722CONCRETE BRIDGE DECK OVERLAYS

722.01Description

This work shall consist of the surface preparation and construction of a bridge deck overlay consisting of latex modified portland cement concrete, LMC, latex modified concrete very early strength, LMC-VE, or silica fume modified concrete, SFMC, on an existing or new bridge deck, or it shall consist of patching an existing concrete overlay on a bridge deck in accordance with 105.03.

722.02Quality Control 10

LMC-VE overlays shall be placed in acco rdance with the QCP, which shall be prepared and submitted in accordance with ITM 803. The QCP shall include the Contractor’s experience placing LMC-VE over lays within the last three years. The QCP shall be submitted to the Engineer at least 14 days prior to commencing the overlay operation. Work shall not begin until written notice has been received that the QCP was accepted by the Department’s Division of Materials and Tests.

MATERIALS

722.03Materials 20

Materials shall be in acco rdance with the following:

Admixtures .................................................................. 912.03 Coarse Aggregate, Class A or Higher, Size No. 11* ... 904.03 Epoxy Resin Adhesive ................................................ 909.11 Fly Ash ........................................................................ 901.02 Latex Modifier ............................................................. 912.04 PCC Sealer/Healers ..................................................... 901.06 Portland Ceme nt .......................................................... 901.01(b) 30 Rapid Hardening Hydraulic Cement ........................... 901.01(d) Silica Fume .................................................................. 901.04 Water ........................................................................... 913.01 * Crushed stone only.

Evaporation retardant shall be a product that produces a monomolecular film. A Type D certification in accordance with 916 shall be provided for the evaporation retardant.

Citric acid shall be marked “food grade” on the packaging. 40

722.04Storage and Handling of Materials

Fine and coarse aggregates shall be stored and handled avoiding contamination and maintaining uniform moisture content. Fine and coarse aggregates which are stored in piles or bins shall remain separated and shall be covered with a moisture proof material which prevents variations in moisture content of the aggregates. The maximum variation of moisture content in successive concrete batches shall be 0.5%. 722.01

Cement shall be shipped and stored in accordance with 702.04 and 901.01.

The latex modifier, liquid silica fume sl urry, and dry condensed silica fume shall be stored in accordance with the manuf acturer’s recommendations. Latex modifier shall be strained to remove solid particles during transfer of the material from storage drums to the mobile mixer tank.

722.05Proportioning

A mix design shall be submitted a minimum of 14 days prior to use and calibration of the mobile mixer in accordance with 72 2.09. The proportioning of the ingredients 60 for the LMC shall be in accordance with 702.05 except as modified herein.

The amount of fine aggregate shall be 60% ±5% by dry weight of the total aggregate and shall be considered as the amount of aggregate blend passing the No. 4 (4.75 mm) sieve. The coarse aggregate sh all be No. 11, class A crushed stone. The cement content shall be a minimum of 658 lb/cu yd of concrete. The same brand of cement shall be used throughout a bridge structure. The amount of latex modifier shall be 3.5 gal. per 94 lb of cement. The net water added shall produce a slump of 5 in. ±1 in. at 4 to 5 minutes after discharge from the mixer. The moisture content of the aggregates shall be controlled such that the slump is within the specified limits. The 70 maximum water/cement ratio shall be 0.400 including the water in the latex. The air content shall be a maximum of 6%, by volume, of the plastic mix.

The yield will be checked using the 1/4 cu yd box method as follows. The chute shall be cleaned and the box shall be posi tioned to receive the discharged concrete. The mixer shall be operated until the cement counter indicates that 1/4 cu yd of concrete has been produced. The contents of the box shall be consolidated and struck off. Where the box is not essentially full, the gates shall be adjusted and the procedure shall be repeated until the actual and calculated volumes of concrete agree. Yield tests shall be run on the first load of each truck and every third load per truck thereafter. 80 The air content shall be tested on the first load of each truck prior to placing concrete onto the deck. Additional tests will be required after making any adjustments.

Slump and air content tests will be perf ormed after each acceptable yield test. The slump test shall be in accordance with AASHTO T 119 and will be performed 4 to 5 minutes after the concrete is discharged from the mixer. The water flow meter reading will be recorded at the time the slump test is taken. The concrete shall not be disturbed during the waiting period for the slump test. The air content test shall be in accordance with 505. Any concrete mixture which is not properly proportioned or does not conform to the specified slump will be rejected. 90

Class F or class C fly ash may be used in the latex modified portland cement concrete. The maximum cement reduction shall be 15% and the minimum replacement 722.05

ratio by weight of fly ash to cement shall be 1.25:1. Where portland pozzolan cement, Type IP is to be used in the concrete mix design, the cement content shall be increased by a multiplier of 1.06 times the specified cement content.

Proportioning of ingredients for LMC-VE shall be in accordance with 722.05(a) except as follows. 100

Cement shall be a rapid hardening hydraulic cement. Fly ash or other pozzolanic materials shall not be used. Citric acid ma y be used as a retardant. The maximum content of citric acid shall be 1% of the cement weight. The minimum compressive strength shall be 2,500 psi at 3 h and 3,500 psi at 24 h. The net water added shall produce a minimum slump of 7 in. and maximum slump of 10 in. at 4 to 5 minutes after discharge from the mixer. The maximum water-cement ratio shall be 0.440 including the water in the latex.

A trial batch shall be produced to verify that the mix design complies with the physical properties specified, as well as, simulating the placement properties unique to the conditions of the contract such as profile grade, cross slope, delivery time, discharge rate, slump loss with time, air content and target compressive strength. All testing of the trial batch concrete shall be performed by an ACI certified concrete field testing technician, grade I.

The trial batch demonstration shall include a meeting between the Contractor, material suppliers, and Department to discuss LMC-VE, mixing, delivery, placement, finishing, curing, and compressive testing. Representatives from the rapid hardening 120 cement manufacturer shall be present for tr ial batch demonstrations and the start-up for initial bridge deck placement. The Department’s Division of Materials and Tests may waive the required atte ndance for these representatives where the Contractor provides sufficient evidence of adequate experience with producing and placing LMC- VE. The trial batch demonstration may be conducted in conjunction with calibration of the mobile mixer in accordance with 722.13.

