552.01 Description
This work is constructing concrete structures, and portions of prestressed concrete, steel, timber, stone masonry, and composite structures.
552.02 Materials
Furnish materials in accordance with the following section and subsection: Bearing Devices ...................................................... 565 Compression Joint Seals ......................................... 711.15 Concrete ................................................................. 551 Concrete Sealants ................................................... 717 Expansion Joint Filler .............................................. 707.01 Reinforcing Steel and Structural Steel ..................... 555 and 711 Water Stops ............................................................ 707.03
552.03 Construction Requirements
552.03.1 Foundations
Construct foundations in accordance with Section 209. Place concrete only after the foundations are inspected and approved.
552.03.2 Falsework
Construct falsework that supports the concrete work without detrimental deformation or settlement and to the plan lines and grades. Use piling to support falsework not on solid footings. Temporary camber all spans allowing for shrinkage and settlement. The contract specifies those bridges that require a permanent camber. Provide “tattletales” or other approved devices at locations to indicate form settlement or deflection. Adjust falsework as required to maintain plan line and grade. Stop the work if detrimental settlement occurs in the falsework that cannot be adjusted. Remove and replace all concrete work affected by detrimental settlement at Contractor expense. The Contractor is responsible for the adequacy and execution of the falsework plans. Submit a Contractor approved copy of the falsework plans upon request. The Contractor approval must be shown on the drawings.
552.03.3 Forms
Construct forms so their removal does not damage the concrete. Remove all forms and form members not designated to remain in place. The term “exposed surfaces” means those concrete surfaces that are above the finished ground line. Use metal or plywood forms for exposed surfaces and countersink all bolt and rivet holes. Ensure the forms are mortar-tight providing a smooth finished concrete surface meeting the specified shape. Rough lumber, tongue-and-groove lumber, and steel-framed wooden panel forms may be used for surfaces not exposed in the finished structure that do not adversely affect the strength or appearance of the finished structure. Use only 1 type of material in any form or group of forms for exposed concrete surfaces on similar parts of a structure. 552 – CONCRETE STRUCTURES 2020 EDITION V5.1 552-2 Use filleted forms for re-entrant angles. Chamfer forms ¾-inch (19 mm) for all exposed corners and edges with an enclosed angle of less than 120°. Design the forms and falsework to withstand the vertical loads and horizontal pressure of the plastic concrete. Include in the design allowances for temporary construction loads. Do not place concrete exceeding the designed form pressure. Use forms for completed structures that are removable without disturbing adjacent forms. Form marks must conform to the general lines of the structure. Column form marks may be horizontal or vertical or both, being as symmetrical as practical. Provide form openings that permit ready access for form cleanout, inspection, placement, and compaction of the concrete. Provide cleanout ports at the top surface of the concrete where placing is stopped in narrow forms for walls or columns or where the bottom of the form is inaccessible. Remove all extraneous material within the forms before placing concrete. Treat the forms interior surfaces to prevent mortar adhesion. Water soak wooden forms to close shrinkage cracks. Set and maintain forms to the specified alignment, grade, and section and leave in place after concrete is placed for the specified time in Subsection 552.03.10 . Form defects are cause to stop work until corrected. Furnish metal or fiberglass tie rods or anchorages within the forms with cones or other devices that permit the rod and anchorage to be removed to 1-inch (25 mm) below the surface without damaging the concrete. Use metal or fiberglass tie fittings that leave the smallest possible size cavities. Dry pack cavities with cement mortar to produce a sound, smooth, even finished surface closely matching that of the adjacent concrete after form removal. Use deck slab forms that permit vertical adjustment of the bottom of the slab form.
552.03.4 Placing Concrete
A.General. Schedule a pre-placement meeting to be held 2-14 calendar days before the first deck or deck overlay concrete placement. The minimum required attendees are the superintendent, concrete foreman, concrete supplier, other contractor personnel that will supervise the concrete placement operations, and key Department inspection personnel. The purpose of the meeting is to review specification requirements, lines of communication, placement plan, quality control, safety, sampling, and review the Bridge Deck Pre-Placement Agenda. Transport and place concrete in accordance with Subsections 551.03.4 and 551.03.5 respectively. Do not allow concrete to drop from a height exceeding 5 feet (1.5 m) unless it is within a conduit. Support bars to maintain their position as shown in the contract. Deposit concrete in small quantities at many points and then work or run it along the forms. Carefully fill each part of the forms, depositing the concrete as close as possible to its final position, working the coarse aggregates back from the face and forcing the concrete under and around the reinforcing bars. Do not allow concrete to segregate by falling through or over reinforcing steel, tie rods, or similar items. 2020 EDITION V5.1 CONCRETE STRUCTURES – 552 552-3 Deposit concrete around steel shapes and closely spaced reinforcing bars, on one side of the steel, uniformly working it until the concrete flushes under the steel to the opposite side before any concrete is placed on the opposite side or over the steel. Once the concrete has taken initial set, avoid jarring the forms or straining the projecting reinforcement ends. Thoroughly consolidate all concrete, except seal concrete, during and immediately after depositing using mechanical vibration as follows:
1.Apply the vibration internally unless otherwise approved or as provided herein.
