Standard Specifications for Road, Bridge, and Municipal Construction 2020 (M 41-10)

Bituminous Surfacing on Structure Decks

6-08

6-08.3(2) Contractor Survey for Grade Controlled Structure Decks

Prior to removing existing Bituminous Pavement from a Grade Controlled Structure Deck,
the Contractor shall complete a survey of the existing surface for use in establishing
the existing cross section and grade profile elevations. When removal of Bituminous
Pavement is to be achieved by rotary milling/planing, the Contractor’s survey shall also
include the depths of the existing surfacing at each survey point.

The Contractor is responsible for all calculations, surveying, installation of control points,
and measuring required for setting, maintaining and resetting equipment and materials
necessary for the construction of the overlay to the Final Grade Profile.

6-08.3(2)A

Survey Requirements

The Contractor shall establish at least two primary survey control points for controlling
actual Bituminous Pavement removal depth and the Final Grade Profile. Horizontal
control shall be by station and offset which shall be tied to either the Roadway centerline
or the Structure centerline. Vertical control may be an assumed datum established by the
Contractor.

Primary control points shall be described by station or milepost and offset on the baseline
selected by the Contractor. The Contractor may expand the survey control information to
include secondary horizontal and vertical control points as needed for the project.

Survey information collected shall include station or milepost, offset, and elevation for
each lane line and curb line. Survey information shall be collected at even 20 foot station
intervals, and along the centerline of each bridge expansion joint. The survey shall extend
300’-0” beyond the bridge back of pavement seat or end of Structure Deck. The survey
information shall include the top of Bituminous Pavement elevation and, when rotary
milling/planing equipment is used, the corresponding depth of Bituminous Pavement
to the Structure Deck. The Contractor shall ensure a surveying accuracy to within ±
0.01 feet for vertical control and ± 0.2 feet for horizontal control.

Voids in HMA created by the Contractor’s Bituminous Pavement depth measurements
shall be filled by material conforming to

Section 9-20

or another material acceptable to

the Engineer.

6-08.3(2)B

Survey Submittal

The Contractor’s survey records shall include descriptions of all survey control points
including station/milepost, offset, and elevations of all secondary control points. The
Contractor shall maintain survey records of sufficient detail to allow the survey to be
reproduced. The Contractor shall submit a Type 2 Working Drawing consisting of the
compiled survey records and information. Survey data shall be submitted as an electronic
file in Microsoft Excel format.

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Bituminous Surfacing on Structure Decks

6-08.3(2)C

Final Grade Profile and Adjusted Removal Depth

Based on the results of the survey, the Engineer may develop a Final Grade Profile and
Adjusted Removal Depth. If they are developed, the Final Grade Profile and Adjusted
Removal Depth will be provided to the Contractor within three working days after
receiving the Contractor’s survey information. When provided, the Adjusted Removal
Depth supersedes the Design Removal Depth to become the Bituminous Pavement
removal depth for that Structure Deck.

6-08.3(3) General Bituminous Pavement Removal Requirements

Contractor shall remove Bituminous Pavement and associated deck repair material from
Structure Decks to the horizontal limits shown in the Plans and to either the specified or
adjusted Bituminous Pavement removal depth as applicable.

Removal of Bituminous Pavement within 12-inches of existing permanent features that
limit the reach of the machine or the edge of the following items shall be by hand or by
hand operated (nominal 30-pounds class) power tools: existing bridge expansion joint
headers; steel expansion joint assemblies; concrete butt joints between back of pavement
seats and bridge approach slabs, bridge drain assemblies; thrie beam post steel anchorage
assemblies fastened to the side or top of the Structure Deck.

When removing Bituminous Pavement with a planer,

Section 5-04.3(14)

shall apply. If the

planer contacts the Structure Deck in excess of the specified planing depth tolerance, or
contacts steel reinforcing bars at any time, the Contractor shall immediately cease planing
operations and notify the Engineer. Planing operations shall not resume until completion
of the appropriate adjustments to the planing machine and receiving the Engineer’s
concurrence to resume.

6-08.3(4) Partial Depth Removal of Bituminous Pavement from Structure Decks

The depth of surfacing removal, as measured to the bottom of the lowest milling groove
generated by the rotary milling/planing machine shall be +0.01, -0.02-feet of the specified
or Adjusted Removal Depth as applicable.

