610CONCRETE STRUCTURES

610.1Description.

This work consists of providing, placing, finishing, and curing concrete bridges, culverts, and miscellaneous structures.

610.2Materials.

610.3Construction.

610.3.1 Submittals.

workmanship meet the contract requirements. Provide detailed personnel, equipment, methods, and procedures to ensure the specified quality of all applicable materials and related production and field operations. Follow the submittal procedures outlined in Section 105.4. Upon receipt of approved quality control plans, the contractor may begin work. At a minimum, provide the following information in the plan:

placing, protecting, curing, temperature monitoring, and consolidating the concrete mix in approved forms to make a dense homogeneous concrete, in accordance with the requirements of Section 610.3.4.

placement in the plan and mix design. Submit a placement plan for placing concrete by pump. At a minimum, include pump location, vertical and horizontal work reach, pump capability, placement sequence, delivery configuration, and contingency for equipment malfunction.

Provide proof of the flatwork certification to the engineer before concrete placement.

weather. Include detailed procedures for reducing the hazards of an increased rate of cement hydration, flash set, loss of water due to evaporation, high concrete ingredient temperatures, and the increased difficulty of concrete placement and finishing, in accordance with the requirements of Section 610.3.5.A.

occurred within 7 calendar days of anticipated concrete placement. Include detailed procedures for production, transporting, placing, protecting, curing, and temperature monitoring of concrete during cold weather, in accordance with the requirements of Section 610.3.5.C.

accordance with Section 105.4.

and temperature control of concrete in mass elements. Include a resume for the specialty engineer, detailing relevant experience on at least 5 thermal control projects. Ensure that the specialty engineer follows the procedure outlined in Section 207 of the ACI Manual of Concrete Practice to formulate, implement, administer, and monitor a temperature control plan, making adjustments as necessary to ensure compliance with Sections 610.3.4.D.3 and 610.3.6.B. ii. Provide an analysis of the anticipated thermal developments in the mass concrete elements for all expected project temperature ranges using the selected mix design, casting procedures, and materials. Submit a copy of any software models used for the prediction of peak temperatures with the site and element specific data to the engineer for approval with the analysis, including electronic files in the software used. Describe the measures and procedures intended to maintain, monitor, and control the temperature differential between the interior and exterior of the mass concrete elements, and the maximum temperature. iii. Describe methods for preventing thermal shock. iv. Include a minimum of 1 level of redundancy for all equipment and materials to maintain a continuous pour as part of the contractor's proposal.

placements to the engineer. Designate an employee, approved by the specialty engineer, as qualified to inspect monitoring device installation and record temperature readings.

texture, true to the required grade and cross-section, in accordance with the requirements of Sections 610.3.4.D.4 and 610.3.6.A. Include detailed procedures for production, transporting, placing, protecting, curing, and temperature monitoring, consolidating the concrete mix in approved forms to make a dense homogeneous concrete, and contingency for equipment malfunction.

provisions and details for emergency construction joints including shear keys, bonding agents, joint sealants, waterstops, and additional reinforcement, in accordance with the requirements of Section 610.3.3.

contract.

steel, the physical and section properties for all permanent steel bridge deck form sheets, and a clear indication of locations of form support by steel beam flanges subject to tensile stresses. Have an engineer registered in the State of Delaware sign and seal these drawings and calculations.

welds meet the AASHTO/AWS D1.5 Bridge Welding Code.

projected plan area of the metal forms. If the weight calculated exceeds the weight allowance for SIP metal forms and the concrete required to fill the forms shown in the contract, submit a method to modify the supporting components to support the excess weight.

pounds per square foot for construction loads. Use a unit working stress in the steel sheet of not more than 0.725 of the specified minimum yield strength of the material provided, but not to exceed 36,000-PSI.

exceed 1/180 of the form span or 1/2-inch, whichever is less, for form spans of 10-feet or less, or 1/240 of the form span or 3/4-inch, whichever is less, for form spans greater than 10-feet. In all cases, do not use a total loading of pounds per square foot that is less than 20 plus the product of the deck thickness measured in inches multiplied by 12.5.

