STRUCTURAL CONCRETE 509.04 377 SECTION 509
509.01 Description
This work consists of providing, placing, finishing, and curing structural concrete in bridges, culverts, and other structures.
509.02 Material S
Provide materials in accordance with the following sections and subsection: Material: Section or Subsection: Portland Cement Concrete 701 Supplementary Cementitious Materials 702 Water 701.04 Concrete Surface Finish for Structures 737
509.03 Equipment
Meet the requirements of 414.03A, “Plants and Equipment. ”
509.04 Construction Methods
A.General Handle and measure materials, batching, and mixing in accordance with Subsection 414.04.B, “Handling, Measuring, and Batching Materials,” Subsection 414.04.C, “Mixing Concrete,” and Subsection 414.04.D, “Light and Weather Limitations, ” unless otherwise required by the Contract. Use falsework and forms in accordance with Section 502, “Forms, Falsework, and Temporary Works.” Support concrete until it reaches the Contract required strength. If approved by the Engineer, use maturity meters for form removal or for opening roadways. Submit a plan for using maturity meters at no additional cost to the Department. Perform related work for concrete structures in accordance with Section 502, “Forms, Falsework, and Temporary Works,” Section 503, “Prestressed Concrete Bridge Members, ” Secti on 504, “Bridge Decks, Approaches, Rails, and Parapets,” Section 511, “Reinforcing Steel for Structures ,” and Section 517, “Post -Tensioning.”
B.Protection of Concrete from Environmental Conditions
1.General Protect the concrete from environmental damage during placement and curing. Replace or repair frozen or damaged concrete.
509.04 Structural Concrete
378 Place concrete with a temperature from 50 °F to 90 °F [10 °C to 32 °C] except for bridge decks and, approach slabs . Place b ridge deck and approach slab s concrete at temperature from 50 °F to 85 °F [10 °C to 29 °C]. Place concrete overlays in accordance with 505.04E.(3)(g) , “Temperature Limitations.” During hot weather, place concrete deck at dawn, at dusk, or at night . Measure the concrete temperature immediately before placement. Place the concrete against forms, the ground, or reinforcement with a temperature from 35 °F to 100 °F [2 °C to 38 °C]. Keep at least two recording thermometers on the Project that can record the maximum and minimum temperatures within 5 °F [3 °C]. Install the thermometers and submit the temperature data as directed by the Engineer. Report readings and reset thermometers daily.
2.Rain Protection The Department will not allow the placement of concrete during rain. If rain occurs, protect the surface of the concrete.
3.Hot Weather Protection Use a water spray to cool surfaces hotter than 100 °F [38 °C] that come in con tact with poured concrete. Maintain the Contract required concrete temperature using a combination of the following methods: Shade the material storage areas and the production equipment, Cool the aggregates by sprinkling them with water in accordance with Subsection 701.04, “Water, ” Cool the aggregates or water by refrigeration or replace the mix water with ice, ensuring it melts during mixing, and Inject liquid nitrogen.
4.Cold Weather Protection The Department defin es cold weather as the time during the concrete placement or curing period that the ambient temperature drops below 35 °F [2 °C]. To determine ambient temperature, measure the air temperature in the shade 5 ft [1.5 m] above the ground. Before placing con crete in cold weather, ensure the availability of protection material and equipment. Remove snow, ice, and frost from the surfaces coming in contact with the concrete. Ensure the temperatures of the surfaces that come into contact with fresh concrete are at least 35 °F [2 °C]. Place the heaters, if used, and direct ducts in a manner that prevents fire hazards and excessive localized drying. Vent exhaust flue gases from combustion heating units to the outside of enclosures. Apply and withdraw the heat gra dually and uniformly so the concrete surface does not heat to more than 90 °F [32 °C] before setting. When removing protection, prevent the temperature from varying by more than 20 °F [11 °C] in 8 hr. Prevent the cement from coming into contact with aggre gates hotter than 100 °F [38 °C] during concrete mixing. The Department will not allow heating aggregates with a direct flame or on sheet metal over a fire. Do not use direct steam to heat fine aggregate. The Department will not allow salts to prevent f reezing. STRUCTURAL CONCRETE 509.04 379 Place concrete with a uniform temperature and free of frost lumps. During cold weather, protect the concrete for at least 7 calendar days so the surface temperature does not drop below 50 °F [10 °C]. Provide and install recording thermometers, maturity meters, or other recording temperature measuring devices to verify that the concrete is protected. Extend the protection period to 10 days if fly ash, slag, and silica fume are used in the concrete.
