ITEM 511  CONCRETE FOR STRUCTURES

511.01  Description

511.02  Materials

511.03  Concrete

511.04  Quality Control Requirements and Mass Concrete

511.05  Mixing of Concrete

511.06  Slump

511.07  Placing Concrete

511.08  Slipform Construction of Bridge Railing

511.09  Construction Joints

511.10  Work Stoppage

511.11  Depositing Concrete Under Water

511.12  Depositing and Curing Concrete During Cold Weather

511.13  Removal of Forms

511.14  Curing and Loading

511.15  Surface Finish

511.16  Roadway Finish

511.17  Bridge Deck Grooving

511.18  Sidewalk Finish

511.19  Sealing Joints and Cracks

511.20  Compressive Strength

511.21  Air Content

511.22  Pay Factors

511.23  Method of Measurement

511.24  Basis of Payment

 

511.01  Description.  This work consists of providing falsework and forming, furnishing, placing, consolidating, finishing, and curing portland cement concrete.  This work also includes diamond saw cutting longitudinal grooves into the surface of superstructure concrete.  Construct falsework and forms as required in Item 508.

 511.02  Materials.  Furnish materials conforming to 499.02, except as modified below.

Use the same kind and color of aggregate for all concrete above the ground line in a given substructure unit and for all concrete in a given superstructure.

Use high molecular weight methacrylate resin sealer conforming to 705.15.

Use curing materials conforming to 705.05; 705.06 (white opaque); or 705.07;Type 1 or 1D.

Use 1/4-inch (6 mm) gray sponge joint filler conforming to 711.28, or use preformed filler conforming to 705.03.

Use preformed elastomeric compression joint seals conforming to 705.11.

511.03  Concrete.  Provide concrete for structures according to 499.03, using Class QC 1, QC 2, QC 3 or QC 4 as specified in the Contract.

At least 10 days before placing concrete, submit, in writing, the Department accepted Job Mix Formula (JMF) to the Engineer.  The Engineer will review the mix design for conformance to contract requirements; otherwise the mix design is for the Engineers information.

511.04  Quality Control Requirements and Mass Concrete.  When the concrete bid item requires QC/QA, develop and submit a Quality Control plan (QCP) for the work and perform quality control testing of the concrete conforming to Item 455.

When the concrete bid item requires QC/QA, The Engineer will perform Quality Assurance conforming to 455.

When the concrete bid item does not require QC/QA, the Engineer will make acceptance test cylinders as follows:

1.          Structures over 20-foot (6.1 m) span. A set of test cylinders from each 200 cubic yards (150 m) of concrete, or fraction thereof that is incorporated into the work each day.

2.          Structures of 20-foot (6.1 m) span or less. At least one set of test cylinders for each 50 cubic yards (35 m) of concrete.

With any 511 concrete bid item provide and maintain a Concrete Cylinder Curing Box (CCCB) capable of holding at least 12 4 8 inch (100 200 mm) cylinders at a temperature of 60 to 80 F (15 to 27 C) degrees no matter what the ambient temperature.  The box will have a sealed lid.  If the project has numerous 511 concrete bid items CCCB are not required for each bid item.  Locate the CCCB at a site that is convenient to the concrete work and will eliminate handling damage to both the Contractor QC or QA cylinders and the Department Cylinders.  Move the CCCB as needed during the project when the distance from the concrete work increases the possibility of cylinder handling damage. 

A. Mass Concrete Requirements.  For concrete components with a minimum dimension of 5-ft (1.5-m) or greater, develop a concrete mix design QC-4 for mass concrete according to 499.03. Develop a Thermal Control Plan (TCP) to control placement of the mass concrete so that the highest maximum internal temperature of the placed concrete is not greater than 160 F (71 C) and the maximum differential concrete temperature does not exceed 36 F (20 C) over 28 days from time of placement.

For drilled shafts with a dimension of 7-ft (2.1-m) diameter or greater, develop a concrete mix design QC-4 for mass concrete, QC 4 according to 499.03. Develop a TCP to control placement of the mass concrete so that the highest maximum internal temperature of the placed concrete is not greater than 160F (71C).

Submit the TCP to the Engineer for acceptance at least 10 calendar days prior to placement along with the approved JMF (s).

As a minimum, the TCP shall include the following information:

1. Duration and method of curing.

2. Procedures to control concrete temperature at the time of placement. The mix shall contain no frozen pieces of ice after blending and mixing components.

3. Methods and equipment used for controlling temperature differentials.

4. Temperature sensor types, locations and installation details. As a minimum, concrete temperatures shall be monitored at the calculated hottest location, on at least 2 outer faces, 2 corners, and top surfaces.

5. Temperature monitoring and recording system; operation plan; recording and reporting plan with example output; and a remedial action plan.

Criteria for form removal to control the maximum temperature differential.

As an alternative to the maximum differential concrete temperature specified above, the Contractor may propose maximum differential temperature limits based on strength gain with time.   The TCP for the alternative proposal shall include the methods used to determine the temperature and supporting data and design to support the accuracy of the method chosen.  Provide complete calculations and basis for increasing the maximum differential temperature specification. The TCP for the alternative proposal shall also provide the Engineer with tables that define ambient temperatures for acceptable concrete placement, the required temperature of the concrete for the ambient air temperature, the maximum predicted concrete temperature, the maximum predicted differential temperature, the time for removal of forms, the allowable air temperature for form removal, and the predicted maximum and differential temperature from placement to age of 28 days.  The Department will consider all cracking of a mass concrete placement where the differential temperature exceeded 36 F (20C) the responsibility of the Contractor.

