555Structural Concrete

(Last Revised September, 2025)

555-1DESCRIPTION. This work shall consist of furnishing and placing Performance

Engineered Mixture (PEM) Portland Cement Concrete for structures as indicated in the contract documents and as directed by the Engineer.

555-2MATERIALS

555-2.01General. The materials used for structural concrete shall comply with the material

requirements of Section 501, Portland Cement Concrete, Production. Additional materials, listed below, required specifically for use in conjunction with structural concrete items shall meet the requirements of the following subsections: Concrete Grout Material 701-05 Vertical and Overhead Patching Material 701-08 Rapid Hardening Concrete Repair Material 701-09 Concrete Repair Material - High Early Strength 701-12 Preformed Cork Joint Filler 705-01 Preformed Rubber Joint Filler 705-03 Caulking Compound for Structures 705-06 Preformed Elastic Bridge Joint Sealer 705-09 Polyvinyl Chloride Extruded Shapes and Sheet Material 705-11 Lubricant for Preformed Elastic Joint Sealer 705-13 Bar Reinforcement, Grade 60 709-01 Wire Fabric for Concrete Reinforcement 709-02 Quilted Covers (for curing) 711-02 Plastic Coated Fiber Blankets (for curing) 711-03 Polyethylene Curing Cover (White Opaque) 711-04 Membrane Curing Compound 711-05 Burlap 711-06 Form Insulating Materials for Cold Weather Concreting 711-07 Admixtures 711-08 Water 712-01 Asphalt Roofing Felt 712-12 Epoxy Resin System 721-01 Epoxy Polysulfide Grout 721-03 Copper Flashing 725-01 Sheet Gasket (treated both sides) 728-06 Concrete Cylinder Curing Equipment 637-2.03 555-2.02 283

555-2.02Concrete for Structures. Concrete required for the various structural concrete items will be

indicated in the contract documents and designed in accordance with the appropriate requirements specified in Table 2 of Materials Procedure (MP) 501-2 Mix Design and Approval Procedure for Performance Engineered Mixtures - Structural Concrete. The same source of aggregates and cementitious material shall be used for all faces and surfaces of concrete elements exposed to view to maintain a uniform appearance.

555-3CONSTRUCTION DETAILS

555-3.01Concrete Manufacturing and Transportation. Unless otherwise specified in the

contract documents, the construction details for manufacturing and transporting concrete shall comply with §501 Portland Cement Concrete Production and Materials Procedure (MP) 501- 1 Plant Production Requirements and Procedures for Portland Cement Concrete Facilities

555-3.02Falsework. Falsework plans shall be submitted by the Contractor and approved

by the Engineer before falsework construction is started. Falsework or centering shall be designed for the dead load of the concrete forms, the dead load of the plastic concrete (based on 150 pcf) and a live load resulting from a weight of 50 psf applied to all horizontal surfaces. Falsework which cannot be founded upon a solid footing, shall be supported by falsework piling. Screw jacks or hardwood wedges may be required for falsework centering or to take up any slight settlement in the form work, either before or during the placing of concrete. Falsework shall be set to give the finished structure the specified camber, plus allowance for shrinkage and settlement.

555-3.03Forms

firm, securely braced, and fastened together in their final position. They shall be strong enough to prevent the fresh concrete from bulging the forms between supports and to withstand the action of mechanical vibrators. If required by the Engineer, form work plans shall be submitted by the Contractor and approved by the Engineer before forms can be used on the work. Forms shall be designed to resist a dead load resulting from a weight of 150 pcf for the plastic concrete and a live load resulting from a weight of 50 psf on horizontal surfaces. The form and falsework design shall provide for the loads resulting from any conveyance system in addition to the live load. When concrete is transported by buggies, conveyor belt, or other approved methods of conveyance, the forms shall be capable of supporting the distribution equipment and any concentrations of concrete which may occur during transportation and distribution. Buggy runways and other supporting platforms shall be supported directly by the forms. Forms shall be adequately braced to resist concrete design loads. If the forms are inadequately braced concrete placement shall stop until adequate bracing has been provided. All forms shall be set and maintained true to the line designated until the concrete is sufficiently hardened. Forms shall be maintained to eliminate the formation of joints due to shrinkage of the lumber. Forms shall be sufficiently tight to prevent leakage of mortar. Forms may be constructed of wood, metal, or other approved materials, except when a particular material is specified in the contract documents. The use of fiber forms will be permitted for round columns only if the interior surface of the forms 555-3.04 284 have been treated in such a manner as to prevent helical corrugation marks on the finished concrete surfaces. Forms shall be filleted 1 inch with forming material at all exposed corners to create a chamfer in the finished concrete unless otherwise shown in the contract documents. When curved, patterned, or other special forms are required, the Contractor shall submit details of the form construction to the Engineer for approval prior to constructing the forms. Forms shall be so constructed that those surfaces on which finishing may be required may be stripped without disturbing the remaining forms. Premanufactured formliner panels, if used, shall be capable of imprinting the surface of the concrete with a uniform and aligned pattern and texture. The panels shall be composed of elastomeric urethane, polyvinyl chloride (PVC), ABS plastic, or other suitable material for their intended shape and number of reuses to achieve the desired effects. Formliners shall leave crisp, sharp definition of the architectural surface. Sufficient liners shall be used to minimize pattern repeat. Formliners shall not compress more than 1/4 inch when concrete is poured at a rate of 10 vertical feet per hour. Any metal ties or anchorages within the forms shall be so constructed that the embedded portion of the ties can be removed to a depth of at least 2 inches from the surface of the concrete without damage to such surface. Wire ties shall not be used without written approval of the Engineer. In case wire ties are approved, all wires, upon removal of the forms, shall be cut back at least 1/4 inch from the face of the concrete with sharp chisels or nippers (nippers are necessary for green concrete). All cavities produced by the removal of metal ties shall be filled in conformance with requirements of §555-3.11, Corrective Finishing. For walls where access to the bottom of the forms is not practicable, the lower form boards or panels shall be left loose so that the inside of the forms can be readily cleaned of all chips, dirt, sawdust, or other extraneous material, immediately prior to the placing of concrete. Forms to be reused shall be maintained in good condition as to accuracy of shape, strength, rigidity, watertightness, and smoothness of surface. Any warped or bulged forms must be carefully resized before being re-used. Forms that are unsatisfactory in any respect shall not be used. All form surfaces that will be in contact with the concrete shall be thoroughly treated with an approved form coating in the manner, and at the rate specified by the manufacturer. Only those coatings listed on the Approved List published by the Materials Bureau are acceptable. Forms so treated shall be protected against damage or dirt prior to placing concrete. If metal forms are used, the material shall be of such thickness that the forms will remain true to shape. All bolt and rivet heads shall be countersunk. Clamps, pins, or other connecting devices shall be designed to hold the forms rigidly together and to allow removal without damage to the concrete. Metal forms, which do not present a smooth surface or line up properly, shall not be used. Special care shall be exercised to keep metal forms free from rust, grease, or other foreign matter that would tend to discolor the concrete.

