- 347 - SECTION 510 -- COLD MILLING
510.01 Description
1.Cold milling shall consist of removing and disposing existing surfacing material as shown in the contract. Cold milling is divided into the following classes and types:
2.Bituminous Surfaces:
a.Cold Milling, Class 1. The surface shall be milled to remove surface irregularities, including longitudinal wheel ruts. When milling is finished, there shall be no evidence of longitudinal wheel ruts. Milling to a specified transverse slope will not be re quired. Milling will include inlays to meet fixed elevations.
b.Cold Milling, Class 2. The surface shall be milled to remove surface irregularities and to attain the transverse slope shown in the contract. Milling will include inlays to meet fixed elevations.
c.Cold Milling, Class 3. The surface shall be milled to a uniform depth shown in the contract. Milling to a specified transverse slope will be required if shown in the contract. M illing will include inlays to meet fixed elevations.
d.Cold Milling, Class 4. The entire depth of existing surfacing shall be milled to the underlying base or subgrade. Approximately 1 inch (25 mm) of existing surfacing ma y be left in place to serve as a working platform. Milling will include inlays to meet fixed elevations.
e.Cold Milling, Class 5. Irregular sections of surfacing shall be milled as shown in the contract. Milling will include inlays to meet fixed elevations.
3.Concrete Surfaces: a. Milling Concrete Curb. Concrete curbs shall be milled to a uniform depth shown in the contract.
b.Milling Concrete for Inlays. Concrete surfaces shall be milled to create an area to place an inlay.
c.Concrete Surface Milling. The concrete surface shall be milled as shown in the contract.
510.02 Material Requirements
1.Milled material shall be pulverized to pass a 2 inch (50 mm) sieve.
2.The Contractor shall not includ e any underlying material in the millings.
510.03 Equipment
1.The milling machine shall be able to perform this work to the Engineer's satisfaction. The milling mach ine shall be self-propelled and shall have sufficient power, traction, and stability to maintain an accurate depth of cut and transverse slope. Pavement removal by scarifying, blading, or heating will not be allowed as milling.
2.a. The milling machine shall be equipped with automatic controls capable of establishing profile line and grade at each edge of the machine. The reference shall be the existing pavement or taut reference lines, true to
510.03 Cold Milling
- 348 - line and grade, erected and maintained by the Contractor. A single reference may be used if the machine can maintain the designated transverse slope.
b.When referenced from existing pavement, the milling machine shall be controlled by a self-containe d grade reference system provided by the machine's manufacturer for that purpo se. The sensing point shall react to compensate for 25% of the actual change in elevation due to a hump or dip that is 3 feet (900 mm) or less in le ngth. The self-contained grade reference system shall be used at or near the centerline of the roadway. On the adjacent pass with the milling machine, a joint matching shoe may be used.
3.Broken, missing, or worn teeth shall be replaced. 4. The machine shall be equipped with a loading elevator to remove the milled material from the roadway surface.
5.The machine shall be equipped with means to effectively control dust generated by the cutting operation.
510.04 Construction Methods
1.a. When the milled surface is open to traffic, vertical cuts resulting in an elevation differential of greater than 2 inches (50 mm) along a gutter line or shoulder line shall be protected by temporary barricades and warning signs erected by the Contractor in accordance with the requirements of Section 422.
b.When milling removes pavement markings, the Contractor must place temporary pavement marking before opening the road for public use.
2.If the milled surface is to be ope n to traffic for more than 30 days, the texture produced by the cold milling operation shall be uniform and provide a satisfactory riding surface and skid resistance. Continuous longitudinal striations will not be allowed.
3.a. When milling is done under traffic maintained conditions, the Contractor shall uniformly mill the entir e lane width with one machine or a combination of milling machines in tandem.
b.The Contractor shall not leav e a milled vertical edge greater than 1 inch tall between lanes overnight. One of the following options shall be performed if the milling will result in a vertical grade separation greater than 1 inch (25 mm) between lanes:
1.Milling shall be performed in all adjacent traffic lanes on the same day so that at the end of each day, no drop off of over 1 inch (25 mm) remains.
2.The milling shall create a tapered edge between the traffic lanes. The tapered edge shall have a slope from 3 [H]: 1 [V] to 4 [H]: 1 [V], not measured more than one foot in width nor extend into the lane more than one foot. Temporary pavement markin g shall be placed at the top and contiguous with the tapered edge.
c.If the Contractor fails to complete the above options, the Contractor shall provide – at no cost to the Depart ment – additional traffic control necessary to maintain traffic on the milled lane (or lanes) as directed by the Engineer. This additional traffic control may require the use of a pilot car, flaggers, lighted fl agger station, etc. Cold Milling 510.05 - 349 - d. Transitions between milled and unmilled surfaces in the direction of travel will be feathered either by milling or with wedges of bituminous material (maximum slope 1 vertical to 12 horizontal).
4.Surfacing material that cannot be removed by cold milling equipment because of physical or geom etric constraints shall be removed by other methods approved by the Engineer.
5.The milled surface shall be swept with a mechanical broom before traffic is placed on it.
6.For Cold Milling, Class 4, approximately 1 inch (25 mm) of existing surfacing may be left in place to serve as a working platform. Bituminous surfacing left on the roadway as a working platform shall be disposed of in the subsequent operations at no ad ditional cost to the Department.
7.The Contractor shall mill curbs in accordance with the contract.
