[Summary of State DOT Provisions for Placing & Curing]{.underline}

[Silica Fume Concrete Bridge Decks -- February 29, 2008]{.underline}

**1) [Silica Fume User's Manual]{.underline}**, prepared for FHWA, April
2005

Report \# FHWA-IF-05-016:

The Manual refers to NYSDOT recommendation that concrete not be allowed
to be placed more than 1.5m to 2.5m ahead of the finishing machine. SFA
recommends that curing be started within 10-15 minutes after concrete
placement. Uninterrupted wet curing is recommended for a minimum of 7
days.

**2) [Alabama DOT Special Provisions]{.underline}**: **(Note: 5-7% range
of cement replacement is now preferable)**

> b\. Guidelines for High Performance Concrete (HPC) Mix Proportions:

The minimum strength for the cast-in place HPC concrete shall be 6000
psi. However, mix proportions shall be selected using f'cr.

The cement shall be Type II and the cementitious content of the mix
shall be sufficient to meet the compressive strength requirements. The
concrete mix shall contain fly ash, or microsilica, or a combination of
fly ash and microsilica to provide improved durability. Acceptable
ranges of cement replacement for these mineral admixtures are:

Class "F" fly ash 15 to 25%

Class "C" fly ash 20 to 35%

Microsilica 7 to 15%

When combinations of fly ash and microsilica are used, the fly ash
content shall satisfy the above-specified ranges, and the microsilica
will be considered an addition. The microsilica addition shall be at
least 3% of the total cement plus fly ash content and no more than 15%.

The maximum water to total cementitious material ratio shall be 0.40.

Coarse aggregate shall be ALDOT \# 57 or \# 67 crushed limestone. Fine
aggregate shall be natural sand.

An air entrainment admixture shall be used. The air content of the fresh
concrete shall be 3.5% to 6.0%.

Concrete shall not be placed at a slump exceeding the following limits:

Superstructure concrete: Maximum slump of five inches (5").

Substructure concrete: Maximum slump of eight inches (8").

Any concrete delivered with a slump less than the maximum acceptable
slump value shall be acceptable as long as it is sufficiently workable
to consolidate and finish properly

The maximum allowable temperature of the fresh concrete shall be 95F.
When the temperature of the concrete is above 95F., the approved "Hot
Weather Concrete Plan" submitted by the Contractor shall be used.

  ------------ ----------------------------------------------------------
               **FIGURE 1. Evaporation Rate of Surface Moisture**

               ![](media/image1.emf)

               *Note: Example shown by dashed lines is for an air
               temperature of 80°F, relative humidity of 50 percent,
               concrete temperature of 87°F, and a wind velocity of 12
               miles per hour. This result is a rate of evaporation of
               0.24 pounds per square foot per hour.*
  ------------ ----------------------------------------------------------

2\. BRIDGE DECK CURING.

Moist curing shall be used for all bridge deck curing, and shall be used
for curing any other flatwork concrete as designated on the plans or as
approved by the Engineer. Concrete to be moist-cured shall be maintained
continuously wet for the entire curing period, commencing immediately
after finishing operations have been completed. Beginning immediately
after the screeding operations have been completed, the concrete surface
shall be kept continuously moist by fogging, and the fogging operations
shall be maintained continuously until the moist curing procedures have
begun. If water or curing materials stains or discolors concrete
surfaces which are to be permanently exposed, the concrete surfaces
shall be cleaned as approved. When wooden forms are left in place during
curing, they shall be kept wet at all times. If steel forms are used in
hot weather, nonsupporting vertical forms shall be broken loose from the
concrete and curing water continually applied in this void. If the forms
are removed before the end of the curing period, curing shall be carried
out as on unformed surfaces, using suitable materials. Surfaces shall be
moist cured by continuous sprinkling, by continuously saturated burlap
or cotton mats, or by continuously saturated plastic coated burlap.
Burlap and cotton mats shall be clean and free from any contamination
and shall be completely saturated before being placed on the concrete.
Burlap and cotton mat sheets shall extend at least 18 inches beyond the
concrete surface at all edges, and shall be overlapped at least 12
inches where two individual sheets join. All joints between burlap or
cotton mat sheets, and edges of burlap or cotton mat sheets along the
edge of the concrete surface being cured, shall be secured so that the
concrete surface remains covered during the entire curing period. Burlap
or cotton mat sheets shall be immediately repaired or replaced if tears
or holes appear in the sheets during the curing period. The Contractor
shall have an approved work system to ensure that moist curing is
continuous 24 hours per day.

3\. EXPOSED SURFACE CURING.

a\. Membrane Forming Curing Compounds.

"...except that membrane forming curing compound shall not be used for
curing bridge deck concrete, ..."

5\. BRIDGE DECK CONCRETE SLAB FINISHING.

a\. General.

Overfinishing or overworking water into the surface of a fresh concrete
slab can cause crazing, dusting, or scaling, which is detrimental to the
performance of the bridge deck.

**3) [Arkansas DOT Special Provision, August 2006]{.underline}:**

***Subsection 802.05 is amended to include the following for Class S(HP)
concrete:***

> (**f) Silica Fume.** Silica fume may be used as a partial replacement,
> not exceeding 5% by weight, for Type I cement, in Class S(HP)
> concrete. When silica fume is used in the mix a special batching
> sequence may be required to prevent balling. The Contractor and/or his
> concrete supplier should consult with the silica fume supplier to
> determine the proper batching sequence for the products being used.

***Subsection 802.16 is modified as follows for Class S(HP) concrete:***

***The first sentence of the first paragraph is deleted and the
following substituted therefore:***

> When the ambient temperature at the placement site is 75° F and
> rising, an approved retarding agent shall be required.

The first and second sentence of the second paragraph is deleted and the
following substituted therefore:

> When the internal temperature of the plastic concrete in bridge decks
> reaches 75° F, the Contractor shall take the necessary precautions to
> ensure that the temperature of succeeding batches does not exceed
> 80° F. Concrete batches with temperatures in excess of 80° F will be
> rejected.

***Subsection 802.17 is DELETED and the following substituted therefore
for Class S(HP) concrete:***

> **Curing of Class S(HP) Concrete.** Curing of Class S(HP) concrete
> shall be in accordance with Special Provision Job 030339 "Curing
> Concrete for Bridge Decks".

**SPECIAL PROVISION**

**JOB NO. \-\-\-\-\-\-\--**

**CURING CONCRETE FOR BRIDGE DECKS**

**BRIDGE NO. 06702**

**DESCRIPTION:** This special provision covers the curing requirements
for Bridge No. 06702. The curing requirements for "Wet Curing" are
included in this special provision.

The curing requirements for the concrete in the sidewalk and parapet
railing shall be in accordance with **Section 802.17** of the Standard
Specifications.