6-08.3(5) Full Depth Removal of Bituminous Pavement from Structure Decks

6-08.3(5)A

Method of Removal

The Contractor shall perform full depth removal by a method that does not damage or
remove the Structure Deck in excess of the specified Bituminous Pavement removal
tolerance. The Contractor shall submit a Type 2 Working Drawing consisting of the
proposed methods and equipment to be used for full depth removal.

6-08.3(5)B

Planer Requirements for Full Depth Removal

The final planed surface shall have a finished surface with a tolerance of +0.01, -0.02
feet within the planed surface profile, as measured from a 10-foot straight edge. Multiple
passes of planing to achieve smoothness will not be allowed.

Bituminous Surfacing on Structure Decks

6-08

In addition to

Section 6-08.3(3)

, the planing equipment shall conform to the following

additional requirements:
1. The cutting tooth spacing on the rotary milling head shall be less than or equal to

¼ inch.

2. The rotary milling/planing machine shall have cutting teeth that leave a uniform

plane surface at all times. All teeth on the mill head shall be kept at a maximum

differential tolerance of ⅜-inch between the shortest and longest tooth, as measured

by a straight edge placed the full width of the rotary milling head.

3. Cutting tips shall be replaced when 30 percent of the total length of the cutting tip

material remains.

Prior to each day’s Bituminous Pavement removal operations, the Contractor shall confirm
to the satisfaction of the Engineer that the rotary head cutting teeth are within the
specified tolerances.

6-08.3(5)C

Structure Deck Cleanup after Bituminous Pavement Removal

Waterproofing membrane that is loose or otherwise not firmly bonded to the Structure
Deck shall be removed as an incidental component of the Work of surfacing removal.
Existing waterproofing membrane bonded to the Structure Deck need not be removed.

6-08.3(6) Repair of Damage due to Bituminous Pavement Removal Operations

All concrete bridge deck, pavement seat, and steel reinforcing bar damage due to
the Contractor’s surfacing removal operations shall be repaired by the Contractor in
accordance with

Section 1-07.13

, and as specified below.

Damaged concrete in excess of the specified Bituminous Pavement removal tolerance
shall be repaired in accordance with

Section 6-08.3(7)

, with the bridge deck repair

material placed to the level of the surrounding bridge deck and parallel to the final grade
paving profile.

Damaged steel reinforcing bar shall be repaired as follows:
1. Damage to steel reinforcing bar resulting in a section loss less than 20-percent of

the bar with no damage to the surrounding concrete shall be left in place and shall
be repaired by removing the concrete to a depth ¾-inches around the top steel
reinforcing bar and placing bridge deck repair material accepted by the Engineer to
the level of the bridge deck and parallel to the final grade paving profile.

2. Damage to steel reinforcing bar resulting in a section loss of 20-percent or more in

one location, bars partially or completely removed from the bridge deck, or where
there is a lack of bond to the concrete, shall be repaired by removing the adjacent
concrete and splicing a new bar of the same size. Concrete shall be removed to
provide a ¾-inch minimum clearance around the bars. The splice bars shall extend a
minimum of 40 bar diameters beyond each end of the damage.

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Bituminous Surfacing on Structure Decks

6-08.3(7) Concrete Deck Repair

This Work consists of repairing the concrete deck after Bituminous Pavement has been
removed.

6-08.3(7)A

Concrete Deck Preparation

The Contractor, with the Engineer, shall inspect the exposed concrete deck to establish
the extent of bridge deck repair in accordance with

Section 6-09.3(6)

. Areas of Structure

Deck left with existing well bonded waterproof membrane after full depth Bituminous
Pavement removal are exempt from this inspection requirement.

All loose and unsound concrete within the repair area shall be removed with jackhammers
no heavier than the nominal 30 pound class or chipping hammers no heavier than the
nominal 15 pound class, or other mechanical means acceptable to the Engineer, and
operated at angles less than 45 degrees as measured from the surface of the deck to the
tool. If unsound concrete exists around the existing steel reinforcing bars, or if the bond
between concrete and steel reinforcing bar is broken, the Contractor shall remove the
concrete to provide a ¾ inch minimum clearance to the bar. The Contractor shall take care
to prevent damage to the existing steel reinforcing bars and concrete to remain.

