550 Page 374550 BRIDGE DECK PREPARATION AND RESURFACING
550.1DESCRIPTION
This work consists of preparation of the existing bridge deck and approaches and the furnishing, handling, placing, curing, and finishing of a latex concrete or low slump dense concrete overlay.
550.2MATERIALS
Materials will conform to the following Sections: A.Cement: Section 750, Type I cement. B.Fine Aggregate: Section 800. C.Coarse Aggregate: Section 820. D.Water: Section 790. E.Admixtures: Section 751 and Section 752. F.Curing: Section 821. G.Latex Emulsion Admixture: The latex admixture will be a nonhazardous, film forming, polymeric emulsion in water. All stabilizers will be added at the point of manufacture and will be homogeneous and uniform in composition. Physical properties: The latex admixture will conform to the following requirements: The latex admixture will be styrene-butadiene polymeric emulsion containing 46% to 53% polymer. The polymer will contain 60% to 70% styrene and 30% to 40% butadiene. The polymeric emulsion will be stabilized with an anionic, nonionic surfactant and have a pH between 8.5 and 12.0. The latex admixture will be prequalified prior to use. A list of qualified products is available on the Department’s Approved Products List. The admixture selected or specified will be certified to be of identical formulation to the admixture submitted for prequalification testing. Along with the certification the supplier will furnish the polymer percent of the total emulsion and pH of the formulation. Tests of latex admixture furnished will meet these formulation values within the following tolerances: Percent polymer of Total Emulsion .................... ±1.5% pH...................................................................... ±1.0 The latex admixture will be stored in enclosures which protect the material from freezing and exposure to direct sunlight during periods when temperatures are in excess of 85°F. As a minimum, insulating blanket material will be placed over both the top and sides of drums stored at the work site. Storage at the work site will not exceed 10 calendar days. 550 Page 375H.Grout Admixtures: Grout admixtures will be a one component acrylic bonding additive. The additive will be one of the grout admixtures from the Department’s Approved Products List, or an approval equal as determined by the Office of Bridge Design.
550.3CONSTRUCTION REQUIREMENTS
A.Quality and Proportioning: 1.Latex Modified Concrete Mixture Design: Latex modified concrete will conform to the following mixture requirements: Material or Property Mixture Proportions or Test Limits Cement content 7.25 bags / cubic yard. Latex Emulsion Admixture 3.5 gallons / bag Water*1±2.5 gallons / bag Water cement ratio*10.40 max Entrained Air 5.0% ±1.0% Slump 4 - 8 inches Fine Aggregate*260% *1The water added will be adjusted to control the slump within specified test limits and produce a water cement ratio not to exceed 0.40 by weight. Forms DOT-84 and DOT-83 provide methods, which will be used to determine aggregate moisture and water/cement ratio. Only the coarse aggregate quantity will be adjusted to compensate for changes in water quantity. *2The initial aggregate weights will be established by using specified mix proportions for cement, latex emulsion, and water assuming 5% entrained air to determine volume available for total aggregate. Using actual specific gravity for the materials, determine the weights of coarse and fine aggregates by using 60% by weight fine aggregate. 2.Low Slump Dense Concrete Mixture Design: The low slump dense concrete mixture design will conform to the following: Basic absolute volume per unit volume of concrete: Coarse Aggregate 0.312088 Fine Aggregate 0.312088 Air 0.060000 Water 0.160255 Cement 0.155569 1.000000 Approximate quantities of dry materials per cubic yard of concrete: Coarse Aggregate 1,394 pounds Fine Aggregate 1,394 pounds Cement 823 pounds (8.75 bags) 550 Page 376These quantities are based on the following assumptions: Specific gravity of cement 3.14 Specific gravity of aggregate 2.65 Actual specific gravities will be used for adjustments in mix proportions. An approved water reducing admixture for improving workability will be added in accordance with manufacturer recommendations. The slump when measured according to SD 404 will be 1 inch maximum. The entrained air content of the freshly consolidated concrete, as determined by SD 403, will be 6.0% with a tolerance of ±1.0%. Grout for bonding new concrete to old concrete will consist of equal parts by weight of Portland cement and sand, mixed with sufficient water to form a thick slurry. When backfilling extra depth holes in accordance with Section 550.3 C.1.f.2 , an admixture will be added to the grout mixture in accordance with the manufacturer’s recommendations. The consistency of the slurry will be such that it can be applied with a stiff brush or broom to the old concrete in a thin, even coating that will not run or puddle in low spots. For sealing vertical joints between adjacent areas of placement, grout will be thinned to consistency of paint. B.Equipment: Equipment for deck preparation, mixing, placing, and finishing of latex modified concrete or low slump dense concrete will be approved by the Engineer prior to start of work. 1.Surface Preparation Equipment: Surface preparation equipment will consist of the following: a.Power operated mechanical scarifier or grinder capable of removing at least 1/4 inch from the existing concrete surface in one pass. b.Concrete sawing equipment capable of sawing concrete to the specified depth. c.Power driven hand tools for concrete removal on the bridge deck will be limited by the following: 1)Jack hammers heavier than 30 pound will not be permitted. 