**The Research Section of the Arkansas Highway and Transportation
Department shall be given a minimum of two (2) business days advance
notification of the planned date for the bridge deck pour.**

**WET CURING: Section 802.17 Curing Concrete for Structures** of the
Standard Specifications, Edition of 1996, is hereby deleted and the
following curing requirements substituted.

**General.** The exposed surface of the bridge deck shall be kept
continuously wet from immediately after the initial strike-off to the
end of the required curing period. The curing requirements for "Wet
Curing" include fogging, moist curing (if necessary), and final curing
to prevent loss of water. Care shall be exercised to prevent increasing
the water content in the concrete by the water used during the curing
process.

All concrete shall be cured for a period of seven (7) uninterrupted
days. The required curing period shall begin at the time of initial
strike-off.

The water used for curing shall meet the requirements for concrete
mixing water as specified in **Subsection 802.02(d).** Water which
stains for leaves an unsightly residue shall not be used.

If there is a likelihood that the air temperature will be below 2 C
(35 F). during the curing period, the contractor shall submit a plan
detailing the method and equipment which will be used to prevent the
water used for curing from freezing. This includes the fog, water spray,
standing water, and water in the mats, blankets, and sand. The plan
shall be approved by the Engineer prior to placing concrete.

Inadequate curing and/or facilities shall be cause for the Engineer to
delay all concrete placement until remedial action is taken.

**SPECIAL PROVISION**

**JOB NO. R80094**

**CURING CONCRETE FOR BRIDGE DECKS**

**BRIDGE NO. 06702**

**DESCRIPTION:** This special provision covers the curing requirements
for Bridge No. 06702. The curing requirements for "Wet Curing" are
included in this special provision.

The curing requirements for the concrete in the sidewalk and parapet
railing shall be in accordance with **Section 802.17** of the Standard
Specifications.

**The Research Section of the Arkansas Highway and Transportation
Department shall be given a minimum of two (2) business days advance
notification of the planned date for the bridge deck pour.**

**WET CURING: Section 802.17 Curing Concrete for Structures** of the
Standard Specifications, Edition of 1996, is hereby deleted and the
following curing requirements substituted.

**General.** The exposed surface of the bridge deck shall be kept
continuously wet from immediately after the initial strike-off to the
end of the required curing period. The curing requirements for "Wet
Curing" include fogging, moist curing (if necessary), and final curing
to prevent loss of water. Care shall be exercised to prevent increasing
the water content in the concrete by the water used during the curing
process.

All concrete shall be cured for a period of seven (7) uninterrupted
days. The required curing period shall begin at the time of initial
strike-off.

The water used for curing shall meet the requirements for concrete
mixing water as specified in **Subsection 802.02(d).** Water which
stains for leaves an unsightly residue shall not be used.

If there is a likelihood that the air temperature will be below 2 C
(35 F). during the curing period, the contractor shall submit a plan
detailing the method and equipment which will be used to prevent the
water used for curing from freezing. This includes the fog, water spray,
standing water, and water in the mats, blankets, and sand. The plan
shall be approved by the Engineer prior to placing concrete.

Inadequate curing and/or facilities shall be cause for the Engineer to
delay all concrete placement until remedial action is taken.

SP JOB R80094 Page 2 of 4

**CURING CONCRETE FOR BRIDGE DECKS**

**Curing Materials.** Materials used in curing concrete shall conform to
one of the following types:

1.  Burlap-polyethylene sheeting meeting the requirements of AASHTO M171
    and free of visible defects.

2.  Polyethylene sheeting meeting the requirements of AASHTO M171 and
    having a minimum thickness of 0.10 mm (4 mils), is free of visible
    defects, and having a uniform appearance.

> 3\) Other approved sheeting materials meeting the requirements of
> AASHTO M171 and free
>
> of visible defects that do not discolor or otherwise damage the
> concrete.

4.  Copolymer/synthetic blankets shall meet the requirements of AASHTO
    M171. Copolymer/synthetic blankets shall be a composite of a
    copolymer membrane material coated over a layer of absorbent
    nonwoven synthetic fabric weighing at least 200 grams per square
    meter (6 ounces per square yard), free of visible defects, and
    having a uniform appearance.

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5.  Cotton mats consisting of a filling material of cotton, weighing at
    least 400 grams per square meter (12 ounces per square yard),
    covered with unsized cloth, weighing at least 6 ounces per square
    yard, tufted or stitched to maintain stability, free of visible
    defects, and having a uniform appearance.

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7.  Unfaced burlap blankets consisting of burlap blankets weighing at
    least 250 grams per square meter (9 ounces per square yard) and free
    of visible defects.

**Fogging.** [Immediately]{.underline} after initial strike-off and
until the final curing is in place, the exposed concrete surfaces of the
bridge deck shall be kept continuously and visibly moist by fogging.

The fog shall be produced using equipment that pumps water, or water and
air, under pressure through a suitable atomizing nozzle that does not
cause significant surface runoff. The fogging equipment shall be capable
of applying water in a mist, not a spray, too fine to damage the
concrete surface. The equipment shall be capable of being hand operated,
sufficiently portable for use in the direction of any prevailing winds,
and adaptable for intermittent use as directed by the Engineer to
prevent excessive wetting of the concrete. Care shall be exercised
during finishing to prevent fogged water from becoming part of the
concrete. The fogging equipment and procedure shall be approved by the
Engineer prior to placing concrete.

**Moist Curing.** After final finishing, moist curing is required if the
initial surface test, as specified in **Subsection 802.20(c)**, cannot
be completed in a timely manner. The deck shall be kept continuously wet
by fogging, water spray, or prewetted unfaced burlap blankets placed in
direct contact with the concrete surface until final curing begins. The
method used shall not damage the finished concrete surface.

SP Job R80094 Page 3 of 4

**CURING CONCRETE FOR BRIDGE DECKS**

**Final Curing.** Final curing shall begin immediately after completing
the initial surface test specified in **Subsection 802.20(c)** of the
Standard Specifications. All exposed surfaces of the concrete deck shall
be kept continuously and thoroughly wet for the remainder of the
required curing period using one of the following methods. Supplemental
heating or insulation may be required to meet the requirements of
**Section 802.16** of the Standard Specifications. The contractor shall
submit the proposed method of water curing to the Engineer for approval.

1.  **Wet Mat Curing.** This curing method consists of one of the
    following:

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a.  **Prewetted** cotton mats in direct contact with the concrete
    surface shall be used. The mats shall be kept **saturated** until
    the required curing period has elapsed. Dry cotton mats may be
    placed if unfaced **prewetted** burlap blankets are initially placed
    in direct contact with the concrete surface for temporary
    protection. The dry cotton mats shall then be immediately and
    continuously **saturated** after their placement until the required
    curing period has elapsed. The mats shall be weighted down
    adequately to provide continuous contact with the exposed concrete.

