Section 553 — Prestressed Concrete
Description
553.01This work consists of prestressing precast or cast -in-place concrete by providing, placing, and tensioning prestressing steel. This work also includes installing precast, prestressed members, except piling.
Material
553.02Conform to the following Subsections: Anchorage devices 722.01 Grout for post- tensioned structures 701.04(c) Non-shrink gr out 701.04(b)(1) Prestressing steel 709.02
Construction Requirements
553.03Qualifications. Provide a professional engineer, a precast concrete manufacturing plant and QCM , grouting supervisor, and grouting personnel with experience in prestressing precast or cast -in-place concrete. A t least 30 days before starting prestressed concrete work , subm it the following for approval:
(a)Professional engineer. PCI Plant Quality Control Technician/Inspector Certification , Level I or higher;
(b)Precast concrete manufacturing plant and QCM . Appropriate certifications;
(c)Grouting supervisor. A résumé describing experience on projects of similar complexity and American Segmental Bridge Institute (ASBI) grouting certification;
(d)Grouting personnel. A résumé for each individual describing experience on projects of similar complexity; and
(e)Plant certificatio n. PCI or equivalent NPCA certification.
553.04Submittals. Perform prestressing by either pre -tensioning or post -tensioning methods. If a method is proposed that is not in the contract, submit detailed drawings of the method, material, and equipment proposed for approval at least 30 days before starting prestressing. At least 30 days before starting prestressed concrete work, submit the following according to Subsection 104.06:
(a)Method and sequence of stressing;
(b)Complete de tails and test results for the prestressing steel and anchoring devices;
(c)Anchoring stresses;
(d)Arrangement of the prestressing steel in the members;
(e)Tendon elongation calculations for jacking procedures;
(f)Number, spacing, and method of draping pre-tensioned s trands;
(g)Other substantiating calculations for the pre -tensioning or post- tensioning method;
(h)Type of tendon ducts for post-tensioning;
(i)Pressure grouting material and equipment for post-tensioning;
(j)Locations of grout inlets and outlets;
(k)Samples of wire or strand; and
(l)Additions or rearrangement of reinforcing steel and changes in concrete dimensions.
553.05Prestressing Steel. Provide prestressing steel that is bright and free of corrosion, dirt, grease, wax, scale, rust, oil, and other foreign material that may prevent bond between the steel and the concrete. Do not use prestressing steel that has sustained physical damage or is pitted. Do not splice prestressing steel strands. Do not weld or ground welding equipment on forms or other steel in the member afte r the prestressing steel is installed. Failure of one wire in a 7 -wire prestressing strand is acceptable if 8 5 percent of the required tension load is attained before failure and if the failed strand does not constitute more than 2 percent of the total area of strands in an individual beam or girder. Extend bars using couplers which, when assembled, have at least the tensile strength of the bars. Package prestressing steel to protect it from physical damage and corrosion during shipping and storage. Place a corrosion inhibitor in the package. Use a corrosion inhibitor that has no deleterious effect on the steel, co ncrete, or bond strength of steel to concrete. Replace or restore damaged packaging. Mark the shipping package with a statement that the package contains high -strength prestressing steel and a warning to use care in handling. Identify the type, kind, and quantity of corrosion inhibitor used, including the date when placed, safety regulations, and instructions for use. Assign a lot number and tag for identification purposes to wire, strand, anchorage assemblies, and bars. Provide representative samples of pr estressing steel from prestressed members fabricated off site. In the case of wire or strand, take the sample from the same master roll.
(a)Pre-tensioning method. Provide a sample at least 6 feet long of each strand size from each coil.
(b)Post-tensioning method. Provide samples of the following lengths:
(1)For wires requiring a head, 15 feet.
(2)For wires not requiring a head, sufficient length to make up one parallel -lay cable 5 feet long consisting of the same number of wires as the cable to be provided. (3) For strands provided with fittings, 5 feet between near ends of fittings.
(4)For bars to be provided with threaded ends and nuts, 5 feet between threads at ends.