documents shall be considered as approximate only, and when ordered in writing by the Deputy Chief Engineer Structures (DCES), shall be changed to such dimensions as will give a satisfactory foundation. Concrete shall not be placed in any foundation form without the Engineer’s approval.

555-3.04Handling and Placing Concrete

555-3.04 285

temperature is below 45°F unless the Engineer grants approval to a written proposal from the Contractor. No concrete shall be placed during rain. When concrete is to be placed in contact with steel members, reinforcing steel, or previously placed concrete, the temperature of the steel and concrete shall be raised to a minimum of approximately 45°F. The use of enclosures and heating equipment, including but not limited to the use of forced hot air, hot water boilers, and hoses, or other methods suitable to the Engineer, may be required before concreting begins. When concrete is to be placed in contact with earth or rock, within piles, or for tremie placements, the temperature of the earth or rock shall be 35°F or higher. The earth or rock shall not have any snow, ice, frost, or standing water on its surface. The use of insulating materials and heating equipment may be required before concreting begins.

displacement of reinforcement. All equipment used for conveying the concrete mix, from the point of delivery and material acceptance to the discharge point, shall be capable of meeting the permissible variations given in Table 555-1, Concrete Conveyance Uniformity. Prior to the actual placement of concrete, the Contractor shall demonstrate the capability of the equipment to convey the concrete mixture. Tests according to Department written instructions will be performed by, and at the discretion of the Engineer. No further verification of the equipment capability will be required unless evidence of nonuniform concrete is observed during placement. When concrete pumps are used, the lines shall have a minimum diameter of 5 inches. Concrete pumps with smaller hose diameters may be used for small placements, where mixtures using an aggregate having a Nominal Maximum Aggregate Size (as defined in ASTM C125) of ½ inch are allowed. The pumping operation shall be performed in such a manner as to discharge concrete horizontally a minimum distance of 3 feet. Where horizontal discharge is not possible, the use of double 90-degree bends at the end of the pump hose, reducer hoses, or other equipment capable of maintaining a head of concrete in the pump line may be allowed, subject to the approval of the Director, Materials Bureau. All chutes, troughs, and pipes shall be kept clean and free from coatings of hardened concrete by thoroughly flushing with water after each use. Water used for flushing shall be discharged clear of the concrete already in place. Concrete shall not come in contact with any aluminum during conveying and placing operations. TABLE 555-1 CONCRETE CONVEYANCE UNIFORMITY Test Permissible Variation (Concrete samples taken at two locations in the handling process) Air Content, % by volume of Concrete 1.5% Slump Average slump 4 inches or less 1 inch Average slump greater than 4 inches 1 1/2 inches

equipment, shall meet the plastic concrete mixture performance criteria requirements 555-3.04 286 in Table 2 of MP 501-2.