After removing sufficient concrete to establish the limits of the repair area, the Contractor
shall make ¾ inch deep vertical saw cuts and maintain square edges at the boundaries of
the repair area. The exposed steel reinforcing bars and concrete in the repair area shall be
abrasive blasted and blown clean just prior to placing the bridge deck repair material.

6-08.3(7)B

Ultra-Low Viscosity, Two-Part Liquid, Polyurethane-Hybrid

Polymer Concrete

The ultra-low viscosity, two-part liquid, polyurethane-hybrid polymer concrete shall be
mixed in accordance with the manufacturer’s recommendations.

Aggregate shall conform to the gradation limit requirements recommended by the
manufacturer. The aggregate and the ultra-low viscosity, two-part liquid, polyurethane-
hybrid polymer concrete shall be applied to the repair areas in accordance with the
sequence and procedure recommended by the manufacturer.

All repairs shall be float finished flush with the surrounding surface within a tolerance of

⅛ inch of a straight edge placed across the full width and breadth of the repair area.

6-08.3(7)C

Pre-Packaged Cement Based Repair Mortar

The Contractor shall mix the pre-packaged cement based repair mortar using equipment,
materials and proportions, batch sizes, and process as recommended by the manufacturer.

All repairs shall be float finished flush with the surrounding surface within a tolerance of

⅛ inch of a straight edge placed across the full width and breadth of the repair area.

Bituminous Surfacing on Structure Decks

6-08

6-08.3(7)D Cure

All bridge deck repair areas shall be cured in accordance with the manufacturer’s
recommendations and attain a minimum compressive strength of 2,500 psi before
allowing vehicular and foot traffic on the repair and placing waterproofing membrane on
the bridge deck over the repair.

6-08.3(8) Waterproof Membrane for Structure Decks

This work consists of furnishing and placing a waterproof sheet membrane system over
a prepared Structure Deck prior to placing an HMA overlay. The waterproof membrane
system shall consist of a sheet membrane adhered to the Structure Deck with a primer.

The Contractor shall comply with all membrane manufacturer’s installation
recommendations.

6-08.3(8)A

Structure Deck Preparation

The Structure Deck and ambient air temperatures shall be above 50°F and the Structure
Deck shall be surface-dry at the time of the application of the primer and membrane.

All areas of a Structure Deck that have fresh cast bridge deck concrete less than
28 days old (not including bridge deck repair concrete placed in accordance with

Section 6-08.3(7)

) shall cure for a period of time recommended by the membrane

manufacturer, or as specified by the Engineer, before application of the membrane.

The entire Structure Deck and the sides of the curb and expansion joint headers to
the height of the HMA overlay shall be free of all foreign material such as dirt, grease,
etc. Prior to applying the primer or sheet membrane, all dust and loose material shall
be removed from the Structure Deck. All surface defects such as spalled areas, cracks,
protrusions, holes, sharp edges, ridges, etc., and other surface imperfections greater than
¼ inch in width shall be corrected prior to application of the membrane.

6-08.3(8)B

Applying Primer

The primer shall be applied to the cleaned deck surfaces at the rate according to the
procedure recommended by the membrane manufacturer. All surfaces to be covered by
the membrane shall be thoroughly and uniformly coated with primer. Structure Deck
areas left with existing well bonded waterproof membrane after bituminous surfacing
removal shall receive an application of primer in accordance with the membrane
manufacturer’s recommendations. Precautionary measures shall be taken to ensure that
pools and thick layers of primer are not left on the deck surface. The membrane shall not
be applied until the primer has cured or volatile material has substantially dissipated, in
accordance with the membrane manufacturer’s recommendations.

The primer and waterproof membrane shall extend from the bridge deck up onto the curb
face and expansion joint header face the thickness of the HMA overlay. The membrane
shall adhere to the vertical surface.

Page 6-234

Bituminous Surfacing on Structure Decks

6-08.3(8)C

Placing Waterproof Membrane

Membrane application shall begin at the low point on the deck, and continue in a lapped
shingle pattern. The overlap shall be a minimum of six inches or greater if recommended
by the membrane manufacturer. Membrane seams shall be sealed as recommended by
the membrane manufacturer. Hand rollers or similar tools shall be used on the applied
membrane to assure firm and uniform contact with the primed Structure surfaces.