Upon the Engineers acceptance of the TCP, continuously monitor all temperature sensors over the required age of the concrete. If the maximum limit or differential temperature limits are exceeded at any time, immediately take action to retard and reduce the out-of-specification temperatures.  If a mass concrete placement temperature exceeds the specification limits of the currently accepted TCP, re-engineer, revise and resubmit the TCP.  Do not place additional mass concrete until the revised TCP is accepted.

The Department will consider in-place mass concrete that exceeds the temperature limits or that cracked, as defective and resulting delays as non-excusable. Determine the extent and effect of the damage and submit a proposed repair plan to the Engineer to return the concrete to acceptable quality.  The Department will determine if the proposed repair methods are acceptable or if removal is required.

511.05  Mixing of Concrete.  Mix concrete according to 499.08.

When an air temperature of 60 F (16 C) or higher prevails at the time of placing concrete in a bridge superstructure over 20-foot (6.1 m) span, add a chemical admixture conforming to 705.12, Type B or D to the concrete unless waived by the Engineer. 

511.06  Slump.  Within the slump ranges specified in 499.03, provide a slump that produces concrete that is workable in the required position, flows around reinforcing steel, and coats individual particles of coarse aggregate with mortar containing the proportionate amount of sand.

511.07  Placing Concrete.  Submit to the Engineer a description of proposed placing procedures and notify the Engineer at least 24 hours in advance of placing concrete.  If the concrete bid item requires QC/QA, include the submittal as part of the QCP.

Place and finish concrete to the lines and grades shown in the plans.

Provide coverage over or around reinforcing steel as described in 509.04.

Conform to the following tolerances from plan dimensions:

TABLE 511.07-1

PLACEMENT TOLERANCES

Deviation from plumb for exposed surfaces

      inch (19 mm)

Vertical alignment (Deviation from a line parallel to the grade line)

inch in 20 feet (13 mm in 6 m)

 

Longitudinal alignment (Deviation from a line parallel to the centerline or baseline)

inch in 20 feet (13 mm in 6 m)

 

Width dimensions of walls for exposed surfaces

    inch (13 mm)

Bridge Slab thickness

inch (6 mm)

Elevations of beam seats

1/8 inch (3 mm) 

Slope, Vertical Deviation from Plane

0.2%

Slope, Horizontal Deviation from Plane

0.4%

 

Until discharged in the work, ensure that the temperature of all concrete does not exceed 95 F (35 C).  . 

When placing superstructure concrete assure the ambient air temperature is 85 F (30 C) or less and not predicted to go above 85 F (30 C) during the concrete placement; and evaporation rates, determined according to Figure 1 in ACI 308, do not exceed 0.1 lbs/ft2/hour (0.5 kg/m2/hour).

Determine and document the ambient air temperature, concrete temperature, deck surface temperature, relative humidity, and wind velocity, subject to verification by the Engineer.  Measure data required in Figure 1 from within 10 feet (3 m) of the area where the superstructure concrete is placed.

Figure 1 does not apply to substructure items and formed parapets.  Figure 1 applies to slip-formed parapets.

To meet favorable atmospheric conditions, may require the Contractor to place concrete at night.  At least 24 hours before placing concrete at night, submit a lighting plan for the work area to the Engineer.  Obtain the Engineers approval of the lighting plan before placing the concrete.  Direct lights so that approaching traffic is not affected or distracted.

Before placing a concrete deck on continuous steel beams or girders, complete all of the main beam or girder splices at least two piers beyond the pier or piers supporting the concrete.

Before placing concrete for backwalls above the approach slab seat with steel expansion joints, backfill the abutments to within 2-feet (0.6 m) of the bridge seat elevation, erect structural steel or prestressed concrete beams and place superstructure concrete in the adjacent span,.  Use the steel expansion joint as a template for the top of the backwall.  If temporary bolts are used to support the backwall portion of an expansion device during the placing of the backwall concrete, remove the bolts after the concrete has taken its initial set and before a change in temperature causes superstructure movement sufficient to damage the backwall.

Before placing concrete, assure the Engineer of an adequate and uniform source of supply of concrete to allow proper placing and finishing, and of the availability of coverings to protect the concrete from rain.

Do not add or apply water to the concrete after it has left the truck and before applying curing materials according to 511.14.

Before placing concrete, thoroughly clean all forms and structural steel that contact the concrete and ensure that the space to be occupied by the concrete is free of laitance, silt, dirt, shavings, sawdust, loose and built-up rust, and other debris.

Deposit concrete using methods that ensure reinforcing steel is completely enveloped in concrete mortar and that allow inspection of concrete enveloping the reinforcing steel.  Use a method or device to convey the concrete from the mixer to the work that prevents coarse aggregate separating from the mortar.  If depositing concrete in shallow members, such as slabs, place it with as short a vertical drop as possible.  Place the concrete over a section to maintain a practically horizontal surface.  If using a chute, slope the chute to allow concrete to flow without segregation.  Place concrete as near as possible to its final position.

Drop concrete into the forms with a free-fall distance of 5 feet (1.5 m) or less.  As necessary, use drop chutes to limit the free fall to 5 feet (1.5 m) and to ensure the delivery ends as vertical as possible.

Deliver and distribute the concrete at a uniform and adequate rate no more than 10 feet (3 m) directly in front of the finishing machine by suitable mechanical equipment. For structures with a skew angle greater than fifteen (15) degrees, Orient the finishing machine according to 511.16.  For structures with a skew angle greater than fifteen (15) degrees and up to fifty (50) degrees, load the concrete at the skew angle.  For structures with a skew angle greater than fifty (50) degrees, load the concrete as close to the skew angle of the structure as possible, but do not allow the leading edge of the concrete placement to exceed twenty (20) feet (6.1 m) ahead of the finishing machine.

