, as determined.
Fill all depressions, potholes, and other irregularities using an asphalt mix after the milling is complete. Construct an asphalt wedge at existing water valves, meters, manhole covers, etc. as specified in Section 106. Where sound pavement has been gouged, torn, or otherwise damaged during the milling operations or damage is done to other property including utility frames, grates and covers, make repairs at no additional cost.
Areas varying from a true surface more than the tolerance stated in 508.03.02 may be accepted without correction if the Engineer determines that they were caused by a pre-existing condition that the milling operation cannot repair.
The Engineer may require milling of any area where a surface delamination causes a non-uniform texture to occur, at the Contract unit price. Where a surface delamination between asphalt layers or a surface delamination between asphalt on Portland cement concrete causes a non-uniform texture to occur, the depth of milling shall be adjusted in small increments to a maximum of + 1/2 in. Tie into curb and gutter as directed.
The finished milled surface shall provide a smooth surface with straight longitudinal striations, free from scallops, scabs, gouges, ridges and have a uniform texture suitable as a temporary riding surface.
Monitor milled surface after opening to traffic. Immediately notify the Administration of any defective areas. Correct all unsatisfactory surface conditions as directed at no cost to the Contractor.
508.03.04 Temporary Tie-ins. Construct temporary tie-ins before allowing traffic to cross the transverse joint. Temporary tie-ins shall be at least 4 ft in length for each 1 in. of pavement milling depth when milling roadways carrying traffic with a posted speed ≤ 40 mph, and at least 10 ft in length for each 1 in. of pavement milling depth when milling roadways carrying traffic with a posted speed > 40 mph. If the tie-in length is 10 ft or greater, a paver meeting 504.03.01 shall be used for compaction.
508.03.05 Cleanup. Use a vacuum equipped or mechanical street sweeper, in addition to any other equipment required, to remove dust and debris after milling and prior to allowing traffic on the milled surface.
508.03.06 Delay Penalty. Do not open traffic on the milled surface for more than 10 calendar days, beginning at the first day of milling until the start of paving. A deduction of $1500 per day for interstates and $750 per day for all other roadways will be assessed for each additional day the milled surface remains open to traffic. The delay penalty will be deducted from the next progress payment and is a permanent deduction.
508.04 MEASUREMENT AND PAYMENT
Milling Asphalt Pavement will be measured and paid for at the Contract unit price per square yard for the pertinent depth of milling asphalt pavement. The amount will be computed from the width and length measurements of the actual milled areas. The payment will be full compensation for milling, measurement, testing, disposal of milled material, and for all material, labor, equipment, tools, and incidentals necessary to complete the work.
(a) Standard Milling Asphalt Pavement (0-1 in. depth)
(b) Standard Milling Asphalt Pavement (Over 1-2.5 in. depth)
(c) Standard Milling Asphalt Pavement (Over 2.5-4 in. depth)
(d) Standard Milling Asphalt Pavement (Over 4 in. depth)
(e) Fine Milling Asphalt Pavement (0-1 in. depth)
(f) Fine Milling Asphalt Pavement (1-2.5 in. depth)
(g) Micro Milling Asphalt Pavement (0-0.5 in. depth)
(h) Micro Milling Asphalt Pavement (0.5-1 in. depth)
(i) Micro Milling Asphalt Pavement (1-2 in. depth)
Asphalt mixes for filling depressions and potholes, and for wedging manholes, valve boxes, inlets, temporary tie-ins and other structures will be measured and paid as specified in 106.04.
Asphalt patches will be measured and paid for as specified in 505.04.