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b.  If the air temperature is expected to drop below 4 C (40 F).
    during the final curing period, polyethylene sheeting, **prewetted**
    burlap-polyethylene blankets, or **prewetted** copolymer/synthetic
    blankets in direct contact with the concrete surface shall be used.

    The blankets shall be kept saturated until the required curing
    period has elapsed. Dry blankets may be placed if unfaced
    **prewetted** burlap blankets are initially placed in direct contact
    with the concrete surface for temporary protection. The dry blankets
    shall then be immediately and continuously **saturated** after their
    placement until the required curing period has elapsed. These curing
    materials shall be weighted down with dry cotton mats to maintain
    direct contact with the concrete and provide insulation against the
    cold.

    The polyethylene sheets shall be of the widest practicable width and
    the sheets shall overlap a minimum of 6 inches.

> Surfaces which cannot be cured by direct contact shall be covered with
> blankets or cotton mats forming an enclosure well anchored so that
> outside air cannot enter the enclosure. Sufficient moisture shall be
> provided inside the enclosure to keep all surfaces of the concrete
> wet.

2.  **Water Spray.** This curing method shall consist of overlapping
    sprays or sprinklers that keep all exposed concrete surfaces
    continuously wet.

SP Job R80094 Page 4 of 4

**CURING CONCRETE FOR BRIDGE DECKS**

3.  **Ponding.** This curing method requires the covering of the surface
    with a minimum of 50 mm (2 inches) of clean sand, kept saturated at
    all times, or a minimum of 25 mm (1 inch) depth of water.
    Satisfactory provisions shall be made to provide a dam to retain the
    water or saturated granular material. Cover material and dams shall
    be removed in such a manner that will not damage the bridge.

**PAYMENT:** No direct payment will be made but will be considered
subsidiary to the pay item "Class S(AE) Concrete - Bridge".

SP JOB R80094 Page 2 of 4

**CURING CONCRETE FOR BRIDGE DECKS**

**Curing Materials.** Materials used in curing concrete shall conform to
one of the following types:

3.  Burlap-polyethylene sheeting meeting the requirements of AASHTO M171
    and free of visible defects.

4.  Polyethylene sheeting meeting the requirements of AASHTO M171 and
    having a minimum thickness of 0.10 mm (4 mils), is free of visible
    defects, and having a uniform appearance.

> 3\) Other approved sheeting materials meeting the requirements of
> AASHTO M171 and free
>
> of visible defects that do not discolor or otherwise damage the
> concrete.

5.  Copolymer/synthetic blankets shall meet the requirements of AASHTO
    M171. Copolymer/synthetic blankets shall be a composite of a
    copolymer membrane material coated over a layer of absorbent
    nonwoven synthetic fabric weighing at least 200 grams per square
    meter (6 ounces per square yard), free of visible defects, and
    having a uniform appearance.

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6.  Cotton mats consisting of a filling material of cotton, weighing at
    least 400 grams per square meter (12 ounces per square yard),
    covered with unsized cloth, weighing at least 6 ounces per square
    yard, tufted or stitched to maintain stability, free of visible
    defects, and having a uniform appearance.

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8.  Unfaced burlap blankets consisting of burlap blankets weighing at
    least 250 grams per square meter (9 ounces per square yard) and free
    of visible defects.

**Fogging.** [Immediately]{.underline} after initial strike-off and
until the final curing is in place, the exposed concrete surfaces of the
bridge deck shall be kept continuously and visibly moist by fogging.

The fog shall be produced using equipment that pumps water, or water and
air, under pressure through a suitable atomizing nozzle that does not
cause significant surface runoff. The fogging equipment shall be capable
of applying water in a mist, not a spray, too fine to damage the
concrete surface. The equipment shall be capable of being hand operated,
sufficiently portable for use in the direction of any prevailing winds,
and adaptable for intermittent use as directed by the Engineer to
prevent excessive wetting of the concrete. Care shall be exercised
during finishing to prevent fogged water from becoming part of the
concrete. The fogging equipment and procedure shall be approved by the
Engineer prior to placing concrete.

**Moist Curing.** After final finishing, moist curing is required if the
initial surface test, as specified in **Subsection 802.20(c)**, cannot
be completed in a timely manner. The deck shall be kept continuously wet
by fogging, water spray, or prewetted unfaced burlap blankets placed in
direct contact with the concrete surface until final curing begins. The
method used shall not damage the finished concrete surface.

SP Job R80094 Page 3 of 4

**CURING CONCRETE FOR BRIDGE DECKS**

**Final Curing.** Final curing shall begin immediately after completing
the initial surface test specified in **Subsection 802.20(c)** of the
Standard Specifications. All exposed surfaces of the concrete deck shall
be kept continuously and thoroughly wet for the remainder of the
required curing period using one of the following methods. Supplemental
heating or insulation may be required to meet the requirements of
**Section 802.16** of the Standard Specifications. The contractor shall
submit the proposed method of water curing to the Engineer for approval.

2.  **Wet Mat Curing.** This curing method consists of one of the
    following:

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b.  **Prewetted** cotton mats in direct contact with the concrete
    surface shall be used. The mats shall be kept **saturated** until
    the required curing period has elapsed. Dry cotton mats may be
    placed if unfaced **prewetted** burlap blankets are initially placed
    in direct contact with the concrete surface for temporary
    protection. The dry cotton mats shall then be immediately and
    continuously **saturated** after their placement until the required
    curing period has elapsed. The mats shall be weighted down
    adequately to provide continuous contact with the exposed concrete.

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c.  If the air temperature is expected to drop below 4 C (40 F).
    during the final curing period, polyethylene sheeting, **prewetted**
    burlap-polyethylene blankets, or **prewetted** copolymer/synthetic
    blankets in direct contact with the concrete surface shall be used.

    The blankets shall be kept saturated until the required curing
    period has elapsed. Dry blankets may be placed if unfaced
    **prewetted** burlap blankets are initially placed in direct contact
    with the concrete surface for temporary protection. The dry blankets
    shall then be immediately and continuously **saturated** after their
    placement until the required curing period has elapsed. These curing
    materials shall be weighted down with dry cotton mats to maintain
    direct contact with the concrete and provide insulation against the
    cold.

    The polyethylene sheets shall be of the widest practicable width and
    the sheets shall overlap a minimum of 6 inches.

> Surfaces which cannot be cured by direct contact shall be covered with
> blankets or cotton mats forming an enclosure well anchored so that
> outside air cannot enter the enclosure. Sufficient moisture shall be
> provided inside the enclosure to keep all surfaces of the concrete
> wet.

3.  **Water Spray.** This curing method shall consist of overlapping
    sprays or sprinklers that keep all exposed concrete surfaces
    continuously wet.

SP Job R80094 Page 4 of 4

**CURING CONCRETE FOR BRIDGE DECKS**

4.  **Ponding.** This curing method requires the covering of the surface
    with a minimum of 50 mm (2 inches) of clean sand, kept saturated at
    all times, or a minimum of 25 mm (1 inch) depth of water.
    Satisfactory provisions shall be made to provide a dam to retain the
    water or saturated granular material. Cover material and dams shall
    be removed in such a manner that will not damage the bridge.