2)Chipping hammers heavier than 15 pound will not be permitted to remove concrete beneath any reinforcing bar. d.Abrasive blasting equipment capable of removing rust and old concrete from exposed reinforcement and removing surface laitance from new substrate concrete. 2.Proportioning and Mixing Equipment: The proportioning and mixing equipment will be a self- contained, mobile, and continuous mixer meeting the following requirements: a.The mixer will be capable of carrying sufficient unmixed dry bulk cement, fine aggregate, coarse aggregate, admixtures, and water in separate compartments to produce not less than 6 cubic yards of concrete. 550 Page 377For full depth bridge deck placements, the production capacity will be a minimum of 60 cubic yards per hour. More than one mixer may be required to provide a satisfactory placement rate. b.The mixer will be capable of positive measurement of cement being introduced into the mix. A visible recording device, equipped with a ticket printout, will indicate this quantity. c.The mixer will provide positive control of water introduced into the mixer. Water flow will be coordinated with the cement and aggregate feeding mechanisms and will be readily adjustable to provide for minor variations in aggregate moisture. Water flow will be controlled by a calibrated metering device. In addition to the metering device, mixers will be equipped with recording water meters recording the number of gallons introduced into the mixer to the nearest 0.1 gallon. d.The mixer will be capable of being calibrated to automatically proportion and blend all components on a continuous or intermittent basis. e.The mixer will provide positive control of admixtures introduced into the mix. Admixture flow will be coordinated with the feeding mechanisms of the other ingredients and will be readily adjustable. The admixture injection system will meet the mixer recommendations of the manufacturer regarding type and design. f.When mixing latex modified concrete, the mixer will be equipped with recording meters capable of recording, to the nearest 0.1 gallon the number of gallons of latex emulsion introduced into the mix. g.Equipment Calibration: 1)Calibration and inspection by the Department will be required for each mixer before the start of the first project on which the mixer will be used each year. The calibration will establish the meter count, e.g., the number of revolutions and discharge time in seconds required to dispense 94 pounds of cement. Gate openings and pointer adjustments for aggregates and general operating condition of the equipment will also be inspected. The Contractor will have a representative to witness the calibration, and a qualified mixer operator. The Contractor will furnish all scales, containers, stop watches, mixer operating manuals, materials, and equipment necessary for the calibration and inspection. 2)A materials discharge verification check may be ordered whenever conditions warrant. Individual components may be ordered verified. On latex modified mixtures, cement, and latex emulsion discharge will be verified prior to the first placement on each project. 3.Consolidation Equipment: Consolidation equipment will be internal vibration (spud vibrator) equipment. 550 Page 3784.Placing and Finishing Equipment: Placing and finishing equipment will include hand tools for placement and brushing in freshly mixed modified concrete or grout. The hand tools will be used to distribute the concrete to the correct level prior to striking off with the finishing machine. The finishing machine will be capable of forward and reverse motion under positive control and be capable of raising all screeds, cylinders, augers, and vibratory pan or pans to clear the surface when traveling in reverse. Modifications of the factory product will require approval. Screed rails will be capable of rigidly supporting the finishing machine without significant deflection and will be securely fastened to their supports. A portable lightweight or wheeled work bridge will be required for use behind the finishing operation. The finishing machine for latex modified concrete will be a self-propelled rotating cylinder type, with one or more rotating steel cylinders, augers and variable frequency vibratory pans. The machine will span the concrete placement width. The cylinders, augers, and vibratory pans will be capable of placing and consolidating the concrete to the established profile by traversing the placement width, transverse to the roadway centerline. The finishing machine for low slump dense concrete will have a mechanical strike off to provide uniform thickness of concrete in front of an oscillating screed. The finishing machine will have at least one oscillating screed capable of consolidating the concrete to the specified density. A sufficient number of identical vibrators will be installed to provide at least one vibrator for each 5 foot of screed length. The bottom face of the screed will be at least 5 inches in width with a turned up or rounded leading edge to minimize surface tearing. Each screed will have an effective weight of at least 75 pounds per square foot of bottom face area. Each screed will be provided with position control of vertical position, tilt angle, and crown shape. The finishing machine and appurtenant equipment will provide positive machine screeding of the concrete within 1 inch of the face of existing curbs. The screed will extend at least 6 inches beyond the line where a saw cut is intended to form the edge of a subsequently placed lane. The screed will overlap the sawn edge of a previously placed adjacent lane by at least 6 inches. C.Surface Preparation: 1.Concrete Removal: a.Concrete removal Type 1A will consist of removing the surface of the existing concrete deck by machine scarifying. Areas designated for concrete removal Type 1A will be scarified at least 1/4 inch in depth by a power operated scarifier or grinder. When specified, scarifying deeper than the 1/4 inch will be required. The area around existing deck floor drains will be hand chipped in accordance with the details in the plans to provide clearance for placement of the overlay. The overlay will be tapered to meet the existing floor drain top in accordance with the details in the plans. 