Place concrete in structures using vibration.  Furnish and use sufficient vibration equipment of the type and size approved by the Engineer to properly compact the concrete immediately after it is placed in the forms.  The vibrators shall generally be of a type that is applied directly to the concrete and have a frequency of at least 4500 impulses per minute.  If the concrete is inaccessible for this method of vibration, apply the vibrators to the outside of the forms.

Do not move concrete using a vibrator.  Vibrate freshly deposited concrete at the point deposited.  Slowly insert and withdraw the vibrators vertically into the concrete until the concrete is thoroughly compacted but not segregated.  During vibration, do not disturb partially hardened concrete.

As necessary, spade along form surfaces, in corners, and in locations impossible to reach with vibrators to ensure smooth surfaces and dense concrete.  Closely observe the results obtained on the first concrete placed, and, if necessary, modify the mix according to this specification to secure the best results.

Figure 1 ACI 308-81

511.08  Slipform Construction of Bridge Railing.  If slipforming, provide finished concrete conforming to the following tolerances from plan dimensions:

 

TABLE 511.08-1

SLIPFORMED BRIDGE RAILING TOLERANCES

Reinforcing steel cover

-1/2 inch, +1/2 inch (-13 mm, +13 mm)

Top width dimension

-0, +1/4 inch (+6 mm)

Bottom width dimension

-0, +1/2 inch (+13 mm)

Surface flatness

1/4 inch in 10 feet (6 mm in 3 m)

Vertical alignment (Deviation from a line parallel to the grade line)

1/2 inch in 20 feet (13 mm in 6 m)

 

Tie all joints and splices in bridge railing reinforcing steel.  Before placing concrete, perform a slipforming dry run to verify reinforcing clearance and rigidity of the reinforcing cages.  Adjust and stabilize the cage as necessary to establish the required clearances and to ensure the cage will not move during slipforming.  The Contractor may add any additional diagonal reinforcing steel between the front and rear vertical reinforcing faces to establish the required rigidity.

Repair or patch honeycombing, cracking, tearing, and other defects immediately after concrete exits the slipform equipment.  Completely fill defects with concrete without using water to smooth or close the surface.  If the slipforming exhibits more than infrequent defects, stop work and make adjustments to produce a slipformed surface that does not require repairs. Do not broom finish the surface of the bridge railings.

After the concrete initially sets, but before any shrinkage cracks develop, saw control joints 1 1/4 inches (32 mm) deep into the perimeter of the parapet.  Generally, initial set is within 6 hours of batching of the concrete.  Ensure that all joints are sawed within 24 hours of placement. Saw control joints using an edge guide, fence, or jig to ensure that the joint is straight, true, and aligned on all faces of the parapet.  The joint width shall be the width of the saw blade, a nominal 1/4 inch (6 mm).  Caulk the control joints with a polyurethane or polymeric material conforming to ASTM C 920, Type S.

Slip formed concrete requires different slumps than those listed in Item 499 or other plan specified concrete.  Provide a slump such that the concrete exiting the slipform does not pull but is stiff enough to prevent waviness and sags in the finished surfaces.  Cure slipform concrete according 511.14, Method A.  Because slipformed concrete has a low water-cement ratio, timely application of the water cure is critical in helping control shrinkage cracks.

Furnish platforms as necessary to protect traffic passing under the bridge from falling debris during the slipforming operation, to allow access for completing the finishing operation, and to allow the Engineer access to the outside of the parapet.

The Engineer will inspect the slipformed surface for horizontal cracking no earlier than 21 days after completion of the slipforming operation.  Repair all horizontal cracks by epoxy injection.  If a concrete sealer was applied, repair damage to the sealer after completing the epoxy injection.

511.09  Construction Joints.  If construction joints are shown on the plans, place all concrete between consecutive joints in a continuous operation.  Do not place concrete against a joint for at least 12 hours, or as required by 511.14.

Obtain the Directors approval before placing any construction joint not shown on the plans or required by 511.07.

Before placing concrete, determine the location where the days concrete placing ends.  If practical, end placing the days concrete perpendicular to the lines of principal stress and in regions of small shear.  Do not install horizontal joints in concrete girders and beams.

Form construction joints using bulkheads with keyways.  Locate keyways clear of exposed surfaces by approximately one-third the thickness of the joint.

Where practical, avoid horizontal joints in piers, abutments, and retaining walls, otherwise locate horizontal joints 2 feet (0.6 m) or more above the normal water level.

For construction joints not shown on the plans and above ordinary low water, in abutments, and in retaining walls that retain earth fills, install a 36-inch (1 m) strip of Type 2 membrane waterproofing according to Item 512 to the back of the joint.

Avoid joints in cantilevered members.

Dampen the surface of the concrete of the horizontal construction joints immediately before placing adjoining concrete.

Place and protect horizontal construction joints between bridge slabs and superimposed curbs, parapets, sidewalks, and median strips in the same manner as the remainder of the slab.  Cure the construction joints according to 511.14.

Avoid disturbing the bond between protruding reinforcing steel and the deck concrete.  If using the curb areas to place the deck, tie and brace the reinforcing steel to prevent its movement.

Where walls or columns support slabs or beams, place concrete in wall or column to the bottom of the slab or beam and allow the concrete to settle for at least 2 hours before placing concrete in the slab or beam.