2.Vibrate the concrete at a minimum of 4,500 impulses per minute or as recommended by the vibrator manufacturer.
3.The vibration must visibly affect the concrete mass, producing a 1-inch (25 mm) slump over a minimum 18-inch (455 mm) radius.
4.Use enough vibrators to compact each batch immediately after it’s placed.
5.Vibrate the concrete around the reinforcement and imbedded fixtures and into the form corners and angles. Vibrate at the point of deposit in areas of freshly deposited concrete. Slowly insert and remove the vibrators from the concrete. Vibrate to thoroughly consolidate the concrete without causing segregation or forming localized grout areas. Vibrate at uniformly spaced points and no farther apart than twice the radius over which the vibration is visible.
6.Do not apply vibration directly to or through the reinforcement or to non-plastic sections or layers of concrete. Do not use vibrators to transport concrete in the forms. Use plastic or rubber tipped vibrator heads when placing concrete near epoxy coated reinforcing steel.
7.Supplement vibration by spading and tamping to produce smooth surfaces and dense concrete along form surfaces, in corners and locations impractical to reach with the vibrators. These requirements apply to precast piling, concrete cribbing, and other precast members unless the manufacturer’s vibration methods are approved. Place and secure all reinforcing, dowels, and other embedded items as specified. Clean rust, scale, oil, dried mortar deposits or foreign material from all embedded materials before placing the concrete. Continuously place concrete in each section of the work in horizontal layers, working continuously, if necessary, to prevent stoppage planes. Place the concrete in layers to thoroughly consolidate them with the concrete beneath. Place the succeeding layer before the previous layer has reached initial set. Compact each layer to prevent separation planes between the preceding layer and the layer being placed. The Project Manager may require an emergency bulkhead if concrete placement in a section is delayed longer than 20 minutes. A construction joint is any place where concrete placement has stopped, and the concrete has taken initial set. Make construction joints in accordance with Subsection
552.03 6
. Inset construction joints where a “feather edge” might be produced in the succeeding layer. Provide a minimum thickness of 6 inches (150 mm) in all succeeding layers. 552 – CONCRETE STRUCTURES 2020 EDITION V5.1 552-4 Place concrete so all construction joints are across low shear stress regions and out of view to the greatest extent possible. Place deck slab concrete a minimum of 7 calendar days after placing diaphragm concrete or when standard compressive strength test results verify that the diaphragm concrete has attained a compressive strength of 1,360 psi (9.5 MPa).
B.Pumping Concrete. Pump concrete in accordance with Subsection 551.03.5(A).
C.Concrete Columns. Place concrete in one continuous operation, unless otherwise specified. Allow columns to set at least 12 hours before placing the caps. Place concrete in the superstructure after the column forms have been stripped and the column is inspected by the Project Manager. The superstructure load may be placed on the columns when the column concrete reaches 80% of the required 28-day compressive strength, determined by testing standard 6 x 12-inch (152 x 305 mm) or 4 x 8-inch (102 x 203 mm) test cylinders.
D.Reserved.
E.Concrete Slab and Girder Spans. Place slabs and girders having spans less than 30 feet (9.1 m) in one continuous operation. Concrete slabs with girders spanning 30 feet (9.1 m) or more may be placed in two operations, first placing the girder stems to the bottom of the slab haunches, and then placing the slab. Use shear keys made of beveled timber blocks inserted at least 1½ inches (38 mm) in the fresh concrete at the top of each girder stem. Place the blocks to uniformly cover about ½ of the girder stem top surface. Remove the blocks when the concrete has set enough to retain its shape. Do not place the slab until the girders have been in place for at least 24 hours. Check all falsework for shrinkage, settlement, and tighten all wedges to ensure minimum deflection of the stems caused by the slab weight before placing the slab. Place concrete in girder haunches less than 3 feet (915 mm) high at the same time as the girder stem. When any haunch or filler has a vertical height of 3 feet (915 mm) or more, place the abutment or columns, the haunch, and the girder in 3 successive stages: • First, up to the lower side of the haunch. • Second, to the lower side of the girder. • Third, to completion.
F.Concrete Slip-forming. Concrete barrier rails on bridges may be slip-formed. Hand-finish the traffic face and top of the barrier to remove air holes and other blemishes, followed by a light broomed finish. Sections with concrete slumps or bulges causing barrier rail misalignment or inadequate concrete cover for reinforcing steel will be rejected.