A CMDS shall be submitted a minimum of 14 days prior to the trial batch utilizing the Department provided spreadsheet. The proportioning of ingredients for each batch of SFMC shall be in accordance with 702.05 except as modified below and shall meet the mix design, trial batch demonstration, and job-use requirements as specified.

The portland cement content shall be 658 lb/cu yd. Silica fume shall be added at 50 lb/cu yd.

722.05

The SFMC shall utilize a Type F or G admixture to be combined with an air- entraining admixture, AEA, a HRWR admixture system or a HRWRR admixture 140 system and shall be selected from the QPL of PCC Admixtures and Admixture Systems.

The water/cement ratio shall be no less than 0.370 and shall not exceed 0.400. Portland cement and silica fume shall be included in the total amount of cementitious material.

The same brand of cement and silica fume shall be used throughout the structure. The HRWR or HRWRR admixture system shall not be changed during any individual contiguous pour. 150

The Contractor shall obtain a written st atement from each admixture manufacturer stating the compatibility of the HRWR admixture system and satisfactory performance in SFMC.

The SFMC shall have a relative yield and air content in accordance with 702.05. The slump will be tested in accordance with AASHTO T 119 at the time of placement and shall be at least 4 1/2 in. but shall not exceed 7 1/2 in. The SFMC shall have a minimum compressive strength of 4,500 psi at 7 days and 5,500 psi at 28 days. The compressive strength shall be in accordance with 702.24. 160

A trial batch shall be produced to verify that the mix design complies with the physical properties specified, as well as simulating the placement properties unique to the conditions of the contract such as profile grade, cross slope, delivery time, discharge rate, slump loss with time, air co ntent, and target compressive strength. All testing of the trial batch concrete shall be performed by an ACI certified concrete field- testing technician, grade I.

The trial batch demonstration shall include a meeting between the Contractor, 170 material suppliers, and Department to discuss SFMC, batching, mixing, delivery, placement, finishing, curing, and compressive testing. Representatives from the silica fume and chemical admixture manufacturer shall be present for trial batch demonstrations and the start-up for initial bridge deck placement. The Department’s Division of Materials and Tests may waive the required attendance for these representatives where the Contractor pr ovides sufficient evidence of adequate experience with producing and placing SFMC.

Batching shall be in accordance with 702.06 except the minimum batch shall be 180 4 cu yds and the maximum shall not exceed 80% of the truck rated capacity. Dry condensed silica fume shall be either sacked or bulk and it shall be batched in accordance with the requiremen ts for cement as specified in 702.06. No partial sack of dry condensed silica fume shall be used in a batch of SFMC. Dry condensed silica 722.05

fume shall be typically added after the initial water and aggregates, with premixing prior to the addition of cement and fly ash, to facilitate dispersion. An alternate batching sequence will be allowed as recommended by the manufacturer of the silica fume and as approved by the Engineer. Liquid silica fume slurry shall be batched as required by the manufacturer and as approved by the Engineer. The AEA shall be added initially with either the first portion of mix water or the fine aggregate. Where 190 a Type A or Type D chemical admixture is used as part of the HRWR admixture system, it shall be added separately with a portion of the mix water, after the AEA is premixed in the concrete. A Type F or Type G chemical admixture shall be added separately at the end of the batching sequence with some mix water held in reserve to aid dispersion.

.

A change in the sequence of batching may be approved if it is in accordance with

the chemical admixture and silica fume manufacturer’s recommendations and is

agreed to in writing prior to any trial batch demonstration.

200

722.06Preparation of the Bridge Floor

When an existing deck overlay is to be removed, the removal shall be performed

with a milling machine. The milling shall include the depth of the existing deck overlay

and an additional depth as shown on the plans. If no additional depth is shown on the

plans, the additional depth shall be 1/2 in. Removal in areas that are inaccessible to the

milling machine, shall be performed by chipping hammers or handchipping in

accordance with 722.06(b)3.

210

When an existing concrete deck without an overlay surface is to be removed, the

removal shall be performed with a milling machine. The milling shall be to a depth

shown on the plans. If no depth is shown on the plans, the milling shall be 1/2 in.

depth. The surface removal operation shall be limited to that portion of the bridge deck

that is closed to traffic at any one time. After this initial surface removal, additional

milling may be required as directed.

220

The milling machine shall uniformly remove the required depth of concrete

surface in a satisfactory manner. Surface removal in areas adjacent to the curb that are

inaccessible to milling, shall be done by handchipping in accordance with 722.06(b)3.

All surface removal residue, including water, dust, and concrete, shall be immediately

removed.

Where the milling operation results in the snagging of the top mat of steel

reinforcing bars, the milling operation shall cease and the depth of removal adjusted.

Damaged reinforcing bars shall be repaired as directed with no additional payment.

230

722.06

777

When shown on the plans, removal of unsound concrete shall be performed by

hydrodemolition. Following the cleanup from the surface removal operation, areas of

unsound concrete to be removed will be marked. The hydrodemolition equipment shall

consist of a self-propelled computerized machine that utilizes a high pressure water jet

stream capable of removing concrete as specified, as well as removing rust and

concrete particles from exposed reinforcing bars.

Prior to hydrodemolition, the equipment shall be calibrated on an area of sound

original deck concrete as designated by the Engineer. Calibration shall be performed240

at the bottom depth of the overlay shown on the plans.

The initial settings shall be verified on an area of unsound concrete. This area

shall not contain existing patches. The initial settings shall be adjusted to achieve total

removal of unsound concrete within the verification area. Equipment shall be

calibrated at each project bridge deck prior to operation. Where directed, equipment

shall be recalibrated to ensure removal of known areas of unsound concrete and to

guard against removal of sound concrete. The Engineer shall be notified of the final

equipment settings resulting from the calibration process.