C.Handling and Placing Concrete
1.General Place and consolidate concrete, preventing mix segregation and producing a dense homogeneous concrete, free of voids and rock pockets. Prevent displacement of reinforcing steel and other embedded materials in the concrete. Place and consolidate concrete befor e initial set. Place the concrete in accordance with the time limits in Table 509:1 . Begin measuring time when adding the cement to the mix. If submitted as part of the mix design, add high range water -reducing admixtures at the Project site in accordance with Section 701, “Portland Cement Concrete.” Table 509:1 Time Limits for Completion of Concrete Placement/Consolidation Cement Type Time Limit, hr Type I or II 1 Type I or II with retarding admixture 1.5 Type III 0.75 Type III with retarding admixture 1.25 Place the concrete after the Engineer approves the forms, materials, and footing foundation material. Remove mortar, debris, and foreign material from the forms and reinforcing steel. Moisten the forms and subgrade before placing the concrete against them. Remove temporary form spreaders when the concrete placement precludes prevent ing their need. Place concrete uninterrupted between construction or expansion joints. Place and consoli date fresh concrete against previously placed concrete before initial set. Place successive batches within 20 min of the preceding batch. Increase this period to 30 min if the ambient temperature falls below 60 °F [15 °C]. If placement is delayed and th e initial set occurs, make an emergency construction joint in accordance with Subsection 509.04.D, “Construction Joints.” Do not break the bond with reinforcing steel or damage the concrete during and after concrete placement. Keep foot traffic off the fresh concrete. The Department will not allow placing support platforms on reinforcing steel. After the concrete sets, do not apply force to reinforcing steel and forms projecting from the concrete until the concrete is strong enough to resist damage.
2.Sequence of Placement Release the forms and falsework in accordance with Subsection 502.04.(C), “Removal of Forms and Falsework. ”
509.04 Structural Concrete
380 (a) Substructures and Vertical Members Before placing loads on walls, decks, approach slabs, bents, piers, or abutments verify to determine if they meet strength re quirements specified in 509.04.I, "Application of Loads Including Bridge Decks and Approach Slabs ."
b.Superstructures Remove substructure forms before placing concrete in the superstructure to ensure the substructure can support the superstructure. Place concrete in the superstructure when the substructure attains the Contract required strength. Place concrete for cast -in-place T-beams or pan girders in one to two operations. If the section exceeds 4 ft [1.2 m] deep, place in two operations. Wait at least 5 calendar days after stem placement before placing the top deck slab concrete. Place concrete for box girders in two to three operations consisting of the bottom slab, girder webs, the top slab, or as required by the Contract. Place the bottom slab first. Place the top slab at least 5 calendar days after placement of the girder webs.
c.Arches Place concrete in arch rings to uniformly load the centering.
d.Box Culverts Allow the box culvert base slab to set 24 hr before placing the culvert walls. For walls shorter than 5 ft [1.5 m], place the walls and top slab in one operation. For walls hig her than 5 ft [1.5 m], place the walls and top slab in accordance with Table 509:02 , "Time and Strength Requirements for Concrete Placement and Loading."
e.Precast Elements Place and consolidate concrete to prevent shrinkage cracks.
3.Placing Methods
a.General Place concrete close to its final position. The Department will not allow the use of vibrators to move a mass of fresh concrete. Place concrete in horizontal layers less than 18 in [0.5 m] thick. Ensure the vibrators consolidate and merge new layers with the previous layer. When placing concrete, do not exceed the design loading for forms. Drop unconfined concrete from a height of less than 6 ft [2 m]. Confine concrete using a tube fitted with a hopper head or other device that prevents mix segregation and mortar spattering. STRUCTURAL CONCRETE 509.04 381 (b) Equipment Provide equipment that will not damage the concrete from vibration or cause mix segregation or mortar loss. Provide equipment with no aluminum parts that come in contact with the concrete. Remove mortar fr om inside surfaces of placing equipment. Use chutes lined with smooth, watertight material. Equip the chutes with baffles or reverses if working around steep slopes. Operate concrete pumps to discharge a continuous concrete stream without air pockets. Use conveyor belt systems less than 550 ft [170 m] measured from end to end of the belt assembly. Arrange the belt assembly so sections discharge into a vertical hopper without mortar adhering to the belt. Use a hopper, chute, and deflectors at the dischar ge end of the conveyor belt so that the concrete drops vertically.
c.Lighting Provide lighting required by the Contract if placing concrete at night and avoid interruptions to concrete placement. Repair damage to the lighting system and replace burned o ut lamps.