553.06Concrete. Construct concrete according to Sec tion 552. Construct reinforcing steel according to Section 554. Make at least one set of release strength test cylinders according to AASHTO T 23 in addition to those required to determine the 28- day compressive strength. C ure the release strength test cylinders with the concrete member they represent. Rough cast the top surface of members against which concrete will be cast. Rake the top surface of members receiving a concrete overlay to a depth of ⅜ inch. Sidewalk finish t he top surface of members receiving an asphalt overlay according to Subsection 552.12(c)(2) . For bridge deck surfaces to be covered with a waterproofing membrane, finish to a smooth surface without ridges and other projections, and according to the waterproofing membrane manufacturer’ s recommendations. Cure the girder in a saturated atmosphere of at least 90 percent relative humidity. Cure time may be shortened by heating the outside of impervious forms with radiant heat, convection heat, conducted steam, or hot air. Apply radiant heat by pipes circulating steam, hot oil, hot water, or electric heating elements. Inspect casting beds to ensure uniform heat application. Use a suitable enclosure to contain the heat. Minimize moisture loss by covering exposed concrete surfaces with plastic sheeting or liquid membrane curing compound according to Subsection 552.13. Sandblast curing compound from concrete bonded surfaces. Envelop the entire surface with saturated steam. Completely enclose the casting bed with tightly constructed housing to prevent the escape of steam and exclude outside air. Use steam at 100 percent relative humidity. Do not apply the steam directly to the concrete. If using hot air, obtain approval of the method to envelop and maintain the girder in a saturated atmosphere. Do not allow dry heat to touch the girder surface. For heat curing methods:
(a)Keep unformed girder surfaces in a saturated atmosphere throughout the curing time.
(b)Embed a thermocouple, linked with a thermometer accurate to ±5 °F, 6 to 8 inches from the top or bottom of the girder on its centerline and near its midpoint.
(c)Monitor with a recording sensor, accurate to ±5 °F, arranged and calibrated to continuously record, date, and identify concrete temperature throughout the heating cycle.
(d)Submit the temperature record when requested.
(e)Heat concrete to no more than 100 °F during the first 2 hours after placing concrete, and increase the temperature no more than 40 °F per hour to a maximum of 160 °F.
(f)Cool concrete, after curing is complete, no more than 40 °F per hour until a temperature 20 °F above the temperature of the air to which the concrete will be exposed has been attain ed.
(g)Keep the temperature of the concrete above 60 °F until the girder attain s release strength. Cure precast, prestressed members to the release compressive strength. Release compressive strength is attaine d when the average strength of two representative test cylinders is greater than the minimum required strength and the individual strength of any one cylinder is no more than 5 percent below the required strength. Do not expose the concrete to temperatures below 40 °F for at least 7 days after casting.
553.07Tensioning. Use hydraulic jacks to tension prestressing steel. Calibrate measuring devices at least once every 6 months and if they appear to be giving erratic results. Calibrate the jack and gauge as a unit with the cylinder extension in the approximate position that it will be at final jacking force. Keep a certified calibration chart with each gauge. If a pressure gauge is used, only gauge loads from one -fourth to three -fourths of the total graduated capacity of the gauge, unless calibration data clearly establishes consistent accuracy over a wider range. Use a pressure gauge with an accurate reading dial at least 6 inches in diameter. Measure the force induced in the prestressing steel using calibrated jacking pressure gauges, load cells, or a calibrated dynamometer. Take elongation measuremen ts of the prestressing steel. Determine the required elongation from average load-elongation curves for the prestressing tendons used. For pre -tensioned members, if there is a discrepancy between the gauge pressure and elongation of more than 5 percent in tendons over 50 feet in length or 7 percent in tendons of 50 feet or less in length, determine the source of error before proceeding. Do not allow discrepancies in post -tensioned members to exceed 7 percent. If the jacking system is equipped with an automa tic release valve that closes when the required prestressing force is achieved , measure strand elongation for the first and last tendon tensioned and for at least 10 percent of the remaining tendons. If a load cell is used, do not use the lower 10 percent of the manufacturer’s rated capacity of the load cell to determine the jacking force. Do not exceed a temporary tensile stress of 80 percent of the specified minimum ultimate tensile strength of the prestressing steel. Anchor prestressing steel at an initial stress that will result in the retention of the required working stress after all losses. For pre -tensioned members, do not allow the initial release stress after seating, and before other losses, to exceed 70 percent of the specified minimum ultimate tensile strength of the prestressing steel for stress- relieved strands and 75 percent for low -relaxation strands. For post -tensioned members, do not allow the initial release stress after seating to exceed 70 percent of the specified minimum ultimate tensile strength of the prestressing steel.