550 Page 379For projects where the bridge deck overlay is placed in phases, it will not be permissible to accomplish concrete removal Type 1A over the entire deck surface and then allow traffic on the scarified surface. The mechanical scarifying operation will be immediately suspended, if the scarifier contacts reinforcing steel, until the limits of the high reinforcing steel have been determined by the Engineer. A minimum depth of 1/4 inch of concrete surface will be removed from the area of high reinforcing steel by hand chipping. Hand chipping removal in these areas will be measured and paid for at the contract unit price for concrete removal Type 1B. b.Concrete removal Type 2A areas will be determined by the Engineer after the concrete removal Type 1A has been accomplished. Concrete removal Type 2A will be the removal of relatively large areas of unsound existing overlay below the concrete removal Type 1A, using machine scarification equipment. After completion of the concrete removal Type 1A, the Engineer will inspect the deck and mark remaining areas of unsound existing overlay. Remaining unsound existing overlay will be removed using machine scarification equipment when the unsound area is relatively large, as determined by the Engineer. The Engineer will order the use of concrete removal Type 2A and will determine the required depth of pass or passes. The total depth of concrete removal Type 2A will not exceed 1 inch or the depth to the top of the top bar in the top mat of reinforcing steel, whichever is less. Areas of unsound existing overlay that are not large enough to warrant the use of machine scarification equipment may be removed using concrete removal Type 1B, at the Engineer's discretion. Extreme care will be taken to avoid damaging the reinforcing steel with the scarification equipment during concrete removal Type 2A. Concrete removal Type 2A will stop in any area where reinforcing steel is encountered, until further direction by the Engineer. Reinforcing steel that is damaged during concrete removal Type 2A will be repaired by the Contractor, as directed by the Engineer, and will be paid for as per Section 4.4. Reinforcing steel that is damaged due to scarification below the depth specified by the Engineer will be repaired by the Contractor, as directed by the Engineer, at no additional cost to the Department. c.Concrete removal Type 1B areas will be determined by the Engineer after concrete removal Type 1A (or concrete removal Type 2A if specified) has been accomplished. Concrete removal Type 1B will consist of removing delaminated or unsound concrete by chipping below the concrete removal Type 1A (or concrete removal Type 2A if specified) and extending down to the top of the top bar in the top mat of reinforcing steel. Unintentional concrete removal below the top of the top bar in the top mat of reinforcing steel during concrete removal Type 1B will be considered a part of the concrete removal Type 1B. d.Concrete removal Type 1C areas will be determined by the Engineer after concrete removal Type 1B has been accomplished. Concrete removal Type 1C will consist of 550 Page 380removing unsound concrete below the concrete removal Type 1B and above the top of the top bar of the bottom mat of reinforcing steel. If concrete removal Type 1C extends down to the top of the top bar of the bottom mat of reinforcing steel, concrete removal Type 1D will be required regardless of the condition of the concrete remaining. e.Concrete removal Type 1D will consist of removing concrete below concrete removal Type 1C to the full depth of slab. The edges of the resulting hole in the deck will be nearly vertical or tapered inward from the top down. A reversed taper will not be permitted. The underside of the deck will have a neat appearance. Feather edging of the concrete fill will not be permitted. Saw cutting the underside of the slab may be required if satisfactory results cannot be achieved by other means. f.Concrete removal Type B will consist of the removal of existing concrete from around the periphery of reinforcing bars. When concrete removal Type 1A and concrete removal Type 1B has been accomplished in an area, the Engineer will determine the sections of reinforcing requiring concrete removal Type B. Normally, concrete removal Type B will be ordered when an isolated bar has lost bond on more than one-half of its circumference. On those sections the concrete will be removed from around the periphery of the bar using chipping hammers and hand tools. A minimum clearance of 3/4 inch around the bar will be provided. Care will be exercised to prevent cutting, stretching, and damaging all exposed reinforcing steel. Concrete removal Type 1C may be ordered in lieu of concrete removal Type B if damage to sound concrete between bars is suspected or when deemed appropriate for other reasons. 1)When the extent or location of concrete removal Type 1C and concrete removal Type 1D becomes critical to the structural integrity of the deck, the Office of Bridge Design will be requested to make a determination. Shoring, when required, will be accomplished under the provisions of Section 9.4. 