span parallel to the form flutes.

of Cold Formed Steel Structural Members, latest published edition.

supporting structural members. 610.3.2 Formwork.

temporary protective shield in accordance with Section 604.

sheets directly on the top of steel beam flanges. Fasten sheets securely to form supports and maintain a minimum bearing length of 1-inch at each end for metal forms. Place form supports in direct contact with the flange of the steel beam. Make all attachments for coated metal forms using bolts, clips, screws, or other approved means. Secure forms to flanges in tension or to structural steel bridge elements fabricated from non-weldable grades of steel by means other than welding directly to the member.

brush, and paint with 2 coats of galvanizing compound to the satisfaction of the engineer. Do not touch up minor heat discoloration in areas of welds.

steel bridge deck forms such that they are mortar tight. Ensure that slurry does not leak through the forms during the deck pour. Responsibility for any damage to persons or property due to leaking through the forms is in accordance with Section 107.10. Additional shielding may be placed beneath the forms to catch leakage during the deck pour if desired. 610.3.3 Joints.

construction joint plan.

otherwise in the contract. Leave the joint with a scored finish in accordance with Section 610.3.4.C. Bevel the forms for keys so that removal will not damage the concrete. Clean construction joints of surface laitance, curing compound, and other materials before placing fresh concrete against the surface of the joint. Use an abrasive blast or other approved methods to clean horizontal construction joints to expose clean aggregate. Flush construction joints with water and allow to dry to a saturated surface dry condition immediately before placing concrete.

no less than 3-inches from the face of the concrete. Extend the water-stop into each section of the concrete a distance of at least 2-inches or as specified in the contract.

locations identified in the construction joint plan. Apply concrete adhesive compound in accordance with manufacturer's recommendations.

finish true to line and elevation. All exposed construction joint edges shall have a 3/4-inch v- notch. Construct all construction joints so that feather edging does not occur.

joints sealed with sealants or water-stops, and joints with combinations of these features.

Remove mortar and other debris from open joints.

polystyrene board. Use a single piece of joint filler for each joint. Anchor joint filler material to 1 side of the joint with a waterproof adhesive.

damage to the joint material. Splice, weld, or solder joints to be continuous and watertight. Prevent contamination of water-stop surfaces while embedding the water- stop in concrete. Ensure that all portions of the water-stop designed for embedment remain tightly enclosed by concrete.

610.3.4 Placing Concrete.

threaded projection above the nut to between 3/16-inch and 1-inch.

lighting system before starting the concrete operations.

from tools, screeds, and conveying equipment. Clean and clear all surfaces that come in contact with concrete. Moisten the forms with water before placing concrete.

concrete placement plan. Place concrete continuously to prevent unplanned cold joints or damage to newly set concrete. Regulate concrete placement so that the pressures caused by the wet concrete do not exceed those used in the design of the forms. Place concrete into forms using a method that does not segregate the mix from a homogenous consistency. Deposit concrete mix as near as possible to final position. Discharge concrete within 5-feet of final placement point. Limit lift thickness to 2-feet. Do not exceed the capacity of the vibrators to consolidate and merge the concrete with the previous lift.

placed through any conveyance. Equip chutes on steep slopes with baffles or reverses. Do not place concrete with chute arrangements longer than 25-feet.

diameter pipe. Prime pump with a cementitious grout material. Discharge priming grout into an approved collection area until fresh undiluted concrete discharges from the pump line. Operate the pump to produce a continuous stream of concrete without air pockets or segregation. Upon pumping completion, eject any concrete remaining in the pipeline planned to use in the work in such a manner that no contamination or separation of the concrete ingredients occurs. Provide samples of concrete for test purposes taken from the discharge end of the conduit system as close as possible to the final position of the concrete.

the surface coating of the reinforcement steel. Protect protruding steel for subsequent pours. Clean any protruding steel upon completion of the pour before subsequent pours.