250

After calibration of the equipment, concrete removal by hydrodemolition shall be

performed on the bridge deck. The removal will be verified as necessary, every 30 ft

along the cutting path. Handchipping shall be used in areas that are inaccessible to the

hydrodemolition equipment. Handchipping tools may be handheld or mechanically

driven. The removal operation shall cease where it is determined that sound concrete

is being removed. Equipment shall be recalibrated, or approved changes to equipment

and methods shall be performed, prior to resuming the removal operation.

The Contractor shall submit a wastewater control and disposal plan for approval

seven days prior to commencing hydrodemolition activities. The wastewater control260

and disposal plan shall detail how all wastewater generated by the hydrodemolition

activities shall be contained, tested for pH, stored, and transported to a disposal facility

in accordance with 202.

The Contractor shall provide sufficient shielding to ensure containment of all

dislodged concrete during hydrodemolition operations and to prevent damage to

surrounding property from flying debris, both on and under the work site.

Cleaning of the hydrodemolition debris and slurry shall be performed with a

vacuum system equipped with fugitive dust control devices and be capable of270

removing wet debris and water in the same pass. The vacuum equipment shall be

capable of washing the deck with pressurized water during the vacuum operation to

dislodge all debris and slurry from the bridge deck surface. Debris and slurry shall not

be allowed to dry prior to vacuuming.

After hydrodemolition has been completed, the deck will undergo sounding to

722.06

778

identify remaining areas of unsound concrete. Ponded or standing water shall be

removed from the deck prior to sounding.

Additional concrete removal of remaining unsound concrete shall be as directed280

by the Engineer and shall be performed by handchipping or hydrodemolition.

When hydrodemolition is not shown on the plans, all removal of unsound concrete

shall be performed by handchipping. Following the cleanup from the surface removal

operation, areas of unsound concrete to be removed will be marked. Handchipping

tools may be hand or mechanically driven. Jackhammers shall not be heavier than

nominal 45 lb class and chipping hammers shall not be heavier than nominal 15 lb

class. Only chipping hammers shall be used when removing concrete within 1 in. of

reinforcing bars. Mechanically driven tools shall be operated at a maximum angle of290

45° from the bridge floor surface.

Regardless of the method of removal, the removal operation shall cease where it

is determined that sound concrete is being removed. Agreed upon changes in

equipment and methods shall be performed prior to resuming the removal operation.

Where reinforcing bars have been exposed for a length greater than 2.0 ft and the

bond between the existing concrete and reinforcing bars has been destroyed, the

concrete adjacent to the bars shall be removed to a minimum clearance of 1 in. around300

the entire periphery of the exposed bars.

Regardless of the method used for unsound concrete removal, where the deck is

unsound for more than 1/2 of its original depth, the concrete shall be removed full

depth, except for limited areas as determined by the Engineer. Forms for areas of up

to 4 sq ft may be suspended from wires attached to the reinforcing bars. For areas

greater than 4 sq ft, the forms shall be supported from the structural members of the

superstructure or by shoring from below.

310

Prepared cavities which are deeper than the level of the adjacent prepared deck

surface, but are not full depth, shall require partial depth patching in accordance with

722.07(b). Prepared partial depth cavities shall be made full depth when directed

Exposed reinforcing bars shall not be damaged by the removal operation. Any

damaged reinforcing bars shall be repaired as directed with no additional payment.

The removal areas shall be thoroughly cleaned of all dirt, foreign materials, and

loose concrete to the extent necessary to produce a firm solid surface for adherence of

the new concrete. A minimum 1 in. vertical surface shall remain, or be cut, 1 in. outside

and around the entire periphery of each removal area after removal of all loose and320

unsound concrete. The 1 in. vertical cut may be waived where it is determined that a

722.06

779

cut will damage the reinforcing bars. Where hydrodemolition is utilized on the

adjacent surface, the 1 in. vertical surface will not be required.

After the concrete removal operation is completed and just prior to placing the

patches or the overlay, the entire deck shall be heavily sandblasted to expose fine and

coarse aggregates and to remove unsound concrete or laitance layers from the surface.

Exposed reinforcing bars and the concrete under and around the exposed bars shall be

thoroughly cleaned by sandblasting. The surface shall be then cleaned free of all dust,330

chips, water, and foreign material to the extent necessary to produce a firm, solid

surface for adherence of the new concrete.

The air lines for sandblasting and air cleaning shall be equipped with oil traps.

When hydrodemolition is utilized, water blasting may be used in lieu of

sandblasting. The sandblasting or water blasting shall be performed using two passes

with the second pass being at a right angle to the first pass or a cross-blasting

technique. The minimum pressure of the water blast shall be 6,000 psi.

340

Patching of the Bridge Floor

A vacuum device shall be used to remove all water from the prepared cavities.

The material used for full depth patching shall be either bridge deck patching

concrete, overlay concrete, or concrete patching material from the QPL of Rapid

Setting Patch Materials.

Full depth patching shall be performed prior to the overlay operation. The

patching material shall be consolidated by internal vibration at the time of placement.350

Equipment shall not be operated on the repaired deck areas until the test beams indicate

a minimum modulus of rupture of 550 psi.

Epoxy resin adhesive shall be used to coat the surfaces of the prepared cavities

and all the exposed reinforcing bars within the cavities. The epoxy coating shall be

tacky at the time that the patching concrete is placed. Where the epoxy coating has

cured beyond the obvious tacky condition, it shall be re-applied prior to patching. The

coated cavities shall then be filled with the patching concrete to the level of the

adjacent deck surface. Curing of the patching concrete shall be as directed.360

Bridge deck patching concrete shall be composed of the following:

aggregate used.

722.07

780

III or Type IIIA, or 846 lb/cu yd of portland cement Type I

or Type IA.

370

8% entrained air.

6 in. and a maximum water/cement ratio of 0.450.

The surfaces of the prepared cavities shall be coated with a bond coat in

accordance with 722.10. The cavities shall then be filled with the overlay concrete to

the level of the adjacent deck surface.380

Concrete patching materials shall be as approved by the overlay supplier for

compatibility with the overlay material. Concrete patching materials shall be placed

and cured in accordance with the manufacturer’s recommendations.