2)Backfill of Extra Depth Holes : When concrete removal type 1D is necessary, or when holes deeper than 4 inches below the top of the scarified surface are encountered, they will be backfilled as follows: a)Class A45 concrete will be used to fill extra depth removal holes up to the level of the surrounding prepared deck area. In lieu of using Class A45 concrete, the extra depth removal holes may be filled with the same mix used for low slump dense concrete provided the following properties apply: 1.The concrete will attain a minimum compressive strength of 4500 psi in 28 days. 2.The concrete will contain 5.5 to 7.5% entrained air. 3.The concrete slump will be from 1 to 4½ inches. 4.The water-cement ratio will not exceed 0.40. 550 Page 381b)Concrete used to backfill extra depth holes will be cured with a double layer of wet curing blankets and polyethylene sheeting until a minimum compressive strength of 2000 psi has been attained. Curing compound will not be used. 2.General: a.Exposed reinforcing steel will be thoroughly cleaned by abrasive blasting to the satisfaction of the Engineer. b.Concrete adjacent to or within 6 feet of fresh placed overlay concrete will not be scarified or chipped until the fresh overlay concrete has cured for a minimum of 96 hours. c.Jack hammers and mechanical chipping tools will not be operated at an angle in excess of 45 degrees measured from the surface of the concrete, except in areas where concrete removal Type 1D is required. d.Reinforcing steel damaged during the concrete removal will be repaired or replaced at the expense of the Contractor. e.Within 24 hours prior to the placement of the overlay concrete, the deck surface will be thoroughly cleaned of all loose or foreign material by abrasive blasting. The abrasive blasting will be to an extent that all surface laitance is removed. Abrasive blasting, of old decks being overlaid, will expose the coarse aggregate and remove rust from exposed reinforcing steel. If precipitation or any other contamination occurs on the deck surface within the 24 hour requirement, the deck surface will be abrasive blasted again and thoroughly cleaned. After abrasive blasting, the surface will be cleaned by air blast using a compressor equipped with a satisfactory operating filter. If necessary to remove rust, oil, and other foreign materials detrimental to achieving bond, detergent cleaning, abrasive blasting, and air blast or vacuum will be required. The edges of previously placed overlay and bottom of curb faces will be abrasive blasted. Immediately prior to placement of latex modified concrete, the clean surface will be thoroughly wetted for a minimum of one hour. Standing water in depressions or holes will be blown out with compressed air or removed by other acceptable means. f.The Contractor will prevent spilling fuel and oil or bringing asphalt or other foreign materials onto the prepared deck. Equipment for use on the deck will not leak fuel, oil, or drag foreign material onto the prepared deck. g.On low slump dense concrete overlays, before an adjacent course is placed, transverse and longitudinal joints of previously placed surface course will be saw cut the full thickness of the overlay. The material will then be removed back a minimum 550 Page 382of 6 inches to provide a straight and vertical edge. At the abutment ends of the bridge, the saw cut will be made as shown on the plans so as to minimize reflective cracking of the overlay. Concrete breakout will be done using chipping hammers no heavier than 15 pounds. The previously placed surface course will cure a minimum of 12 hours prior to sawing. If this work is started before the end of the 72 hour curing period, the work will be restricted as follows: 1)Sawing or other operations, which interfere with the curing, will be kept to a minimum time and in the immediate work area. 2)Curing will be resumed promptly upon completion of the work. 3)The exposed area will be kept damp until the curing media is replaced. 4)Power driven tools heavier than a 15 pound chipping hammer will not be permitted. When bridge deck resurfacing is being performed on one-half of the width and traffic is carried on the other one-half of the deck, only the portion the deck being resurfaced will be scarified. Traffic is not allowed on the scarified surface of the deck before it is resurfaced. D.Resurfacing Operation Limitations: 1.Latex Modified Concrete Limitations: Under normal working conditions placement and finishing will proceed at a rate of not less than 40 lineal feet per hour, measured parallel to the centerline of the bridge. Latex modified concrete will be between 45°F and 80°F at the time of placement and will be maintained in this temperature range for at least 48 hours after placement. The concrete surface at the time of placement of the mixture will be at least 40°F as measured by a thermometer placed under an insulating blanket and laid against the surface. The latex modified concrete may not be placed after October 1 or before May 1, without written authorization. The latex modified concrete will not be placed when the air temperature in the shade exceeds 85°F. It may be necessary to place concrete during evening or early morning hours to comply with this requirement. Traffic will not be permitted on the latex modified concrete surface until 96 hours after placement. A longer curing period may be required when temperatures fall below 55°F. Acceptable lighting will be in place prior to surface preparation or concrete placement planned during hours of darkness. A construction dam or bulkhead will be installed when a delay in the placement operation exceeds one hour. During minor delays of less than one hour the end of the concrete may be protected from drying with several layers of wet burlap. Adequate precautions will be taken to protect freshly placed concrete from sudden or unexpected rain. Placing operations will stop when it starts to rain. Fresh concrete damaged by rainfall will be removed. 