511.10  Work Stoppage.  If the work is unexpectedly interrupted by breakdowns, storms, or other causes, rearrange the freshly deposited concrete to provide a suitable construction joint.  If this joint occurs at a section with shear stress, prevent a plane of weakness by providing an adequate mechanical bond across the joint by forming a keyway, inserting reinforcing steel, or by some other means satisfactory to the Engineer.

511.11  Depositing Concrete Under Water.  Except for cofferdam seals and drilled shafts, do not place concrete under water.

511.12  Depositing and Curing Concrete During Cold Weather.  If placing concrete when the atmospheric temperature is 32 F (0 C) or less, or if weather forecasts predict these temperatures during the curing period, follow the procedures of this subsection.

Heat the water or aggregate, or both, as necessary to produce concrete with a temperature when placed of at least 50 F (10 C) but not greater than 70 F (21 C).

Place concrete against materials with a temperature of greater than 32 F (0 C).  If necessary, heat the forms, reinforcing steel, and foundation materials before placing the concrete.

Maintain the concrete surface temperature between 50 and 100 F (10 and 38 C) for a period of not less than 5 days, except as modified in 511.12.C.  After the minimum cure period of 5 days, reduce the concrete surface temperature at a rate not to exceed 20 F (11 C) in 24 hours until the concrete surface temperature is within 20 F (11 C) of atmospheric temperature.

Install sufficient high-low thermometers to readily determine the concrete surface temperature.  For deck slabs, install high-low thermometers to measure deck bottom surfaces, deck fascia surfaces, and deck top surfaces.

Maintain the concrete curing temperature using a heated enclosure, insulated forms, or by flooding, except cure deck slabs less than 10 inches (250 mm) thick using more than just insulated forms.

Remove falsework and open cold weather concrete to traffic according to 511.14.

A.      Heated Enclosure.  Construct the heated enclosure to surround the top, sides, and bottom of the concrete.  Construct strong and wind proof enclosures that contain adequate space to allow free circulation of air around the forms and concrete.

Before placing concrete, construct the enclosure and heating devices to the extent allowed by the concrete operation.  As the concreting operation progresses and as soon as possible after placing concrete, complete construction of the enclosures and apply heat.  Supply heat by a method that continuously maintains a reasonably uniform temperature throughout the enclosures and does not discolor the concrete.

Vent combustion-type heating devices outside the enclosure.

If dry heat, other than free steam, maintains the enclosure temperature, immediately cover exposed concrete with two thicknesses of burlap.  Continuously wet the burlap and, except for required rubbing of the concrete, do not remove the burlap during the heating period.

If wood forms without liners are left in place more than 2 days after the placing of concrete, thoroughly wet the forms at least once each day for the remainder of the heating period.  If forms are removed during the heating period, thoroughly drench the concrete with water and, for the remainder of the heating period, cover and wet the concrete with burlap as specified above.

B.      Insulation.  Install sufficient thermometers to readily determine the concrete surface temperature.  If the surface temperature approaches 100 F (38 C), loosen or otherwise vent the forms or insulation to keep the surface temperature within the limits specified above.  If insulation does not maintain the minimum required temperature, promptly enclose the concrete as specified in 511.12.A or flood the concrete as specified in 511.12.C.

Use a wind and water resistant insulating material.  Ensure edges, corners, and other points of extreme exposure are adequately insulated.  Place a tarpaulin or other Engineer approved waterproof cover over the insulation to protect the concrete top surface.

C.      Flooding with Water.  The Contractor may flood the concrete with water provided flooding does not damage the concrete.  Heat the water to a temperature from 50 to 100 F (10 to 38 C).  The Contractor may stop using heated water after 48 hours if the concrete remains flooded to a depth of 1 foot (0.3 m) above its highest elevation for at least the next 120 hours.

511.13  Removal of Forms.  To facilitate finishing, remove forms from vertical surfaces that receive a rubbed surface finish as soon as the concrete has hardened sufficiently that rubbing will not damage it.

511.14  Curing and Loading.  Remove falsework and open structures to traffic only after the concrete has reached the strength specified by Table 511.14-1A for concrete bid items requiring QC/QA.  Use Table 511.14.1B for concrete items not requiring QC/QA. Do not shorten the minimum required Method A curing time regardless of strength test results.

Table 511.14-1a

Loading requirements For concrete requiring QC/QA

 

Span[1]

Required Strength [2]

Removing Falsework

Any Span

Compressive Strength ≥ 0.85% fc

orFlexural Strength (Center point)

≥ 650 psi (4.5 Mpa)

All pier caps

Traffic [3]

Any

[1]  Span is defined as the horizontal distance between faces of the supporting elements when measured parallel to the primary reinforcement.

[2]  Field cured samples.  The maturity curve method may be used for determining the strength according to Supplement 1098 in lieu of field curing samples

[3]  When placing concrete for a superstructure between October 15 and March 15, open the deck to traffic no sooner than 30 days after placement.

 

 

 

 

Table 511.14-1b

Loading requirements for concrete not requiring qc/qa

 

Span[1]

Age of Concrete in Days

No Beam Test

Beam Test [2]

Removing Falsework

Over 10 feet (3 m)

14

5

10 feet (3 m) or less and all pier caps

7

3

Traffic [3]

Any

14

7

[1]  Span is defined as the horizontal distance between faces of the supporting elements when measured parallel to the primary reinforcement.

[2]  Applicable only when the average modulus of rupture for two tests is not less than 650 psi (4.5 MPa).