4.Consolidation Consolidate concrete using internal mechanical vibrators, unless placing concrete in drilled shafts. Use external form vibrators on thin sections if the forms are designed for external vibration. Ensure vibrators transmit at fr equencies of at least 75 Hz. Use vibrators to consolidate the concrete batches immediately after placing them. Provide at least one spare vibrator in case of breakdown. Use vibrators to work the concrete around reinforcement, embedded fixtures, corners, and angles in the forms. Beginning at the deposit point, vibrate the concrete at uniformly spaced locations. Ensure the distance between the locations is no greater than one and one -half times the visible effective radius of the vibration. Vertically in sert vibrators so the affected vibrated areas overlap, then slowly withdraw them from the concrete. Ensure the vibration consolidates the concrete without causing segregation. Do not cause grout formation. The Department will not allow vibrating reinfor cement or through reinforcement to layers of concrete that has become non - plastic. Alternatively, spade to make smooth surfaces and dense concrete along forms, in corners, and areas inaccessible to vibrators.
5.Underwater Placement
a.General The Engine er will allow underwater placement for seal concrete and drilled shafts. Use seal concrete to seal structures from water. For concrete placed underwater, increase the cement content in the concrete mix by 10 percent to compensate for loss. Place drilled shafts in accordance with Section 516, “Drilled Shaft Foundations.” Place concrete underwater in a compact mass and prevent seal concrete segregation. Maintain still water at the deposit point. Make underwater forms watertight . During
509.04 Structural Concrete
382 placement and curing, vent cofferdams to equalize the hydrostatic pressure and prevent water from flowing through the seal concrete. Maintain a continuous concrete flow when placing seal concrete underwater. Keep the concrete surface level. To ensure bonding, place layers of seal concrete before the preceding layer sets. For large pours, use more than one tremie or pump.
b.Equipment
1.Tremies Use watertight tremies with a diameter of at least 10 in [250 mm]. Fit the top with a hopper. Use multiple tremies required by the Contract. Ensure tremies can lower rapidly to retard or stop the concrete flow. Seal the discharge end at the start of concrete placement and fill the tremie tube with concrete. Keep the tremie tube full of concrete durin g placement. If water enters the tube, withdraw the tremie and reseal the discharge end. Maintain a continuous concrete flow until completing the placement.
2.Concrete Pumps Do not pump concrete directly into drilled shafts, pump concrete into a tremie in accordance with 516. 04.C.(6) , “Tremies.” Pump concrete into footings and other members as approved by the Engineer. Use pumps that seal out water while concrete fills the tube. When the concrete begins to flow, keep the end of the discharge tube full of concrete and below the surface of the d eposited concrete until completing the placement.
c.Cleanup Dewater after test specimens, cured under similar conditions, indicate that the seal concrete has sufficient strength to resist the expected loads. Remove all laitance or other unsatisfactory m aterials from the exposed surface by scraping, chipping, or other means which will not injure the surface of the seal concrete before placing the foundational concrete.
D.Construction Joints
1.General Make construction joints in a ccordance with Section 518.04 .A, "Construction Joints and Expansion Devices" where required by the Contract. Extend reinforcing steel through joints. Wait at least 24 hours before placing deck concrete in adjacent simple spans where the deck is continuous over the pier. Place emergency construction joints as approved by the Engineer, and add steel dowels across the joint at no additional cost to the Department .
2.Bonding Unless otherwise required by the Contract, construct horizontal joints without shear keys and vertical joints with shear keys. Rough float the fresh concrete at a horizontal joint to consolidate the surface. Leave the joint roughened. The Department defines shear keys as depressions in the surface that cover one -third of the contact surface. Bevel the key forms so that removal does not damage the concrete. STRUCTURAL CONCRETE 509.04 383 Clean debris from construction joints before placing fresh concrete against the joint surface. Use an abrasive blast with an amplitude of ¼ in [6 mm], or other m ethods to clean joints without shear keys to expose clean aggregate. Clean joints with shear keys. Flush construction joints with water and allow them to dry before placing new concrete.
3.Doweling into Existing Concrete Do not use dowels in an overhea d position or permanent sustained tension. Before bonding new concrete to existing concrete structures, clean and flush the existing concrete in accordance with Subsection 509.04.D(2), “Bonding.” Drill holes for g routed reinforcing dowels at construction joints to the depth required by the Contract without damaging adjacent concrete. Extend the holes to the greater of 15 bar diameters or the epoxy manufacturer’s recommended depth for the dowel bar hole depth. When doweling into reinforcing steel, consider manufacturer’s requirements for tension, compression, and overlaps. For epoxy coated reinforcing steel, increase embedment by a minimum of 30%. Ensure the hole diameter does not exceed the dowel diameter by more than ¼ in [6 mm]. Use Type H epoxy in accordance with Subsection 701.13, “Epoxy Resin Adhesives for General Use with Concrete.” Submit information on the proposed epoxy including the brand name, specification, type, cl ass, and grade for Engineer approval before use. Use equipment and techniques to proportion, mix, and place the epoxy in accordance with the manufacturer’s recommendations. Inject epoxy into the hole through a tube or hose long enough to reach the closed end of the hole. Start filling the hole from the closed end. Except in horizontal applications, fill the hole to a level that after dowel insertion, excess epoxy runs out. Twist the dowel to ensure a uniform epoxy coating. Clean excess epoxy around the hole while the epoxy remains fluid. If the epoxy is inconsistent using this procedure, use the manufacturer’s recommended procedure.