552.03.5 Depositing Concrete Underwater
Use Class General or Drilled Shaft concrete for seals specified in the contract. All costs for concrete placed outside of the plan dimensions and any change in the seal mix design for the Contractor’s convenience is at Contractor expense. Do not place concrete underwater without Project Manager approval. 2020 EDITION V5.1 CONCRETE STRUCTURES – 552 552-5 When it is impractical or inadvisable to de-water an excavation before placing concrete, place a seal course underwater to seal the cofferdam. Place the entire seal in one continuous operation, in accordance with the following: • Use a tremie system. • Pump directly into a tremie hopper; or • Pump directly to the deposit point. Use tremie systems made of rigid, watertight steel tube having a minimum diameter of 10 inches (255 mm) with a hopper at the top. Keep the tremie’s discharge end submerged in the deposited concrete, and the tremie tube full to the hopper bottom at all times during the concrete placement. When a load is dumped into the hopper, raise the tremie to start the flow of concrete until the load discharges to the hopper bottom. Use a tremie support that allows free movement of the discharge end and permits rapid lowering of the tremie to retard or stop the flow. Pump seal concrete in accordance with Subsection 551.03.5(A) . Have a backup concrete pump or tremie available at the site to ensure uninterrupted placing of the entire foundation seal. Pump concrete into a tremie meeting the placing requirements for tremie-placed concrete. When concrete is pumped directly, the discharge tube must be a rigid pipe extending at least 5 feet (1.5 m) above the water level during placement. The discharge line from the top of the rigid pipe to the concrete pump may be flexible. Prevent water from entering the tube while placing concrete. Fill the tubes without washing the concrete. Place concrete in a consolidated mass without disturbing it once deposited. Do not place concrete in running water or expose it to the action of water before it has reached final set. Keep water still at the point of deposit. Do not pump from the cofferdam while depositing concrete underwater. Make all formwork retaining concrete underwater practically watertight. Deposit concrete to produce horizontal surfaces. After the seal concrete has cured and can withstand the hydrostatic pressure, de-water the cofferdam and place the remaining concrete in the dry. Prepare the top surface of the foundation seal in accordance with Subsection 552.03.6 before joining fresh concrete to the seal concrete. Remove high spots to provide the clearances for reinforcing steel or projection of embedded piling.
552.03.6 Construction Joints
Obtain the Project Managers approval for construction joint locations. If the concrete develops initial set due to placement delays, the stopping point is considered a construction joint. Place concrete continuously from joint to joint. Make the joints perpendicular to the principal lines of stress and locate them at points of minimum shear. Place a gauge strip, at least 2 inches (50 mm) thick, at all horizontal construction joints and at other directed locations inside the forms along all exposed faces to provide a straight line for the joints. Before placing fresh concrete against set concrete, draw the forms tightly against the set concrete face and remove all gage strips and key forms. Remove all latence, loose and foreign materials from the surface by sandblasting, high-pressure water cutting, or light bushhammering. 552 – CONCRETE STRUCTURES 2020 EDITION V5.1 552-6 Keep the surface moist until resuming concrete placement. Apply a thin coat of neat cement to the surface or coat as specified just before resuming concrete placement. Bond the successive courses by keying or doweling, as shown in the contract, at the top layer of each day’s work and at other points where work is interrupted.
552.03.7 Joints for Bridge Approach Slabs
Construct and seal joints between concrete approach slabs and structures or concrete pavement as specified. Use forms for joints that are removable without damaging the concrete. Protect the joint from damage and prevent debris and foreign material from entering the joint before installing the seal. Limit construction equipment and other vehicles operated directly across the joint to rubber- tired equipment, unless approved joint protection is used. Repair all spalls, fractures, breaks, or voids in the concrete joint surfaces as approved. Before placing the seal, clean the joints by abrasive blast or other similar methods, followed with high-pressure air jets to remove all residue and foreign material. Protect expansion joint filler from the blast. Make joint surfaces surface-dry when placing the seal.
552.03.8 Cold Weather Concreting
Perform cold weather concreting in accordance with Subsection 551.03.6.
552.03.10 Removal of Forms and Falsework
Vertical forms may be removed 24 hours following the conclusion of the concrete placement. Other forms and falsework may be removed at 14 calendar days or 80% of the specified design strength. Do not release, loosen, or remove forms or falsework without the Project Manager’s approval. This approval does not relieve the Contractor of responsibility for the safety of work. Remove all forms, blocks, and bracing. Remove mortar lips and all irregularities caused by form joints. The presence of honeycombed areas may cause rejection of the work, and upon written notice, require removal and rebuilding of the work in whole or part at Contractor expense. After the forms are removed, cut back and repair all projecting wires, tie bolts, and other metal form ties passing through the concrete in accordance with Subsection 552.03.3 . Repair honeycombed concrete in all parts of the work and voids and depressions in exposed portions of the work as follows:
1.Chip back all coarse and broken material to a dense, uniform concrete surface with exposed solid coarse aggregate.
2.Cut back feather edges to form faces perpendicular to the surface being patched.
3.Saturate all cavity surfaces with water and apply a thin layer of neat cement.
4.Fill the cavity with a thick mortar mixed in the same proportions as the concrete used in the work and at the same temperature as the surface against which the mortar is placed. Use a blend of hydraulic cement, white hydraulic cement and sand, proportioned to match the color of the concrete being repaired. Tamp the mortar into place and float the surface using a 2020 EDITION V5.1 CONCRETE STRUCTURES – 552 552-7 wooden float before initial set takes place. Cure the patch in accordance with Subsection
551.03 7.