[3]  When placing concrete for a superstructure between October 15 and March 15, open the deck to traffic no sooner than 30 days after placement.

 

 

 

 

Take enough specimens to verify compliance with the strength requirements of Table 511.14-1A.  Obtain samples from the first and last sublots of continuously placed concrete for quantities of 500 yd3 or less, and one extra set of specimens for each additional 500 yd3 or fraction thereof.  Obtain samples in equally spaced increments throughout the placement as directed by the Engineer.  Delays in placements of more than 4 hours are not considered continuously placed and are to be treated as separate placements.

If the air temperature surrounding the concrete is maintained between 32 and 50 F (0 and 10 C), and if the provisions of 511.12 do not apply, maintain the concrete above 32 F (0 C) for 7 days or until a successful strength test conforming to Table 511.14-1, except this time shall not be less than 5 days.

Do not install compression rings on pier columns or similar items of construction for supporting falsework or subsequent construction until after a 72-hour curing period.

Do not apply loads to or perform work on new concrete until workers and  construction materials will not damage the concrete or interfere with its curing.  Allow at least 36 hours or until the field cured compressive strength cylinders or maturity results reach 85% fc; or if using flexural beams, or the average of two beam tests is greater than 650 psi (4.5 MPa) before working on new concrete. Do not interfere with curing of new concrete.

Cure concrete as follows:

TABLE 511.14-2

CURING REQUIREMENTS

Location

Curing Method [1]

Superstructure concrete

Method A

Concrete to which sealer is applied

Method A

Construction joints

Method A

Top surface of concrete deck superstructure concrete

Method A followed by Method B

Concrete with waterproofing

Method A or Method B

All other concrete

Method A or Method B

[1]  Method A is water curing.  Method B is membrane curing.  If using Method B on areas to be waterproofed, remove the curing membrane.

 

Concrete curing methods are as follows:

A.      Method A, Water Curing.  With the exception of the top surface of deck superstructure concrete, protect surfaces not covered by forms immediately after final finishing with two thicknesses of wet burlap.  Keep burlap wet for at least 7 days by the continuous application of water.  If forms are removed before 7 days, immediately drench the exposed concrete with water and cover it with burlap.  Continuously apply water to the burlap for the remainder of the curing period.

Instead of continuous application of water, with the exception of the top surface of deck superstructure concrete, the Contractor may cover the wet burlap with white polyethylene sheeting or plastic coated burlap blankets conforming to 705.06.  Place plastic coated burlap blankets wet and with the burlap side against the previous layer of wet burlap.  Sufficiently lap and secure adjoining plastic coated blankets or polyethylene sheets at the laps and edges to form a seal that maintains the concrete wet at laps and edges.  Cover white polyethylene sheeting or plastic coated blankets containing holes or tears with an additional covering of plastic sheeting or blankets as directed by the Engineer.

Cover the top surface of deck superstructure concrete with a single layer of clean wet burlap after it is bull floated if necessary, and finished.  Keep the burlap wet by a continuous flow of water through soaker hoses and cover the hoses with a 4 mils (100 mm) white opaque polyethylene film for 7 days.  After 7 days, allow the surface of the deck to dry.

After curing the top surface of the deck superstructure concrete for 7 days, remove the burlap and standing water.  Within 12 hours after removing the burlap, apply a curing membrane and cure the concrete according to Method B.

B.      Method B, Membrane Curing.  Immediately after the free water has disappeared on surfaces not protected by forms, apply curing material conforming to 705.07, Type 1 or 1D.  If forms are removed before the end of the 7-day curing period, apply curing material on the concrete exposed by removing the forms.

Thoroughly mix curing material immediately before use.  Apply the membrane curing material at the rate of at least 1 gallon per 200 square feet (1 L/5 m2) of surface and in a fine mist to provide a continuous, uniform, and water impermeable film without marring the concrete surface

Do not allow workers, materials, and equipment on the concrete during the curing period, unless adequately protecting the membrane curing material from damage. .

 If the film is broken or damaged during the specified curing period, reapply curing material as specified above to the damaged or affected areas.

511.15  Surface Finish.  Immediately after removing forms, clean, dampen, and fill with mortar all cavities produced by form ties, honeycomb spots, broken corners or edges, and other defects.  Use a mortar of the same proportions used in the concrete being finished.  Substitute sufficient white cement for the regular cement in the mortar used to fill holes and perform other corrective work to produce finished patches of the same color as the surrounding concrete.  Finish other contiguous exposed surfaces on the structure in a similar manner and to the extent required to produce a uniform appearance.

On all exposed surfaces, remove fins and irregular projections with a stone or power grinder, taking care to avoid contrasting surface textures.

A.      Grout Cleaning.  If grout cleaning is shown on the plans or necessary for corrective work, wet the concrete surface and then uniformly cover the concrete with a grout consisting of one part cement, 1 1/2 parts fine sand conforming to 703.03, and sufficient water to produce a mortar with the consistency of thick paint.  Use white portland cement in the grout in the quantity determined by the Engineer necessary to match the color of the concrete.  Uniformly apply the grout with brushes or spray guns, completely filling air bubbles and holes.  Immediately after applying the grout, vigorously scour the concrete surface with a cork or other suitable float.  While the grout is still in a plastic condition and while the grout does not pull from the holes or depressions, finish the surface with a sponge rubber or other suitable float, removing excess grout.  After the grout thoroughly dries, vigorously rub the surface with dry burlap, removing dried grout until there is no visible film of grout remaining on the surface.  Perform the entire cleaning operation of each area on the same day.  Remove dark spots or streaks that remain after the cleaning operation using a fine grained silicon carbide stone.  Stop rubbing with the silicon carbide stone before the surface texture changes.  Unless otherwise directed by the Engineer, perform grout cleaning during the final project clean up.