4.Forms at Construction Joints Retighten the forms before depositing new concrete if forms overlap previously placed concrete at construction joints. Neatly form the visible joint faces with straight bulkheads or grade strips, or otherwise finish joints.
E.Installing Expansion Devices, Water Stops, and Construction Joints Construct expansion devices, water stops, and construction joints as required by the Contract and in accordance with Section 518, “Construction Joints and Expansion Devices .”
F.Concrete Curing
1.General Cure all new concrete using one or more method in accordance with Subsection 509.04.F(2 ) through Subsection 509.04.F(6) . Unless otherwise required by the Contract, begin curing immediately after the surface water evaporates and finishing is complete. Do not damage the concrete surface during curing operations. If the concrete begins to dry before curing begins, use a fog spray to moisten the surface. Keep surfaces moist after removing forms. Cure immediately after the first rub.
509.04 Structural Concrete
384 Continuous ly cure the concrete for at least 7 calendar days unless using steam or radiant heat curing methods. If more than 10 percent of the portland cement weight consists of pozzolans, cure continuously for at least 10 calendar days. Except for concrete in brid ge floors and pavements, reduce the curing period if cylinders cured under the same conditions indicate that the concrete reaches at least 70 percent of its Contract required strength . For concrete decks and approach slabs, refer to 504.04 .D(5), "Fogging and Curing Requirements." Use curing agents in accordance with Subsection 701.07, “Curing Agents.”
2.Forms -in-Place Method Leave the forms in place without loosening them for f ormed surfaces. If removing forms during the curing period for rubbing, strip forms from areas that can be rubbed in one shift. Keep the surface of the exposed concrete moist during rubbing. After rubbing, continue the curing process by applying the wat er method or a Type 1-D curing compound.
3.Water Method Keep the concrete surface wet using ponding, spraying, or covering material. Ensure covering material does not discolor or damage the concrete.
4.Liquid Membrane Curing Compound Method Use Type 2, white pigmented, liquid membrane on visible bridge deck and approach slab surfaces. Use either Type 1-D, clear curing compounds or Type 2, white pigmented liquid membrane on other surfaces. Mix membrane -curing solutions that contain pigments before use. Continue to agitate during the application. Use equipment that produces a fine spray. Apply the curing compound at a coverage rate of at least 1 gal per 160 ft² [1 L per 4 m²] in one to two applications. If using two applications, apply the second wi thin 30 min at right angles to the first application. Continue curing applications until gray is not visible. Apply a new coat of curing compound if rain damages the membrane during the curing period. Do not use the liquid membrane method on surfaces that receive a Class 2 rub -finish. The Engineer will allow curing compound on construction joints if sandblasting removes the compound before the next concrete placement against the joint. Protect reinforcing steel from the liquid membrane -curing compound.
5.Waterproof Cover Method Cover the wet concrete surface with wide sheets of waterproof material that prevents moisture loss. Lap adjacent sheets at least 6 in [150 mm] and tightly seal the seams with pressure sensitive tape, mastic, glue, or other metho ds approved by the Engineer. Secure the material so wind does not displace it. Repair damaged sheets.
6.Steam or Radiant Heat Method Use the steam or radiant heat method for precast concrete members manufactured in established plants. STRUCTURAL C ONCRETE 509.04 385 Conduct steam or radiant heat curing in an enclosure to contain the heat and steam. Ensure a uniform temperature inside the enclosure. Place the temperature recorder inside the enclosure. Apply steam or radiant heat after the concrete initial set, or from 2 hr to 4 hr af ter final placement for normal set concrete. Allow retarded set concrete to sit from 4 hr to 6 hr. Measure the time of initial set in accordance with AASHTO T 197 (ASTM C 403). After placement, and before using this curing method, use steam or radiant h eat to maintain the curing chamber temperature from 50 °F to 90 °F [10 °C to 32 °C]. Prevent localized high temperatures on the members caused by directly applying steam or radiant heat. Limit the rate of ambient temperature change in the curing enclosure to 40 °F/hr [22 °C/hr]. Ensure the temperature inside the enclosure does not exceed 160 °F [70 °C]. Maintain the curing temperature until it reaches the Contract required concrete detensioning strength. When discontinuing steam or radiant heat, allow t he ambient air temperature in the enclosure to cool to 20 °F [10 °C] above the outside temperature. Do not reapply steam or radiant heat after cooling. For the steam method, use low pressure, saturated steam with 100 percent relative humidity. Apply the radiant heat using pipes that circulate steam, hot oil, hot water, or electric heating elements. If using the radiant heat method, cover exposed concrete with plastic sheeting or a liquid membrane -curing compound. After the curing, remove compound residu e from areas requiring surface bonding. Unless maintaining the ambient temperature above 60 °F [16 °C], transfer the stressing force on prestressed members immediately after discontinuing the curing.
