May 24, 2006
432—Mill Asphaltic Concrete Pavement
Section 432 and add the following:
432—Mill Asphaltic Concrete Pavement (Micro-Mill)
432.1 General Description
includes micro-milling of existing asphaltic concrete
pavement to remove wheel ruts and other surface irregularities,
restore proper grade and/or transverse slope of pavement
as indicated in the Plans or as instructed by the Engineer.
The planed surface shall provide a texture suitable for
use as a temporary riding surface or an immediate overlay
with OGFC or PEM with no further treatment or overlays.
The use of the micro-milled pavement as a temporary riding
surface shall be for a maximum of seven days. Perform
the work according to these Specifications and Plan details.
power-driven, self-propelled micro-milling equipment that
is the size and shape that allows traffic to pass safely
through areas adjacent to the work. Also, use equipment
Equipped with a cutting mandrel
with carbide tipped cutting teeth designed for micro-milling
bituminous pavement to close tolerances.
Equipped with grade and slope
controls operating from a stringline or ski and based
on mechanical or sonic operation
Capable of removing pavement
to an accuracy of 1/16 in (1.6 mm)
Furnished with a lighting
system for night work, as necessary
Provided with conveyors capable
of side, rear, or front loading to transfer the milled material
from the roadway to a truck
the Plans to micro-mill the designated areas and depths
including bridge decks, shoulders, and ramps, as required.
Ensure the following requirements are met:
Prior to commencement of
the work, construct a test section that is 1000 feet in
length with a uniformly textured surface and cross section
as approved by the Engineer.
The final pavement surface
shall have a transverse pattern of 0.2 in. (5 mm) center
to center of each strike area. The difference between
the ridge and valley of the mat surface shall not exceed
1/16 in. (1.6 mm).
Surface acceptance testing
will be performed using the Laser Road Profiler in accordance
with GDT-126. The
measured indices must meet a target of 825 mm/km in the
If any of these requirements
are exceeded in the test section, work shall be halted
and the contractor shall submit a written plan of action
detailing what steps will be taken to improve operations.
If approved by the Engineer, the contractor will construct
another 1000 ft test section. This test section shall
be located in a different area than the initial section
using the approved corrective action. This designated
section shall be micro-milled to conform to the same requirements
as those required in the initial test section. The contractor
shall not be allowed to start continual micro-milling
until an acceptable test section is obtained.
Micro-milling methods that
will produce a uniform finished surface and maintain a
constant cross slope between extremities in each lane.
Provide positive drainage
to prevent water accumulation on the micro-milled pavement,
as shown on the Plans or directed by the Engineer.
Bevel back the longitudinal
vertical edges greater than 2 in (50 mm) that are
produced by the removal process and left exposed to traffic.
Bevel them back at least 3 in for each 2 in (75 mm for
each 50 mm) of material removed. Use an attached mold
board or other approved method.
When removing material at
ramp areas and ends of milled sections, taper the transverse
edges 10 ft (3 m) to avoid creating a traffic hazard and
to produce a smooth surface.
Protect with a temporary asphaltic concrete tie-in (paper
joint) vertical edges at other areas such as bridge approach
structures, and utility apputenance greater than 1/2 in
that are left open to transversing vehicles. Place
the temporary tie-in at taper rate of at least 6 to 1
horizontal to vertical distance.
Remove dust, residue, and loose milled material from the
micro-milled surface. Do not allow traffic on the milled
surface and do not place asphaltic
concrete on the milled surface until removal is complete.
the micro-milling operation produces a uniform pavement
texture that is true to line, grade, and cross section.
pavement surface acceptance testing will be performed
using the Laser Road Profiler method in GDT 126. Micro-milled
pavement will be evaluated on individual test sections,
normally 0.50 mile (0.50km) long. Indices must target
825 mm/km and not exceed the correction index of 900 mm/km.
pavement surfaces are subject to visual and straightedge
inspections. Keep a 10 ft. straightedge near the micro-milling
operation to measure surface irregularities of the milled
pavement surface. Any areas exceeding 1/8 in (3.2 mm)
between the ridge and valley of the mat surface or fail
to meet pavement surface acceptance testing using The
Laser road Profiler shall require that the underlying
layer be removed and replace with material as directed
by the Engineer at no additional cost to the Department.
All corrective work shall be preformed in a minimum 1000
the cross slope is uniform and that no depressions or
slope misalignments greater than 1/4 in per 12 ft (6 mm
in 3.6 m) exist when the slope is tested with a straightedge
placed perpendicular to the center line.
existing asphaltic concrete pavement is measured by the
square yard (meter) as described in Subsection
109.01, “Measurement and
asphaltic concrete pavement, measured as specified, will
be paid for at the Contract Unit Price bid per square
yard (meter). No adjustment in the unit price for
this item or other items will be considered for variations
in the amount of RAP actually recovered.
is full compensation for furnishing equipment, micro-milling,
hauling, stockpiling milled material, and satisfactorily
performing the work.
reclaimed asphaltic pavement becomes the Contractor’s
property unless otherwise specified.
will be made under:
asphaltic concrete pavement, ___ in (mm) depth
square yard (meter)