The fabric shall be neatly cut and contoured at all expansion joints and drains. The cuts
at bridge drains shall be two right angle cuts made to the inside diameter of the bridge
deck drain outlet, after which the corners of the waterproof membrane shall be turned
down into the drains and laid in a coating of primer.

6-08.3(8)D

Membrane Repair and Protection

The waterproof membrane will be visually inspected by the Engineer for uniformity, tears,
punctures, bonding, bubbles, wrinkles, voids and other defects. All such deficiencies shall
be repaired in accordance with the membrane manufacturer’s recommendations prior to
placement of the HMA overlay.

The membrane material shall be protected from damage due to the paving operations
in accordance with the membrane manufacturer’s recommendations. No traffic or
equipment except that required for the actual waterproofing and paving operations will
be permitted to travel or rest on the membrane until it is covered by the HMA overlay.
The use of windrows is not allowed for laydown of HMA on a membrane.

Where waterproofing membrane is placed in stages or applied at different times, a strip
of temporary paper shall be used to protect the membrane overlap from the HMA hand
removal methods.

6-08.3(9) Placing Bituminous Pavement on Structure Decks

HMA overlay shall be applied on Grade Controlled Structure Decks using reference lines
for vertical control in accordance with

Section 5-04.3(3)C

The compacted elevation of the HMA overlay on Structure Decks shall be within
± 0.02 feet of the specified overlay thickness or Final Grade Profile as applicable.
Deviations from the final grade paving profile in excess of the specified tolerance and
areas of non-conforming surface smoothness shall be corrected in accordance with

Section 5-04.3(13)

Final grade Roadway transitions to a Structure Deck with Bituminous Pavement shall not
exceed a 0.20 percent change in grade in accordance with the bridge deck transition for
HMA overlay Standard Plan, unless shown otherwise in the Plans.

Final grade compacted HMA elevations shall be higher than an adjacent concrete edge

by ¼ inch ± ⅛ inch at all expansion joint headers and concrete butt joints as shown in the

concrete to asphalt butt joint details of the bridge paving joint seals Standard Plan. This
also applies to steel edges within the limits of the overlay such as bridge drain frames and
steel joint riser bars at bridge expansion joints.

Bituminous Surfacing on Structure Decks

6-08

6-08.3(9)A

Protection of Structure Attachments and Embedments

The Contractor is responsible for protecting all Structure attachments and embedments
from the application of BST and HMA.

Drainage inlets that are to remain open, and expansion joints, shall be cleaned out
immediately after paving is completed. Materials passing through expansion joints shall be
removed from the bridge within 10 working days.

All costs incurred by the Contractor in protective measures and clean up shall be included
in the unit Contract prices for the associated Bid items of Work.

6-08.3(10) HMA Compaction on Structure Decks

Compaction of HMA on Structure Decks shall be in accordance with

Section 5-04.3(10)

Work rejected in accordance with

Section 5-04.3(11)

shall include the materials, work,

and incidentals to repair an existing waterproof membrane damaged by the removal of the
rejected work.

6-08.3(11) Paved Panel Joint Seals and HMA Sawcut and Seals

Bridge paving joint seals shall be installed in accordance with

Section 5-04.3(12)B

and the

details shown in the Plans and Standard Plans.

When concrete joints are exposed after removal of Bituminous Pavement, the joints shall
be cleaned and sealed in accordance with

Section 5-01.3(8)

and the paved panel joint seal

details of the bridge paving joint seals Standard Plan, including placement of the closed
cell backer rod at the base of the cleaned joint. If waterproofing membrane is required,
the membrane shall be slack or folded at the concrete joint to allow for Structure
movements without stress to the membrane. After placement of the HMA overlay, the
second phase of the paved panel joint seal shall be completed by sawing the HMA and
sealing the sawn joint in accordance with

Section 5-04.3(12)B2

6-08.4 Measurement

Removing existing Bituminous Pavement from Structure Decks will be measured by the
square yard of Structure Deck surface area with removed overlay.

Bridge deck repair will be measured by the square foot surface area of deck
concrete removed with the measurement taken at the plane of the top mat of steel
reinforcing bars.