550 Page 383After the bridge deck overlay has cured, it will be tested for smoothness in accordance with 2.Low Slump Dense Concrete Limitations: Placement and finishing will proceed at a rate of not less than 40 lineal feet per hour, measured parallel to the centerline of the bridge. Unless otherwise authorized by the Department’s Bridge Construction Engineer, pours will not exceed 24 feet in width. Overlay placement will not be delayed for periods exceeding 20 minutes. All exposed concrete will be covered with wet burlap if placement operations are delayed. Placement operations will cease if delay exceeds 20 minutes and placed concrete will be removed to a point determined by the Engineer. The existing surface at the time of concrete placement will be at least 40°F in the shade. The concrete will be at least 45°F and 80°F at the time of placement and will be maintained at or above 45°F for at least 72 hours. Concrete placement will not be permitted after October 1 or before May 1 or when the air temperature is above 85°F in the shade. It may be necessary to place concrete during evening or early morning hours and not during periods of low humidity and high wind to comply with this requirement. During periods of extreme and sustained hot weather, it may become extremely difficult to maintain the 80°F maximum concrete temperature for low slump dense concrete. When such conditions exist, the Engineer may authorize the maximum concrete temperature to be increased to 85°F provided that the concrete is placed when the ambient air temperature is below 80°F and the following conditions are met. a.The coarse aggregate piles will be flushed with cool water. b.The wet burlap will be placed as soon as the concrete surface will support it without deformation. c.In an effort to keep the temperature of the water as cool as possible and minimize heating of the water due to warm weather, the water tank on the mobile mixer will not be filled until immediately prior to the concrete placement, at which time the tank will be filled with cold water. The addition of ice to the water will be allowed. The placement of low slump dense concrete will not be allowed to begin when it is anticipated that the ambient temperature will exceed 80°F at any time during the duration of the concrete placement, unless the Contractor has approved fogging equipment on the project and ready for use. Fogging equipment will be capable of applying a fine fog (water droplets no larger than 75 microns), not a spray, under pressure through an atomizing nozzle over the entire exposed concrete surface until such time that the wet burlap can be applied. The manufacturer's literature, equipment specifications, and operating instructions for the fogging equipment will be submitted to the Office of Bridge Design for approval prior to use. The fogging option will not be allowed when the wind conditions are such that the fog cannot be maintained over the exposed concrete surface. 550 Page 384Traffic will not be permitted on the completed surface for 72 hours after placement. A longer period of no traffic may be required when temperatures are below 55°F. Acceptable lighting will be in place prior to surface preparation or concrete placement planned during hours of darkness. The Contractor will avoid placing longitudinal joints in the traffic wheel paths. The location of longitudinal joints will be subject to approval.
Concrete will not be placed adjacent to a surface course less than 36 hours old. Continuation in the same lane from a transverse joint will be permitted after the concrete is 12 hours old. E.Proportioning and Mixing Concrete Materials: Proportioning and mixing will conform to the following: 1.Proportioning Tolerances: Proportioning of individual components will be within the following tolerances: Cement (weight percent) 0% to +4% Fine aggregate (weight percent) ±2% Coarse aggregate (weight percent) ±2% Water (weight or volume percent) ±1% Latex emulsion (weight percent) ±1% Yield (volume percent) ±2% The discharge time interval for components, other than aggregates, will be the time established for the discharge of 94 pounds of cement. A lesser discharge time may be used for aggregates. Individual components used during discharge checks will be from the sources to be used on the project. When performing materials discharge checks, manufacturer recommendations relative to minimum quantities of materials in the bins will be adhered to. If the cement discharge is not within tolerance a new meter count and discharge time will be established using calibration form DOT-293. 