**PAYMENT:** No direct payment will be made but will be considered
subsidiary to the pay item "Class S(AE) Concrete - Bridge".

**5) [Arizona DOT Special Provision:]{.underline}**

> **(B) Placing and Finishing of High Peformance Concrete**

A trial placement of at least four cubic yards is required and shall be
performed by the contractor before the initial placement of HPC concrete
on the bridge deck. The contractor will be required to demonstrate
proper batching, placement, finishing and curing of HPC. The trial
placement shall be conducted on-site to simulate the actual job
conditions in all aspects including plant conditions, transit equipment,
travel conditions, admixtures, forming, placement of equipment and
personnel. If the results of the trial placement do not meet project
requirements, the Engineer may require additional placements and or more
trial placement to confirm HPC compliance to Specifications. Trial
placements and batches are the responsibility of the contractor and must
be repeated until the procedure for production; placement finishing,
pumping and curing of HPC is acceptable and approved by the Engineer.

The placement of concrete shall conform to the requirements of
Subsection 601-3.03, the weather limitations described in Subsection
1006-5, and the requirements listed below.

Finishing concrete surfaces shall conform to the following requirements.
As soon as the concrete is placed, mechanical screeding shall take
place. These steps shall be completed in sequence, and without delay.
Delays between these steps, such as awaiting strength development or any
other reason are unacceptable.

> 1\) Prior to placement of concrete, the bridge deck forms area that
> will receive the concrete shall be moist for a period of one hour. All
> freestanding water shall be removed prior to concrete placement.
> During the concrete placement, the lane or strip shall be kept moist.
>
> 2\) Placing concrete shall be a continuous operation throughout the
> pour. The concrete shall be placed slightly above grade and then
> struck-off, screed, and finished to final grade. All flat concrete
> surfaces shall be finished using vibratory screeds. The forward speed
> of the finishing machine or machines shall be adjusted to the average
> progress of the concrete production, in order that the strike-off
> operations shall be as continuous and uninterrupted as possible. Hand
> finishing with a float may occasionally be required to produce a tight
> uniform surface and at the edges of the bridge deck. When such hand
> finishing is needed it shall be kept to a minimum to avoid overworking
> of the surface. The addition of water directly to the concrete surface
> during the finishing operations will not be permitted. Moisture shall
> be maintained above the concrete surface by an approved fogging system
> attached to the bridge screed until concrete receives curing cover as
> described in Section 3(C)(1)(b), Wet Mat Curing. An approved fogging
> system shall be capable of maintaining a fine mist fog over the entire
> surface of the fresh concrete.

3.  Fresh concrete, three inches or more in thickness, shall be
    internally vibrated in addition to surface screeding.

4.  A monomolecular film product that aids in retarding the evaporation
    and acts as a finishing aid may be used provided the manufacturer's
    recommendations are followed and approval of the Engineer is
    obtained in advance.

> 5\) The use of an approved monomolecular film may be allowed as an
> evaporation retarder after the finishing has been completed. The
> application of such evaporation retarder shall not be in lieu of the
> water fogging of the surface above the concrete. The application of
> this material shall be in a form of a fine mist using a suitable
> sprayer, impacting the plastic concrete with a stream shall not be
> allowed. This material shall not be mixed into the plastic concrete
> during any phase of the construction. The use of a monomolecular film
> shall conform to the written manufacturer's recommendations
>
> 6\) If the concrete placement is stopped for a period of one-half hour
> or more, the contractor shall install a bulkhead transverse to the
> direction of the placement at a position where the concrete can be
> finished full width up to the bulkhead. The bulkhead shall be full
> depth of the bridge deck and shall be installed to grade. For delays
> of less than one-half hour, the end of the concrete placement shall be
> protected from drying with wet burlap. The concrete previously placed
> shall be finished, covered and cured in accordance with these
> Specifications. Further placement is permitted only after a period of
> twelve hours unless a gap is left in the lane or strip. The gap shall
> be of sufficient width for the finishing machine to clear the
> transverse bulkhead installed where the concrete placement was
> stopped. The previously poured concrete shall be sawn back from the
> bulkhead, to a point designated by the Engineer, to straight and
> vertical edges and shall be water blasted or sandblasted before new
> concrete is placed.
>
> 7\) Texturing or grooving concrete shall conform to the requirements
> of Subsection 601-3.05(D) of the Standard Specifications as modified
> in these Special Provisions.
>
> **(C) Curing High Performance Concrete**

Proper curing is critical to ensure the quality and performance of HPC.
Because of its typical low water content and low water-to-cementitious
materials ratio, HPC mixes require additional attention to curing as
compared to normal concrete. This extra emphasis on curing insures that
the water needed for the development of the desired HPC properties is
provided. Fresh concrete surfaces of HPC that contain silica fume
require immediate and continuous protection from drying as they do not
possess bleeding water and are susceptible to surface drying and the
potential of early crack formation in fresh concrete. The contractor
must give special consideration to curing procedures to prevent these
cracks.

The contractor shall inform the Engineer of the methods proposed for
curing; shall provide the proper equipment and material in adequate
amounts; and shall have the proposed methods, equipment and material
approved by the Engineer prior to placing concrete. Immediately prior to
placing the concrete, the contractor shall demonstrate to the Engineer
the initial curing procedure, described below, for the Engineers
approval. Inadequate curing and/or facilities shall be cause for the
Engineer to delay or stop all concrete placements on the job until
remedial action is taken.

Curing shall begin immediately, and within 10 minutes after final
finishing of concrete surface.

All concrete shall be cured for a minimum period of seven curing days. A
curing day is defined as a calendar day when the temperature, taken in
the shade away from artificial heat, is above 50^o^F for at least 19
hours or on colder days if satisfactory provisions are made to maintain
the temperature of all surfaces of the concrete above 40^o^F for the
entire 24 hours. The required curing period shall begin when all
concrete therein has attained its initial set.

All exposed surfaces of the concrete shall be kept wet continuously for
the required curing time. The water used for curing shall meet the
requirements for concrete mixing water as specified in the Standard
Specifications for water. Concrete water that stains or leaves an
unsightly residue shall not be used.

The following methods are permitted for curing the HPC bridge deck.
Water curing will be required for the upper surfaces of the bridge
roadway and all other concrete.