B.      Rubbed Finish.  If a rubbed finish is shown on the plans, if possible, remove forms within 2 days after placing concrete.  Finish the surface as specified above to correct defects.  After the mortar used for finishing is thoroughly set, and for a minimum of 2 hours before starting the rubbed finish, thoroughly saturate the concrete with water.

Rub surfaces to be finished with a medium coarse silicon carbide stone until all form marks, projections, and irregularities are removed, all voids are filled, and a uniform surface is obtained.  Leave the paste produced by rubbing in place.  Other than water, do not apply additional material to the surface.  After placing concrete above the finishing area, obtain the final finish by rubbing the concrete with a fine silicon carbide stone and water until the entire surface is of a smooth texture and uniform in color.  Protect surfaces with a rubbed finish from damage caused by subsequent construction operations.  If damaged, clean and refinish the surface as specified above.

511.16  Roadway Finish.  Finish and test concrete deck slabs according to 451.12. Do not groove or broom finish a strip of surface 9 to 12 inches (220 to 300 mm) wide adjacent to curbs and barriers.  Provide a broom drag finish on concrete deck slabs in the longitudinal or transverse direction.

The Engineer will approve the finishing machine.  Provide a self-propelled machine with forward and reverse drive mechanisms that enable precise control of machine velocity in both directions.  The machine shall have two rotating rollers, leveling augers, and either a vibrating pan or vibrating rollers.  Field verify that the vibrating frequency of the pans or rollers are from 1500 to 5000 pulses per minute.  Do not use vibrating rollers that have fins protruding more then 1/4 inch (6 mm) from the roller.  Use a finishing machine capable of finishing transversely while traveling in both directions across the deck.  Provide screeds capable of rising above the concrete surface.  Provide a finishing machine capable of finishing the full width of the decks between curbs or parapet walls.  The wheels of the finishing machine shall run on temporary riding rails adequately supported on the structural steel or falsework of the deck.  Make the rail and rail supports of steel and arrange the rail and rail supports so that the weight of the finishing machine and the operator cause zero vertical deflection while traveling across the deck.  Ensure the rail is straight, with no sections exceeding a tolerance of 1/8 inch in 10 feet (3 mm in 3 m) in any direction.  Elevate support rails a sufficient distance above the slab to allow the simultaneous hand finishing of areas not machine finished.  Fabricate and install rail supports to allow removal to at least 2 inches (50 mm) below the top of the slab.  Fill holes formed by the removal of rail supports during the final finishing of the slab. 

For structures with a skew angle greater than fifteen (15) degrees and up to fifty (50) degrees, place the finishing machine within 5of the skew angle of the structure.  For structures with a skew angle greater than fifty (50) degrees, place the finishing machine at fifty (50) degrees.

511.17  Bridge Deck Grooving.  After water curing the concrete and either before applying curing compound or some period after applying curing compound and before opening the bridge to traffic, saw longitudinal grooves into the deck. If sawing grooves after applying the curing compound and the concrete deck is less than 30 days old, reapply the curing compound after removing standing water, within 12 hours after sawing grooves in the deck.

Use diamond blades mounted on a multi-blade arbor on self-propelled machines that were built for grooving of concrete surfaces. The groove machines shall have depth control devices that detect variations in the pavement surface and adjust the cutting head height to maintain the specified depth of the groove. The grooving machines shall have devices to control alignment. Do not use flailing or impact type grooving equipment. More than one size grooving machine may be required in order to saw the grooves as specified.

 Provide an experienced technician to supervise the location, alignment, layout, dimension, and grooving of the surface.

Saw grooves parallel to the bridge centerline in a continuous pattern across the surface. Begin and end sawing 9 to 12 inches (220 to 300 mm) from any device in place in a bridge deck, such as scuppers or expansion joints. Stop sawing a minimum of 2 inches (50 mm)  to a maximum of 24 inches (600 mm) from skewed expansion joints. Maintain a clearance of a minimum of 2 inches (50 mm) and a maximum of 4 inches (100 mm) from the grooves to longitudinal joints in the deck.  Maintain a minimum clearance of 9 inches (220 mm) to a maximum of 30 inches (750 mm) clearance between the grooves and the curb or parapet toe. However, at no point shall un-grooved portions of deck extend beyond edge line and into the temporary or permanent travelled lanes.  Saw grooves in a uniform pattern spaced at 3/4 inch minus 1/4 inch or plus 0 (19 mm minus 6 mm or plus 0). Saw grooves approximately 0.15 inches (4 mm) deep and 0.10 inches (3 mm) wide.

For staged, or phase bridge deck work, saw the grooves parallel to the final, permanent bridge centerline. If the different stages or phases of the bridge deck work occur within one construction season, any stage opened to traffic shall receive an interim coarse broom finish during placement, then saw the longitudinal grooves after the final stage. The interim broom finish will not be allowed as a surface texture when opened to traffic over a winter season. Saw longitudinal grooves in the deck prior to opening to traffic for a winter season.

For bridge decks that widen from one end to the other, saw the longitudinal grooves parallel to the centerline of the roadway. On the side of the bridge that widens, saw the longitudinal grooves to follow the edge line. Saw longitudinal grooves in the gore areas, avoiding the overlapping of grooves.

At the beginning of each work shift, furnish a full complement of grooving blades with each saw that are capable of cutting grooves of the specified width, depth, and spacing.