of the forms before placing concrete. Temporary studs or braces within the forms shall be removed when the concrete has reached an elevation rendering their further use unnecessary. Dropping concrete a distance of more than 5 feet or depositing a large quantity at any point and running or working it along the forms shall not be permitted. Drop chutes shall be used between vertical forms unless conveyance equipment can be inserted between forms. Special care shall be taken to fill each part of the form by depositing concrete directly into the form as near to its final position as possible, to work the coarser aggregates back from the face of the concrete and to force the concrete under and around the reinforcement without displacing the reinforcement. After the concrete has taken its initial set, care shall be exercised to avoid jarring the forms or placing any strain on the ends of the projecting reinforcement. Concrete shall be placed in horizontal layers not more than 1 foot thick except as hereinafter provided. When less than a complete layer is placed in one operation, it shall be terminated in a vertical bulkhead. Each layer shall be placed and consolidated before the preceding layer has taken its initial set to prevent damage to the green concrete and avoid cold joints between batches. Each layer shall be consolidated using appropriate vibrating practices so as to avoid the formation of a joint with a preceding layer which has not taken initial set. When concrete placement is temporarily discontinued, the concrete, after becoming firm enough to retain its form, shall be cleaned of laitance and other objectionable material to a depth sufficient to expose sound concrete. To avoid visible joints as far as possible upon exposed faces, the top surface of the concrete adjacent to the forms shall be smooth and level whenever concreting is discontinued. Where a “feather edge” would be produced at a construction joint, as in the sloped top surface of a wing wall, an inset form work shall be used to produce a blocked out portion in the preceding layer which shall produce an edge thickness of not less than 6 inches in the succeeding layer. Work shall be continuous from the bottom to the top of any face. When embedding structural shapes in concrete, the placement of concrete shall be progressed on one side of the shape only until it flushes up over the bottom flange of the shape on the opposite side, after which concrete shall be placed on both sides to completion.

consolidated by vibrating the concrete internally with mechanical vibrating equipment. The use of external vibrators will be permitted when satisfactory surfaces cannot be obtained by internal vibration alone or when it is impossible to use internal vibrators. The use of external vibrators shall be subject to the approval of the Engineer. External vibrators shall be attached to or held on the forms in such a manner as to effectively vibrate the concrete in a horizontal plane. Internal mechanical vibrators shall be adequately powered, capable of transmitting vibration to the concrete in frequencies of not less than 5,000 vibrations per minute while inserted in concrete and shall produce a vibration of sufficient intensity to consolidate the concrete into place without separation of the ingredients. If any of the reinforcing steel has epoxy coating, an internal mechanical vibrator shall have a rubberized or elastomeric cover to prevent damage to the epoxy coating 555-3.05 287 on the reinforcing bars. The vibrators and covers shall be inspected for defects prior to use. A sufficient number of vibrators shall be employed, so that at the required rate of placement, thorough consolidation occurs throughout the entire volume of each layer of concrete. Extra vibrators shall be on hand for emergency use and when other vibrators are being serviced. The vibrating element shall be vertically inserted in the concrete mass at a depth sufficient to vibrate the bottom of each layer effectively inserting the vibrator into the underlying lift. It shall be withdrawn completely from the concrete before being advanced to the next point of application. Internal vibrators shall not be placed directly on the forms or the reinforcing steel. The vibratory element shall be inserted vertically into the concrete at the point of deposit and in areas of plastic concrete at evenly spaced intervals not farther apart than the radius over which the vibration is visibly effective and at a distance close enough to the forms to effectively vibrate the surface concrete. The time of vibration shall be of sufficient duration to accomplish thorough consolidation, complete embedment of the reinforcement, produce dense, smooth surfaces free from aggregate pockets, honeycombing, and air bubbles and to work the concrete into all angles and corners of the forms however, over-vibration shall be avoided. Vibration shall be continued in one place until the concrete has become uniformly plastic, but not to the extent that pools of grout are formed. Vibration shall be supplemented by working or spading by hand in the corners and angles of forms and along form surfaces while the concrete is plastic. Vibrators shall not be used to push or distribute the concrete laterally.

555-3.05Depositing Structural Concrete Under Water

- 90°F water in one continuous operation. Since the tremie tube and the pipeline are both tubes, the word "tube" in this specification refers to either type, except where specific reference is made to either the tremie tube or the pipeline. Unless noted differently on the plans, use concrete in conformance with the appropriate mix design requirements specified in Table 2 of Materials Procedure (MP)

501-2Mix Design and Approval Procedure for Performance Engineered Mixtures -

Structural Concrete. The maximum aggregate size shall meet the requirements of MP 501-2, MATERIALS, Subsection 3 B - Maximum Aggregate Size. In addition to §555-3.03 Forms, place concrete on prepared areas cleaned of all debris, mud, or other unsuitable material. Submit a list of equipment, including back-up, and a schedule for transporting and placing concrete, to the Engineer for review at least 20 working days prior to concrete placement. The Contractor shall be responsible to design a tremie placement, with appropriate forming, that maintains a minimum vertical rise of 1 foot per hour for the overall area and a minimum placement rate of 40 cubic yards per hour, unless fluid concrete pressure requires a reduced placement rate. Place fresh concrete before stiffening and initial set of the adjacent concrete to ensure a good bond and avoid cold joints. If a delay occurs, determine stiffening and initial set by probes or other methods approved by the Engineer. Stop the operation if the placement cannot be continued before initial set of the adjacent concrete. The Engineer must then immediately contact the DCES.

555-3.05 288 methods. Obtain approval of the DCES for any other method.

at the top, where concrete is delivered to the top and falls down the tube.

Delivery System Inside Diameter Large volume, such as a crane and bucket 10 inches minimum small volume, such as a pump line or conveyor 5 inches minimum

tremie tube diameter to transfer concrete into the tremie tube. The capacity and shape of the hopper or funnel depends on the volume and type of concrete delivery system. A device with the same size bottom opening may be used if a 1 1/2 to 2 inch diameter breather tube is installed to reach 1 foot or more down into the tremie tube.

tube attached to a closed tube system, where concrete is pumped to the top and falls down the tube.

pipe joint loose without a gasket, near the high point of the downgrade, 1 to 4 feet below the point where concrete starts falling down the pipe, to allow air displaced by concrete to escape, and admit air to prevent a siphoning effect.

used for pipeline lubrication and placed in the forms. Waste any other concrete mix used to lubricate pipeline.

tube in at least 1 foot increments (numbered every 5 feet) to show depth to the outlet. Use watertight joints. Place tubes no more than 15 feet from the forms and no more than 30 feet on center.

occurs when the embedded end of this tube type is removed from fresh concrete under water. Once started, do not relocate or remove open end tubes until completion of the concrete placement at that location. If loss of seal occurs, remove and seal the tube with a watertight plate or plug for restarting. Restart tremie placement only if a seal can be reestablished using a dewatered tube where the outlet can be surrounded by fresh concrete.