> 1\) Water Curing

a)  Initial Curing

> Immediately after the concrete is placed and brought to grade, the
> entire area above the surface of the concrete shall be kept
> continuously moist by applying a water mist with a nozzle that
> atomizes the flow so that a mist and not a spray is formed. The
> nozzles shall be pointing away from the surface of the concrete and
> the moisture from the nozzle shall not be applied under pressure
> directly upon the concrete and shall not be allowed to accumulate on
> the concrete surface in a quantity sufficient to cause a flow or wash
> the surface. Such initial curing shall be continued until concrete
> surfaces are being cured according to section (b) below.

b)  Wet Mat Curing

> Wet mat curing shall immediately follow the final finishing but no
> later than 10 minutes after the initial curing. This curing method
> shall consist of keeping the concrete surfaces continuously wet by
> maintaining layer(s) of wet burlap and plastic sheeting combination in
> direct contact with the fresh concrete for the required curing time.
> The burlap/plastic sheeting combination (Burlene) must be wetted down
> prior to being placed over the concrete surfaces. The burlap/plastic
> sheeting must be kept wet during the entire curing period. Wetting can
> be accomplished by supplying water through holes made in the plastic
> sheeting and distributed throughout to saturate the burlap sheeting.
> The blankets shall be weighted down adequately to provide continuous
> contact with all concrete where possible.
>
> Surfaces that cannot be cured by direct contact shall be covered with
> mats forming an enclosure well anchored to the forms or ground so that
> outside air cannot enter the enclosure. Sufficient moisture shall be
> provided inside the enclosure to keep all surfaces of the concrete
> wet.
>
> Polyethylene sheeting, burlap-polyethylene blankets, laminated mats or
> insulating curing mats placed in direct contact with the slab will be
> required when the air temperature is expected to drop below 40^o^F
> during the first 72 hours of the curing period. These curing materials
> shall be weighted down with dry mats to maintain direct contact with
> the concrete and to provide insulation against cold weather.
> Supplemental heating or insulation may be required in cold and/or wet
> weather if the insulating cotton mats become wet or if the concrete
> drops below the specified curing temperature.
>
> 2\) Form Curing
>
> When forms are left in contact with the concrete, other curing methods
> will not be required except for exposed surfaces and for cold weather
> protection.

**6) [Colorado DOT Special Provision (June 2003): ]{.underline}**

**601.16 Curing Concrete Bridge Decks.** Except for Class H and HT
concrete, the minimum curing period shall be 120 hours. The concrete
surface shall be kept moist at all times by fogging with an approved
atomizing nozzle or applying a monomolecular film coating to retard
evaporation until the curing material is in place.

For Class H and HT concrete the minimum curing period shall be 168 hours
and from May 1 and until September 30 the water cure method as described
below shall be used without the membrane forming curing compound.

Concrete bridge decks, including bridge curbs and bridge sidewalks shall
be cured as follows:

(a) Decks placed from May 1 to September 30 shall be cured by the
    membrane forming curing compound method followed by the water cure
    method as follows:

    1.  Membrane Forming Curing Compound Method*.* A volatile organic
        content (VOC) compliant curing compound conforming to AASHTO M
        148, Type 2 shall be uniformly applied to the surface of the
        deck, curbs and sidewalks at the rate of 40 L/100 m^2^ (1 gallon
        per 100 square feet). The curing compound shall be applied as a
        fine spray using power operated spraying equipment. The power
        operated spraying equipment shall be equipped with an
        operational pressure gage and a means of controlling the
        pressure. Before and during application the curing compound
        shall be kept thoroughly mixed by recirculation or a tank
        agitator. The application shall be within 6 m (20 feet) of the
        deck finishing operation. When the finishing operation is
        discontinued, all finished concrete shall be coated with curing
        compound within ½ hour. The curing compound shall be thoroughly
        mixed within one hour before use.

    2.  Water Cure Method. The water cure method shall be applied as
        soon as it can be without marring the surface and shall be
        continued for five days. The surface of the concrete, including
        bridge curbs and bridge sidewalks, shall be entirely covered
        with cotton, burlap, or combination polyethylene sheeting and
        burlap mats. Approved combinations of a barrier and a water
        retaining layer may be used. Prior to being placed, the mats
        shall be thoroughly saturated with water. The mats shall extend
        at least twice the thickness of the bridge deck beyond the edges
        of the slab and shall be weighted to remain in contact with the
        surface. The mats shall remain in contact and be kept wet for a
        minimum of five days after concrete placement.

(b) Decks placed between November 1 and March 31 shall be cured by
    application of a membrane forming curing compound followed by the
    blanket method as follows:

    1.  Membrane Forming Curing Compound Method. This method shall be
        applied in accordance with 601.16(a)1 above.

    2.  Blanket Method. Curing blankets with a minimum RValue of 0.5
        shall be placed on the deck as soon as they can be without
        marring the surface. Blankets shall be loosely laid (not
        stretched) and adjacent edges suitably overlapped with
        continuous weights along the lapped joints. The blankets shall
        remain in place for a minimum of five days after placement.

(c) Decks placed in April or October may be cured in accordance with
    either subsection 601.16(a) or 601.16(b) above.

(d) For decks placed above an elevation of 2500 m (8,000 feet) above
    mean sea level, the Engineer may modify the time of year
    requirements for the cure methods defined in subsection 601.16(a)
    and 601.16(b) above.

(e) Class H, Class HT and Class S50 concrete shall be cured as follows:

    1.  The concrete surface shall be kept moist at all times by fogging
        with approved atomizing nozzles until the surface has been
        covered by the final cure.

    2.  At lease two atomizing nozzles shall be in operation at all
        times. A fogging nozzle that has shown acceptable performance is
        FOGG-IT Waterfog, low volume (7.5 liters per minute),
        manufactured by Fogg-it Nozzle Co. at P.O. Box 16053, San
        Francisco, California, 94116, or an approved equal.

    3.  From October 1 and until April 30 continuous fogging will not be
        required if the evaporation rate is less than 0.50 kg/m2/hr
        (0.10 lb/ft2/hr). Ambient temperatures during initial curing
        shall be warm enough that the water from fogging does not freeze
        before insulating blankets are applied. The internal concrete
        temperature shall be determined by using thermocouples and a
        continuous recording device. The Contractor shall provide the
        thermocouples and a continuous recording device and install the
        thermocouples at locations designated by the Engineer. The
        continuous recording device connected to the thermocouple shall
        be calibrated to provide accurate temperature readings. During
        the cure period the continuous recording device shall be
        visible, show visible readings, and the Contractor shall
        continuously monitor the concrete temperature and provide the
        recorded data to the engineer after the monitoring of
        temperature for that placement is complete.

**7) [Delaware DOT Special provision:]{.underline}**

**[Limitations on Placing Material]{.underline}**:

The Contractor shall be responsible for the quality of the concrete
placed in any weather or atmospheric conditions. The Contractor is
responsible for determining the rate of set of the mix based on ambient
temperature, concrete temperature, time of day, thickness of slab,
concrete mix proportions, etc. and the amount and proper type of
superplasticizer and/or retarder necessary to match the placement and
finishing rate. Failure to achieve a satisfactory product due to poor
workability or rapid-set of the concrete shall be corrected as directed
by the Engineer at the Contractors expense.