Waterproof membrane will be measured by the square yard surface area of Structure
Deck and curb and header surface area covered by membrane.

Page 6-236

Bituminous Surfacing on Structure Decks

6-08.5 Payment

Payment will be made for each of the following Bid items that are included in the
Proposal:

“Structure Surveying”, lump sum.
“Removing Existing Overlay From Bridge Deck___”, per square yard.
The unit Contract price per square yard for “Removing Existing Overlay From Bridge
Deck___”, shall be full pay for performing the Work as specified for full removal
of Bituminous Pavement on Structure Decks, including the removal of existing
waterproof membrane and disposing of materials.
“Bridge Deck Repair Br. No.___”, per square foot.
The unit Contract price per square foot for “Bridge Deck Repair Br. No.___” shall be
full pay for performing the Work as specified, including removing and disposing of
the concrete within the repair area and furnishing, placing, finishing, and curing the
repair concrete.
“Waterproof Membrane Br. No.___”, per square yard.
The unit Contract price per square yard for “Waterproof Membrane Br. No.___” shall
be full pay for performing the Work as specified, including repairing any damaged
or defective waterproofing membrane and repair of damaged HMA overlay.

Modified Concrete Overlays

6-09

Modified Concrete Overlays

6-09.1 Description

This Work consists of scarifying concrete bridge decks, preparing and repairing bridge
deck surfaces designated and marked for further deck preparation, and placing, finishing,
and curing modified concrete overlays.

6-09.2 Materials

Materials shall meet the requirements of the following Sections:

Portland Cement

9-01.2(1)

Blended Hydraulic Cement

9-01.2(1)B

Fine Aggregate

Coarse Aggregate

Mortar

Burlap Cloth

Admixtures

Fly Ash

Microsilica Fume

Water

Portland cement shall be either Type I or Type II. Type III portland cement will not be
allowed.

Blended hydraulic cement shall be Type IP(X)MS and shall only be used in modified fly
ash overlay. The required proportions for Type I cement and Type F fly ash shall be in
accordance with Section 6-09.3(3)C. Only Type IP(X)MS that is blended with Type F
fly ash is permitted for use. Type IP(X)MS that is blended with natural pozzolans are
not allowed.

Fine aggregate shall be Class 1. Coarse aggregate shall be AASHTO grading No. 7 or
No. 8.

Fly ash shall be Class F only.

Microsilica admixture shall be either a dry powder or a slurry admixture. Microsilica will be
accepted based on submittal of a Manufacturer’s Certificate of Compliance in accordance
with Section 1-06.3. If the microsilica is a slurry admixture, the microsilica content of the
slurry shall be certified as a percent by mass.

Page 6-238

Modified Concrete Overlays

Latex admixture shall be a non-toxic, film-forming, polymeric emulsion in water to which
all stabilizers have been added at the point of manufacture. The latex admixture shall be
homogeneous and uniform in composition, and shall conform to the following:

Polymer

Type

Styrene

Butadiene

Stabilizers:

Latex

Non-ionic

surfactants

Portland Cement

Polydimethyl siloxane

Percent Solids

46.0 to 49.0

Weight per Gallon

8.4 pounds at 77ºF

Color White PH (as shipped)

9 minimum

Freeze/Thaw Stability

5 cycles (5ºF to 77ºF)

Shelf

Life

years

minimum

Latex admixture will be accepted based on submittal of a Manufacturer’s Certificate of
Compliance in accordance with Section 1-06.3.

High Molecular Weight Methacrylate (HMWM) resin for crack and joint sealing shall
conform to the following:

Viscosity

<25 cps (Brookfield RVT with UL adaptor,

50 rpm at 77°F) … California Test 434

Density

8.5 to 8.8 pounds per gallon at 77°F… ASTM D2849

Flash Point

>200°F, PMCC (Pinsky-Martens CC)

Vapor Pressure

<0.04 inches Hg at 77°F, ASTM D323

Tg (DSC)

>136°F, ASTM D3418

Gel Time

60 minutes minimum

The promoter/initiator system for the methacrylate resin shall consist of a metal drier and
peroxide.