555-3.05 289 placement rate defined in A. General, as the seal is maintained when the embedded end of this type is removed from fresh concrete under water. Raise the end of the tube to about 3 feet below the fresh concrete surface. Then, close the valve with the tube 1/2 full of concrete (1/2 the water depth), and slowly remove the tube. Reverse this procedure upon relocation in fresh concrete.

completion of concrete placement, unless noted differently on the Contract Plans or as ordered by the Engineer. After dewatering, continue curing and excavate one or more sumps to provide for pumping of accumulated water. Excavate sumps outside of areas which will receive new concrete, or as approved by the Engineer.

shown on the contract plans. Take NX size (2 1/8 inch) cores, no earlier than 7 days after concrete placement, according to §648-3.04, Rock Core Samples, B. Sampling, the 1st sentence. Use drill bits meeting the requirements of Subsection 732-06, Coring Bits. Obtain 100% recovery from each core hole, as less is presumed to indicate defective concrete. Use a 5 foot nominal length of core drill run. Record core boring log data in accordance with §648-3.01B, Driller’s Logs. Label and pack all cores according to §648-3.04 C, Marking, Packaging and Transporting Samples. Deliver and store the core boxes at a site approved by the Engineer, where they become the property of the Department. Provide assistance in moving and arranging core boxes at the site to facilitate evaluation by the Department.

contain voids, honeycombing, seams, or other defects. The DCES will determine the number and location of additional core holes. Repair defects with grout when approved by the DCES. Placements with defects determined to be unrepairable by grouting will be rejected. Alternate repair techniques require DCES approval.

placements limited to quickly filled areas, such as core drill holes, small piles up to 1 foot in diameter, and other small voids. Use materials meeting §701-05, Concrete Grout Material, for the grout proportioned as specified or as approved by the DCES. When the DCES grants approval for repairs, the proposed grouting method shall be performed by cleaning out and filling all defects and core drill holes with grout. Position a grout tube (2 inches or less in diameter) about 1 inch off the bottom of the prepared hole until the grouting operation is complete. Start pumping (closed system) or filling a tremie tube (open system) faster than the grout can fall through water. Continue placing grout until the grout coming back out the hole is the same consistency as that going in. Then withdraw the tube. Additional cores may be required to verify acceptable repairs.

concrete to within 3 inches of the elevation shown on the plans. When joining fresh 555-3.06 290 concrete to concrete that has already set, the concrete in place shall have its surface scoured or abraded with a suitable tool to remove all loose and foreign materials. After the surface preparation, the concrete surface, and all porous surfaces to be in contact with new concrete shall be thoroughly wet using potable water for 12 hours with soaker hoses or the use of burlap/burlene/etc. to maintain moisture. The Contractor shall remove any puddles of free-standing water with oil-free compressed air, and protect the surfaces from drying, so the existing concrete remains in a clean, saturated, surface-dry condition until placement of the new concrete. Fill any low areas with a leveling course of concrete that meets the appropriate mix design requirements specified in Table 2 of MP 501-2. Concrete Mixtures. Fill sumps with concrete or stone, as ordered by the Engineer.

555-3.06Concrete Joints

joints used to provide for interruptions in the placement of concrete. Construction joints shall be placed only where shown in the contract documents or where approved by the Deputy Chief Engineer (Structures). Bulkheads required during placement shall be constructed at the direction of the Engineer. Unless otherwise shown in the contract documents, a shear key shall be provided at each construction joint by embedding water-saturated wooden blocks in the plastic concrete. The shear key thus provided shall be approximately 1/3 of the width of the parts joined. The key depth shall equal the thickness of standard form lumber, approximately 1/2 the key width. Shear keys need not exceed 5 1/2 inches in depth regardless of the key width. On steel truss or open-spandrel, concrete arch spans, unless otherwise noted in the contract documents, the concrete in the floor system shall be placed about the center line of the span, beginning at the center and working simultaneously toward each end; or beginning at the ends, and working simultaneously toward the center. Care shall be taken to prevent the displacement of reinforcement during the placing of concrete. If, for any reason, it becomes necessary to introduce a construction joint, this shall be formed by means of a vertical bulkhead so constructed as to produce a key joint, placed as shown in the contract documents or as permitted by the Deputy Chief Engineer (Structures). When joining fresh concrete to concrete that has already set, the concrete in place shall have its surface scoured or abraded with a suitable tool to remove all loose and foreign materials. After the surface preparation, the concrete surface and all porous surfaces to be in contact with new concrete shall be thoroughly wetted, to achieve a saturated surface dry condition, using potable water for 12 hours with soaker hoses or the use of burlap/burlene/etc., to maintain moisture. If conditions or the situation prohibits this, then the surfaces should be wetted for as long as possible. The Contractor shall remove any puddles of free-standing water with oil-free compressed air, and protect the surfaces from drying, so the existing concrete remains in a clean, saturated surface-dry condition until placement of the new concrete. Immediately before placing the new concrete, the forms shall be drawn tightly against the concrete already in place. Forms for female shear keys shall be beveled on four sides to facilitate their removal and shall be securely fastened to the forms to prevent displacement before the concrete has set. Key forms shall be removed in such a manner as to avoid damage to the concrete. 555-3.07 291

contract documents and unless otherwise specified, shall be formed the same as construction joints, except that reinforcement shall not extend through the joint.