G.Finishing Formed Concrete Surfaces Replace or repair rock pockets or honeycombed concrete. Provide a durable, uniformly textured and colored, tightly bonded surface finish. Except for Class 7 finish, apply a penetrating water repellent treatment in accordance with Section 515, “Penetrating Water Repellent Treatment.” Apply coatings, grout, and mortar when the surface temperature is 40 °F [5 °C] or higher, except for Class 6 Mortar Finish (see below). Comply with the Manufacturer’s temperature requirements when they are more restrictive. When finish treatment is not specified in the plans, use a Class 1 ordinary surface finish followed by either a Class 2 rubbed finish or a Class 6 mortar finish.
1.Class 1, Ordinary Surface Finish Finish formed concrete surfac es with a Class 1, ordinary surface finish. Apply Class 1 finish prior to applying other concrete finishes. Finish upon form removal. Remove irregularities from exposed surfaces or those specified for waterproofing. Remove bulges and offsets with carb orundum stones or discs. Remove poorly bonded rock pockets or honeycombed concrete, and replace them with concrete or packed mortar in accordance with Subsection 509.04.H, “Mortar and Grout. ” The Engineer may identi fy rock pockets or honeycombed concrete areas that may materially affect structural strength or steel reinforcement effectiveness, determine that the areas are defective, and require their replacement.
509.04 Structural Concrete
386 Clean and point defects, and saturate the area with wa ter. Finish the area with less than 1 hr old mortar in accordance with Subsection 509.04.H, “Mortar and Grout. ” After the mortar sets, rub and continue curing if required by the Contract. Match exposed surfaces to surrounding concrete. Tool and remove free mortar and concrete from construction and expansion joints. Leave joint filler exposed along its length with clean edges. Rub or grind bearing surfaces on piers and abutments to the elevation and slope shown on the Plans. If the final finished surface is not uniform, provide a Class 2, rubbed finish.
2.Class 2, Rubbed Finish Finish concrete surfaces with a Class 2, rubbed finish except for superstructure soffits, concrete girder bottoms, concrete girder interi or faces, and the interior faces of reinforced concrete boxes. Saturate the concrete surfaces with water immediately before rubbing with a medium coarse carborundum stone with a small amount of mortar on the face. Mix mortar from cement and fine sand in t he same proportions as the finished concrete. Continue rubbing to remove form marks, projections, and irregularities, and to obtain a uniform surface. Leave the paste in place. Rub with a fine carborundum stone and water until smooth and uniform in color after completing other surface work. After the surface dries, rub with burlap to remove loose powder. Ensure the surface is without unsound patches, paste, powder, and marks. Achieve a rubbed finish for slip formed surfaces.
3.Class 3, Tooled Finish Provide a Class 3 surface finish if required by the Contract. Let the concrete set for at least 14 calendar days. Use air tools. Chip away the surface mortar and break the aggregate particles to expose a group of broken aggregate particles in a matrix of mortar.
4.Class 4 Sandblasted Finish Provide a Class 4 surface finish required by the Contract. Let the concrete set for at least 14 calendar days. Protect adjacent surfaces that are not sandblasted. Sandblast the surface to produce a fine -grained su rface exposing the aggregate.
5.Class 5 Wire Brushed or Scrubbed Finish Provide a Class 5 surface finish if required by the Contract. Begin after form removal. Scrub the surface with stiff wire or fiber brushes and a solution of 1 part muriatic acid to 4 parts water. Scrub away the cement film to expose the aggregate particles. Leave an even pebbled texture. Wash the surface with water and ACI recommended amount of ammonia.