Sand for abrasive finish shall be crushed sand, oven dried, and stored in moisture proof
bags. The sand shall conform to the following gradation:

Sieve Size

Percent Passing

Minimum

Maximum

No. 10

100

No. 16

No. 20

No. 30

No. 50

No. 100

All percentages are by weight.

Modified Concrete Overlays

6-09

6-09.3

Construction Requirements

6-09.3(1) Equipment

6-09.3(1)A

Power Driven Hand Tools

Power driven hand tools may be used for concrete scarification in areas not accessible
to scarification machines, and for further deck preparation Work, and shall meet
the following:
1.  Jack hammers no heavier than the nominal 30-pound class.
2.  Chipping hammers no heavier than the nominal 15-pound class.
3.  Other mechanical means acceptable to the Engineer.

The power driven hand tools shall be operated at angles less than 45 degrees as
measured from the surface of the deck to the tool.

6-09.3(1)B

Rotary Milling Machines

Rotary milling machines used to remove an upper layer of existing concrete overlay,
when present, shall have a maximum operating weight of 50,000 pounds and conform to

Section 6-08.3(5)B

6-09.3(1)C

Hydro-Demolition Machines

Hydro-demolition machines shall consist of filtering and pumping units operating in
conjunction with a remote-controlled robotic device, using high-velocity water jets to
remove sound concrete to the lesser of 2 inches or the nominal scarification depth shown
in the Plans with a single pass of the machine, and with the simultaneous removal of all
deteriorated concrete. If the nominal scarification depth is greater than 2 inches then
the multiple passes shall be required. Rotary heads are required for the final pass of the
hydro-demolition machine. Hydro-demolition machines shall also clean any exposed
reinforcing steel of all rust and corrosion products.

6-09.3(1)D

Vacant

6-09.3(1)E

Air Compressor

Air compressors shall be equipped with oil traps to eliminate oil from being blown onto
the bridge deck.

6-09.3(1)F

Vacuum Machine

Vacuum machines shall be capable of collecting all dust, concrete chips, freestanding
water and other debris encountered while cleaning during deck preparation. The
machines shall be equipped with collection systems that allow the machines to be
operated in air pollution sensitive areas and shall be equipped to not contaminate the
deck during final preparation for concrete placement.

Page 6-240

Modified Concrete Overlays

6-09.3(1)G

Water Spraying System

The water spraying system shall include a portable high-pressure sprayer with a separate
water supply of potable water. The sprayer shall be readily available to all parts of
the deck being overlaid and shall be able to discharge water in a fine mist to prevent
accumulation of free water on the deck. Sufficient water shall be available to thoroughly
soak the deck being overlaid and to keep the deck wet prior to concrete placement.

The Contractor shall certify that the water spraying system meets the following
requirements:

Pressure

2,200 psi minimum

Flow Rate

4.5 gpm minimum

Fan Tip

15° to 25° Range

6-09.3(1)H

Mobile Mixer for Latex Modified Concrete

Proportioning and mixing shall be accomplished in self-contained, self-propelled,
continuous-mixing units conforming to the following requirements:
1. The mixer shall be equipped so that it can be grounded.
2. The mixer shall be equipped to provide positive measurement of the portland

cement being introduced into the mix. A recording meter, visible at all times and
equipped with a ticket printout, shall be used.

3. The mixer shall be equipped to provide positive control of the flow of water and

latex admixture into the mixing chamber. Water flow shall be indicated by a flow
meter with a minimum readability of ½ gallon per minute, accurate to ± 1 percent.
The water system shall have a bypass valve capable of completely diverting the
flow of water. Latex flow shall also be indicated by a flow meter with a minimum
readability of 2 gallons per minute, accurate to ± 1 percent. The latex system shall be
equipped with a bypass valve suitable for obtaining a calibrated sample of admixture.

4. The mixer shall be equipped to be calibrated to automatically proportion and blend

all components of the specified mix on a continuous or intermittent basis as required
by the finishing operation, and shall discharge mixed material through a conventional
chute directly in front of the finishing machine.

Inspection of each mobile mixer shall be done by the Contractor in the presence of the
Engineer and in accordance with the following requirements:
1. Check the manufacturer’s inspection plate or mix setting chart for the serial number,

the proper operating revolutions per minute (rpm), and the approximate number of
counts on the cement meter to deliver 94 pounds of cement.