553.08Pre -tensioned Members. Construct pre -tensioned members to the tolerances shown in Table 553-1.
(a)Prestressing steel. Protect prestressing steel placed in the stressing bed fro m contamination and corrosion if the stressing bed is to be exposed to weather for more than 36 hours before encasement in concrete. Ensure strands are free of kinks or twists. Accurately hold prestressing steel in position and tension. Do not allow strands to unwind more than one turn. Keep a record of the jacking force and elongation measurements after the strands are tensioned to 20 percent of final jacking force. Tension prestressing steel to the required stress. Provide a professional engineer to perform elongation computations. Include in elongation computations the strand anchorage slippage, splice slippage, in place horizontal movement of the structural member during prestressing operations, and prestressing steel temperature changes between the time of tensioning and the time when the concrete takes its initial set. Maintain the prestress bed forms, strands, and reinforcement bar temperature within 25 °F of the temperature of the concrete to be placed in the forms. Support strands with rollers at points of direction change when strands are tensioned in a draped position. Use free- running rollers with minimal friction. Initially, when strands are tensioned and then pulled into the draped position, tension to no more than the required tension minus the increased tension due to forcing the strand to a draped profile. If the load in a draped strand at the dead end, as determined by elongation measurements, is less than 95 percent of the jack load, tension the strand from both ends of the bed. Ensure the load, as computed from the sum of elongations produced by jacking at both ends, is within 5 percent of the jack load. Within 3 hours before placing concrete, check the tension on the prestressing strands. Obtain approval for the method and equipment for checking the loss of prestress. If strands are tensioned individually, check each strand for loss of prestress. Retension to the original computed jacking stress for strands that show a loss of prestress more than 3 percent. If strands are tensioned in a group, check the entire group for total loss of prestress. Release and retension the entire group if the total prestress shows a loss more than 3 percent or if individual strands appear significantly different from the rest of the strands in the group.
(b)Releasin g steel. Release the prestress load to the concrete after the concrete has attained its required release compressive strength. Cut or release strands so that lateral eccentricity of the prestress force is minimized. Cut off prestressing steel flush with th e end of the member, except as shown in the plans.
(c)Debonding strands. Use solid or split plastic sheathing with a thickness of at least ⅟ 32 inch to debond strands. Before placing concrete, use tape to thoroughly seal split and solid sheathing including ends to prevent the migration of concrete mortar along the strand. Table 553-1
Prestressed Concrete Member Tolerances
Property Tolerance
Post-Tensioned Members
Position of post -tensioning ducts ±¼ in Position of tendon anchorage bearing plates ±¼ in
Precast Concrete I -Beams and T -Beams
Length ±⅛ in per 10 ft Width (overall) +⅜ in, -¼ in Depth (overall) +½ in, -¼ in Depth (flanges) -¼ in Width (web) +⅜ in, -¼ in Deviation from straight line parallel to centerline of member ⅛ in/10 ft Variation from end squareness or skew ±3⁄16 in/ft, ±1 in maximum Camber variation from design camber ±⅛ in/10 ft, ±1 in maximum Position of strands ±¼ in Position of hold -down points for depressed strands ±6 in Position of plates other than bearing plates ±1 in Position of bearing plates ±⅝ in Tipping and flushness of plates ±¼ in Tipping and flushness of bearing plates ±⅛ in Position of inserts for structural connections ±½ in Position of stirrups: Longitudinal spacing ±2 in Projection above top ±¾ in Local smoothness(1) ±¼ in per 10 ft
(1)Does not apply to top surface left rough to receive a topping or to visually concealed surfaces. Table 553- 1 (continued)
Prestressed Concrete Member Tolerances
Property Tolerance
Precast Concrete Box Beams, Flat Slabs, and Decked Girders Length ±⅛ in per 10 ft Width (overall) ±¼ in Depth (overall) ±¼ in Depth (top flange) ±½ in Depth (bottom flange) +½ in, -⅛ in Width (web) ±⅜ in Deviation from straight line parallel to centerline of member: Up to 40 ft member length ±¼ in 40 to 60 ft member length ±⅜ in Greater than 60 ft member length ±½ in Variation from end squareness or skew ±⅛ in per ft Horizontal ±½ in maximum Vertical ±½ in Camber variation from design camber ±¼ in per 10 ft, ±½ in maximum Differential camber between adjacent members of the same design ±⅛ in per 10 ft, ½ in maximum Position of strands ±¼ in Position of hold-down points for depressed strands ±6 in Position of plates other than bearing plates ±1 in Position of inserts for structural connections ±½ in Position of stirrups: Longitudinal spacing ±1 in Projection above top +¼ in, -¾ in Position of dowel tubes ±⅝ in Position of tie rod tubes: Parallel to length ±½ in Vertical ±⅜ in Position of slab void: End of void to center of tie hole ±½ in Adjacent to end block ±1 in Local smoothness(1) ±¼ in per 10 ft
(1)Does not apply to top surface left rough to receive a topping or to visually concealed surfaces.