6.Class 6 Mortar Finish Provide a Class 6 surface finish except for bearing surfaces, or unless other wise required by the Contract . Use cement mortar in accordance with Section 737, “Concrete Surface Finish for Structures. ” Unless otherwise specified by the Contract, use a lighter color than the concr ete. Build 18 in × 36 in [0.5 m × 1 m] concrete finish sample panels. Obtain the Engineer’s approval of the color. Protect the approved sample panel during the work. Finish designated surfaces to match the color of the approved sample. STRUCTURAL CONCRETE 509.04 387 Complete other ad jacent work before applying the mortar finish. After completing the Class 1 surface finish, remove deleterious material by lightly abrasive -cleaning the surface. Wash the surface with a jet spray of water. Protect the untreated surfaces. Apply the finis h to a dry surface when the surface temperature reaches at least 50 °F [10 °C] with a forecast of at least 50 °F [10 °C] during the 24 hr following application: Apply the finish as the manufacturer specifies. Apply the coating using a plaster -type spray gu n or the brush and float method. Cure cement -based mortar coatings as specified for curing concrete. Clean concrete areas that will not be finished. Clean and recoat defective areas at no additional cost to the Department.
7.Class 7 Paint Finish Paint concrete if the Contract requires. Before painting, apply water repellent in accordance with Section 515, “Penetrating Water Repellant Treatment.” Paint concrete in accordance with Section 737, “Concrete Surface Finish for Structures.” Before painting, clean surfaces with a power washer with a pressure of at least 3,000 psi [21 Mpa]. Submit the manufacturer’s specifications to the Engineer 14 days before application. Use anti -graffiti coatings in accordance with subsection
737.04 , "Anti -Graffiti Coating System." Apply all coatings in accordance with the manufacturer
recommendations.
H.Mortar and Grout
1.General This work consists of making and placing of mortar and grout for use in concrete structures, other than in prestressed ducts. The use of mortar includes filling voids and repairing surface defects. The use of grout includes filling sleeves for anchor bolts.
2.Materials and Mixing Provide materi als for mortar and grout to fill voids, repair surface defects, and fill sleeves for anchor bolts in accordance with Section 701, “Portland Cement Concrete.” If the width or depth of the void is less than ¾ in [20 mm], modify th e sand grading for use in grout or mortar so material passes through a No. 8 sieve. Use Type I Portland Cement and air entraining admixture. Unless otherwise required by the Contract, use 1 part cement to 2 parts sand for mortar and 1 part cement to 1 part sand for grout. If using non -shrink motor or grout as required by the Contract, use a non -shrink admixture or expansive hydraulic cement in accordance with ASTM C845 . Use enough water to allow placing and packing. For mortar, limit the amount of water so the mortar forms a ball if squeezed. Use hand methods or rotating paddle -type machines to mix. Mix to thoroughly blend ingredients. Do not re -temper mortar or grout and place it within 1 hr of mixing.
509.04 Structural Concrete
388 (3) Placing and Curing Clean foreign material fro m areas that contact the mortar or grout. Flush the areas with water and allow them to dry before placement. Fill and tightly pack holes and locations identified by the Engineer with mortar or grout. For structural repairs, use the water method to cure m ortar and grout surfaces for at least 3 days. Apply loads on mortar or grout after completion of curing. Replace defective mortar and grout.
I.Application of Loads Including Bridge Decks and Approach Slabs Apply loads to concrete structures only after t he concrete has attained sufficient strength and, when applicable, sufficient prestressing. Determine strengths from test cylinders cured at the work site under similar environmental conditions in accordance with Section 701, “Po rtland Cement Concrete.” Use the cylinder test to ensure the concrete reaches required concrete strengths. Provide a minimum of 7 calendar days curing before loading the concrete if the ambient temperature falls below 50 ºF [10 ºC] in accordance with 509.04.B(4), “Cold Weather Protection.” Limit construction loads on structures to the load carrying capacity in accordance with AASHTO Standard Specifications for Highway Bridges. Calculate capacities using the lowest measured, actual strength of the structure. Remove forms in accordance with Section 502.04.C, “ Removal of Forms and Falsework. ” For post -tensioned structures, complete the span tensioning before applying loads more t han 4,500 lb [2000 kg]. Place earth loads or backfill around structures to minimize overturning or sliding forces. For a rigid frame bridge or a bridge where the abutments are integral with the superstructure, place the superstructure and remove the for ms that support the girders and deck before backfilling the abutments. The Department will not allow placement of embankments around supporting forms. Place and load concrete in accordance with time and strength requirements provided in Table 509:02 “Ti me and Strength Requirements