For patching large or deep areas, add coarse aggregate to the patching material to provide a dense, well-bonded, and cured patch. Pull or remove all falsework piling 1-foot (305 mm) below the finished ground line or streambed unless otherwise specified.
552.03.11 Concrete Finish
A.Broomed Finish. Finish the surface of concrete curbs and sidewalks to the lines and grades in the contract. Work the concrete until the coarse aggregate is forced into the body of the concrete and no coarse aggregate is exposed. Float the surface with a wooden float producing a smooth and uniform surface. Apply a broom finish to curbs or sidewalks. The texturing broom may be any medium- stiff bristled broom. Broom at right angles to the curb face or sidewalk and produce a uniform close spaced texture not exceeding ⅛-inch (3 mm) deep.
B.Bridge Decks. Finish deck slabs by the machine method, excluding small or irregularly shaped areas where a machine is impractical. Calculate form elevations at tenth points, including compensation for dead load deflections shown in the plans, and submit them prior to forming the deck.
1.Machine Method. Use a self-propelled transverse finishing machine to strike off and finish the surface of deck-slab concrete. Furnish the Project Manager with information on the location and method of rail support, size of rail members, and a description of the machine. Trial-run the finishing machine over the entire deck area to be finished before placing any concrete. Attach a spacer to the bottom of the strike-off ⅛-inch (3 mm) in thickness less than the concrete cover shown in the contract. Make all adjustments necessary to produce the correct finished grade, section, concrete cover over slab reinforcement, and slab thickness. While placing the concrete, make enough strike-off passes to produce the required profile and section. Maintain the heading of concrete placement nearly parallel to and not more than 10 feet (3 m) ahead of the strike-off. The concrete carried ahead of the strike-off must not cause wheel slippage or other unsatisfactory operation. Orient the transverse axis of the finishing machine parallel to centerline of bearing on all pre-stress and steel girder spans skewed more than 15°. Make the concrete placement heading parallel to the strike-off heading to produce equal loads on each girder.
2.Hand Finishing. Obtain the Project Manager’s approval for hand finishing on deck slabs. Strike off concrete using a template or vibrating screed and finish to a smooth, even surface meeting the required profile and section using longitudinal and transverse floating. Power trowels are not allowed.
3.Straight-edging. Test the plastic concrete surface for surface smoothness behind the finishing machine with a 10-foot (3 m) straightedge. Ensure the straightedge contacts the surface in successive positions parallel to the centerline of roadway across the entire slab width. Make longitudinal advances in maximum 5-foot (1.5 m) increments. 552 – CONCRETE STRUCTURES 2020 EDITION V5.1 552-8 Immediately fill depressions with fresh concrete, consolidate, strike off, and finish. Remove high areas with a 10-foot (3 m) cutting straightedge and refinish. Correct all other surface defects using a 10-foot (3 m) float or combination float and cutting straightedge. Provide footbridge(s) that clear span the fresh concrete for complete finishing, texturing, curing, straightedge testing, and surface correction. Continue straightedge testing and surface correction until the entire surface meets the specified surface-smoothness requirements. Limited hand floating may be used to correct defects left by the finishing machine. Hand floating is not required if the machine-finished surface meets surface- smoothness requirements and is free of defects.
4.Bridge Deck Surface Texture. Perform transverse deck grooving prior to allowing traffic on the new deck. After the Project Manager approves the finished deck surface and concrete has cured for the specified cure period, saw cut transverse grooves into the finished deck. Use grooving equipment capable of saw cutting ⅛ ± 1⁄16-inch (3 ± 2 mm) wide and 3⁄16 ± 1⁄16-inch (5 ± 2 mm) deep at 1¼ ± 1⁄16-inch (30 ± 2 mm) center-to-center spacing. Do not overlap grooves during succeeding passes. Terminate grooves 1-foot (305 mm) from the face of rail or face of barriers and 4 inches (100 mm) from the paving notch, guard angles or expansion joints.
5.Broom Texture. Hand-finish the traffic surface of curbs, sidewalks, and other horizontal surfaces to receive a broom finish in accordance with Subsection
552.03 11(A).
6.Surface Smoothness. The finished surface must not vary more than 3⁄16-inch (5 mm) from a 10-foot (3 m) straightedge placed parallel to the roadway centerline. High spots are measured as ½ the distance between the end of the straightedge and the pavement surface with the straightedge centered on the apex and the opposite end held in contact with the surface. Low spot variations are measured as the distance from the straightedge to the surface with the straightedge centered on the low point. Correct unacceptable surface variations by grinding off high spots and patching or filling low areas. Subsequent surface sealing will not be required where the grooved surface is produced using a diamond-faced saw-type cutter for grinding. Perform surface sealing as follows for areas ground using conventional star- wheel-type cutters. Seal all areas where removal exceeds ¼-inch (6 mm) in depth with an approved, concrete-colored, low-viscosity epoxy-resin adhesive. Produce a non-skid texture using a steel-tine broom or by applying medium-coarse silica sand to the plastic epoxy surface. Meet the surface smoothness requirements.