documents. Expansion joints shall provide for expansion, contraction, and the transfer of shear at the joint, unless otherwise specified. When expansion joints are formed by the insertion and subsequent removal of joint templates, this work shall be done in such a manner that joint edges are not chipped or broken down in the process. When concrete is to be placed against a joint filler, holes or joints in the filler shall be suitably filled with mastic to prevent mortar or concrete from entering the joint and restricting its movement. The face edges of all joints shall be carefully finished or formed true to line and elevation for a minimum distance of 2 inches back from all exposed surfaces. When caulking compound is used to seal a joint containing premolded bituminous joint filler, a layer of an approved type of pressure-sensitive release tape shall be placed between these materials due to their incompatibility.

contraction movements at joints. Place waterstop at all joints exposed to view, as shown in the contract documents, or as ordered by the Engineer. Waterstop shall be a polyvinyl chloride or other approved flexible material, copper, or zinc strip. The waterstop shall extend at least 3 inches into the concrete on each side of the joint, shall be joined to be continuous and watertight, and shall be carefully protected from damage until covered by concrete or backfill.

555-3.07Finishing

joints, shall be finished by placing an excess of material in the forms and striking off the excess with a suitable float, forcing the coarse aggregate below the level of the finished surface, and troweled to a suitable finish. The use of mortar topping for surfaces shall not be permitted. Steel trowel finishing is not allowed. Following the discontinuance of placing concrete, all accumulation of mortar splashed upon the reinforcing steel and the surfaces of forms shall be removed. Dried mortar chips and dust shall not be puddled into the plastic concrete.

floated and troweled to true grade or, at the option of the Contractor, left approximately 1/4 inch high and bush hammered or otherwise finished to the exact elevations indicated in the contract documents.

555-3.08Curing

days unless otherwise stated. The curing period shall begin only after all curing procedures and practices for a given placement are established. A curing day is defined as any day during which the ambient air temperature at the concrete surface is 45°F or higher for the entire day. Conditions may occur which prevent an entire day from qualifying as a curing day, but do not prevent portions of that day from reaching temperatures that 555-3.08 292 qualify as curing temperatures. If these conditions occur and with the Engineer's approval, the Contractor may aggregate curing hours. A curing hour is defined as any hour during which the curing temperature remains at, or above 45°F. An aggregation of 24 curing hours will be credited as one curing day. Aggregations of less than 24 curing hours will not be credited. Curing hours will be determined with continuous recording thermometers. The number and placement of the thermometers will be determined by the Engineer. Thermometers used to monitor curing temperatures shall consist of the following types:

continuously recording temperatures within a range of 0°F to 120°F for a minimum of 24 hours.

thermometer shall be capable of recording maximum and minimum temperatures within a range of 0°F to 120°F. Provide all equipment, supplies, and labor necessary for calibration. The curing temperature of concrete is the air temperature at the concrete surface, or the air temperature between the concrete surface and its protective covering. Temperatures at these locations are critical for proper concrete curing. For the purposes of this section the temperatures at the foregoing locations shall be maintained between 45°F and 85°F inclusive. All structural concrete surfaces must be cured by any one, or a combination of, the following methods unless otherwise noted: • Polyethylene curing covers - white opaque. • Plastic coated fiber blankets. • Clear (fugitive dye) membrane curing compound. • Continuous burlap wetting. • Wet burlap and curing covers. • Forms left in place. Curing shall commence on all exposed surfaces no later than 30 minutes after completion of finishing. Finishing and curing operations shall progress with concrete placement. Curing covers shall be placed as soon after concrete finishing as the Engineer determines will not cause damage to the concrete surface. However, under no circumstances shall the curing be delayed beyond 30 minutes of the completion of finishing. Care shall be taken so as not to damage the finished surface or texturing. Curing covers shall be lapped a minimum of 1 foot. All lapped edges shall be sealed with pressure sensitive tape. Covers shall be protected from displacement. Clear (fugitive dye) membrane curing compound shall be sprayed on the concrete surface immediately following the finishing operation, or form removal, whichever is applicable. The compound shall be applied by means of a pressure spraying system, or by distributing equipment, at a minimum rate of 150 sf per gallon of surface. The equipment for applying the compound shall be such that the compound is applied as a fine spray with no surface damage to the concrete. The equipment shall also provide for adequate agitation of the compound during application and shall be approved by the Engineer before work is started. Should the application method produce a nonuniform film, or should the spraying 555-3.08 293 equipment fail and back-up equipment is not immediately available, the application shall cease. Curing shall then be continued by another acceptable method. The Contractor shall provide sufficient approved covers for protection of the concrete surface in the event of rain or equipment breakdown. If covers or forms are removed during the curing period (refer to §555-3.09), the concrete curing shall be continued using a clear (fugitive dye) membrane curing compound applied immediately to concrete surfaces after form removal.

