TH55_ConstrNotes_ RFP-_9-30-11_ notes

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TH55_ConstrNotes_ RFP-_9-30-11_ notes Powered By Docstoc

Top of grading subgrade and grading grade, is defined as the bottom of the aggregate base.

Suitable Grading Materials shall consist of all soils encountered except topsoil, debris,
organic material, silt, silt loam and other unstable material.

Compaction Subcut is defined as suitable grading material excavated in a subgrade and
reused in the subgrade as directed by the engineer to achieve a uniform material layer in the
roadbed. when the soils are so varied that selection and placement of uniform soils is not
practical, the contractor shall use disks, plows, graders or other equipment to blend and mix
suitable soils to produce a uniform soil texture, moisture content, and density. All compaction
subcuts will be capped with a Type V Geotextile fabric (Spec.3733).

Strip all inplace topsoil and slope dressing in areas to be disturbed by construction and reuse
as slope dressing.

All disturbed roadway materials such as concrete, bituminous, and aggregates may be utilized
according to Mn/DOT specifications and project special provisions. Materials not utilized on
this project will become the property of the contractor and disposed of off the right of way in
accordance with Mn/DOT Specification 2104.3C3 and as agreed upon by the Engineer.

Provide a sawcut where placing new pavement next to existing pavement to ensure a uniform
joint. Locate all longitudinal sawcuts along proposed lane lines, all transverse sawcuts
perpendicular to proposed lane lines and tack the edge prior to paving.

In the proposed construction, the contractor should strive to substantially match the soils and
layers inplace in the upper 4’ of the roadways. Granular backfill shall not be permitted
adjacent to inplace non-granular (frost susceptible) soils in order to prevent an abrupt soils
differential. Provide a 1(V):2(H) transverse transition taper between the changes in material to
prevent an abrupt soils differential, where widening adjacent to non-granular (frost
susceptible) existing soils.

“insert grading taper detail here”

In any case where granular embankments or backfill join non-granular soil embankments or
backfill, provide a 1(V):20(H) longitudinal transition taper between the changes in material to
prevent an abrupt soils differential. The 1(V):20(H) taper shall be constructed so that the
granular backfill material overlays the adjacent non-granular soil backfill.

As a precautionary measure from a soils standpoint, traffic lanes to be used during
construction must be delineated to keep vehicles a safe distance away from the adjacent
excavation. The delineation should coincide with points established by projecting 1(V):2(H)
or greater (flatter) slope between the edge of the traffic surface and the bottom of the

Obtain compaction on the Grading portion of construction in accordance with the “Specified
Density Compaction Method” requirements.

Obtain compaction on 4 inch or greater Aggregate Base lifts in accordance with the
“Modified Penetration Index Method” requirements. The tests shall be performed in
accordance with MnDOT Spec. 2211.3C3. This would include any areas where crushed
concrete or salvaged asphalt may be used for Aggregate Base. For lifts of less than 4 inches
obtain compaction in accordance with Quality Compaction Method (MnDOT Spec.

Test rolling shall not be required.

For the Aggregate Shouldering Class 2, obtain compaction in accordance with “Quality
Compaction Method”.

The contractor may substitute, at no cost to Mn/DOT, the Aggregate Shouldering Class 2 with
Aggregate Shouldering Class 1 Mod. The Aggregate Shouldering Class 1 Mod. shall be
modified to contain 40%-60% (by weight) salvaged bituminous or concrete aggregate. The
crushed concrete and/or bituminous shall be blended into a homogeneous composite mixture.
The gradation of the composite mixture shall meet the gradation requirements of the Class 2
aggregate, Mn/DOT Spec. 3138.

Where matching the bituminous overlay at access locations, transition zones, at roadway
crossings, and at the ends of construction, mill a notch at least 1.5 inch deep to allow for
placement of the wearing course at the ends of transitions.

The Contractor is hereby reminded of his responsibility under State Law to contact all
Utilities that may have facilities in the area. Contact must be made through Gopher State


Any existing subcut drains disturb by construction shall be replaced or extended in
accordance with Standard Plan 5-297.430 (SUBSURFACE DRAIN, SUBCUT DRAIN

Existing Subcut Drains
Stationing                       Outlet
702-703                          702+00 Left
747-748                          Unknown Left and Right
755-756                          Unknown Left and Right
775-776                          775+42 Left and Right
1120-1121                        1121+32 Left and Right


After milling the pavement to the required depth and prior to overlaying, air blast any
deteriorated cracks and joints to remove loose or deteriorated bituminous surfacing. The air
blasting shall be done with high-pressure (100+ psi) equipment. Removal of areas that the
milling machine was not able to get to, may require the use of a small milling machine or
hand work, in addition to high pressure air blasting at some locations as directed by the
Engineer. Payment for this work shall be made under Specification 2232.501.

Depressions resulting after air blasting, sweeping or milling operations, which are greater than
2” in depth and 4” in width and joints and cracks that are greater than 1.5” in depth and width,
shall be patched with Bituminous Patching Mixture as directed by the Engineer. Patching of
these areas shall be done ahead of the paving operation and compacted with a small vibratory
or pneumatic roller. Depressions of lesser dimensions shall be filled with the Wear Course
Mixture. Payment for this work shall be made under Specification 2231.

The Contractor shall provide outlet trenches and take measures necessary, as directed by the
Engineer, to allow surface drainage of the milled surface. Payment for milling and patching
the outlet trenches shall be made under Specification 2231.

The bituminous mixtures shall meet the most current Spec. 2360 requirements.

For this project, use the current version of Bituminous Tack Coat Specification 2357, revised
January 10, 2008.

Bituminous Pavement Smoothness requirements will be evaluated by IRI Equation HMA-A
(3 lifts) as specified in S-2399 (PAVEMENT SURFACE SMOOTHNESS) Table 2399-4 of
the Special Provisions.

Item 2331.608 Joint Adhesive shall be used between concrete/bituminous and
bituminous/bituminous interfaces: driving lanes, shoulder, and gutter paving joints. If
echelon paving is utilized, the joint adhesive shall be omitted in those locations.


Transverse joints shall be spaced every 15 feet and be non-skewed. The Contractor shall use
dowels within the joints, and these shall consist of 1.25 inch diameter epoxy coated steel and
spaced 12 inches apart. Seal all transverse joints with hot pour joint sealant according to
Standard Specification 3725.

Longitudinal joints for concrete pavement shall be L1TH in accordance with Mn/DOT
Standard Plan Sheet 5-297.221, tie bars shall consist of #13 bars and joints sealed with hot
pour joint sealant according to Standard Specification 3725.

Provide for removal by cold milling of 5.5 inches of bituminous pavement from driving lanes
of the roadway. After milling, patch as necessary, and overlay milled mainline with 7.0 inches
of concrete 27 feet wide.

Four inches of structurally sound bituminous pavement is factored into the mainline
whitetopping design. If any of the following conditions exist on proposed mainline, then 4” of
bituminous will be constructed as a base course.
-If the depth of existing bituminous is less than 4 inches
-If the condition of the remaining upper 4 inches of bituminous is less than structurally sound.
-If constructing mainline in the widening sections (the 4 inches of bituminous pavement will
be constructed over Class 6 aggregate base to the existing adjacent grading grade or bottom of
pavement, whichever is greater).
Supplimental reinforcement will be required in mainline widening taper areas in accordance
with Standard Plate number 1070M.

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