Deck material shall be placed only when the local ambient temperature is
above, and forecast to remain above, 45F (7C) for the entire 7 day
curing period. If actual conditions adversely change after the placement
is made, the material shall be adequately protected at no additional
cost to the Department.

Deck material shall not be placed when rain is forecast within the
intended working period required to complete placement and finishing the
deck material.

Deck material shall be placed only if the surface evaporation rate, as
affected by ambient air temperature, concrete temperature, relative
humidity, and wind velocity, is less than or equal to 0.15 pounds per
square foot (0.73 kilograms per square meter) per hour. The Contractor
shall determine and document the atmospheric conditions, subject to
verification by the Engineer. The chart contained in Plastic Cracking
of Concrete by Delmar Bloem for the National Ready Mixed Concrete
Association and published in ACI 305R-89 shall be used to determine the
loss of surface moisture for the deck material. The chart may be
obtained from the Materials & Research Section.

Deck material shall not be placed if the ambient air temperature is
above, or predicted to go above, 85F (30C) during the planned deck
material placement period, regardless of the surface evaporation rate.

Deck material shall not be placed adjacent to previously placed deck
material which has cured for less than three cure-days. A cure-day is
defined as a 24 consecutive hour period of time when the temperature of
the overlay surface material is maintained above 35F (2C). Any day
during which the ambient air temperature at the overlay surface falls
below 45F (7C) will not be counted as a cure-day unless precautions
are taken to maintain the overlay surface material above 35F (2C).

Prior to the placement of any deck material, provisions shall be
available for the protection of that material in the event of inclement
environmental conditions, such as rain.

If the placement of the deck is to be made at night, the Contractor
shall submit a plan which provides adequate lighting for the work area.
The plan shall be submitted at least 15 calendar days in advance and be
approved by the Engineer before the deck is placed. The lights shall be
so directed that they do not adversely affect traffic.

If micro-silica is chosen for the High Performance Concrete, the
micro-silica manufacturers technical representative shall be present
during the placement of the deck material at no additional cost to the
Department. Work which this representative or the Engineer considers
detrimental to the integrity of the deck will be rejected.

Prior to placing any deck material, the Contractor shall conduct a
pre-placement conference with the Engineer to discuss the detailed
schedule and procedures for the work. This discussion shall establish
the Contractors ability to place the deck material on a continuous
basis and to consolidate, finish, and commence curing within the time
intervals required.

**[Placing the Material]{.underline}**:

The maximum time allowed between the start of mixing of a truck to the
completion of the discharge of the deck material in that truck shall be
sixty minutes.

The maximum water/cement ratio of 0.40 shall not be exceeded. Any
admixture added at the job site shall be mixed for an additional minimum
of 5 minutes, or 30 revolutions, at mixing speed. After all components
have been added, the slump range shall be 4 to 8 (100 to 200 mm).

If slump loss occurs after mixing and before placement of the deck
material, the charge may be re-tempered with the admixture to restore
plasticity; re-tempering with water shall not be allowed. The slump and
the air content will be rechecked to ensure conformance to the allowable
values. If the consistency of the charge after the re-tempering causes
segregation of the mixture components, the material shall be rejected.
The deck material must still be placed within the original sixty minute
limitation or it will be rejected.

**[Consolidating and Finishing the Material]{.underline}**:

The maximum allowable time between the discharge and the final finishing
of the deck material of a truck shall be ten minutes.

The deck material shall be placed, consolidated, and finished to the
Plan grades. Once the finishing machine has made the first pass, workers
shall not walk in the freshly placed material.

If micro-silica is chosen for High Performance Concrete, an evaporation
retardant shall be applied immediately after finishing. The retardant
shall be applied as per the manufacturers recommendations.

During delays in the deck material placement of more than 10 minutes,
the work face of the material shall be covered with wet burlap until
placement operations resume. If an excessive delay of thirty minutes or
greater is anticipated, a bulkhead shall be installed at the work face
and the deck placement operation terminated.

A 10 foot (3 meter) straightedge shall be supplied and used by the
Contractor to check the deck surface directly behind the finishing
machine. It shall also be used to check transversely along the edges of
the deck where hand finishing is done. Any irregularities exceeding 1/8
in 10 feet (3 mm in 3 meters) shall be corrected immediately. Any bumps
or ponding problems shall be corrected at no cost to the Department.

As soon as the finishing operation is complete, the finished deck
surface shall be covered with a layer of clean, fully-saturated, wet
burlap.

If rain occurs during placing of the deck material, all operations other
than protection of the already placed deck material shall immediately
cease. Material damaged by rain shall be rejected and replaced at no
additional cost to the Department.

**[Curing the Material]{.underline}**:

The burlap shall be kept wet by the continuous application of water
through soaker hoses until the 7 cure-days is reached. A 4 mil (100 m)
\[minimum\] thick white opaque polyethylene film shall completely cover
the wet burlap for the entire 7 day wet-cure period.

Any improperly cured material is subject to rejection by the Engineer
and shall be replaced at no cost to the Department.

Any cracking which occurs in the deck shall be sealed or repaired in a
manner approved by the Engineer at no cost to the Department.

**8) [Montana DOT Special provision, September 2003]{.underline}**

1\) Proportioning, Mixing and Placing

Perform concrete proportioning according to the QC/QA HPC Provisions.
Submit the proposed mixing procedure for approval prior to production.
[Allow 30 days for Review]{.mark}. Mix the concrete a minimum of 90
seconds at mixing speed before discharge. Use hand vibrators, shovels,
come-alongs and other tools used to place and consolidate the concrete
having non-metallic surfaces when working near epoxy-coated
reinforcement. Slip-on covers are not allowed. Do not locate bridge deck
finishing machine rails within the pour. Place concrete within the
specified time limits and temperature limits in Standard Specifications
Sections 551.03.4 and 552.03.5. Provide a Broom texture meeting the
requirements of Standard Specification Subsection 552.03.12(E)(5) using
a broom or plastic turf drag. Do not tine while plastic.

2\) Superstructure Fogging. Use fogging equipment consisting of a
mechanically operated pressurized system having triple headed nozzle or
an equivalent nozzle that produces a fine fog mist that will increase
the relative humidity of the air just above the fresh concrete surface
without accumulating significant water on the concrete. Mount the
fogging equipment on either the finishing equipment or a separate work
bridge behind the finishing equipment. Hand-held fogging equipment can
be used only to supplement stationary equipment.

Operate fogging equipment unless the evaporation rate is less than 0.1
lb/ft^2^/hr (0.5 kg/m^2^/hr), according to the Figure in the Portland
Cement Association's publication titled "Design and Control of Concrete
Mixtures". Provide temperature, relative humidity and wind speed
measuring equipment at the site whenever concrete is being placed.
Measure and record the evaporation rate each hour until all concrete is
covered with wet curing per the requirements of Section C. Adjust the
fogging equipment to ensure adequate cover of the fog mist without
ponding water on the fresh concrete surface.