7.Protective, Remedial, and Corrective Work on Deck Slab Concrete. Do not place concrete for deck slabs and stop work when rain appears imminent. Take immediate action to strike off all concrete in place to promote drainage and prevent ponding. Do not perform placing or finishing work that manipulates the concrete during precipitation. Deck slabs areas where precipitation has been incorporated into the concrete may be rejected. Make a maximum of 3 light passes with a straightedge float to remove excess water after the precipitation stops. 2020 EDITION V5.1 CONCRETE STRUCTURES – 552 552-9 Protective work is that work necessary to protect unhardened concrete from damage by hail and rain. This includes covering the concrete with a protective covering when conditions warrant. Remedial work is that work to restore a surface profile and texture on unhardened, rain-damaged concrete. Concrete damaged by rain to the extent the texture is obliterated and has a sandy appearance may be repaired by removing excess water and restoring it to the specified surface smoothness and texture. Hardened concrete is concrete that is non-plastic and does not allow the vibrator to penetrate under its own weight. Corrective work is work to provide an acceptable profile and texture on hardened, rain-damaged concrete. Do not place fresh concrete against hardened concrete until a construction joint is placed in accordance with Subsection 552.03.6 . Correct areas exceeding the specified surface-smoothness tolerance and areas where the specified texture cannot be produced by grinding and grooving using concrete grinding machines. Use a diamond saw type grooving machine. Grooves may be either longitudinal or transverse. Space grooves at ¾-inch (19 mm) centers and be ⅛-inch (3 mm) wide by ⅛ to 3⁄16-inch deep (3 to 5 mm). Grooving is not required on areas that measure 10 feet (3.0 m) or less in length parallel to centerline of roadway. Do not grind or groove so that concrete cover is reduced over the top reinforcing bars to less than 2 inches (50 mm). Remove, replace, or overlay areas that cannot be corrected to the required surface smoothness and texture by grinding and grooving. Submit proposed overlay methods in writing for approval before use. Remove all latence and hardened, excess concrete from construction joints before placing curbs, barriers, or other concrete. Furnish all protective, remedial, and corrective work to provide an approved deck slab at Contractor expense.
C.Bridge Seats and Tops of Walls. Bring the concrete at bridge seats and tops of walls up to the required grade elevation, strike off with a straightedge, and float to a smooth, uniform texture. Slope the concrete surfaces in areas of bridge bearing assemblies to drain water away from the bearing devices as specified. Bushhammering is permitted only for leveling the concrete surface under the bearing plate and removing latence and loose and foreign material. Bushhammer to produce full, level bearing. When necessary, place shims in accordance with Subsection 565.03.2 .
D.Ordinary Finish. An ordinary finish is the concrete surface left once the forms are removed and all holes caused by form ties, trapped air, and all other defects are repaired. The finished surface must be true and even, free from stone pockets, depressions, or projections beyond the surface. Ordinary finish is produced as follows: 552 – CONCRETE STRUCTURES 2020 EDITION V5.1 552-10 • Soak the concrete surface with water and use the patching mortar specified in Subsection 552.03.10, working it into the small air holes and other voids in the concrete face with a sponge float or wooden float. • Rub off excess mortar after the mortar is partially set using burlap or carpet. • Remove uneven mortar surfaces that have set too hard by rubbing the entire surface with a carborundum stone and water. • Produce a finished surface that is uniform in texture and color. Rub-finish all surfaces not repairable by the ordinary finish method in accordance with Subsection 552.03.11(E). The ordinary finish may not be required for exposed vertical concrete surfaces listed below, if the forming produces a true and uniform surface and minor defects are repaired as specified: • Interior surfaces of box type concrete structures such as culverts, stock passes, and minor grade separations; or • Concrete diaphragms for prestress girders; or • Pier shafts, abutment walls, columns, struts, crossbeams, or other substructure components located where they are not readily subject to public access or view. In general, substructure elements on bridges in undeveloped rural areas and more than 25 feet (7.6 m) from the edge of the public road, located in or over streams not used extensively for recreation, or exclusively over railway property are not considered subject to public access and view. Good forming practice is considered as: • Using materials with a smooth surface free from holes, tears, dents, and gouges. • Using the largest practical pieces to minimize joints. • Arranging joints to be vertically or horizontally symmetrical; and • Using bracing to prevent bulges, offsets, and other major defects in the concrete surface. Repair major surface defects and finish the substructure unit surface or other structural components to a uniform appearance. Major surface defects are large rock pockets, offsets at form joints exceeding ¼-inch (6 mm), bulges, projections and depressions that deviate from the surface plane by more than ¼-inch (6 mm) in any 4-foot (1.2 m) length, and all other defects that reduce plan reinforcing bar cover by more than ¼-inch (6 mm). Minor surface defects may be corrected without finishing the surrounding surface. Remove mortar fins even with the surrounding surface. Fill air holes exceeding ¾-inch (19 mm) in the longest dimension with mortar and strike off even with the surrounding surface. Patch minor rock pockets, tie holes, and the like as specified in Subsection
552.03 10
.