2.Proportioning and Mixing: The operations of proportioning and mixing concrete will comply with the following requirements: a.The proportioning and mixing equipment operator will be thoroughly familiar with the equipment and its operation. b.Mixers will be clean and ingredients accurately proportioned. c.Concrete will be mixed at the site in accordance with the specific requirements for the equipment used. d.Concrete discharged from the mixer will be uniform in composition and consistency. Mixing capability will be such that finishing operations can proceed at a steady pace and the final finishing is completed before the formation of a plastic surface film. 550 Page 3853.Termination of Use: Permission for continued use of a mixer may be rescinded for failure to maintain acceptable production or inability to meet the specifications. F.Placing, Finishing, and Curing: Surfaces will be completely cleaned and approved prior to placing concrete. If the mixing unit or any other piece of equipment is allowed on the prepared deck, the portion of the deck which may come in contact with or be directly under the equipment will be protected with clean polyethylene or other suitable material. Polyethylene sheeting or other suitable material is required on all areas in which concrete buggies or other equipment will be operated. Any concrete buggy or other equipment that has picked up dirt, debris, or other contaminants on the tires will not be allowed on the bridge deck until properly cleaned. Screed rails will be placed and fastened in position to ensure finishing the new surface to the required profile. The mixture will be placed and struck off to approximately 1/4 inch above final grade. The mixture will then be consolidated and finished to final grade with the finishing machine. The finished surface will meet the surface smoothness requirements for bridge deck surfaces specified in Section 460.3 L.4. Hand finishing with a wood float may be required along the edge of the pour or on small repair areas. Edge tooling is required at joints, except next to metal expansion dams, curbs, and previously placed lanes. The overlay material will be consolidated with suitable spud vibrators in all areas where concrete has been removed below existing reinforcement. The following additional requirements will apply for each specific type of overlay. 1.Latex Modified Concrete Overlay : Longitudinal construction joints in the overlay will be located on the lane lines with no pour to be less than 24 feet wide. The latex modified mixture will be brushed onto the wetted prepared surface. All vertical and horizontal surfaces will receive an even thorough coating. The rate of progress will be limited so that the brushed material does not become dry before it is overlayed. All remaining latex modified brushing material, after the brushing process is complete, will be disposed of as directed. When a tight, uniform surface has been achieved, and before the plastic film forms, the surface will be given a transverse metal-tine finish. The metal-tine finish will provide a groove width of 1/8 inch and a groove depth of 3/16 inch ±1/16 inch. The spacing between the individual tines will meet the following: 550 Page 386Inches (ten foot tining rake) 2-5/16, 2-15/16, 1-1/4, 2-7/16, 2-1/16, 1-1/4, 13/16, 1, 1-5/16, 1-1/8, 2-5/16, 2-1/2, 2-7/8, 2-3/4, 1-1/8, 2-3/4, 2-1/8, 1-15/16, 13/16, 7/8, 2-5/8, 3-1/16, 3-1/16, 7/8, 9/16, 9/16, 1-5/8, 2-3/8, 1, 1-1/4, 1-9/16, 2-15/16, 1-1/8, 1-15/16, 2-3/16, 2, 2-13/16, 1, 2-11/16, 13/16, 1-7/8, 9/16, 2-5/16, 1-7/8, 2-1/2, 1-5/16, 3-3/16, 1-3/8, 15/16, 7/8, 1-5/8, 9/16, 1-3/4, 2-7/8, 3, 1-5/8, 1-5/8, 7/8, 9/16, 5/8, 2-13/16, 1-5/8, 2-7/16, 13/16, 1-1/4, 11/16, 2-3/4, 2-5/16, 1-1/8 Successive passes of the tining will not overlap. The screed rails and construction bulkheads will be separated from the newly placed material by passing a pointing trowel along their inside face. Metal expansion dams will not be separated from the overlay. Care will be exercised to ensure that this trowel cut is made for the entire depth and length of rails or bulkheads after the mixture has stiffened sufficiently. In lieu of separation by pointing trowel, bulkheads with inside surfaces covered with a material that prevents bonding to the concrete may be utilized when approved. The surface will be covered with a double layer of clean wet burlap as soon as the surface can support the burlap without deformation. Within one hour of covering with wet burlap, a layer of 4 mil minimum thick polyethylene film will be placed on the wet burlap and the surface cured for 48 hours. The curing material will then be removed for an additional 48 hour air cure. Combination burlap-polyethylene sheets may be substituted for one layer of burlap and the polyethylene film with the Engineer’s approval. 2.Low Slump Dense Concrete Overlay: The grout will be applied on a dry surface immediately before concrete placement. The thin coating of grout will be scrubbed into the surface, abutting curb faces, and the vertical surface of previously placed lanes. The area to receive the overlay will receive an even thorough grout coating. Care will be taken to ensure that excess grout does not collect in pockets and that the rate of application is limited to an amount that will be covered with concrete before it dries. The low slump dense concrete overlay will be mechanically consolidated to a lot average minimum of 98% of the rodded unit weight determined in accordance with SD 411. The lot will contain no more than 1 test below the specification and no test 2% or more below the specification. Hand finishing with a float may be required to provide a tight, uniform surface. Internal vibration (spud vibrators) will be used to consolidate the concrete along the abutment ends of the bridge, longitudinal edges, curb lines, and for any areas in which the overlay thickness is greater than 3 inches. As soon as finishing has been completed, all vertical joints with adjacent concrete will be sealed by painting with thinned grout and the deck surface given a broomed and transverse metal-tine finish. The metal-tine finish will provide a groove width of 1/8 inch and a groove depth of 3/16 inch ± 1/16 inch. The spacing between the individual tines will conform to Section 550.3 F.1. 