hot weather the forms shall require wetting to reduce surface heat. If the ambient air temperature exceeds 85°F, continuous, uniform wetting for curing shall be required until the seven (7) day curing period is complete and forms are removed. Use of plastic sheeting over the established curing is not allowed in hot weather conditions.

expected to fall below 45°F, the requirements of Table 555-2 shall apply. TABLE 555-2 COLD WEATHER CURING REQUIREMENTS Ambient Temperature (AT) at time of concrete placement and as anticipated during curing duration Curing requirements 32°F < AT < 45°F for less than 24 consecutive hours Contractor proposed/Engineer approved method for maintaining temperatures used 32°F < AT < 45°F for more than 24 consecutive hours Heated enclosure required AT < 32°F Heated enclosure required Prior to use, all proposed methods must meet the approval of the Engineer. If the curing temperature falls below 32°F at any time during the curing period, the concrete will be rejected. To provide assurance of the curing temperatures, the Contractor shall supply thermometers meeting the requirements of §555.3.08A. Temperature measurements will be taken by the Engineer and a record will be maintained for the curing period. As a minimum, thermometers shall be placed adjacent to forms at the bottom, middle, and top of a placement. Additional thermometers may be placed in areas where extreme cold or heat, from external sources, can be expected. If the existing method employed by the Contractor to maintain the curing temperature fails, the Contractor shall modify the existing method immediately to reestablish an acceptable curing temperature. The length of the curing period will be extended until the required number of curing days are accumulated.

concreting, the curing temperature shall be maintained between 45°F and 85°F for the curing duration by provision of external heat or utilization of heat of hydration retained by insulated forms. Only when temperatures are maintained between 45°F and 85°F will the time be considered acceptable curing hours.

555-3.08 294 maintain curing temperatures by this method, the Contractor shall furnish sufficient canvas and framework, or other type of housing, to enclose and protect the structure. The enclosure and heat source(s) shall be established in such a way that the air surrounding the fresh concrete, on all sides, be kept at a temperature between 45°F and 85°F for the specified curing period. At the end of the curing period, the heat shall be gradually reduced at a rate not to exceed 1 degree F per hour until the temperature within the enclosure equals the temperature outside the enclosure. Materials and equipment necessary to erect the enclosure and provide external heat shall be present on the job site and approved by the Engineer before any concrete is placed. External heat shall be provided by means of stoves, salamanders, heated hoses, steam equipment, warmed curing water, or other equipment supplied by, operated by the Contractor. Heating appliances shall not be placed in such a manner as to endanger formwork, centering, or expose any area of concrete to drying out or damage due to excessive temperatures. Sufficient equipment shall be supplied to continuously maintain the specified temperature with a reasonable degree of uniformity in all parts of the enclosure. The enclosures shall be properly vented to prevent surface disintegration of fresh concrete due to an accumulation of carbon dioxide gas. All exposed concrete surfaces within the heated area shall be protected from drying by one of the following methods: • Use of live steam. • Continuous wet burlap or wet burlap used with curing covers. • Curing compounds used with curing covers. TABLE 555-3 INSULATION REQUIREMENTS FOR CONCRETE WALLS, PIERS AND ABUTMENTS ABOVE GROUND Wall Thickness (Inches) Minimum ambient air temperatures (°F) allowable for concrete placed at 50°F (Thermal Resistance Values (R): hr·ft2·F/Btu ) R = 2 R = 4 R = 6 R = 8 Portland Cement Content: 400 lb/cy 6 47 44 40 36 12 43 35 26 17 18 39 25 11 -2 24 34 16 -2 -20 36 25 -1 -27 -53 48 18 -10 -38 * 60 18 -10 -38 * Portland Cement Content: 500 lb/cy 6 47 43 38 33 12 42 31 20 9 18 36 19 2 -15 24 30 7 -16 -39 36 18 -15 -46 -79 48 10 -25 -60 * 60 10 -25 * * Portland Cement Content: 600 lb/cy 6 46 41 35 29 12 40 28 14 0 555-3.08 295 18 33 13 -7 -29 24 26 -1 -28 -55 36 12 -27 -66 * 48 4 -40 * * 60 4 -40 * * Portland Cement Content: 700 lb/cy 6 45 39 32 25 12 38 24 8 -8 18 30 7 -16 -42 24 22 -9 -41 -74 36 5 -40 -85 * 48 -4 -54 * * 60 -4 -54 * * Portland Cement Content: 800 lb/cy 6 45 38 30 22 12 37 20 2 -16 18 28 1 -26 -55 24 18 -18 -54 -91 36 -2 -54 * * 48 -11 -68 * * 60 -11 -68 * * *< - 60 °F When using concrete containing pozzolans, do not consider the pozzolons as part of the cement content. Use values given for a Portland cement content that are equal to or less than the actual cement content of the mix, due to a lower heat of hydration when using pozzolans.