553.09Storing, Transporting, and Erecting. Do not ship prestressed concrete members until concrete cylinder tests, manufactured of the same concrete and cured under the same conditions as the members; indicate that the concrete in each member has attained the minimum required design strength and is at least 7 days old or at least 10 days old for decked Bulb- T sections. Before transporting prestressed concrete members, provide written certification from a professional engineer that the members were fabricated, visually inspected, and meet minimum quality requirements. Install points of support designed by a professional engineer to prevent cracking or damage during hoisting and handling. Store, transport, and erect precast, prestressed girders, slab units, and box units in the upright position with the points of support and directions of the reactions, with respect to the member, approximately the same as when the member is in its final position. Prevent cracking or damage during hoisting, handling, and storing of the precast units. Use high- pressure water blasting to remove debris and paste in the keyways immediately before placing mortar. Remove free -standing water and allow keyways to surface dry. Use non-shrink grout in keyways between multibeam members, blockouts, and set anchor bolts and dowels. Strike off exposed grout on surfaces until flush. Cure the non- shrink grout according to the manufacturer’s recommendations. Apply the same surface texture finish to the surrounding concrete as soon as the non- shrink grout or concrete has sufficiently set. Repair concrete defects according to Section 572. Replace units damaged by improper handling or storing if the CO determines them irreparable.
553.10Post -Tensioned Members. Construct post -tensioned members to the tolerances shown in Table 553-1. Construct supporting falsework so that the superstructure is free to lift off the falsework and shorten during post -tensioning. Detail formwork left inside box girders to support the roadway slab to offer minimum resistance to girder shortening due to shrinkage and post- tensio ning.
(a)Ducts. Use mortar -tight ducts that are sufficiently rigid to maintain their shape and alignment during concrete placement and grout installation. Use ducts with minimum wall thicknesses conforming to Table 553-2. Table 553-2
Minimum Duct Wall Thicknesses
Duct Minimum Thickness, gauge
Metal duct, diameter ≤ 2⅝ in 26 Metal duct, diameter > 2⅝ in 24 HDPE 14 HDPP 14 Metal duct with bar tendons preassembled with duct 31 For tendons composed of single prestressing bars, provide ducts with an internal duct diameter of at least ¼ inch larger than the outside diameter of the prestressing bar. For multiple wire, bar, or strand tendons, provide a duct nominal internal cross -sectional area of at least 2¼ time s the net area of the prestressing steel. When tendons are to be placed by the pull through method, provide a duct nominal internal cross -sectional area of at least 2½ times the net area of the prestressing steel. Make positive joints between duct sections. Do not make angles at the joints. Use waterproof tape at the joints. Do not use duct tape. Bend ducts without crimping or flattening. Use ferrous metal or polyethylene couplings to connect ducts to anchoring devices. Protect ducts against crushin g, excessive bending, dirt contamination, and corrosive elements during transport, handling, and storing. In case of duct damage, seal duct with waterproof tape, or splice a duct coupler over the damaged section to form a seal that prevents cement paste fr om entering the duct during the placement of concrete and to prevent leakage during grouting operations. Provide ducts and anchorage assemblies with inlets for the injection of grout into the duct after prestressing according to PTI, Guide Specification for Grouting of Post-Tensioned Structures . Provide ducts with outlets to allow the escape of air, water, grout, and bleed water according to PTI, Guide Specification for Grouting of Post-Tensioned Structures . Provide inlets and outlets with an inner diameter of at least ¾ inch for strand tendons and of at least ½ inch for single bar tendons. Extend the length of outlets a sufficient distance out of the concrete member to allow for the proper closing of the outlets. Place inlets and outlets, at a minimum, in the following locations:
(1)Anchorage area of the tendon;
(2)High points of the duct, when the vertical distance between the highest and lowest point is more than 24 inches;
(3)Inlet at or near the lowest point of the tendon;