8.a. The Contractor shall stockpile salvaged material for the Department at the locations shown in the contract.
9.a. All milling shall be done in such a manner to prevent ponding of water.
b.When the surfaced shoul ders are not milled, drainage channels in the shoulders shall be cut by milling or by any other method approved by the Engineer. The width shall be 1.5 feet (450 mm) minimum, and the depth shall be the same as the m illing depth with sufficient spacing and slope to provide proper drainage.
c.Drainage channels shall be repaired by patching with asphaltic concrete of the type in the adjacent surfacing. This work shall be done before the outside surfaced shoulders are fog sealed or surfaced.
d.Earth shoulders must be cut to an elevation that will allow drainage.
10.Concrete or asphalt millings from inlays will not be salvaged but shall be disposed of in accordance with the removal requirements of Section 203.
510.05 Method of Measurement
1.The contract will indicate whether the milling will be measured for payment by the ton (Mg), station, or square yards (m2) of completed and accepted work.
a.Roadways that are measured by the station [100 feet (100 m)] shall be measured horizontally along the project centerline between the beginning and ending points of the work.
1.Areas outside the typical cross section shown in the contract will be measured in equivalent stations based on one station's area for the immediately adjacent roadway.
2.If there is a length of the roadway where the entire roadway width is not milled, the length of that portion of the roadway shall be deducted from the payment stations.
b.Each shoulder will be me asured separately in stations of 100 feet (meters) without regard to width.
510.05 Cold Milling
- 350 - (1) Stations will be measur ed horizontally along the project centerline between the beginning and ending points.
2.Areas where there is no shoulder for 100 feet (30 m) or more shall be deducted from the total measured length of shoulder. Small [less than 100 feet (30 m)] intersections shall not be deducted from the shoulder station measurements.
c.Roadways that are measured by the square yard (square meter) shall be measured to ± 1 SY (+1 m2).
1.Areas outside the typical cross section shown in the contract will also be measured to ± 1 SY (1 m2).
2.Deductions will be made for all areas greater than 1 SY (1m2) that are not milled.
d.Only "Cold Milling Class 4" is measured by the ton (Megagram). The amount of Class 4 millings shall be weighed on approved scales if the contract indicates pa yment is by the ton (Megagram).
2.Measurement of temporary tra ffic control devices will be made in accordance with Section 422.
3.Milling concrete or asphaltic concrete for inlays will be measured for payment by the each.
4.Milling concrete curb is measured in linear feet (meter) along the back face of the curb.
5.Milling of areas patched prior to cold milling, will not be measured separately, regardless of material used for patching, but will be included in the measurement for t he Cold Milling item.
510.06 Basis of Payment
1.P a y I t e m P a y U n i t Cold Milling, Class _____ Station (Sta) [ S t a t i o n ( S t a M ) ] Cold Milling, Class _____ Square Yard (SY) [Square Meter (m2)] Concrete Surface Milling Station (Sta) [ S t a t i o n ( S t a M ) ] Concrete Surface Milling Square Yard (SY) [Square Meter (m2)] Milling Concrete Curb Linear Foot (LF) [Meter (m)] Milling Concrete for Inlays Each (ea) Cold Milling, Class 4 Ton (Tn) [Megagram (Mg)] 2. Payment for temporary traffic control devices will be made in accordance with Section 422. Cold Milling 510.06 - 351 - 3. Asphaltic concrete for patching the drainage channels will be measured and paid for as "Asphaltic Concrete, Type _____" and "Performance Graded Binder, Type _____" as described in Section 503. Construction and patching of the draina ge channels is subsidiary to these bid items.
4.Payment is full compensation for all work described in this Section. - 352 - SECTION 511 -- SALVAGING AND STOCKPILING BITUMINOUS MATERIAL
511.01 Description
1.This work will consist of salv aging, hauling, and stockpiling existing bituminous surfacing for the Department to locations shown in the contract.
2.The bituminous surface shall be removed by cold milling. If the road is closed to all but local traffic, the Contractor may use other approved methods, except heating, to remove and pulverize the bituminous material.
511.02 Material Requirements
1.The salvaged material shall be pu lverized until all of the material will pass a 2 inch (50 mm) sieve. The Contractor shall avoid including any of the underlying material with the salvaged bituminous surfacing material.
511.03 Equipment
Cold milling equipment shall c onform to the requirements of Subsection 510.03.
511.04 Construction Methods
1.Cold milling shall be performed in accordance with Section 510.
2.a. The Engineer will locate each stockpile. b. The Contractor shall prepare stockpile sites by removing all vegetation on the portion of the site on which the material will actually be placed. The stockpile area shall be graded so that water will drain away from the stockpiled material. Unsurfaced areas upon which material is stockpiled shall be smoothed and rolled so that the salvaged material may later be removed with a minimum of loss.
c.The maximum height of stockp iles is 10 feet (3 m). Equipment shall not be driven over the stockpiled material.
511.05 Method of Measurement
1.The work of salvaging and stockpiling bituminous material will be measured for payment by the ton (Meg agram) of material placed into stockpile sites.
511.06 Basis of Payment
1.P a y I t e m P a y U n i t Salvaging and Stockpiling Bituminous Material Ton (Tn) [Megagram (Mg)]
2.Cold milling will be paid for under Section 510.
3.Payment is full compensation for all work described in this Section.
Source: Nebraska Standard Specifications for Highway Construction, 2017 Edition. Pages 381–385 of 1,048.