for Concrete Placement and Loading .” STRUCTURAL CONCRETE 509.04 389 Table 509:02 Time and Strength Requirements for Concrete Placement and Loading Item Required Concrete Strength Time Placing concrete for integral horizontal members on walls < 16 ft [5 M] tall None 30 Minutes Placing concrete for integral horizontal members on walls > 16 ft [5 M] tall None 12 Hours Placing Columns on Footings or Drilled Shafts < 16 ft [5 M] tall 80% or 3 Days Placing Columns on Footings or Drilled Shafts > 16 ft [5 M] tall 80% or 7 Days Installing Friction Collar or Falsework Brackets on Columns 100% or *7 Days Placing Beams/Girders on piers & abutments (substructure members) 80% and *7 Days OR - Leave underlying forms and falsework in place at piers 100% or *7 Days Earth Loads or backfill causing flexural stress in concrete unless otherwise provided by the Engineer 80% and *7 Days Decks and Approach Slabs: Light truck traffic < 5 tons [4.5 metric tons] and/or concrete placement for barrier or traffic rail when underlying forms and falsework still in place 80% or * 7 Days Decks: Legal Loads when underlying forms and falsework still in place 100% or *14 Days Decks: Open to traffic 100% and *14 Days Deck Patching: Bridge deck repair areas with underlying forms still in place and having areas less than 100 sq yds [84 sq M] 100% and * 7 Days Approach Slabs: Open to traffic including legal loads 100% and * 10 Days Deck and Approach Slabs: Permit loads and Stationary loads > 10 tons [9.0 metric ton] **Load specific **Load Specific
509.04 Structural Concrete
390 Table 509:02 Time and Strength Requirements for Concrete Placement and Loading Item Required Concrete Strength Time Decks : Heavy Stationary loads 5 - 10 tons [4.5 - 9.0 metric ton] when underlying forms and falsework still in place 100% or *14 Days Approach Slabs: Heavy Stationary loads 5 - 10 tons [4.5 - 9.0 metric ton] 100% or *10 Days *When Ambient Temperatures drops below 50o F [10o C], provide a minimum of 7 days before applying any loads and add a day to the original curing time for form and falsework release period in accordance with "502.04C,"Removal of Forms and ** Requires Bridge Divi sion review and approval of Engineer in writing. Distribute stationary loads as specified by the Bridge Division.
J.Concrete Anchorage Devices Use chemical, grouted, or cast -in-place concrete anchorage devices to attach equipment or fixtures to concrete. Provide the following: Concrete anchorage device sample, Manufacturer’s installation instructions, and Material data and certifications. Fabricate metal parts of the anchorage devices from stainless steel or steel protected with a corrosion -resistant metallic coating that does not react to concrete. Supply anchorage devices with hardware. For chemical or grouted anchors, conduct a system approval test at the job site on one anchor, unincorporated in the work. Conduct a static load test in acco rdance with ASTM E 488. Show that the anchorage device can withstand a direct tension test load for at least 48 hr. Ensure the device can withstand at least the values shown in Table 509:3 and Table 509:4 , and moves no more than 0.035 in [1 mm]. Show that, if loaded to failure, the steel of the anchor device fails and not the chemical, grout, or concrete. STRUCTURAL CONCRETE 509.04 391 Table 509:3 Sustained Load Test Values (English) Anchorage device stud size, in Tension test load, lbf ¼ 1,000 ⅜ 2,100 ½ 3,200 ⅝ 4,100 ¾ 5,100 Table 509:4 Sustained Load Test Values (Metric) Anchorage device stud size Tension test load, kN M8 7.1 M12 12.7 M16 18.3 M20 24 Install concrete anchorage devices in accordance with the manufacturer recommendations. Ensure the attached equipment or fixtures bear firmly against the concrete. Torque nuts in accordance with Table 509:5 and Table 509:6 , unless otherwise recommended b y the manufacturer. Table 509:5 Torque for Anchorage Devices (English) Anchorage device stud size, in Torque, lb ft ¼ 10 ⅜ 35 ½ 60 ⅝ 90 ¾ 125
509.05 Structural Concrete
392 Table 509:6 Torque for Anchorage Devices (Metric) Anchorage device stud size Torque, N m M8 30 M12 80 M16 130 M20 180 Test a random sample of at least 10 percent of the anchors in the Engineer’s presence. Proof -load the anchors to 90 percent of the steel yield stress. If an anchor fails, reset and proof -torque it and the remaining anchors. To apply the proof load, torque the anchors against load indicator washers, and apply direct tension load to the anchor, or another method approved by the Engineer. After proof -loading, release the load on the anchor and retighten to the load specified in Table 509:4 and Table 509:5 , or to the manufacturer recommended load.
K.Girder Bearings Surfaces Finish concrete bearing surfaces in accordance with Subse ction 509.04.G(2), “Class 2, Rubbed Finish.” Check concrete bearing surfaces before erecting girders for smoothness, levelness, and elevation in the Engineer’s presence. Build the concrete bearing surfaces within ¼ in [6 mm] of the elevations shown on the Plans. Ensure the bearing surfaces do not slope more than 0.5 percent from horizontal. If bearing surfaces do not meet the Contract required tolerances, notify the Engineer, and submit a written proposal to modify the installation.