550 Page 387Successive passes of the tining will not overlap. After the joint painting brooming and grooving is completed, the surface will be promptly covered with a double layer of clean wet curing blanket. Care will be taken to ensure that the curing blanket is well drained and that it is placed as soon as the surface will support it without deformation. The surface will receive a wet curing blanket cure for at least 72 hours. For the first 24 hours, the curing blanket will be kept continuously wet by means of an automatic sprinkling or wetting system. Care will be taken to ensure free water does not migrate into fresh concrete. After 24 hours, the Contractor may cover the wet curing blanket with a layer of polyethylene film for a minimum of 48 hours in lieu of using a sprinkling or wetting system. The concrete will be screeded and finished within 30 minutes of being placed on the deck. The Contractor will have an additional 15 minutes after the concrete has been finished to apply wet curing blanket. Failure to comply with these requirements will be cause for rejecting the work. Surface concrete in all rejected areas will be removed and replaced. Combination burlap-polyethylene sheets may be substituted for one layer of curing blanket and the polyethylene film with the Engineer’s approval. After the bridge deck overlay has cured, it will be tested for smoothness in accordance with Section 460.3 L.4. G.After the curing period, the Engineer will chain drag the entire surface of the new bridge deck overlay to check for any areas that are not bonded to the substrate. Any areas that are not bonded to the substrate will be repaired in accordance with the following: 1.The entire perimeter of the unbonded area will be sawcut the full depth of the overlay. 2.Concrete breakout will be done using chipping hammers no heavier than 15 pounds. 3.The exposed surfaces, including the vertical faces, of the breakout area will be thoroughly cleaned by abrasive blast cleaning. 4.The exposed surfaces, including the vertical faces, of the breakout area will be coated with an approved bonding agent in accordance with the manufacturer's recommendations immediately prior to concrete placement. 5.Low Slump Dense Concrete will be placed in the breakout areas within 24 hours of abrasive blast cleaning. In the event that the breakout area is contaminated with rain, dirt, debris or other contaminants before concrete is placed, the area will be re-cleaned prior to concrete placement. 6.The concrete will be cured with wet curing blanket and polyethylene sheeting for at least 72 hours. 550 Page 388Bridge deck overlay repair, including traffic control measures, will be accomplished at no additional cost to the Department.
550.4METHOD OF MEASUREMENT
A.Concrete Removal Type 1A: Concrete removal Type 1A will be measured to the nearest 0.1 foot and the area computed to the nearest 0.1 square yard. B.Concrete Removal Type 2A: Concrete removal Type 2A will be measured to the nearest 0.1 foot and the area computed to the nearest 0.1 square yard, irrespective of the areas measured as Concrete removal Type 1A. C.Concrete Removal Type 1B: Concrete removal Type 1B will be measured to the nearest 0.1 foot and the area computed to the nearest 0.1 square yard, irrespective of the areas measured as Concrete removal Type 1A. D.Concrete Removal Type 1C: Concrete removal Type 1C will be measured to the nearest 0.1 foot and the area computed to the nearest 0.1 square yard, irrespective of the areas measured for Concrete removal Type 1A and Concrete removal Type 1B. E.Concrete Removal Type 1D: Concrete removal Type 1D will be measured to the nearest 0.1 foot and the area computed to the nearest 0.1 square yard, irrespective of the areas measured for Concrete removal Type 1A, Concrete removal Type 1B, and Concrete removal Type 1C. F.Concrete Removal Type B: Concrete removal Type B will be measured to the nearest 0.1 foot, irrespective of measurement for other types of removal. G.Class A45 Concrete Fill: Class A45 concrete fill will be measured to the nearest 0.1 cubic yard as determined from the theoretical yield of the design mix and documented by the ticket batch printouts. If ticket printouts are not used, the Engineer may use cross section measure or net truck weight to determine theoretical volume based upon 150 pounds per cubic foot. When cross section measure is used, the methods of survey and computations will be agreed to prior to the pour. H.Latex Modified Bridge Deck Overlay: Latex modified bridge deck overlay will be measured to the nearest cubic yard as determined from the theoretical yield of the design mix and documented by the batch ticket printouts of the cement used and the yield tests performed. Deductions will not be made for aggregate thrown out due to brushing operations or material wasted in finishing operations, unless such waste becomes excessive. Material wasted or rejected due to other causes will not be included for payment. I.Low Slump Dense Concrete Bridge Deck Overlay: Low slump dense concrete bridge deck overlay will be measured to the nearest cubic yard of concrete placed. Measurement of concrete produced will be determined from the documented amount of cement used, as shown by the mixer cement meter readings and supported by yield tests. Deductions will not be made for material wasted in the finishing operations and removed to form longitudinal joints, unless the waste becomes excessive. Concrete wasted or rejected for other causes will not be included for payment. 550 Page 389J.Finishing and Curing: Finishing and curing will be computed to the nearest 0.1 square yard. The actual area finished and cured will be measured to the nearest 0.1 foot, exclusive of areas of metal expansion dams exposed in the finished surface.