The material used for partial depth patching shall be either bridge deck patching

concrete, overlay concrete, or concrete patching material from the QPL of Rapid

Setting Patch Materials. The patching material shall be consolidated by internal390

vibration at the time of placement.

Partial depth patching with bridge deck patching concrete shall be in accordance

with 722.07(a) and 722.07(a)1. Curing of the patching concrete shall be as directed.

The surfaces of the prepared cavities shall be coated with a bond coat in

accordance with 722.10, except where hydrodemolition is utilized. The cavities shall

be filled with the overlay concrete at the time that the overlay is placed. Concrete400

overlay material used for patching shall be cured in accordance with 722.12.

Concrete patching materials shall be as approved by the overlay supplier for

compatibility with the overlay material. Concrete patching materials shall be placed

and cured in accordance with the manufacturer’s recommendations.

722.08Overlay Dam

An overlay dam shall consist of the removal of existing concrete from the bridge

floor and replacing it with new concrete as shown on the plans or as otherwise directed.410

Overlay dam material shall be in accordance with 722.05.

722.08

781

The existing concrete shall be removed as required in accordance with 722.06(b).

Exposed reinforcing bars shall not be cut or otherwise damaged.

Power driven hand tools for removal by handchipping will be allowed. Pneumatic

hammers with a maximum weight of 69 lb may be used for the tops of mudwalls.

Where, during the removal process, the tools or methods being used appear to cause

damage such as cracks or spalling on the concrete which is to remain, the work shall

cease immediately and agreed upon changes in equipment and methods shall be420

performed prior to resuming the removal operation.

The surface to be repaired, the reinforcing bars, and the concrete under and around

the bars shall be cleaned in accordance with 722.06(c). The cavity shall be coated with

an epoxy resin adhesive in accordance with 722.07(a)1, then filled with class C

concrete in accordance with 702.

722.09Mixing

Very Early Strength

Proportioning and mixing of the latex modified concrete shall be performed in a

self-contained, self-propelled continuous mixer. The mixer shall be calibrated to

accurately proportion the specified mix prior to starting the work. The calibration shall

be in accordance with 722.13. Sufficient mixing capacity or mixers shall be provided

to enable the intended pour to be placed without interruption. The mixer shall carry

sufficient quantities of unmixed ingredients to produce at least 6 cu yds of latex

modified concrete at the site.

The mixer shall measure and control the flow of ingredients being introduced into440

the mix and shall record these quantities on an approved visible recording meter

equipped with a ticket printer. Water flow shall be readily adjustable to compensate

for minor variations in aggregate moisture content and shall be displayed by an

approved flow meter. The flow of the latex modifier shall also be displayed by an

approved flow meter. The manufacturer’s inspection plate shall clearly show the serial

number, proper operating revolutions per minute, and the approximate number of

counts on the cement meter to deliver 94 lb of cement.

The mixer shall automatically proportion and blend simultaneously all the

ingredients of the specified mix on a continuous or intermittent basis as required by450

the finishing operation. The latex modified concrete shall be discharged through a

conventional chute directly in front of the finishing machine. The surface ahead of the

deposited mixture shall be kept damp by spraying it with water. Where the water is

applied by the mixer, it shall be dispensed ahead of the water flow meter.

Mixing shall be in accordance with 702.09(a), 702.09(b), and 702.09(c), except

mixing time shall be a minimum of 84 s. Retempering SFMC by adding water or by

722.09

782

other means will not be allowed after 30 minutes from initial batching and mixing.

When concrete is delivered in transit mixers, additional water may be allowed to460

increase a marginally low slump. Water shall not be added once 10% of the load has

been discharged. Additional mixing shall be performed as directed and all operations

completed within the time limits in accordance with 702.09(c). The amount of water

shall be determined accurately and noted on the batch ticket. Such addition of water

will not be allowed as a continuing operation. The total of all water included in the

mix shall not exceed the maximum allowable water/cement ratio.

722.10Placing and Finishing

Existing expansion joints shall be maintained throughout the overlayment unless

otherwise shown on the plans. A construction dam or bulkhead, equal in thickness to470

the joint width, shall be installed to the required grade and profile prior to placing the

overlay. Screed rails for the finishing machine shall be placed to the required profile,

and anchored for stability both vertically and horizontally. Screed rails shall not be

treated with a bond breaking compound.

The overlay shall be placed only when the ambient temperature is 45°F and rising,

unless otherwise approved by the Department in writing. The maximum allowable

ambient temperature during placement is 85°F. The overlay shall not be placed if rain

is expected within 4 h. Adequate precautions shall be taken to protect freshly placed

overlay material from sudden or unexpected rain. Damaged material shall be removed480

and replaced with no additional payment. A construction dam or bulkhead shall be

installed in case of a delay in placement of 1 h or more. During delays of less than 1 h,

the end of the placed overlay material shall be protected from drying with layers of

wet burlap.

After the surface has been cleaned, and immediately before placing the overlay

material, the surface shall be thoroughly soaked and covered with plastic sheeting for

a period of 1 h. The surface shall not be allowed to dry before placing the overlay

material and there shall be no standing water at the time of placement. The surface

shall then be thoroughly and evenly coated with a brush applied bond coat of overlay490

concrete, except a bond coat shall not be applied to surfaces where the removal was

performed by hydrodemolition. The progress of the bond coat application shall be

controlled to ensure that the bond coat does not dry before the overlay is placed to the

required grade. Aggregate segregated in the brush application of the bond coat shall

be removed before the overlay is placed. Surface irregularities shall be filled to

approximately three-quarters of their depth sufficiently ahead of the overlay operation

to allow the material to stiffen and resist rolling back during the finishing.

Following the bond coat application and partial filling of any surface

irregularities, the concrete overlay shall be placed to an elevation approximately 1/2500

in. above final grade. The mix shall then be consolidated and machine finished to the

required grade. The machine finishing shall be to within 12 in. of the curb line or

coping line unless otherwise directed. Supplemental hand finishing with a wood float

shall be performed as needed to produce the required tight and uniform surface.