vibration. Use internal vibration except for thin sections using forms designed for external vibration. Provide adequately sized vibrators to accomplish the work, with 1 or more spare vibrators in case of breakdown. Use immersion-type vibrators featuring heads covered with rubber or other resilient non-metallic material to consolidate concrete reinforced with epoxy- coated reinforcement. Vibrate at the point of deposit. Insert vibrators vertically and withdraw slowly to avoid segregation or grout pockets. Vibrate in a uniform pattern spaced less than 1.5 times the radius of visible effectiveness. Do not move the concrete laterally with vibrators.

finish the surface with a wooden float. Tool construction and expansion joints with an edger. Leave joint filler exposed.

float. Broom the surface lightly in a transverse direction. Use an edging tool on edges and expansion joints. Lay out surfaces in blocks with an approved grooving tool. Correct deviations of more than 1/8-inch when checked with a 5-foot straightedge.

inch depth without dislodging the coarse aggregate or exposing the reinforcing steel.

masonry plate contact area to provide full and even bearing.

with a steel trowel. Provide a finished surface that varies by no more than 1/16-inch. Grind surfaces that fail to conform to the required flatness.

elastomeric bearings, provide a float finish.

are free of mud and silt.

discharge, long enough to reach the bottom of the placement and marked in 1-foot increments. ii. Attach tremie tube to a funnel or hopper with a capacity of at least 1/2 cubic yard. iii. Provide a valve at the lower end of the discharge tube that closes tightly while charging the tremie and lowering it into position. The valve must be able to be fully open in the lowered position. Alternately, provide a foam rubber plug in the hopper that moves through the tremie tube when pushed by the concrete, forcing water or slurry from the tremie tube. iv. Provide at least 2 tremie tubes to ensure continuous concrete placement.

discharge end of the tube. Do not move the tremie laterally during concrete placement. Keep the discharge end of the tremie tube fully submerged in the freshly deposited concrete to prevent water infiltration.

aggregate segregation, allows flow over the entire placement area, and keeps the concrete level in the tremie tube stable. Keep the top surface of concrete as level as possible. Maintain balanced hydrostatic pressures to prevent form failure and movement of water through the plastic concrete. Do not place tremie concrete by pumping directly to the bottom of placement. Place tremie concrete only in the presence of the engineer.

unsatisfactory material from the concrete surface by means that do not damage the concrete surface. Chip off high spots on the concrete surface that would prevent placement of steel reinforcing bars.

interior and the exterior of the element at points approved by the engineer. Monitor a minimum of 2 independent sets of interior and exterior points for each element to provide redundancy in case of a device failure. Locate the monitoring points at the geometric center of the element for the interior point, and 2 inches from the surface along the shortest line from the geometric center to the nearest surface of the element for the exterior point.

information at a maximum interval of 15-minutes. Provide devices that operate for a maximum range of 0 to 200 degrees with an accuracy of +/- 2 degrees F.

approve the installation of monitoring devices.

and the contractor. Review the approved bridge deck placement plan and procedures for deck construction.

easy to control, of sufficient weight to strike off the surface at the specified grade, and provides a uniform treatment over the deck surface. Unless a longitudinal construction joint has received approval under the construction joint plan, use transverse screeds that extend the full width of the deck between curbs or parapets.

support lines. If the skew angle changes at supports, adjust the angle of the screed accordingly as the finishing machine progresses across the deck slab. If a longitudinal construction joint is approved, place the portion on either side of the joint and finish separately.

the main structural members, or on form supports. Ensure that the rails are rigid enough to permit the screed to finish the surface of the deck within the requirements of this section.

simultaneous finishing by hand of any portion not finished by the screed. Fabricate and install rail supports extending above the roadway surface in such a manner as to allow removal to at least 2-inches below the top surface of the deck slab. Place a fusion bonded epoxy coating or other approved corrosion resistant material on all portions of the rail support to remain in the deck concrete. When placing rail supports in that portion of the deck, under the curbs, or parapets, place the supports at least 2-inches from the face of the curb, parapet walls, or outside edge of the slab.