acceptable curing temperatures in accordance with the provisions of Table 555- 2, when ambient temperatures will not drop below 32°F. If the Contractor elects to maintain curing temperatures by this method, sufficient insulation shall be furnished to protect and maintain the temperature between the insulation and formwork within the range of 45°F to 85°F for the specified curing period. Discontinuance of protection shall be accomplished in such a manner that the drop in temperature of any portion of the concrete shall be gradual. The surface temperature of concrete sections more than 2 feet in thickness shall not drop faster than 18°F in a 24 hour period. The surface temperature of concrete sections less than 2 feet in thickness shall not drop faster than 36°F in a 24 hour period. Forms may be removed without restriction, providing the temperature difference between the air and the surface of the concrete is not more than 30°F. If possible, forms shall be removed about the middle of the day to take advantage of the generally higher afternoon temperatures. Form insulating material shall be installed on the forms in such a manner so as to achieve the full benefit of its insulating properties and at the same time provide against the infiltration of wind and water. All portions of steel forms shall be covered by insulating material so that no steel is exposed to the air. Any tears or damaged areas in the insulating material shall be repaired. Special attention shall be given to ensure that all corners and angles are properly insulated and protected against wind damage. 555-3.09 296 Where tie rods extend through the form insulating material, a plywood washer (¾ x 6 x 6 inches approx.) shall be placed over the tie rod and secured against the insulating material. After placement of the concrete, the exposed concrete surfaces shall be covered with insulating blankets, except for areas where protruding reinforcing bars make the use of blankets impracticable. These areas may be covered with other acceptable insulating material. Tarpaulins shall be used to protect the insulating material. Insulating material shall be insulating blankets, solid foam, or sprayed foam meeting the requirements of §711-07, Form Insulating Materials for Cold Weather Concreting. The appropriate R value of material shall be used to insulate the concrete according to Table 555-3. Multiple layers of insulation may be used to attain the desired level of insulation (R value), to maintain the required curing temperatures. Extra care shall be taken in insulating edges and corners where additional layers or overlaps are required.

555-3.09Form Removal. Forms shall be removed in such a way as to permit the concrete to

take the stresses uniformly and gradually. Any method of form removal likely to cause overstressing of the concrete shall not be used. The forms for any portion of a structure shall not be removed until the concrete is strong enough to resist damage. The compressive strength results will be the basis of determining when form removal can occur. For arches and pier caps, concrete shall have a minimum strength of 3600 psi and seven full curing days (with a curing day as defined by subsection §555-3.08 A) prior to form removal. For all other elements, concrete shall have a minimum strength of 2400 psi and two full curing days (a curing day as defined by subsection §555-3.08 A) prior to form removal. Concrete compressive strength shall be determined in accordance with the requirements of §501-3.07 and as modified herein or by use of the Maturity Method in accordance with the requirements of ASTM C1074 and MP 501-2 and MP 501-3. Inform the Engineer of the intent to use this method a minimum of 28 days prior to anticipated placement of concrete. If the form removal causes damage, the operation must stop immediately until such time that sufficient concrete strength is achieved. All damage shall be repaired in conformance with §555-3.13, Damaged or Defective Concrete. Curing shall recommence immediately following form removal in accordance with the requirements of §555-3.08.

555-3.10Loading Limitations. Forms used for substructure concrete placements shall be

removed in accordance with the requirements of §555-3.09 Form Removal. The compressive strength results will be the basis of determining when loading can occur. Minimum requirements for forming subsequent concrete placements shall meet the same requirements for form removal in §555-3.09. For arches and pier caps, concrete shall have full design strength and a minimum of eight full curing days (a curing day as defined in subsection 555-3.08 A) prior to loading. For all other elements, concrete shall have full design strength and a minimum of three full curing days (a curing day as defined by subsection §555-3.08 A) prior to loading or backfilling. Concrete strength shall be determined in accordance with the requirements of §501-3.07 and as modified herein or by use of the Maturity Method in accordance with the requirements of ASTM C1074 and MP 501-2 and MP 501-3. Inform the Engineer of the intent to use this method a minimum of 28 days prior to anticipated placement of concrete. 555-3.11 297 When early loading is requested, the minimum time requirements for loading may be reduced (or extended) based on compressive strength testing results and the element type. The DCES will establish requirements for early loading upon request.

555-3.11Corrective Finishing. Immediately after forms have been removed, surfaces

exposed to view shall have all projections and irregularities carefully removed and all cavities greater than 1 inch in diameter and/or 1/4 inch in depth neatly filled with mortar of the proportion used in the concrete. The same brand of cement and the same kind of aggregate shall be used for filling cavities as was used in the original concrete mix. Plastering of surfaces shall not be allowed. The surface film (drying cement paste) of all such repaired surfaces shall be carefully removed before setting occurs. All rust and other stains shall be removed from concrete exposed to view. Removal shall be accomplished using methods and materials approved by the Engineer. Materials used for rust stain removal shall be as listed on the Approved List published by the Department's Materials Bureau.

555-3.12Weep Holes. The Contractor shall construct weep holes in all retaining walls and

abutments as indicated in the contract documents.