722.10

783

The finishing machine shall be self-propelled and capable of positively controlled

forward and reverse motion. The machine shall be equipped with at least two finishing

devices. The first finishing device shall be a vibrating mechanism, such as a vibrating

pan, for consolidating the deposited mix. The vibrating pan shall be metal and of

sufficient dimensions to ensure proper consolidation. The second finishing device510

shall be either a rotating cylindrical drum, at least 45 in. in length, or a vibrating

oscillating metal faced screed of 4 in. minimum in width. The vertical position of the

finishing devices shall be positively controlled and the devices shall be raised clear of

the finished surface when the machine is operated in the reverse direction. The

vibration frequency of any vibrating finishing device shall be variable, with positive

control between 3,000 and 6,000 vibrations per minute. Alternate finishing machines

may be considered for approval subject to a written request.

Screed rails and construction dams shall be separated from the newly finished

overlay by passing a pointing trowel along the rail-to-overlay and dam-to-overlay520

interfaces after the overlay has sufficiently set such that it does not flow back. This

trowel cut shall be made for the entire length and depth of the rail or dam. The rails

may be removed any time after the overlay has initially set. Adequate precautions shall

be taken during and after the rail removal to protect the edge of the new overlay from

damage.

Protection shall be provided to prevent rapid drying of concrete. The rate of water

evaporation shall be determined both prior to placement based on forecasted

conditions and during placement based on actual conditions in accordance with ACI

308, section 5.2.1 or the following equation:530

E = (T c 2.5 - rT a 2.5 )(1 + 0.4V) x 10 -6

where:

E = Evaporation rate, lb/sq ft/h

T c = Concrete mix temperature, °F

T a = Ambient temperature, °F

r = (Percent of Relative Humidity)/100

V = Wind velocity, mph.

Measurement of T a , r, and V shall be obtained from readings made by the local

weather bureau or the Contractor's measurements made on site. Measurement of T c

shall be determined from the concrete on site at the point of placement. Fog misting

shall be performed after the finishing operation and prior to the wet cure, where the

evaporation rate exceeds or is expected to exceed 0.05 lb/sq ft/h. Fog misting shall540

keep the environment above the concrete surface at high humidity to protect against

plastic shrinkage cracks and shall not be used to apply water directly to the surface to

facilitate finishing. Evaporation retardants shall not be substituted for fog misting

where the evaporation rate exceeds 0.05 lb/sq ft/h.

722.10

784

An evaporation retardant shall be applied in a fine mist immediately after the

finishing is complete to ensure that the surface remains wet until covered. The

evaporation retardant shall be used as such and not as a finishing aid. These products

consist primarily of water and excessive amounts of evaporation retardant shall not be

applied and the product shall not be worked into the overlay surface. Evaporation550

retardant shall only be used on SFMC overlays. Evaporation retardant shall not be

used in any other applications.

722.11Texturing

The overlay surface shall be textured with a double thickness burlap drag or a

minimum 4 ft wide turf drag immediately following the placement of the overlay

material. Areas where the texture is disturbed by other finishing operations shall be

immediately restored to a burlap drag finish.

Grooving or tining in the plastic concrete of the concrete overlay will not be560

allowed. Longitudinal grooving shall not commence until the curing requirements

have been met in accordance with 722.12. Grooves shall be cut into the hardened

concrete surfaces parallel to the centerline using a mechanical cutting device. For

curved bridges, grooves shall be cut along the curve chord within the spans. Grooving

shall be done before traffic is allowed on the surface except as follows.

The Contractor shall have the option of cutting the longitudinal grooves at the end

of each phase of construction or waiting until all phases have been completed. If the

Contractor elects to delay the grooving process until completion of all phases, the

concrete overlay surface for any phase opened to traffic shall receive an interim coarse570

broom finish during placement.

The completion of the grooving process shall be within 30 days of completion of

the last phase of construction. Any additional maintenance of traffic operations

required for the grooving process shall be included in the cost of Maintaining Traffic.

The interim broom finish shall not be allowed as a surface texture when opened to

traffic over a winter season. If the coarse broom texture is present and the Contractor

is not in a position to finish all phases of the project, longitudinal grooving shall be

placed into the hardened concrete in order to establish an acceptable driving surface

texture for the winter season.580

Each groove shall be 1/8 in. ±1/64 in. in width, 3/16 in. ±1/16 in. in depth. The

grooves shall be uniformly spaced at 3/4 in. intervals measured from the center of

groove to center of groove. Grooving shall not be within the area approximately 2 ft

adjacent to the curbs or railings. The grooving shall not be cut closer than 3 in. nor

further than 6 in. from any construction joint running parallel to the grooving. The

grooving shall not be cut within 6 in. of deck drains, curbs, or expansion joints. If the

bridge has a variable width traffic lane, the grooving shall remain parallel to the

centerline of the main roadway. Any staggering of the groove terminations to

accommodate the variable width shall be within the shoulders. Stair stepped ends in590

grooving will be allowed for skewed bridge decks. When a new reinforced concrete

722.11

785

approach slab is placed adjacent to the overlay, the grooving shall extend across the

reinforced concrete approach slab. Grooving shall terminate approximately 6 in. from

the interface with the roadway pavement.

The grooving machine shall contain diamond blades mounted on a multi-blade

arbor on a self-propelled machine built for grooving hardened concrete surfaces. The

grooving machine shall have a depth control device that detects variations in the deck

surface and adjusts the cutting head height to maintain a specified depth of the grooves.

The grooving machine shall have a guide device to control multi-pass alignment.600

The Contractor shall submit a wastewater control and disposal plan for approval

seven days prior to commencing grooving activities. The wastewater control and

disposal plan shall detail how all wastewater generated by the grooving activities shall

be contained, tested for pH, stored and transported to a disposal facility in accordance

with 202.

Cleaning of the grooving debris and slurry shall be performed with a vacuum

system equipped with fugitive dust control devices and be capable of removing wet

debris and water in the same pass. The vacuum equipment shall be capable of washing610

the deck with pressurized water during the vacuum operation to dislodge all debris and

slurry from the bridge deck surface. Debris and slurry shall not be allowed to dry prior

to vacuuming.