necessary to obtain a bridge deck true to the required grade and cross-section, with allowances made for anticipated settlement. Provide supports that will ensure no springing or deflection occurs under the weight of the finishing equipment, and located so that finishing equipment may operate without interruption over the entire bridge deck. ii. Do not use vibrating screeds or longitudinal type screeds unless specifically approved by the engineer.

fog sprays and curing compounds, and for inspection. Support the work bridge or platform outside the limits of the concrete placement.

up maintains clear cover of reinforcement, accounts for roadway grades and cross-slopes, and incorporates deflection from the wet deck concrete to produce the final deck elevations given in the contract. Before placing bridge deck concrete, check all falsework and make all necessary adjustments.

ii. personnel and equipment, as identified in the approved bridge deck placement plan, will deliver, place, spread, finish, and cure a minimum of 20 cubic yards of concrete per hour; iii. all finishing tools and equipment are in satisfactory condition for use; and iv. weather protective equipment is provided.

at the pre-pour meeting. Place particular emphasis on proper concrete vibration to avoid tears, aggregate silhouettes, honeycombs, and voids, especially at construction joints, expansion joints, valleys, and ends of form sheets.

On simple spans, and for all sections between construction joints for continuous spans, place the concrete by beginning at the end and working along the roadway. After the initial placement in any 1 section of a continuous span, do not make any placement until the cylinder strength of all previously placed concrete in the deck of that group reaches at least 0.5f ‘c. ii. During the screeding operation, keep an adequate supply of concrete ahead of the screed and maintain a slight excess immediately in front of the screed.

finishing machines. Use hand finish methods for irregular areas when approved.

dragging fabric over the final screeded concrete. ii. To remove local irregularities, finish the surface with a float or other approved device and to leave sufficient mortar at the surface of the concrete for subsequent texturing. Finish the surface without adding water.

of at least 14-days after placing concrete. Begin curing by fog spraying during the placing and finishing operations. Apply fogging continuously, rather than intermittently, after the finishing operation until wet covering material has been placed over the concrete surface. Augment with hand-held fogging equipment as needed. ii. Keep the surface continuously wet for the entire curing period by covering with two layers of wet burlap or one layer of wet burlap plus a polyethylene sheet or a polyethylene coated burlap blanket. iii. Apply curing protection within 15-minutes after depositing the concrete and before the surface of the concrete has lost its surface wetness or sheen appearance. Submerge the burlap in water for at least 8-hours before the scheduled start of the concrete placement. Drain the burlap of excess water prior to the application. Provide burlap that is free from cuts, tears, uneven weaving, and contaminants. Place the burlap such that the edges are lapped a minimum of 6-inches. Commence continuous burlap wetting 10-minutes after its placement and keep continuously wet and protected from displacement for the entire curing period. iv. Keep bridge decks covered and continuously wet for the entire curing period by the use of soaker hoses. Provide a system of soaker hoses that circulate water continuously and that are located to ensure a completely wet surface for the entire curing period.

Test finished surfaces of concrete in accordance with the contract using an inertial profiler or 10-foot straight edge. The maximum allowable longitudinal and transverse deviation is 1/4-inch in 10-feet. Provide a 10-foot straight edge for testing smoothness. ii. Surface Corrections. Use diamond grinding to remove deviations exceeding 1/4-inch in 10-feet. Submit information on similar types of work performed with the proposed grinding equipment, including references if requested by the engineer.

longitudinal grooves parallel to the centerlines. Complete a longitudinal grooving operation that results in a uniformly grooved deck surface. Saw grooves 1/8 to 3/16-inch wide; 3/16 to 1/4-inch deep; and on 3/4-inch centers. Terminate grooves 18-inches, plus or minus 1-inch, from the face of the parapet or curb line. If metal drainage inlets extend more than 18-

inches from the parapet or curb line, end all grooves on the bridge deck surface within 6- inches of the drainage inlet perimeter. At expansion joints, end all grooves within 6-inches of the joint. Produce grooves that are continuous across joints less than 1/2-inch wide. ii. Perform continuous removal of waste materials, including slurry, resulting from the grooving operations in accordance with Sections 106.8 and 104.12.

sub-foundation concrete.