E.Rubbed Finish. After concrete has hardened, saturate the surface with water and rub using a medium-coarse carborundum stone with a small quantity of mortar on its face. Approved bonding agents may be used. Use mortar consisting of cement and fine sand in the same proportions used in the concrete being rubbed. When forms are removed while the concrete is “green”, wet the surface and rub it with a wooden float. If approved the thin mortar described above may be used for rubbing. 2020 EDITION V5.1 CONCRETE STRUCTURES – 552 552-11 Continue rubbing until all form marks, projections, and irregularities are removed, all voids filled, and a uniform surface is obtained. Keep the paste produced by rubbing moist and allow it to set for at least 5 days. Smooth the surface by rubbing with a fine carborundum stone and water. Rub to produce a smooth texture and uniform color over the entire surface. After the final rubbing is complete and the surface has dried, rub the entire surface with burlap to remove loose mortar. The finished surface cannot have unsound patches, paste, powder, or objectionable marks.
F.Special Tooled Finish. Produce special tooled finishes using a bushhammer, a pick, a crandall, or other approved tools. Use air tools unless otherwise directed. Do not begin tooling until the concrete has set for at least 7 days, or longer, if necessary, to prevent “picking” the aggregate out of the surface. Produce a finished surface showing broken aggregate in a matrix of mortar, each aggregate particle being in slight relief.
552.03.12 Installation of Expansion and Contraction Joints
Construct expansion and contraction joints in accordance with the contract. Use methods and sequencing that prevent stress to fresh joint header concrete resulting from thermal expansion/contraction of bridge span(s).
A.Open Joints. Construct open joints by inserting and removing a template made of wood, metal, or other approved material. Remove the template without chipping or breaking the concrete corners. Do not extend reinforcement across an open joint unless specified.
B.Filled Joints. Construct poured expansion joints similar to open joints. Use filler material listed on the QPL and in accordance with Subsection 707.01 . When pre-molded expansion joints are specified, the thickness of installed filler is specified in the contract. Match the joint filler to the shape and size of the surfaces to be joined and fix it firmly against the existing surface. Do not displace the joint filler while placing concrete. Where more than one piece of filler is used to cover any joint surface, place the abutting pieces in close contact and join them together with a layer of asphalt-saturated roofing felt. Use a minimum 20-pound (1 kg/m
2.grade roofing felt having one side covered with hot asphalt. The filled joints will be inspected immediately after the forms are removed. Neatly cut and remove all concrete or mortar that has sealed across the joint. Fill openings in deck slab joints during construction with an approved tar or asphalt as directed. Place the necessary dowels, load-transfer devices, and other devices as specified.
C.Steel Joints. Fabricate and paint the joints as specified. Ensure that the surface in the finished plane is true and free of warping. Hold joints in the correct position during concrete placement. Use the openings at expansion joints shown in the contract, correcting for installation temperature. Maintain the required clearance. Release horizontal joint restraint mechanisms prior to bridge span thermal expansion/contraction. Provide sufficient support of the joint member within the slab to prevent settling or other undesirable movements from occurring after release.
D.Water Stops. Place water stops as specified. 552 – CONCRETE STRUCTURES 2020 EDITION V5.1 552-12
552.03.13 Placing Anchor Bolts
Install anchor bolts and dowel bars by one of the following methods: • Securing in position prior to casting concrete. • Drilling and grouting; or • Forming holes and grouting. Determine the final bolt and dowel locations, making allowance for thermal effects on the superstructure at the time of grouting. Ensure that all anchor bolts for shoe assemblies project above the plane of the substructure concrete to provide full anchor bolt and nut engagement after the final placement of the shoe assemblies. Form holes by inserting treated wood plugs or metal pipe sleeves into the plastic concrete and withdrawing the devices after the concrete has partially set. Form holes at least 3 inches (75 mm) in diameter to allow for horizontal adjustment. Drill holes at least 1-inch (25 mm) larger than the diameter of the anchor bolts. Verify diameter and depth before setting the beams. Use an approved non-shrink or epoxy grout and fill holes ⅔ full. Force bolts and dowels down using uniform, even pressure or light blows with a hammer until the grout rises to the top of each hole and the bolts and dowels are inserted to the correct depth. Remove all excess grout and clean the metal surfaces for painting. If below freezing temperatures are expected, a non- shrink or epoxy grout product formulated specifically for use at temperatures below freezing must be submitted for approval prior to grouting. Protect holes against damage from ice by filling them with a non-evaporating antifreeze solution. Before grouting, remove the antifreeze and thoroughly flush the holes with clean water. Install the anchor bolt nuts as shown in the contract. Tighten the upper nut against the lower nut so neither nut can be turned by hand. Correct all inaccuracies in bolt and dowel locations using approved methods at Contractor expense.