555-3.13Damaged or Defective Concrete

shall be repaired or replaced at no additional expense to the State. The defects shall include but are not limited to spalling & irregular surface areas, visible surface cracks & cracking at joints, edge spalls, honeycombing, delamination, and any damage or other imperfections caused by traffic and/or construction operations. Concrete with surfaces misshapen by bulges or deformations caused by inadequate forms, or resulting in insufficient cover of reinforcing, shall be removed or corrected. Any concrete requiring complete replacement shall be replaced in kind with concrete as originally specified in the contract documents for the application. The Contractor shall submit a proposed repair plan to the Engineer that will satisfactorily address all identified defects. Any repairs shall be performed to the methods described in these specifications unless otherwise specified and/or approved by the Engineer.

cutting the perimeter to a depth of 1 1/2 inches, chipping the unsuitable material to sound concrete with light, handheld, pneumatic tools at a 45 degree angle into the patch area to achieve a rough bondable surface exposing at least 50 percent of the coarse aggregate. All surfaces to be repaired shall be thoroughly blast cleaned to remove all laitance and clean all exposed reinforcing and concrete surfaces. Prior to placing repair concrete, all surfaces shall be wetted to a saturated surface dry condition. Small spalls of 0.1 cy or less, and areas of 5 sf or less where concrete removal is required may be repaired using approved Concrete repair materials. Vertical or overhead surfaces may be patched with Vertical and Overhead Patching Material, in accordance with the requirements of §701 -08. Surface preparation for small repairs and placement of repair material shall be i n accordance with the repair material manufacturer’s written instructions. After the repair is complete and required curing time has elapsed, the Engineer will hammer sound all repair areas to assure proper bond has been achieved. 555-3.13 298

repaired with §717-05 High Molecular Weight Methyl Methacrylate (HMWM) Crack Sealer in accordance with the HMWM manufacturer’s written instructions and procedural directives issued by the Materials Bureau. Cracks with a width equal to or greater than 0.06 in. shall be repaired by Epoxy Injection in accordance with procedural directives issued by the Materials Bureau. This work shall be completed prior to sawcut grooving and diamond grinding (if applicable) and only when the concrete moisture content is at an acceptable level; no greater than 5% using a moisture detector meter, or no visible moisture after performing ASTM D4263 test method for a minimum of 4 hours. Concrete protective sealer application shall be followed in accordance with the requirements of the contract documents. When an individual crack width exceeds 0.10 in. or when the crack density, as defined by the equation given below, exceeds 1.5 cu. In. the portion of the deck that is not in conformance shall be replaced to the satisfaction of the Department. A replacement procedure with pertinent details shall be submitted to the Engineer for approval or rejection. Crack Density = ∑𝑇𝐶 𝑛=1 (Wn 2 x Ln ) Where: TC = Total number of cracks ≥ 0.02 in. wide within a rectangular 25 sq. ft. area Wn = Width of crack n (in.) Ln = Length of crack n (in.) The shortest side of the rectangle used to determine the 25 sq. ft. area shall be the minimum width of the pour or 5 ft., whichever is less.

by Epoxy Injection in accordance with procedural directives issued by the Materials Bureau. This work shall be completed when the concrete moisture content is at an acceptable level; no greater than 5% using a moisture detector meter, or no visible moisture after performing ASTM D4263 test method for a minimum of 4 hours. If required, concrete protective sealer application shall be followed in accordance with the requirements of the contract documents. When an individual crack width exceeds 0.125 in. or when the crack density, as defined by the equation given below, exceeds 1.5 cu. in. the portion of that component that is not in conformance shall be replaced to the satisfaction of the Department. A replacement procedure and details shall be submitted to the Engineer for approval or rejection. Crack Density = ∑𝑇𝐶 𝑛=1 (W n 2 x Ln ) Where: TC = Total number of cracks ≥ 0.04 in. wide within a rectangular 25 sq. ft. area Wn = Width of crack n (in.) Ln = Length of crack n (in.) The shortest side of the rectangle used to determine the 25 sq. ft. area shall be the minimum width of the pour or 5 ft., whichever is less.

555-4METHOD OF MEASUREMENT

555-4.01 299

555-4.01Concrete for Structures. The work will be measured for payment as the number

of cubic yards of concrete for structures satisfactorily placed, measured to the nearest 0.1 cubic yard within the lines of the structure as shown in the contract documents. No deductions shall be made for the volume of joint material, embedded metal reinforcement, structural shapes, chamfers, tops of piles, or pipe with an end area of less than one square foot.

BASIS OF PAYMENT

555-5.01Concrete for Structures. The unit price bid per cubic yard shall include the cost of

furnishing all labor, materials, and equipment necessary to complete the work, except reinforcement will be paid for separately under its appropriate item. Unless otherwise provided, the unit price bid shall include the cost of furnishing and placing flashing or other metal strips, flexible water stops, sheet packing, pipe drains, bituminous material, water for wetting, joint materials, felt, tar paper, joint sealing compounds, joint fillers, and concrete curing materials. No extra compensation for falsework or falsework piling will be paid. This work is included as part of the formwork. No extra compensation for corrective finishing or repairs to damaged or defective concrete will be paid. Bridge bearings, expansion joints, and anchor bolts will be paid for under their appropriate items. Progress payments will be made, after the concrete and curing applications have been properly placed, to the extent that payment will be made at 90% of the computed quantity of each concrete placement, with the balance to be paid after completion of all curing and corrective work thereon. Item No Item Pay Unit

555.0011 Footing Concrete, Performance Cubic Yard

12 Footing Concrete, Performance - Internal Cure Cubic Yard

21 Concrete for Structures, Performance Cubic Yard

22 Concrete for Structures, Performance - Internal Cure Cubic Yard

31 Concrete for Structures, Performance (Deposited Under Water) Cubic Yard

32 Concrete for Structures, Performance (Deposited Under Water -

Internal Cure) Cubic Yard

555.9901 Performance Concrete Quality Adjustment – Footing Concrete Quality Unit

02 Performance Concrete Quality Adjustment – Concrete for

Structures Quality Unit

03 Performance Concrete Quality Adjustment - Concrete Deposited

Under Water Quality Unit