provisions included in the contract. 610.3.5 Weather and Environmental Conditions.

increased rate of cement hydration, flash set, loss of water due to evaporation, high concrete ingredient temperatures, and the increased difficulty of concrete placement and finishing. Ensure the temperature of the concrete at the point of discharge does not exceed 90 degrees F. Ensure the temperature of the concrete for bridge decks at the point of discharge does not exceed 85 degrees F.

aggregates by fogging or other means that will not result in a high variation of moisture content within the stockpile. Use chipped or crushed ice in the mix as a portion of the mixing water on a pound for pound basis, provided such measure is determined at the time of placement in the mix. If using ice, melt before discharging the batch from the mixing unit. Cool water by refrigeration or other means that will provide a uniform mixing water temperature.

contact with the concrete by water spray or other approved methods when the ambient temperature rises above 90 degrees F. Ensure there is no standing water in the concrete forms as a result of the spraying procedures. Provide personnel and equipment in accordance with the approved placement and curing plan to place the concrete without delays that may cause excessive slump loss and evaporation due to over-mixing or exposure before placement.

may begin as soon as possible. Keep new concrete shaded from the sun, shielded from the wind, and wet with water, or protected by other methods to retain the moisture throughout the curing period. Use windscreens of sufficient dimensions, water fogging, or other approved means of supplying moisture to prevent shrinkage cracking due to moisture loss.

high temperatures by using the methods outlined below. Limit the evaporation rate of the exposed concrete surface to less than 0.15 pounds per square foot per hour as calculated by ACI 305 Hot Weather Concreting Figure 2.1.5. DelDOT Materials & Research Section will provide copies of the chart upon request. To maintain the deck surface evaporation rate below 0.15 pounds per square foot per hour, take 1 or more of the following actions:

application of the curing cover. Produce a fine fog mist with the nozzle to maintain a sheen of

moisture on the concrete surface without ponding. Do not work any applied moisture back into the surface.

placement.

weather, cover new concrete to prevent damage. Provide sufficient material for covering at the site of the work for immediate use.

falling below 40 degrees F or the ambient temperature at the site falling below 50 degrees F, for a period of 12-hours or more.

in the shade, away from artificial heat, is above 35 degrees F. Maintain the concrete mixture at a temperature of 55 degrees F or above by heating aggregate, water, or both. Limit aggregate and water temperature to a maximum of 150 degrees F. Do not heat aggregate by direct gas or oil flame or on sheet metal over fire.

available at the project site before placing concrete. Remove snow, ice, and frost from the surfaces, including reinforcement and subgrade against concrete placement. Place concrete only when the temperatures of all surfaces that will come into contact with the concrete are at least 35 degrees F and maintained at a temperature of 35 degrees F or above during placement.

indicated in Table 610.3-1 for the curing period defined in Section 610.3.6. Monitor maximum and minimum surface temperature with a measuring device that is accurate to within 2 degrees

area in an accessible location. Table 610.3-1. Surface Temperature Requirements During Curing Minimum Section Size Dimension Maximum Temperature of Concrete During Curing Period Maximum Allowable Temperature Drop in Any 24-Hour Period During Curing Under 1 ft 57°F 50°F 1-3 ft 57°F 40°F Over 3ft up to 6 ft 50°F 29°F Over 6 ft 50°F 29°F

for curing. Heat the structure uniformly. Reduce heat gradually in the enclosure so that the temperature will not drop more than 20 degrees F in 8-hours.

faced or covered, top and bottom, with polyethylene or similar waterproofing material. Ensure that sufficient thickness of blankets will maintain the concrete surface temperature at or above the required temperatures indicated in Table 610.3-1, for the curing period defined in Section

610.3.6Secure blankets around the perimeter of the work to minimize infiltration of ambient

air and loss of heat during the protection period. Should the temperature of the work fall below the required temperatures indicated in Table 610.3-1 during the protection period, take immediate corrective actions. 610.3.6 Curing Concrete.

surface of the concrete moist by a water fog spray applied without damaging the surface. Commence curing operations immediately after the free water leaves the surface and completing finishing operations. Cure concrete in accordance with the requirements of Table 610.3-1.