552.03.14 Setting Shoes and Bearing Plates
Set shoes and bearing plates in accordance with Subsection 565.03.2 .
552.03.15 Drainage Holes and Weep Holes
Construct drainage holes and weep holes as specified. Place ports and vents for equalizing hydrostatic pressure where required. Forms for weep holes through concrete may be wood, clay pipe, PVC pipe, concrete drainpipe, wooden boxes, or metal. Remove wooden forms, if used, after the concrete is placed. Paint or galvanize exposed metal drain surfaces as specified.
552.03.16 Pipes, Conduits, and Ducts
Install and rigidly brace pipes, conduits, and ducts encased in concrete before the concrete is placed. Furnish and install 3-inch (75 mm) length plastic, PVC pipe or approved equal in the bottom slab at the low point of each box girder cell to provide drainage for each cell. Extend the pipe ¼-inch (6 mm) below the bottom of the slab and flush with the slab’s top surface.
552.03.17 Loading of Piers and Abutments
Do not place any superstructure load on finished bents, piers, or abutments until approved. Substructures must meet the minimum requirement of 80% of the specified design strength or 7 calendar days, unless otherwise approved. 2020 EDITION V5.1 CONCRETE STRUCTURES – 552 552-13
552.03.18 Silane Sealer
Apply Silane sealer to new and replacement full depth bridge decks that will not receive a polymer overlay in the same year. Apply silane sealer after the deck has been cast for at least 28 days and after transverse deck grooving is completed. Remove any grease, oil, or other contaminants on the deck surface by sandblasting the contaminated areas. Sandblast all area of the deck surface where vehicular traffic has been present. Power wash the entire deck surface to remove concrete swarf, dirt, dust and other debris. Allow the deck to dry until it is visibly dry with no ponding or dark areas indicating moisture in the concrete surface. Submit the method and materials used to contain, collect, and dispose of all debris generated by the application, cleaning, and surface preparation processes. Apply sealer in accordance with manufacturer’s recommendations until refusal. Refusal means that additional applications remain on the surface of the concrete and does not soak in. Provide the Project Manager with the manufacturer’s recommendations for application and storage.
552.03.19 Bridge Deck Crack Sealing
Furnish bridge deck sealant in accordance with Subsection 717.02 .
A.Submittals. Submit for review prior to beginning work:
1.A MSDS for each shipment of the crack sealant components.
2.If high molecular weight methacrylate (HMWM) is supplied, provide certification from an independent testing laboratory that the materials meet the contract requirements.
3.The dates of manufacture of the deck sealant materials, their lot numbers and date of shelf-life expiration for each lot number.
4.A table showing the likely cure time in minutes for the allowable ambient temperature range, in increments of 10 °F (6 °C).
5.A work plan for each structure that includes estimated times for surface preparation and sealant application.
6.The method and materials used to contain, collect, and dispose of all debris generated by the application, cleaning and surface preparation processes.
B.Material Delivery and Storage. Store sufficient quantities of sealant materials at the site to perform the entire application. Store these materials in their original containers and according to the manufacturer’s direction. These containers must bear the manufacturer’s label. The label must show the manufacture date, the batch number, the trade name brand, and quantity. Store containers of promoters and initiators in a manner that prevents leakage or spillage.
C.Surface Preparation. Clean all concrete surfaces for bridge deck crack sealant according to the manufacturer’s recommendations. Remove curing compound, laitance, grease, dirt, dust, salt, oil, asphalt, coating, and other foreign materials. Select the size of shot or sand, and travel speed of the equipment to provide a uniformly clean surface with a uniform profile. Sand blast areas that are not cleaned with the shot blast equipment. Remove striping to the maximum extent determined to be practical by the Project Manager using up to 3 passes with shot blasting, sandblasting, or other approved equipment.
D.Application. Follow the manufacturer’s recommendations. The deck surface must appear dry to a visual inspection at the time of bridge deck crack sealant operations. The 552 – CONCRETE STRUCTURES 2020 EDITION V5.1 552-14 application rates may vary depending on field conditions. Pretreat visible cracks if required. Fill the cracks and keep them full. Continue the pretreating process until refusal of the crack to accept the material. Apply the resin to the deck within 5 minutes of complete mixing. Redistribute excess material continuously, using squeegees or brooms, and stop before resin gels. For HMWM applications, provide a manufacturer’s representative on site for the duration of the work, to provide expert assistance on storage, mixing, application, clean- up, and disposal of materials. The manufacturer’s representative is required to assist the Contractor in determining the application rates. Broadcast sand mechanically over the entire treated area of the bridge deck to obtain a visually uniform coverage of 2.5 pounds per square yard (1.3 kg/m2). Spot sand as necessary to ensure complete coverage. Apply the sand prior to deck sealant cure to ensure adequate bonding. Remove excess sand as required.
E.Limitations. Do not use material after the shelf-life date. Cover membrane and elastomeric material in deck joints, plug deck drain scuppers, seal cracks on underside of deck, and use other protective measures to protect waterways and bridge components. Replace or repair bridge components if materials or solvents harm their appearance or function, at no cost to the Department. The following conditions govern work on each individual portion of a structure unless otherwise approved by the Project Manager in writing.