3\) Special Curing and Protection Requirements. Cure concrete by water
curing per Standard Specification Subsection 551.03.6(A). Do not apply
membrane curing compounds until the concrete has been water cured for a
minimum of four (4) days. Cover the surface of the concrete immediately
after plastic texturing with dry [cotton]{.mark} [mats]{.mark} or
another approved fabric. Use cotton mats having cotton fill material
\[minimum 1.3 oz./ft^2^ (400 grams/m^2^)\] covered with unsized cloth or
burlap \[minimum 0.65 oz./f^2^t (200 grams/m^2^)\], and tufted or
stitched to maintain stability or as approved by the Project Manager.
Use mats free from tears and in good condition. Soak the mats
immediately with a gentle spray of water until saturated.

Place soaker hoses when the concrete has hardened sufficiently to
prevent marring of the surfaces. Other continuous wetting systems that
are not intermittent may be used if approved by the Project Manager.
After placement of the soaker hoses, cover the cotton mats and hoses
with white polyethylene sheeting or white plastic coated burlap. Wet
cure for seven (7) days. At the completion of the seven (7) day curing
period, apply a Type 2 white-pigmented membrane curing compound.

**9) [Nevada DOT Special Provision, October 2006]{.underline}**

**501.03.09 Curing.** (a) General. Cure all bridge decks and approach
slabs according to "(f) Bridge Deck Curing" of this Subsection.

\(f\) Bridge Deck Curing. Submit a quality control plan for concrete
placement and curing, for review and approval, a minimum of 30 days
prior to the pre-pour conference for bridge decks and approach slabs.
The plan shall include, but not be limited to, information on the
procedures for when and how the concrete and the curing system is to be
placed, frequency for monitoring, maintaining, and re-wetting the curing
system chosen, and a list of personnel responsible for performing such
work. Include in the plan, equipment to be used for placement of
concrete and the curing system, methods of protecting the covers from
displacement from wind or weather, and methods of preventing loss of
heat and moisture. Describe procedures to be followed in the event of
equipment breakdown or inclement weather during concrete placement. In
addition, describe the method to be used to protect pedestrian and
vehicular traffic under the structure.

Use Figure 4.1 from ACI 305R, Hot Weather Concreting, to determine the
evaporation rate. Provide additional protection measures if the rate of
evaporation exceeds 0.1 lb/ft2/hr. Provide accurate record of placement
location air temperature, relative humidity, concrete temperature, and
wind velocity. Take readings an hour prior to the concrete placement and
at one hour increments during concrete placement, until the final curing
blanket is placed.

Monitor concrete temperature during the entire curing period by
utilizing recording thermocouples embedded at one inch below the
concrete surface and one inch above the bottom concrete surface. A
minimum of two sets of installation will be required per days pour. The
thermocouple shall be capable of recording the concrete temperature as a
function of time. Acceptable devices include thermocouples connected to
electronic data loggers. The recording time intervals shall be a maximum
of one hour. The recording devices shall be accurate to within ± 1 C (±
1.8 F). Maintain the concrete temperature between the top and bottom of
the slabs and the supporting girders to a maximum differential
temperature of 30 F. If differential temperatures exceed the
requirements, take measures to correct the curing process.

Immediately after the concrete is placed, maintain the moisture content
by humidifying the air directly above the concrete surface until the
curing covers are placed. Use fogging equipment described in "(b) Water
Method" of this Subsection mounted on a finishing bridge which is
separate from hte concrete placing equipment. Fogging will be produced
by a high pressure system. Gravity feed misters will not be considered
for approval.

Begin placing pre-soaked burlap within 30 minutes after finishing has
started.

> Burlap and Polyethylene Covering. Furnish burlap conforming to
> Subsection 702.03.01 and

Polyethylene (white or reflective) conforming to ASTM C-171. Place
soaker hose or other approved method, to provide continuous wetting of
burlap between the burlap and polyethylene covering.

Use a finishing bridge to place pre-wetted curing coverings. Place
covers directly behind the concrete fogging operation

Carded 01/24/06

Maintain the covering uniformly wet during the entire curing period.
Provide 24 hour monitoring of the wet curing for the full length of the
curing period. Water temperature shall not be more or less than 20 F
from the temperature of top of bridge deck.

Lap covers a minimum of 450 mm (18 in.). Seal all lapped edges to
prevent loss of heat and moisture.

If the ambient temperature drops below 7 C (45 F) during the first 4
days of curing, provide additional protection according to "(c) Low
Temperature Protection" of Subsection 501.03.10.

After completion of wet curing and removal of curing covering,
immediately remove excess water and apply an application of curing
compound according to "(c) Curing Compound Method" of this Subsection.

Repair all cracks on new bridge decks and approach slabs. Repair cracks
by epoxy injection as specified below or by 19 mm (3/4in) thick polymer
concrete overlay according to Section 496. The Department may consider
crack sealing in accordance with subsection 646.03.04 in lieu of polymer
concrete overlay if the crack width is less than 0.3 mm and cracking is
observed only in isolated areas. Submit requested method of repair for
approval.

**10) [New York State DOT:]{.underline}**

The control of construction operations is of prime importance. Concrete
placement should be performed during periods of low evaporation, or
environmental controls should be made available. Class HP concrete has
no bleed water and will dry out quickly. Because of this it is important
not to leave the concrete exposed for extended durations. Concrete
should only be placed 5 feet to 8 feet ahead of the finishing machine.
The finishing machine must be set-up properly. If the set-up and
finishing is performed properly, the concrete should require no
additional hand work. Finishing should not result in a glass like
surface since texturing and saw cut grooving will be applied to roughen
the surface. The turf drag texturing must be applied immediately after
finishing. Curing with wet burlap must be initiated immediately after
texturing is complete. A burlap imprint left on the concrete due to
retardation is of less concern than a delay in the application of
curing. If there is any delay in the placement operation, all concrete
not yet finished or textured should be protected from evaporation by
either covering with plastic or wet burlap.

**11) [Oregon DOT Special Provision:]{.underline}**

**(b) Curing Concrete Bridge Decks** - In addition to requirements of
00540.49, cure cast-in-place concrete bridge deck surfaces by doing the
following:

-   Provide wind breaks or other approved methods when exposed to
    conditions which may cause premature drying during placement
    operations. Premature drying is defined as an evaporation rate equal
    to or greater than 0.15 pounds per square foot per hour, as
    determined from Figure 00540-1, or as the loss of surface sheen when
    the evaporation rate at the surface exceeds the bleed rate.

-   Provide high pressure washers, according to 00540.28, fitted with
    fog nozzles during all deck placements to prevent and control
    premature drying. Apply fog spray upwind of the concrete placement
    during finishing. The purpose of fogging is to maintain a layer of
    high humidity above the concrete surface in order to minimize water
    loss in the mix after placement and before application of cure. Do
    not allow larger water droplets that drip from nozzles to fall onto
    the freshly finished plastic concrete.