722.12Curing

When fly ash is used, the requirement for additional wet or dry curing time shall

be determined based on the relative initial, and final time of set and a comparison of

strength versus age using control concrete strengths at conventional cure period ages

as the reference. The additional curing requirements shall be as approved by the

Engineer.620

For LMC overlays the minimum curing period shall be 48 h of wet cure followed

by 48 h of dry cure. An LMC overlaid bridge deck may be opened to traffic during the

dry curing duration when the compressive strength of cylinders is 4,000 psi or greater.

For SFMC overlays the minimum curing period shall be seven calendar days

consisting of 120 h of wet cure followed by 48 h dry cure. The deck shall remain

completely covered during the dry cure period. An SFMC overlaid bridge deck may

be opened to traffic after the dry cure period when the compressive strength of

cylinders is 4,500 psi or greater.630

For LMC-VE concrete overlays the minimum curing period shall be 3 h of wet

cure. An LMC-VE overlaid bridge deck may be opened to traffic after the wet curing

period when the compressive strength of cylinders is a minimum of 2,500 psi.

The wet cure period for all overlay types is not controlled by strength and shall

not be reduced. Membrane forming curing compound shall not be used to cure the

722.12

786

bridge deck overlay. All cylinders shall be 6 in. by 12 in. and compressive strength

shall be determined from the average of a minimum of two cylinders. For LMC and

SFMC, cylinders shall be cast and cured in accordance with 702.24. For LMC-VE640

cylinders shall be cast and field cured at the jobsite under the same conditions as the

LMC-VE overlay.

The plastic film which forms on the surface of the overlay shall be protected from

shrinkage cracking with a single layer of well drained wet burlap. This layer of wet

burlap shall be placed as soon as the overlay surface will support it without

deformation. The entire surface shall be covered with plastic sheeting and maintained

in a saturated wet condition during the wet cure period. A network of soaker hoses

shall be used under the plastic sheeting during the wet cure period for LMC and silica

fume overlays.650

When the ambient temperature falls below 50°F during either the wet or dry

curing periods, the time that the temperature is below 50°F shall not be considered as

part of the total curing period. When there is sufficient rain to wet the surface of the

overlay for 1 h or more during the dry cure period, this number of hours shall not be

considered as part of the dry cure period.

Immediately upon the start of the dry cure period or opening to traffic, the surface

shall be checked for cracks. Upon request, the Contractor shall flood the deck with

water to facilitate inspection for cracks and distress. Where cracks exist, a thorough660

investigation will be conducted prior to sealing cracks. Cores may be required to

determine the actual crack depth. Surface cracks not exceeding 3/8 in. in depth shall

be sealed with a PCC Sealer/Healer followed by an application of an approved sand.

Cracks exceeding 3/8 in. in depth shall not be sealed at this time. Corrective procedures

for repairing cracks exceeding 3/8 in. in depth will be determined after further

investigation which may include additional cores. The Department’s Division of

Materials and Tests will be contacted and the Engineer will determine the method of

repair including possible removal.

Where the area of shallow cracking exceeds 5% of the deck area, then the method670

of repair shall be the same as for cracks exceeding 3/8 in. The shallow crack area will

be calculated by multiplying the total combined linear feet of all cracks less than 3/8

in. deep by a tributary width of 1 lft. The percentage of deck area will be the shallow

crack area divided by the total deck area and multiplied by 100.

Where it is determined by sounding or coring that adequate bonding between the

overlay and the bridge deck has not been attained, the deficient areas shall be removed

and replaced as directed.

722.13Calibration of Continuous Mixers680

A complete calibration shall be performed for each mixer prior to each pour unless

722.13

787

the initial calibration was made within the previous 10 calendar days. A mixer that has

been calibrated within the previous 10 calendar days may be approved for use

providing that the mixer operator is in possession of the completed, signed, certified,

and dated Department calibration form for that mixer. A complete calibration of a

mixer may be required at any time as directed. All mixers which are calibrated within

the 10-day limit but are changing aggregate sources shall have an aggregate blend test

performed.690

All special equipment required for calibration shall be furnished. It shall include

but not be limited to suitable material containers, buckets, stop watches, and a scale

accurate to within 0.1 lb or 0.3% of the test load, whichever is greater, at any point

within the range of use. The minimum capacity of the scale shall be 150 lb. The scale

shall be verified annually per ITM 910. The Contractor shall provide paperwork that

shows the date the scale was verified by a company with NIST traceable class F

weights. Samples shall be obtained and handled by the Contractor. Normal testing

equipment such as aggregate sieves and containers shall also be furnished.700

The aggregate bin shall be clean and the bin vibrators shall be in good working

order. The mixer shall be equipped with a grounding strap. The cement meter feeder,

the fins, and all pockets shall be clean and free of any accumulated cement. The

aeration system shall be equipped with a gauge or indicator to verify that the system

is operating. The main belts and the latex strainer shall be clean and free of any

accumulated material.

The mixer manufacturer’s mix setting chart shall determine the specified

operating revolutions per minute and the approximate number of counts required on

the cement meter to deliver 94 lb of cement. At least 3,760 lb of cement shall be placed

in the cement bin.

The mixing unit shall rest on a level surface. The engine throttle shall be adjusted

to obtain the required revolutions per minute. The unit discharging the cement shall be

operated until the belt has made one complete revolution. The unit shall then be720

stopped and the cement meter shall be reset to zero.

A suitable container shall be positioned to catch the cement and at least 90 lb of

cement shall be discharged. The time required to discharge the cement shall be

measured with a stopwatch, the number of counts on the cement meter shall be

recorded, and the weight of the discharged cement shall be determined. This process

shall be repeated a total of three times. The cement counter shall be reset to zero before

each repetition.

722.13

788

The following formulas shall be used to calculate the number of counts per 94 lb730

of cement and the time required to discharge 94 lb of cement.

Counts per 94 lb of cement = 94 ÷ A

B

Time in seconds per 94 lb of cement = 94 ÷ A

C

where:

A = Total weight of cement in pounds for three trials

B = Total number of counts on the cement meter for three trials

C = Total time in seconds for three trials.