covering with materials kept continuously and thoroughly wet. Use multiple layers of burlap, or other approved materials that do not discolor or otherwise damage the concrete.

surfaces not exposed to view in the completed work, or on surfaces where approval is granted by the engineer. Apply the curing solution uniformly at the manufacturer's specified application rate. Do not use liquid membrane curing compounds on surfaces with a required rubbed finish, or on surfaces of construction joints unless the membrane is removed by sandblasting before placing new concrete against the joint. Apply curing compound immediately after form removal and the concrete is finished. Apply the solution by power operated atomizing spray equipment in 1 or 2 separate applications. Apply the second coating within 30 minutes of the first. Use hand operated sprayers for coating small areas if needed. Thoroughly mix membrane solutions containing pigments. Agitate the mixture during application. Reapply the solution, at the specified rate, to membrane film damaged during the curing period by weather or construction activities.

concrete. Install the cover when the concrete is wet. Use sheets of the widest practical width. Overlap sheets a minimum of 6-inches and seal with pressure sensitive tape, mastic, glue, or other approved methods to form a waterproof cover over the entire concrete surface. Secure the waterproof sheet material to prevent displacement by wind. Immediately repair sheets torn or damaged during the curing period.

Section 610.3.7. Immediately apply liquid membrane-forming curing compound in accordance with Section 610.3.6.B.1.b when forms are removed before 7 uninterrupted calendar days. Allow to cure for at least 7 uninterrupted calendar days after placing concrete.

differential between any 2 adjacent sensors as follows: Table 610.3-2. Maximum temperature differentials Time Temperature First 24 hours 30º F 24 to 48 hours 40º F 2 to 7 calendar days 50º F 7 to 14 calendar days 60º F

blankets, or internal cooling, in accordance with the temperature control plan.

temperature readings is effective before the first placement of each size and type mass component.

the maximum temperature differential and a decreasing temperature differential is confirmed as defined in the temperature control plan. Do not remove the temperature control mechanisms until the core temperature is within 25 degrees F of the ambient temperature. Transmit readings from monitoring devices to the engineer daily or upon request.

receive instructions on making temperature control adjustments.

maximum allowable temperature is exceeded. Take immediate action, as directed by the specialty engineer, to retard further growth of the temperature differential.

includes the maximum temperature, the maximum temperature differential, and a final report within 3 working days of completion of monitoring of each element.

compliance on future placements. Obtain the engineer's approval of revisions to the approved plan before implementation.

exceeded, provide all analyses and test results deemed necessary by the engineer for determining the structural integrity and durability of the mass concrete element.

differential in accordance with Section 610.3.9. 610.3.7 Formwork Removal and Placement of Superimposed Loads.

are listed in Table 610.3-3 and are defined by the strength requirements, unless otherwise noted in the contract. Table 610.3-3. Minimum Strength Requirements Structural Element Removal of Formwork Placing Superimposed Vertical Dead Loads* Placement of Backfill Strength (%f ‘c) Strength (%f ‘c) Strength (%f ‘c) Subfoundation Concrete 20 30 20 Cast-In-Place Concrete Piles n/a 50 n/a Footing 30 40 30 Abutment Wall, Rigid Frame Wall, and Box Culvert Wall 30 50 95 Piers/Columns 30 50 n/a Drilled Shaft Above Grade 55 60 n/a Pile Cap and Pier Cap 50 60 50 Arch [Span ≤ 65’](B.F.) 40 95 95 Arch [Span ≤ 65’](S.F.) 30 95 95 Concrete Beam (B.F.) 60 80 n/a Concrete Beam (S.F.) 30 80 n/a Slab [Span ≤ 10’] and Diaphragms** 30 85 95 Slab [Span > 10’]** 50 85 95 Bridge Decks Section 610.3.6 85 n/a Retaining Wall, Headwall, and Wingwall 30 30 95 Parapet Wall, Curb, and Backwall 20 20 50 B.F. – bottom formS.F. – side form * Examples are placement of parapets on slabs, placement of walls on footings, and placement of beams on pier caps. ** Slab includes slab type bridges, box culvert top slabs, rigid frame top slabs, approach slabs, moment slabs , and sleeper slabs.