550.5BASIS OF PAYMENT
A.Concrete Removal Type 1A: Concrete removal Type 1A will be paid for at the contract unit price per square yard. Payment will be full compensation for removal to the depth specified, required sawing, cleaning, hand removal around deck floor drains, disposal of removed material, labor, equipment, materials, and all incidental work required. B.Concrete Removal type 2A: Concrete removal Type 2A will be paid for at the contract unit price per square yard. Payment will be full compensation for the removal performed with each pass of the scarification equipment to the depth directed by the Engineer. Payment will also include full compensation for any required cleaning, hand removal around deck drains, disposal of removed material, labor, equipment, and all incidental work required. C.Concrete Removal type 1B: Concrete removal Type 1B will be paid for at the contract unit price per square yard. Payment will be full compensation for removal of the specified concrete, required sawing, cleaning, disposal of removed material, labor, equipment, materials, and all incidental work required. D.Concrete Removal type 1C: Concrete removal Type 1C will be paid for at the contract unit price per square yard. Payment will be full compensation for the specified concrete removal, sandblasting, cleaning, disposal of removed material, labor, equipment, materials, and all incidental work required. If the actual ordered quantity exceeds plans quantity, the Department will advise the Contractor, prior to the accomplishment of this additional Concrete removal Type 1C, whether payment will be made under the contract item, by negotiated prices, or under the provisions of Section 9.4. E.Concrete Removal type 1D: Concrete removal Type 1D will be paid for at the contract unit price per square yard. Payment will be full compensation for the specified concrete removal, sawing, sandblasting, cleaning, forming, disposal of removed material, labor, equipment, materials, and all incidental work required. If the actual ordered quantity exceeds plans quantity, the Department will advise the Contractor, prior to the accomplishment of this additional Concrete removal Type 1D, whether payment will be made under the contract item, by negotiated prices, or under the provisions of Section 9.4. F.Concrete Removal type B: Concrete removal Type B will be paid for at the contract unit price per foot. Payment will be full compensation for the specified concrete removal, sandblasting, disposal of removed material, labor, equipment, materials, and all incidental work required. If the actual ordered quantity exceeds plans quantity by more than 25%, the Department will advise the Contractor, prior to the accomplishment of this additional Concrete removal Type B, whether payment will be made under the contract item, by negotiated prices, or under the provisions of Section 9.4. G.Class A45 Concrete Fill: Class A45 concrete fill will be paid for at the contract unit price per cubic yard. Payment will be full compensation for materials, labor, equipment, and all incidental work required. 550 Page 390H.Latex Modified Bridge Deck Overlay: Latex modified bridge deck overlay will be paid for at the contract unit price per cubic yard. Payment will be full compensation for labor, equipment, materials, and all incidental work required. I.Low Slump Dense Concrete Bridge Deck Overlay: Low slump dense concrete bridge deck overlay will be paid for at the contract unit price per cubic yard. Payment will be full compensation for labor, equipment, materials, and all incidental work required. J.Finishing and Curing: Finishing and curing will be paid for at the contract unit price per square yard. Payment will be full compensation for labor, equipment, materials, and all incidental work required. 560 Page 391560 PRECAST AND PRETENSIONED PRESTRESSED CONCRETE
560.1DESCRIPTION
This work consists of furnishing and installing precast and pretensioned prestressed concrete items. Precast concrete drop inlets will conform to the requirements of Section 670.
560.2MATERIALS
A.Concrete: 1.Fine Aggregate : Section 800. 2.Coarse Aggregate : Section 820. 3.Water : Section 790. 4.Admixtures: Section 751 and Section 752. 5.Fly Ash: Section 753. 6.Cement: Section 750. Type II cement will be used, unless otherwise specified. For pretensioned prestressed concrete beams, Type I, II, or III cement may be used. B.Pretensioning Reinforcement: Section 1010 . C.Reinforcing Steel: Section 1010 . D.Drainage Fabric: Section 831, Type A.
560.3CONSTRUCTION REQUIREMENTS
A.General Requirements: The Contractor will satisfy the following for all precast/prestressed concrete items. 1.Notification: The Fabricator will notify the Area Engineer prior to the fabrication of precast and prestressed concrete items. 2.Concrete Mix Requirements: The Contractor will submit a concrete job mix design to the Department’s Concrete Engineer for approval 14 calendar days prior to fabrication. The mix design will include all aggregate sources and admixtures proposed for use. When a plant has been in operation and satisfactorily producing material, the Contractor will only be required to submit a concrete mix design annually for precast concrete, unless changes have been made to the pre-approved mix design or the material used in the mix design. Concrete mix designs will be submitted for each project on all prestressed concrete products.