740

The accuracy of the water flow meter shall be verified by adjusting the flow to

2 gal. per minute. With the equipment operating at the required revolutions per minute,

the water discharged during a 1-minute interval shall be collected and weighed. The

weight in pounds of the discharged water shall be divided by 8.33 to determine the

number of gallons. This procedure shall be repeated with the flow meter adjusted to 3

gal. per minute.

The aggregate gate openings shall be adjusted to provide the required amount of750

aggregate to produce a cubic yard of the designated mix. The gate settings for the fine

aggregate and coarse aggregate shall be determined separately. Each aggregate shall

be verified by stopping the cement discharge and collecting the aggregate discharged

in a container.

Calculations for all aggregates shall be based on SSD weights taken from the mix

design. The calculations shall be adjusted for the tested moisture content. The final

gate setting for each aggregate shall dispense material within a tolerance of ±2% of

the target weights after adjustment for measured moisture content.

760

The latex strainer shall be unobstructed. The latex throttling valve shall be

adjusted to deliver the required amount of latex emulsion admixture for each 94 lb of

cement. With the unit operating at the required revolutions per minute for the

calculated time in seconds per 94 lb of cement, the latex shall be discharged into a

container. The weight of the latex shall be determined and, when necessary, the valve

shall be adjusted such that the amount of latex discharged is within 1/2 lb of the amount

required for each 94 lb of cement. One verification shall be performed to check the

accuracy of the valve setting.

770

This equipment shall be calibrated in accordance with the manufacturer’s

instructions for the specific materials and quantities involved.

722.13

789

722.14Patching an Existing Bridge Deck Overlay

Materials shall be in accordance with 722.03.

Storage and handling of materials shall be in accordance with 722.04.

Proportioning shall be in accordance with 722.05.

Preparation of the bridge floor shall be in accordance with the applicable

provisions of 722.06.

Patching shall be in accordance with 722.07 except as modified herein. Areas

repaired by full depth patching shall not be open to traffic until the test beams indicate

a minimum modulus of rupture of 550 psi.

Mixing shall be in accordance with the applicable provisions of 722.09.

Placing and finishing shall be in accordance with the applicable provisions of

. Machine finishing shall be required when directed.800

The surface texturing shall match the pattern of the adjacent overlay and shall be

in accordance with the following:

Immediately after the finishing is complete and before the surface film has

formed, the surface of the overlay patch shall be textured by grooving in the same

direction as the existing overlay. The grooves may be formed by mechanized

equipment using a vibrating beam roller, a series of discs, or other approved device.

Manual tools such as fluted floats, spring steel tined rakes, or finned floats with a810

single row of fins may be used. The grooves shall be relatively uniform, smooth, and

shall be formed without tearing the surface or bringing coarse aggregate to the top.

The grooves shall be in accordance with 504.03. The grooves shall be terminated the

same distance from the vertical faces of railings as the existing grooves in the adjacent

existing overlay surface.

All areas of hardened grooved overlay patching which do not conform to these

requirements, due to either a deficiency in the grooving or a rough open textured

surface, shall be corrected with no additional payment. Corrections shall be made by

cutting grooves in the hardened overlay with an approved cutting machine or by820

722.14

790

sealing with an approved mixture and retexturing to a satisfactory finish as directed.

Curing shall be in accordance with 722.12 when patching has been performed

using overlay concrete. Patches that have been constructed using bridge deck patching

concrete shall be wet cured until test beams indicate a minimum modulus of rupture

of 550 psi. Patches that have been constructed using rapid setting patch materials shall

be cured in accordance with the manufacturer’s recommendations.

Calibration shall be in accordance with 722.13.

722.15Method of Measurement

Removal of the existing overlay and the additional depth into the existing deck

surface will be measured by the square yard of deck area regardless of the number of

passes with the milling machine.

Removal of the existing concrete deck surface will be measured by the square

yard for the initial depth shown on the plans. Additional surface removal required

below the initial depth will be measured by the square yard for each required 1/4 in.840

depth. The areas of the bridge floor which are shown on the plans to be removed,

except for undefined full depth patching areas, will not be measured for payment.

Hydrodemolition of the bridge deck will be measured by the square yard.

Additional surface preparation around reinforcing bars will be measured by the linear

foot of exposed reinforcing bar. Reinforcing bar repair will not be measured for

payment.

When hydrodemolition is not shown on the plans, partial depth patching will be

measured by the square foot.850

The measurement of bridge deck patching concrete for partial depth cavities

created by handchipping or hydrodemolition will be based on a theoretical quantity

determined by multiplying the area of the appropriate partial depth cavities by an

assumed average depth of 2 in. and converting the resulting volume into cubic yards.

Overlay material used in a partial depth cavity will be measured by the cubic yard. The

quantities of patching material used in a partial depth cavity will be included in the

measurement of additional bridge deck overlay.

The overlay and bridge deck patching concrete used to fill cavities as part of860

patching an existing bridge deck overlay will not be measured for payment.

Overlay material used to fill surface irregularities and partial depth cavities will

be calculated by the cubic yard and will be included for payment for Bridge Deck

Overlay Budget.

722.15

791

Full depth patching will be measured by the square foot. The patching material

used in full depth patching will not be measured for payment.

Bridge deck overlay will be measured by the square yard for the specified870

thickness. Where there is no specified thickness shown on the plans, the specified

thickness shall be 2 in.

Overlay dams and patching an existing overlay will be measured by the square

foot.

Longitudinal grooving will be measured by the square yard. No deduction in

measurement will be made for areas where grooving is terminated or not required.

Epoxy resin adhesive and bond coat will not be measured for payment. Blasting,880

cleaning, finishing, texturing other than the longitudinal grooving, and curing will not

be measured for payment.

722.16Basis of Payment

Removal of the existing overlay and the additional depth into the existing deck

surface will be paid for at the contract unit price per square yard of bridge deck, remove

existing concrete overlay.

Milling of the initial depth of surface will be paid for at the contract unit price per

square yard of bridge deck, remove existing concrete surface. Additional surface890

removal below the initial depth will be paid for at the contract unit price per square

yard for bridge deck, remove existing concrete surface for each required 1/4 in. depth.