minimum required strength of Table 610.3-3, the contractor shall give the engineer written

notice, 48-hours before pouring the concrete, that the start of form removal will depend on the cylinder strength requirements.

under the same conditions as the placed structure concrete. Cure the 7-day and 28-day cylinders for the first 24 to 48-hours in an environment that provides satisfactory moisture and temperature control, in accordance with AASHTO R100. The contractor may supply sure-cure molds instead of match curing specimens.

contractor wants to remove forms or place loads on the concrete.

operations indicated.

restrictions:

compressive strength (f ‘c) and the engineer authorizes crossing. ii. Construction equipment to cross rigid frames, box culverts, or arches until placement of the full fill height and the engineer authorizes crossing. iii. Sea water or brackish water to come into direct contact with concrete before the times indicated in Table 610.3-4, unless otherwise approved. Table 610.3-4. Requirements for Concrete in Contact with Sea Water or Brackish Water Water Salinity (ppm dissolved salts) Days to Elapse Before Salt Water Contact 0 to 10 000 Normal Curing 10 000 to 20 000 15 20 000 to 30 000 25 over 30 000 30 610.3.8 Finishing Formed Concrete Surfaces.

condition.

bonded aggregate pockets or honey combed concrete with sound concrete or packed mortar that matches the color.

proportions as that used in the body of the work. Clean and saturate with water all cavities

produced by form ties and all other holes, broken corners or edges, and other defects. Fill with cement mortar mixed in the same proportions as that used in the body of the work. For exposed surfaces, add white cement to the mortar to achieve a patch that, when dry, matches the surrounding concrete. Use mortar in pointing that is less than 1-hour old. Rub the concrete if required or continue curing. Tool and leave construction and expansion joints free of mortar and concrete. Leave the joint filler exposed for its full length with clean and true edges.

approved.

engineer, apply a Class 2 finish to that surface.

One finish does not produce an acceptable surface. A Class 2 finish does not apply to soffits and the interior faces and bottoms of concrete girders.

set before finishing. Rub surfaces with a medium-coarse carborundum stone, using a small amount of mortar on its face. Mix the mortar using the same proportions of cement and fine sand used in the finishing concrete. Continue rubbing until form marks, projections, and irregularities are removed; voids are filled; and a uniform surface is obtained. Leave the paste produced by this rubbing in place. Produce the final finish by rubbing with a fine carborundum stone and water. Continue rubbing until the entire surface is of a smooth texture and uniform color. Rub the completed surface with burlap to remove loose powder and leave the surface free from unsound patches, paste, powder, and objectionable marks.

only after 14 calendar days or when it is not possible to pick aggregate out of the surface. Provide a tooled finish surface that shows a grouping of broken aggregate particles in a matrix of mortar with each aggregate particle in slight relief.

sand to produce an even, fine-grained surface of cut away mortar, leaving the aggregate exposed.

stiff wire or fiber brushes. Use a muriatic acid solution of 1 part acid to 4 parts water by volume. Remove the cement film or surface and expose the aggregate particles. Leave an even pebbled texture presenting an appearance ranging from fine granite to coarse conglomerate, depending upon the size and grading of the aggregate used. Wash the surface with water mixed with a small amount of ammonia to remove all traces of acid. 610.3.9 Defective Work.

between 7 and 30 calendar days after burdening the component with a full dead load, and a minimum of 7 calendar days after opening the bridge to full unrestricted traffic.

longitudinal grooves, and after completion of required deck planing.

work. Core cracks in locations and to depths specified by the engineer.

location of the crack termination points relative to permanent reference points on the member. The engineer will monitor and document the growth of individual cracks at an inspection interval the engineer will choose to determine if cracks are active or dormant after initial inspection.

and comment on the engineer's crack classification, but the engineer will make the final determination. The engineer will determine if concrete coring is necessary when the engineer cannot determine an accurate measurement of crack depth by using a mechanical probe.