If during the work, a single grooving blade on a machine becomes incapable of cutting a groove, continue work for the remainder of the work shift.  The Contractor is not required to cut the groove omitted because of the failed blade.  Should two or more grooving blades on a machine become incapable of cutting grooves, cease operating the machine until it is repaired.

Continuously remove all slurry and remaining residue from the grooving operation and leave the deck surface in a clean condition.  Prevent residue from grooving operations from flowing across shoulders or across lanes occupied by public traffic or from flowing into gutters or other drainage facilities.  Remove solid residue before the residue is blown by passing traffic or by wind.

Provide water as necessary to saw grooves according to this subsection.

511.18  Sidewalk Finish.  After placing, strike off the concrete with a template and finish the concrete with a float to produce a sandy texture.

511.19  Sealing Joints and Cracks.  After completing all curing operations and allowing the deck to thoroughly dry, seal the following areas with a high molecular weight methacrylate (HMWM) sealer as specified in Item 512 before opening the deck to traffic:

A.      Transverse joints in the deck.

B.      Joints between the concrete deck and steel end dams.

C.      Longitudinal joints in the deck.

D.      Longitudinal joints between the deck and safety curb, barriers, and parapets, etc.

E.      Cracks discovered in the deck that will be checked on the top and bottom surface before opening the deck to traffic.

511.20  Compressive Strength.  Sample and test concrete strength according to 511.04.

A. Concrete Requiring QC/QA.  When the bid item requires QC/QA, the Engineer will evaluate the QC compressive test sublot results according to Supplement 1127 and as follows: 

If a single reported compressive strength test result for a sublot of concrete is less than 88% fc reevaluate the in-place concrete as follows:.

The Engineer will determine the location for evaluating the strength of the sublot represented by the low compressive strength concrete. Evaluate using either nondestructive testing or cores. The Engineer will accept the concrete if the reported nondestructive test results are greater than the specified fc. The Department will use the original cylinder results for calculating the compressive strength pay factor (PFc) if non-destructive testing is used. If cores are tested the core results will be used in place of the original cylinder results for pay factor determination.

If the nondestructive test results are less than the specified fc, the Department will require the concrete to be cored. The Engineer will determine the locations for the required concrete cores. Provide all concrete cores to the Engineer for testing by the Department. Patch core holes with approved patching material. If the core results are above 88% fc, the Department will use the core strength results for calculating the compressive strength pay factor (PFc).

If the core results indicate that the compressive strength of the concrete is below 88% fc, submit a plan for corrective action to the Engineer for approval. If the corrective plan is not approved, the Engineer will require the Contractor to:

1. Remove and replace the unacceptable sublot and retest the new sublot at no cost to the Department or

2. Leave the unacceptable material in place and pay for the sublot with a pay factor of 0.75.

If three or more sublot compressive strength acceptance test results are less than fc but greater than 88% fc the Engineer will require an investigation of the reasons for the consistent low strengths. Until the investigation is completed to the satisfaction of the Engineer no additional placements of the concrete JMF will be made. Investigations should include all facets of the concrete operation including batching, mixing, delivery, clean up, sampling, testing, quality control plan, etc.  If the Engineer is unsatisfied with the results of the investigation, the JMF and the quality control plan will become not approved. Develop and submit a new JMF and quality control plan conforming to the requirements of 499.03 and 511.04.  Pay factors under 511.22 for these low strength sublots will be based on the original reported cylinder strengths.

B. Concrete Not Requiring QC/QA.  When the bid item does not require QC/QA, the Engineer will evaluate the strength results following the requirements of Table 511.22-2 and as follows:

If a single compressive strength test result is less than fc the material will be considered unacceptable material and the Department will determine acceptance according to Item 106.07.

If three or more compressive strength test results are less than fc the Engineer will require an investigation of the reasons for the consistent low strengths. Until the investigation is completed to the satisfaction of the Engineer no additional placements of the concrete JMF will be made. Investigations should include all facets of the concrete operation including batching, mixing, delivery, clean up, sampling, testing, etc.  If the Engineer is unsatisfied with the results of the investigation, the JMF will become not approved. Develop and submit a new JMF conforming to the requirements of 499.03.

  511.21         Air Content.  For concrete that requires QC/QA, test the air content of the concrete according to Item 455.  When QC/QA concrete is not required, the Department will test the air content as directed by the Engineer.

A. Concrete Requiring QC/QA.  Any concrete with air results outside the requirements of Table 499.03-1 that is placed into the structure is unacceptable material according to item 106.07.  The amount of unacceptable material will be the amount represented by the test result. Reevaluate the unacceptable material at no cost to the Department as follows:

1.       Core the location containing the unacceptable concrete.  Patch the core hole with approved material.

a.       For concrete with high air content, test a core for compressive strength.  Concrete with a minimum strength of fc may be left in place.

b.       For concrete with low air content, test the core to determine the in-place hardened air content, specific surface and spacing factor according to ASTM C 457.  Remove and replace unacceptable materials with specific surface results less than 600 in-1 (25 mm-1) or spacing factor results are more than 0.008 in (0.20 mm).

Hire an independent laboratory acceptable to the Department to perform the testing.

B. Concrete Not Requiring QC/QA.  Any concrete with air results outside the requirements of Table 499.03-1 that is placed into the structure is unacceptable material, according to item 106.07.  The amount of unacceptable material will be the amount represented by the test result. Reevaluate the unacceptable material at no cost to the Department as follows:

1.       The Department will core the location containing the unacceptable concrete. Patch the core hole with approved materials.

a.       For concrete with high air content, the Department will test a core for compressive strength.  Concrete with a strength of fc may be left in place.

b.       For concrete with low air content the Department will determine the in-place hardened air content, specific surface and spacing factor according to ASTM C 457. Remove and replace unacceptable materials with specific surface results less than 600 in-1 (25 mm-1) or spacing factor results of more than 0.008 in (0.20 mm).