Hydrodemolition of the bridge deck will be paid for at the contract unit price per

square yard. When hydrodemolition is shown on the plans, additional surface

preparation will be paid for at the established price shown per linear foot for bridge

deck overlay, additional surface prep.

When hydrodemolition is not shown on the plans, partial depth patching will be

paid for at the contract unit price per square foot for bridge deck patching, partial900

depth.

When partial depth cavities are subsequently directed to be made full depth,

additional payment will be made at 80% of the contract unit price per square foot for

bridge deck patching, full depth.

Full depth patching will be paid for at the contract unit price per square foot for

bridge deck patching, full depth.

Bridge deck overlay will be paid for at the contract unit price per square yard, for910

the type of overlay material specified.

722.16

792

Patching an existing bridge deck overlay will be paid for at the contract unit price

per square foot for bridge deck overlay patching.

Overlay dam will be paid for at the contract unit price per square foot, complete

in place.

Longitudinal grooving will be paid for at the contract unit price per square yard.

920

The Department will include the pay item Bridge Deck Overlay Budget, with an

established dollar amount in the proposal to pay for additional surface preparation

completed after hydrodemolition and bridge deck overlay additional quantity used to

fill irregularities and partial depth cavities. The Bridge Deck Overlay Budget amount

shown in the proposal is included in the total bid amount. The Department will pay for

the additional quantity installed to fill irregularities and partial depth cavities as

directed by the Engineer. Where the material exceeds the planned overlay quantity,

payment will be at the invoice cost of the additional bridge deck overlay quantity

installed. An amount equal to 10% of the invoice cost will also be paid for additional

disposal and all other related costs in connection with the additional quantity installed.930

No additional markup shall be applied for additional bridge deck overlay quantity

installed. This amount will be paid using the Bridge Deck Overlay Budget pay item.

Payment will be made under:

Pay Item Pay Unit Symbol

Bridge Deck Overlay Budget .................................................... DOL

Bridge Deck Overlay, Latex Modified ...................................... SYS

Bridge Deck Overlay, LMC-VE ................................................ SYS940

Bridge Deck Overlay, Patching ................................................. SFT

Bridge Deck Overlay, Silica Fume Modified ............................ SYS

Bridge Deck, Remove Existing Concrete Overlay .................... SYS

Bridge Deck, Remove Existing Concrete Surface ..................... SYS

Bridge Deck Patching, Full Depth ............................................. SFT

Bridge Deck Patching, Partial Depth ......................................... SFT

Hydrodemolition ....................................................................... SYS

Longitudinal Grooving .............................................................. SYS

Overlay Dam ............................................................................. SFT

950

Item shown with an established price will be paid at the price shown.

Pay Item Pay Unit Established

Symbol Price

Bridge Deck Overlay, Additional Surface Prep......LFT ............... $20

The cost of overlay removal by handchipping in areas adjacent to the curb or

722.16

793

otherwise inaccessible to the power-operated mechanical milling machine shall be

included in the cost of bridge deck overlay, remove existing overlay. The cost of960

disposing of overlay removal residue, including water, dust, concrete and incidentals

shall be included in the cost of bridge deck, remove existing overlay.

The cost of deck surface preparation by handchipping in areas adjacent to the curb

or otherwise inaccessible to the power-operated mechanical milling machine shall be

included in the cost of bridge deck, remove existing concrete surface or bridge deck,

remove existing overlay. The removal of surface milling residue, including water,

dust, concrete, and incidentals shall be included in the cost of bridge deck, remove

existing concrete surface or bridge deck, remove existing overlay.

970

The cost of the wastewater control and disposal plan, wastewater containment,

testing, storing, transporting and disposal, and any incidentals related to the carrying

out of the plan shall be included in the cost of hydrodemolition. If the wastewater is

found to have a pH of 12.5 or higher and thereby classified as hazardous, the additional

costs associated with this classification will be paid for in accordance with 109.05.

The initial equipment calibration, any re-calibration, equipment shielding,

handchipping curb areas, handchipping unsound concrete, cleaning of debris and

slurry, compressed air cleaning, water blasting, and sandblasting shall be included in

the cost of hydrodemolition.980

When hydrodemolition is shown on the plans, the cost of removal of unsound

concrete shall be included in the cost of hydrodemolition. Preparation of cavity

surfaces, furnishing and applying bond coat or epoxy resin adhesive as required in

handchipped locations, furnishing and placing patching material, and necessary

incidentals shall be included in the cost of bridge deck overlay for the type of overlay

material specified. Additional concrete removal required around exposed bars shall be

included in the cost of additional surface preparation.

When hydrodemolition is not shown on the plans, the cost of removal of unsound990

concrete, preparation of cavity surfaces, furnishing and applying bond coat or epoxy

resin adhesive as required, furnishing and placing patching material, and necessary

incidentals shall be included in the cost of bridge deck patching, full depth, or bridge

deck patching, partial depth.

The cost of patching material used for full depth patching shall be included in the

cost of bridge deck patching, full depth. The cost of texturing patched areas will not

be paid for separately but shall be included in the cost of the patch.

The cost of furnishing and placing patching material in partial depth cavities and1000

necessary incidentals shall be included in the cost of bridge deck overlay, additional.

When the project does not include the installation of a new bridge deck overlay,

the cost of partial depth patching below the bottom of the overlay shall be included in

722.16

794

the cost of bridge deck overlay, patching. The cost of patching and overlay materials

used to fill the cavities shall be included in the cost of bridge deck overlay, patching.

The cost of removing existing concrete, furnishing, hauling, and placing all

materials including the epoxy, preparing the surface, and all necessary incidentals shall

be included in the cost of overlay dam.1010

The cost of deck cleaning shall be included in the cost of other pay items.

The cost of removing and disposing of the slurry created during the longitudinal

grooving shall be included in the cost of longitudinal grooving.

Coring of the bridge deck, patching core holes, and all corrective measures

required in accordance with 722.12 shall be performed at no additional cost to the

Department.