L.Testing Evaluate t he compressive strength in accordance with Subsection 701.01, “Mix Design and Proportioning.” Perform other tests as required by the Contract.
509.05 Method of Measuremen T
The Engineer will measure structural concrete along the neat lines of the structure as shown on the Plans, unless otherwise modified to fit field conditions. The Engineer will not deduct the volume occupied by reinforcing steel, anchors, weep holes, piling, or pipes and ducts less than 8 in [200 mm] in diameter. The Engineer will measure concrete volumes less than 20 yd³ [15 m³] per structure as Class A Concrete, Small Structures, if included as a pay item. STRUCTURAL CONCRETE 509.06 393 509.06 BASIS OF PAYMENT The Department will pay for each pay item at the contract unit price per the specified pay unit as follows: Pay Item: Pay Unit:
A.CLASS AA CONCRETE Cubic Yard [Cubic Meter]
B.CLASS A CONCRETE Cubic Yard [Cubic Meter]
C.CLASS A CONCRETE, SMALL STRUCTURES Cubic Yard [Cubic Meter]
D.CLASS C CONCRETE Cubic Yard [Cubic Meter]
E.CLASS P CONCRETE Cubic Yard [Cubic Meter] The Department may accept concrete with strengths, air content, or both lower than required in for cubic yard units of measure accordance with Subsection 105.03, “Conformity with Plans and Specifications.” The Department will use the following equation to calculate the strength pay factor for concrete volumes with strengths less than the specified requirements: Low Strength Pay Factor = (Actual Strength/Specified Strength) ² Multiply the Contract price by the Low Strength Pay Factor for the represented concrete volume. Check any outlying concrete cylinder breaks in accordance with ASTM E 178 Table 1, “Upper 10% Significance Level.” Use the follo wing table to compute the air content pay factor for volumes of concrete with entrained air less than the specified requirements, except for drill shafts, in accordance with Subsection 105.03, “Conformity with Plans and Specifications. ” Table 509:7 Air Content Pay Factor for Cubic Yard Concrete Below Target, % Air Pay Factor >0.0 – ≤1.5 1 >1.6 – ≤3.0 (1.33 x Actual Air %) / (Target Air %) >3.0 Unacceptable Multiply the Contract price by the air content pay factor for the represented volume of concrete. If testing of subsequent loads of concrete are within 1.5 percent of the entrained air target, the pay factor will only apply to the volume of concrete outsi de the 1.5 percent of the entrained air target. If any concrete entrained air test results are believed to be an outlier, then the Engineer will check each test result in accordance with the ASTM E 178 using Table 1, Upper 10% Significance Level. If the Pay Factors are determined by the Engineer to be less than 100 percent, the Contractor may elect to core the represented concrete at no additional cost to the Department. The proposed method and location of the coring must be approved in advance by the E ngineer. Coring must be performed in the
510.02 Earth Reta Ining Systems and Sound Barrier Walls
394 presence of a Department representative. Testing of compressive strength cores will be conducted by the Materials Division in accordance with AASHTO T -22 and the cores must comply with the sample requirements of th e contract documents. Testing of entrained air content cores will be conducted by the Materials Division or its representative in accordance with ASTM C457. The entrained air portion of the total air content must meet or exceed 3.0% for Class A, 3.5% for Class AA, and 2.0% for Class P. Replace concrete sections with less 3.0% entrained air for Class A, 3.5% for Class AA, and 2.0% for Class P. Do not use volumes of concrete with entrained air 10 percent or greater. Except for Class P, replace concrete with less than 3% entrained air (2% for Class P) at no additional cost. SECTION 510 EARTH RETAINING SYSTEMS AND SOUND BARRIER WALLS
510.01 Description
This work consists of constructing earth retaining systems, sound barrier walls, and slopewalls both cast-in-place and precast.
510.02 Materials
A.General Provide materials in accordance with the following sections and subsections: Material: Section or Subsection: Structural Concrete 509 Reinforcing Steel for Structures 511 Portland Cement Concrete 701 Cover Material for Pipe Underdrains 703.06 Granular Backfill 703.07 Drainage Conduits 726 For cast-in-place earth retaining systems, sound barrier walls, and slopewalls use Class A concrete. For slopewalls, use coarse aggregate for thin section concrete.
B.Precast Elements Provide precast walls (retaining walls and sound walls) from manufacturers certified by the National Precast Concrete Association (NPCA). Use Class AA concrete in accordance with Section 509, “Structural Concrete” for manufacturing precast wall elements.
C.Filter Fabric Provide filter fabric in accor dance with Subsection 712.03, “Geotextiles for Subsurface Drainage Purposes. ”
Source: Oklahoma Standard Specifications for Highway Construction, 2019 Edition. Pages 391–407 of 935.