511.22 Pay Factors.  Apply pay factors as follows:

A.       Concrete Requiring QC/QA

The Department will use pay factors based on the percent within limits (PWL) to establish a final adjusted price.  The PWL will be established per lot(s) accepted in the QCP for each bid item quantity of concrete.  The Department will calculate a PWL according to Supplement 1127 using either the Contractors verified QC compressive test results or core results when the QC could not be verified.  The compressive strength pay factor (PFC) from Table 511.22-1for the lot will be applied to each bid item represented in the lot.   The Department will combine approach slab and deck concrete test results in the same lot to determine final pay factors.


 

TABLE 511.22-1

  PAY FACTORS FOR CONCRETE REQUIRING QC/QA

PWL

PFC

85 % 100 %

1.00

84%

0.995

83%

0.990

82%

0.985

81%

0.980

80%

0.975

79%

0.970

78%

0.965

77%

0.960

76%

0.955

75%

0.950

< 75%

See below

If the PWL value determined for the lot of concrete is below 75%, submit a plan for corrective action to the Engineer for approval. If the corrective plan is not approved, the Engineer will require the Contractor to:

1. Remove and replace the lot of unacceptable material at no cost to the Department, or

2 Leave the unacceptable material in place and pay for the lot of with a pay factor of 0.75.

B.       Concrete Not Requiring QC/QA

For concrete items that the Department performs compression testing, the Department will use pay factors based on the individual compressive strength results for the quantity represented by the test results to establish an adjusted price to the items.  The pay factors from Table 511.22-2 will be applied to items represented by the tests.

TABLE 511.22-2

  PAY FACTORS FOR CONCRETE NOT REQUIRING QC/QA

Individual Test Results

Pay Factor (PFC)

fc

1.00

< fc

Follow 106.07

511.23  Method of Measurement.  The Department will measure the appropriate concrete item by the number of cubic yards (cubic meters) determined by calculations from plan dimensions, in place, completed and accepted.

The Department will make deductions for portions of primary structural members embedded in concrete.  The Department will not make deductions for the volume of reinforcing steel, conduits or embedded piles.

Superstructure concrete includes the concrete in deflective parapets not having a metallic railing.

The Department may measure deck concrete by either volume or area using plan dimensions.

The Department will calculate separate quantities of concrete due to unacceptable compressive strength, 511.21 and air content, 511.22.

511.24  Basis of Payment.  The Department will pay for accepted quantities of concrete as follows.

The Department will not pay for additional reinforcing steel required to adequately stabilize the cages.

The Department will not pay for repairs to horizontal cracks by epoxy injection or, if a concrete sealer was applied, for repairs to the sealer after the completing the epoxy injection.

The Department will not pay extra for any type of surface finish specified in 511.15, the cost being considered as included in the price bid for concrete.

If the Contractor elects to saw the deck after applying the curing compound, the Department will not pay to reapply the curing compound.

All costs for sealing as specified in 511.19 are incidental to the appropriate concrete item.  The Department will not make separate payment for sealing.

The Department will not pay separately for the concrete cylinder curing box (CCCB).

The Department will not pay for the re-evaluation of low strength test results, 511.20.A.

The Department will initially pay the full bid price to the Contractor upon completing the work.  The Department will calculate the final adjusted payment for each item as follows:

PF1 - The final adjusted pay per cubic yard (cubic meter) or square yard (square meter), for accepted quantities of concrete:

PF1 = (Contract Bid Price) x PFC

PF2 - The final adjusted pay per cubic yard (cubic meter) or square yard (square meter) for unacceptable quantities of concrete due to compressive strength or low air content and allowed to stay in place, according to 511.20 or 511.21.

PF2 = (Contract Bid Price) x 0.75

Calculate the adjusted price per bid item by multiplying PF1 or PF2 by the appropriate quantities of concrete, then sum the values. Subtract the full bid price paid to the Contractor from the adjusted price to determine the difference. The Department will execute final adjustments by change order upon receipt of all test data.

The Department will pay for accepted quantities at the contract prices as follows:

Item

Unit

Description

511

Cubic Yard

  (Cubic Meter)

Class ___ Concrete, _____

511

Cubic Yard

  (Cubic Meter)

Class ___ Concrete, _____ with QC/QA

511

Cubic Yard

  (Cubic Meter)

Class QC 1 Concrete, Substructure

511

Cubic Yard

  (Cubic Meter)

Class QC 1 Concrete, Substructure with QC/QA

511

Cubic Yard

  (Cubic Meter)

Square Yard

  (Square Meter)

Class QC 2 Concrete, Bridge Deck

511

Cubic Yard

  (Cubic Meter)

Square Yard

  (Square Meter)

Class QC 2 Concrete, Bridge Deck with QC/QA

511

Cubic Yard

  (Cubic Meter)

Class QC 2 Concrete, Bridge Deck (Parapet)

511

Cubic Yard

  (Cubic Meter)

Class QC 2 Concrete, Bridge Deck (Parapet) with QC/QA

511

Cubic Yard

  (Cubic Meter)

Class QC 3 Concrete,  _____     with QC/QA

511

Cubic Yard

  (Cubic Meter)

Class QC 4 Mass Concrete, Substructure with QC/QA