2. Make a general inspection of the mobile mixer to ensure cleanliness and good

maintenance practices.

3. Check to see that the aggregate bins are empty and clean and that the bin

vibrators work.

Modified Concrete Overlays

6-09

4. Verify that the cement aeration system operates, that the vent is open, and that the

mixer is equipped with a grounding strap. Check the cement meter feeder to ensure
that all fins and pockets are clean and free from accumulated cement. If the operator
cannot demonstrate, through visual inspection, that the cement meter feeder
is clean, all cement shall be removed from the bin and the cement meter feeder
inspected. The aeration system shall be equipped with a gauge or indicator to verify
that the system is operating.

5. Verify that the main belt is clean and free of any accumulated material.
6. Check the latex strainer to ensure cleanliness.

The initial calibration shall consist of the following items:
1. Cement Meter

a. Refer to the truck manufacturer’s mix setting chart to determine the specified

operating rpm and the approximate number of counts required on the cement
meter to deliver 94 pounds of cement.

b.  Place at least 40 bags (about 4,000 pounds) of cement in the cement bin.
c.  Ensure the mixer is resting on a level surface.
d.  Ensure the mixer is grounded.
e.  Adjust the engine throttle to obtain the specified rpm. Operate the unit,

discharging cement until the belt has made one complete revolution. Stop the
belt. Reset the cement meter to zero. Position a suitable container to catch the
cement and discharge approximately one bag of cement. With a stopwatch,
measure the time required to discharge the cement. Record the number of
counts on the cement meter and determine the weight of the cement in the
container. Repeat the process of discharging approximately one bag of cement
until six runs have been made. Reset the cement meter to zero for each run.

Example:

Run No. Cement Counts

Weight of

Cement

Time In

Seconds

31.2

95.5

31.0

29.8

95.25

30.5

30.8

TOTAL

400

571.75

184.3

Pounds of cement per count on cement meter:

Weight of Cement

No. of Counts

= 571.75

400 = 1.43 LB./Count

Page 6-242

Modified Concrete Overlays

Counts per bag (94 pounds):

1.43 = 65.7 Counts Bag

Pounds of cement discharged per second:

Weight of Cement

Time in Seconds =

571.75

184.3 = 3.10 LB./SEC.

Required time to discharge one bag:

Time =

3.10 = 30.32 SEC./Bag

2. Latex Throttling Valve

a. Check to be sure that the latex strainer is unobstructed.
b. The latex throttling valve shall be adjusted to deliver 3.5 gallons of latex (29.4

pounds) for each bag of cement. From the above calculation 30.32 seconds are
required to deliver one bag of cement.

c. With the unit operating at the specified rpm, discharge latex into a container

for 30.3 seconds and determine the weight of latex. Continue adjusting the
valve until 29.4 to 29.5 pounds of latex is discharged in 30.3 seconds. Verify the
accuracy of this valve setting three times.

3. Water Flow Meter

a. Set the water flow meter by adjusting it to flow at ½ gallon per minute.
b. Collect and weigh the water discharged during a 1-minute interval with the

equipment operating at the specified rpm. Divide the weight of water by 8.34
to determine the number of gallons.

c. Repeat items a. and b., above, with the flow meter adjusted to 1½ gallons per

minute.

4. Aggregate Bin Gates

a. Set the gate openings to provide the amount of aggregate required to produce

concrete having the specified proportions.

b. Discharge a representative sample of the aggregates through the gates and

separate on the No. 4 sieve. Aggregates shall meet the requirements for
proportions in accordance with

Section 6-09.3(3)E

c. Adjust the gate openings if necessary to provide the proper ratio of fine

aggregate to total aggregate.

5. Production of Trial Mix – Each mobile mixer shall be operated to produce at least ½

cubic yard of concrete, which shall be in compliance with these Specifications, prior
to acceptance of the mobile mixer for job use. The Engineer will perform yield, slump,
and air tests on the concrete produced by each mixer. Calibration of each mobile
mixer shall be done by the Contractor in the presence of the Engineer. A complete
calibration is required on each mixer on each concrete placement unless, after the

Modified Concrete Overlays

6-09

initial calibration, the personnel having the responsibility of mixer calibration on
subsequent concrete placement were present during the initial calibration of the
mixer and during the concrete placement operations and are able to verify the dial
settings of the initial calibration and concrete placement.