-   Cover the concrete with a single layer of clean initial covering
    immediately after finishing. Apply initial covering no later than 20
    minutes after final pass of the finishing machine [and]{.underline}
    no greater than 20 feet from the back of the finishing machine.
    Provide an initial covering with a minimum length sufficient to
    cover the bridge deck from side to side of the concrete placement.
    Use one of the following:

```{=html}
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-   Saturated wet burlap having a minimum dry weight of 10 ounces per
    yard for material 40 inches wide. Presoak the burlap by immersing it
    completely in water for 72 hours prior to the deck placement and
    presoak new burlap with a wetting agent. Overlap the edges at least
    6 inches.

-   Non-woven, needle punched polypropylene fabric curing blanket from
    the QPL. Thoroughly wet fabric within 15 minutes of fabric
    placement. Overlap the edges at least 12 inches.

    -   Provide soaker hoses for additional soaking of the initial
        covering. Place over the full width of the concrete placement,
        at a maximum of 10 foot intervals. Do not allow initial wetting
        of burlap or fabric to dry before soaker hoses are in place and
        operational. Operate soaker hoses continuously to keep the
        initial covering saturated.

    -   Place a layer of 4 mil polyethylene film over the initial
        covering and soaker hoses. Provide clear or white polyethylene
        film if the air temperature is forecasted to be above 65 °F
        within 24 hours of the concrete placement, and black at other
        times, as determined by the Engineer. Overlap the edges of
        polyethylene film by 12 inches. Keep the film in place by taping
        and weighting the edges where they overlap or are vulnerable to
        movement by wind. Once a particular type of film has been
        placed, do not change it during the curing period.

    -   Maintain a continuous water cure of the concrete surface for 14
        days.

**Additional Cure Time** - If, during the cure time, the surrounding
temperature falls below 45 °F, extend the cure for the number of hours
the temperature is below 45 °F.

**12) [Pennsylvania DOT Special Provision, 2005:]{.underline}**

**Section 1001.3(p) Curing and Protection of Concrete**. Revise first
paragraph to read:

11 Begin curing as soon as the deck concrete has been placed and
finished. Water cure the finished concrete

12 as per Section 1001.3(p) 3.b . Once the requirements of Section
1001.3(p) have been satisfied for a

13 period of fourteen (14) days and the concrete has reached a minimum
compressive strength of 3000 psi,

14 remove the water cure. Apply curing compound (Section 711.2(a)),
either Type 1-D, Clear, Red Fugitive

15

16 Version 1.7 August 13, 2003

17 ITEM 9###-### - BRIDGE DECK HIGH PERFORMANCE CONCRETE

18 ITEM 9###-### - SAWED GROOVES

19 Page 8 of 13

20

21 or White Pigmented Curing Compound immediately after removing the
water cure and burlap while the

22 surface is damp but has no free water standing on it. Apply at an
application rate of 100 to 150 square

23 foot per gallon. Keep areas that will come in contact with fresh
concrete free of curing compound.

24 Maintain curing compound for a minimum of three (3) days prior to
commencing saw grooving. After

25 the concrete has hardened, test the surface where applicable as
specified in Section 501.3(p). Do not

26 permit wet curing measures to freeze.

**13) [Puerto Rico DOT Special Provision, dated October
2003:]{.underline}**

Attached is entire spec; refer only to page 26, section 934-3.20 a. (4)

**14) [Virginia DOT, Standard Spec dated December 2002:]{.underline}**

> **Section 404.03(k) 1. Curing Concrete** is replaced with the
> following:
>
> 1\. **Curing Bridge Deck and Overlay Concrete:** Bridge deck and
> overlay concrete, including latex modified concrete, shall be moist
> cured for a minimum of 7 days and until 70 percent of f¢c is reached.
> Moist curing shall be maintained by wet burlap (keep wet) for the
> duration of the curing and covered with plastic sheeting. Immediately
> after screeding and until the application of wet burlap and white
> plastic sheeting (opaque and transparent sheeting may be used when the
> air temperature falls below 50^°^F), no surface of the freshly placed
> concrete shall be allowed to dry. During moist curing, the concrete
> temperature shall be maintained above 50^°^F at the outer most
> surfaces of the concrete mass. Immediately after removing the burlap
> and plastic sheeting (except for latex-modified concrete), white
> pigmented curing compound shall be applied while the surface is damp
> but has no free water standing on it. The application rate shall be
> 100 to 150 square feet per gallon.

**15) [West Virginia DOT, Special Provision dated July 2003:
]{.underline}**

**601.10.4.1 - Fogging Equipment:** When Class H concrete is used,
fogging

equipment shall be available for use in accordance with these
specifications. The

fogging nozzles shall produce an atomized mist. Fogging nozzles shall
incorporate

compressed air to create the mist. Hand held or hand operated equipment
shall be

permitted when the Contractor has demonstrated that his operator has
been trained in

its use.

**601.10.4.2 - Placement:** The following requirements shall apply
during

placement of the Bridge Deck concrete:

a\) So that the use of hand tools will be kept to a minimum, concrete
shall

be deposited as nearly as possible to its final position. Internal

vibrators shall not be used for moving concrete into position.

b\) A pencil type vibrator shall be used along all construction joints
to

further consolidate the concrete to prevent voids.

c\) The new concrete shall be placed slightly above final grade. It
shall

then be struck-off, screeded, and finished to final grade.

d\) The finished surface, before texturing, shall be uniformly smooth,

dense and even. Variations in pavement surface in excess of ⅛ inch

above, or below, the proper finished elevation, or surface
irregularities

of more than ⅛ inch in 10 feet, will not be accepted.

e\) A construction dam, or bulkhead, shall be installed in case of a
delay in

the placement operations exceeding 30 minutes duration. During any

delays of 30 minutes or less, the placement shall be protected from

drying with several layers of wet burlap. If the concrete placement is

stopped, or delayed, for 90 minutes or more, further placement shall be

discontinued and may be resumed only after the concrete has cured.

This restriction does not prohibit continuation of the placement

provided a gap is left in the placement. This gap shall be sufficient in

July 1, 2003

9 of 12

length to allow the finishing machine to clear the previously placed

concrete.

f\) Adequate precautions shall be taken to protect freshly placed
concrete

from rainfall. All placement operations shall stop when it starts to
rain.

The Engineer may order removal and replacement of material damaged

by rainfall.

g\) The addition of superficial water to the surface of the concrete to
assist

in finishing operations will not be permitted.

Louis N. Triandafilou, P.E.

Senior Structural Engineer

FHWA Resource Center

Structures Technical Service Team

Phone: (410 962-3648

Fax: (410) 962-4586

E-mail: <lou.triandafilou@dot.gov>

February 29, 2008