concrete contains bulged or uneven surfaces, or shows honeycombing that is not repairable, remove and replace the entire section.

registered Delaware professional engineer, that includes recommended repair methods and a determination of structural capacity and durability. Upon the engineer’s approval, repair the cracked concrete.

defective.

work. Take challenge cores within 5 working days of notification by the Department. Take a minimum of 3-inch diameter by 3-inch deep core. Provide a minimum of 2 cores for testing at the central lab. Cut the cores from a location approved by the engineer. Hand deliver cores to a representative of the Department. The representative will return the core to the Department for testing. The contractor may accompany the cores to the central lab and witness all testing.

Department will consider the core testing void and will prorate the payment, in accordance with Section 610.5.D, based upon the field-cast cylinders. The contractor shall apply corrective action in accordance with Table 610.3-5.

decisions regarding structural adequacy, corrective action in accordance with Table 610.3-5, and prorated payment, will stand on the challenge core results. Remove, replace, or reinforce structurally inadequate work to the satisfaction of the engineer. Any result determined by the engineer to be structurally adequate, and to remain in place, may proceed through the process for corrective action and prorated payment in accordance with Table 610.3-5.

Table 610.3-5. Corrective Action and Prorated Payment for Concrete Strength Category PSI below Design Strength Corrective Action and Prorated Payment A 0 to 250 PSI below 28-day Design Strength No repair required, full payment as specified in Section 610.5. B 251 to 500 PSI below 28-day Design Strength Prorated payment as specified in Section 610.5. C 501 to 1,000 PSI below 28-day Design Strength Prorated payment as specified in Section 610.5 plus the application of a protective waterproofing that is approved by the Department’s Materials & Research Section. The clear coating shall only pertain to the pour area that the core represents. D 1,000 PSI or greater below 28-day Design Strength Strengthen area of low strength concrete as approved by the engineer at no cost to the Department. 610.3.10 Barrier Reflectors.

610.3.11 Deck Sealing.

1045.3 in accordance with section 613.3.D.

610.4Method of Measurement.

follows:

less than 24-inches.

formwork or deflection meeting Section 105.5.

610.5Basis of Payment.

and payment constitute full for:

or tests used to determine the structural integrity and durability of a mass concrete element.

for challenge cores taken to determine concrete strength, or for corrective actions taken to remediate defective work.

during deck pours.

calculated by the following equation: * the quantity the compressive strength results represent. ITEM DESCRIPTION UNIT 610000 PCC MASONRY, CLASS A CY 610001 PCC MASONRY, ABUTMENT FOOTING, CLASS A CY 610002 PCC MASONRY, ABUTMENT ABOVE FOOTING, CLASS A CY 610003 PCC MASONRY, PIER FOOTING, CLASS A CY 610004 PCC MASONRY, PIER ABOVE FOOTING, CLASS A CY 610005 PCC MASONRY, SUBSTRUCTURE, CLASS A CY 610006 PCC MASONRY, APPROACH SLAB, CLASS A CY 610007 PCC MASONRY, SUPERSTRUCTURE, CLASS A CY 610008 PCC MASONRY, PARAPET, CLASS A CY 610009 PCC MASONRY, CLASS B CY 610010 PCC MASONRY, ABUTMENT FOOTING, CLASS B CY 610011 PCC MASONRY, ABUTMENT ABOVE FOOTING, CLASS B CY 610012 PCC MASONRY, PIER FOOTING, CLASS B CY 610013 PCC MASONRY, PIER ABOVE FOOTING, CLASS B CY

ITEM DESCRIPTION UNIT 610014 PCC MASONRY, SUBSTRUCTURE, CLASS B CY 610015 PCC MASONRY, CLASS C CY 610016 PCC MASONRY, CLASS D CY 610017 PCC MASONRY, SUPERSTRUCTURE, CLASS D CY 610018 PCC MASONRY, APPROACH SLAB, CLASS D CY 610019 HIGH EARLY STRENGTH CONCRETE CY 610020 CONCRETE ENCASEMENT CY