1.Do not apply deck sealant materials within 48 hours after a rain or when more than 10% probability of rain is forecast within 4 hours following the application.
2.Conduct the work in a continuous operation with the bridge deck crack sealant application immediately following surface preparation.
3.Apply HMWM treatment only if the deck surface temperature and the air temperatures are between 50 and 90 °F (10 and 32 °C) and the weather forecast shows air temperatures will remain within that range for at least 12 hours after the end of the application. Apply Epoxy treatment at temperature requirements in accordance with manufacturer recommendations. Do not permit traffic on the treated surface until the sand cover adheres sufficiently so that no tracking will occur.
F.New Bridge Slab Construction. Upon completion of the water cure and prior to transverse grooving and Silane treatment, treat all visible cracks with crack sealer. In areas where crack sealer has puddled, spread sand on the surface in an amount to ensure adequate skid resistance. Visible cracks are cracks that can be seen unaided from about 4 feet (1.2 m) above the deck. The Project Manager will determine the locations where crack sealing is required.
552.03.20 Opening to Traffic
Open concrete deck bridges to traffic only with the Project Manager’s approval. Do not open concrete bridge decks to traffic when the air temperature during the cure period is 50 °F (10 °C) or higher, until one of the following is met:
1.Twenty-one days after placing concrete unless standard strength test results indicate more time is required: or
2.Test results on field-cured test cylinders indicate that at least 90% of the required minimum strength has been attained. Two cylinders constitute a test, with the test strength being the average of the strengths of the 2 individual cylinders. 2020 EDITION V5.1 CONCRETE STRUCTURES – 552 552-15 The Project Manager will determine the opening date when the ambient temperature during the cure period has been lower than 50 °F (10 °C).
552.03.21 Acceptance
Repair or replace all defective work at Contractor expense. Remove and replace the entire section at Contractor expense when the Project Manager determines the repair is not adequate. Acceptance of the bridge deck concrete placement and water cure is based on meeting the following requirements:
1.Proper use of fogging.
2.Proper water cure; and
3.Application of silane sealer. The Project Manager will determine if these items meet this specification. The Project Manager may apply a 10% deduct on each separate pour, for each item that does not meet specifications. No incentive will be awarded for pay factors calculated from Subsection 551.03.8, if any deductions are applied. The Department may require corrective action for any concrete not in accordance with the contract at Contractor expense.
552.04 Method of Measurement
Concrete is measured in cubic yards (m3) from the plan dimensions. Plan quantities will not be re-measured except as specified in Subsection 552.05. Fillets, scorings, and chamfers 2 inches (50 mm) or less in the greatest dimension are omitted from the quantity calculations. No deductions are made for the concrete volume displaced by reinforcing steel, structural steel, prestressed beams, anchor bolts, drains, weep holes, joint fillers, conduits, or junction boxes. Deductions are made for the concrete volume displaced by steel and concrete piles. When ordered in writing by the Project Manager, concrete quantities placed outside neat lines are calculated and added for payment. No measurement is made for forms, falsework, cofferdams, bracing, and the like. Crack sealing is measured by the square yard (m
2.of deck surface area treated. When required as part of new bridge construction, crack sealing will be measured in accordance with Subsection 109.04 . Fogging, water cure and Silane sealer are not measured for payment. Transverse deck grooving is measured in square yards (m2) for the actual area grooved.
552.05 Basis of Payment
Payment for the completed and accepted quantities is made in accordance with the following:
A.The calculated quantities involved in changes ordered in writing by the Project Manager are added or deducted from the contract quantities.
B.A re-calculation will be made, and the corrected quantity included for payment, in lieu of the contract quantity, when the contract quantity of any complete structure element is in error by 2% or more. A complete structure element is the smallest portion of a total structure for which a quantity is included in the Estimated Plan Quantities Table shown in the contract. The party to the contract requesting an adjustment in quantity must present 552 – CONCRETE STRUCTURES 2020 EDITION V5.1 552-16 to the other party the description and location and recalculated quantities of the structure element that has the quantity error.
C.All Classes of concrete placed in bridges are subject to a payment reduction based on lot payment factors in accordance with Subsection 551.03.8(B)(1) . Partial payments for structure elements will be made based on the contract quantities as follows:
1.40% of superstructure concrete when deck forms are complete in place.
2.80% when all types of concrete are placed.
3.85% when curing is complete.
4.95% when all finishing is complete.
5.100% when the structure element area is cleaned up to the Project Manager’s satisfaction. Pay Item Pay Unit Bridge Deck Crack Seal Square Yard (m2) Concrete Cubic Yard (m3) Transverse Deck Grooving Square Yard (m2)
Referenced in this section
Concrete Structures in other states
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Source: Standard Specifications for Road and Bridge Construction, 2020 (v5.1) Edition. Pages 317–332 of 611. View official source ↗