If these criteria are met, a complete calibration need not be repeated provided that a
single trial run verifies the previous settings of the cement meter, latex throttling valve,
water flow meter, and aggregate gradations, and that the mixer has not left the project
and the Engineer is satisfied that a complete calibration is not needed.

6-09.3(1)I

Ready-Mix Trucks

and Batch Plants

for

Concrete Class M,

Fly Ash

Modified and Microsilica Modified Concrete

Ready-mix trucks and batch plants shall conform to

Section 6-02.3(4)A

6-09.3(1)J

Finishing Machine

The finishing machine shall meet the requirements of

Section 6-02.3(10)

and the

following requirements:

The finishing machine shall be equipped with augers, followed by an oscillating, vibrating
screed, vibrating roller tamper, or a vibrating pan, followed by a rotating cylindrical double
drum screed. The vibrating screed, roller tamper or pan shall be of sufficient length and
width to properly consolidate the mixture. The vibrating frequency of the vibrating screed,
roller tamper or pan shall be variable with positive control.

6-09.3(2) Submittals

The Contractor shall submit the following Working Drawings in accordance with

Section 1-05.3

1. A Type 1 Working Drawing consisting of catalog cuts and operating parameters of

the hydro-demolition machine selected by the Contractor for use in this project to
scarify concrete surfaces.

2. A Type 1 Working Drawing consisting of catalog cuts, operating parameters, axle

loads, and axle spacing of the rotary milling machine (if used to remove an upper
layer of existing concrete overlay when present).

3. A Type 2 Working Drawing of the Runoff Water Disposal Plan. The Runoff Water

Disposal Plan shall describe all provisions for the containment, collection, filtering,
and disposal of all runoff water and associated contaminants and debris generated
by the hydro-demolition process, including containment, collection and disposal of
runoff water and debris escaping through breaks in the bridge deck.

4. A Type 2 Working Drawing of the method and materials used to contain, collect,

and dispose of all concrete debris generated by the scarifying process, including
provisions for protecting adjacent traffic from flying debris.

Page 6-244

Modified Concrete Overlays

5. A Type 1 Working Drawing of the mix design for concrete Class M, and either

fly ash modified concrete, microsilica modified concrete, or latex modified
concrete, as selected by the Contractor for use in this project in accordance with

Section 6-09.3(3)

6. A Type 1 Working Drawing of samples of the latex admixture and the portland

cement for testing and compatibility (if latex modified concrete is used).

7. A Type 2 Working Drawing of the paving equipment Specifications and details of the

screed rail support system, including details of anchoring the rails and providing rail
continuity.

6-09.3(3) Concrete Overlay Mixes

6-09.3(3)A General

For fly ash, microsilica, and latex modified concrete, the Contractor shall adjust the
slump to accommodate the gradient of the bridge deck, subject to the maximum slump
specified.

For fly ash and microsilica modified concrete, the maximum water/cement ratio shall be
calculated using all of the available mix water, including the free water in both the coarse
and fine aggregate, and in the microsilica slurry if a slurry is used.

For fly ash and microsilica modified concrete, all water-reducing and air entraining
admixtures, and superplasticizers, shall be used in accordance with the admixture
manufacturer’s recommendations.

6-09.3(3)B

Concrete Class M

Concrete Class M for further deck preparation patching concrete shall be proportioned in
accordance with the following mix design:

Portland Cement

705 pounds

Fine

Aggregate

1,280

pounds

Coarse

Aggregate 1,650

pounds

Water/Cement Ratio

0.37 maximum

Air (± 1½ percent)

6 percent

Slump (± 1 inch)

5 inches

The use of a water-reducing admixture conforming to AASHTO M194 Type A will
be required to produce patching concrete with the desired slump, and shall be used
in accordance with the admixture manufacturer’s recommendations. Air entraining
admixtures shall conform to AASHTO M154 and shall be used in accordance with the
admixture manufacturer’s recommendations. The use of accelerating admixtures or other
types of admixtures is not allowed.

Standard Specifications for Road, Bridge, and Municipal Construction 2020 (M 41-10) - page 36