(4)Outlet at low points of the duct;
(5)Major changes in the cross- section of the duct, such as couplers and anchorages; and
(6)Outlet at a distance less than 36 inches downstream from high point outlets. Provide positive mechanical shut -off valves for inlets and outlets. Provide inlets and outlets with valves, caps, or other devices that can withstand the grouting pressure. Securely fasten ducts in place to prevent movement. Maintain distances from the forms by stays, blocks, ties, hangers, or other approved supports. Use precast mortar blocks of approve d shape and dimensions. Separate layers of ducts by mortar blocks. Space duct supports according to PTI, Guide Specification for Grouting of Post -Tensioned Structures. Cover the ends of ducts to prevent the entry of water or debris . Connect inlets and outl ets to the duct with metallic or plastic structural fasteners. Do not use components that react with concrete, cause corrosion of the prestressing steel, or contain water soluble chlorides.
(b)Placing concrete. Where the end of a post -tensioned assembly is not covered by concrete, recess the anchoring devices so that the ends of the prestressing steel and all parts of the anchoring devices are at least 2 inches inside the end surface of the members. Before placing concrete, demonstrate that ducts are unobstruc ted. Immediately after concrete placement, blow out ducts with compressed, oil -free air to break -up and remove mortar in the conduit before it hardens. Approximately 24 hours after the concrete placement, flush ducts with water containing lime (calcium oxide) or slaked lime (calcium hydroxide) at a rate of 0.1 pound per gallon. Blow the water out with compressed, oil- free air. For post- tensioned members that are to be steam cured, do not install prestressing steel until curing is complete.
(c)Anchorages and distribution. Provide at least 10 days’ notice before installing end fittings or heading wires. When wires are used, provide an edge distance for any hole for prestressing wire through a stressing washer, unthreaded bearing ring, or plate of at least ¼ inc h from the root of any threads or the edge of any ring, plate, or washer. Anchor post -tensioned prestressing steel at the ends by permanent type anchorage devices that can develop equal to or greater than 95 percent of the ultimate tensile strength of the prestressing steel. Provide a steel distribution plate or assembly to effectively distribute the compressive stresses from the anchoring device to the concrete. Do not exceed 3000 pounds per square inch for the final unit compressive stress on the concrete directly beneath the plate or assembly. Do not allow bending stresses induced by prestressing to exceed the yield point of the material in the plates or assemblies or cause visible distortion in the anchorage plate when 100 percent of the nominal load is applied. Enclose loop tendon anchorages in ducts for their entire length. (d) Prestressing steel. Use a corrosion inhibitor to protect prestressing steel installed in ducts before placing and curing the concrete. Use a corrosion inhibitor that does not adverse ly affect the steel, concrete, or bond strength of the steel to concrete. If prestressing steel is installed in the ducts within 10 days after concrete curing, stressing, and grouting are completed, no corrosion inhibitor is required. (e) Post-tensioning. Wait at least 10 days after the last concrete has been placed in the member or until tests on concrete cylinders indicate that the concrete has attained the minimum required compressive strength. Demonstrate that the prestressing steel is free and unbonded in the duct. Straighten wires if necessary to produce equal stress in all wires, wire groups, or parallel lay tendons that are stressed simultaneously. Remove side forms for girders before post-tensioning. Record gauge pressures and prest ressing steel elongation continuously while tensioning prestressing steel and submit records. Determine the loss due to friction in the prestressing process according to AASHTO, LRFD Bridge Design Specifications . Use shims or other approved devices to achi eve the specified anchor set loss.
(f)Grouting. Provide grout and prestressing steel that is free of dirt, loose rust, grease, or other deleterious material. Bond post -tensioned prestressing steel to the concrete by filling the void space between the duct and tendon with grout according to PTI, Guide Specification for Grouting of Post - Tensioned Structures . Before starting grouting operations, provide the required testing equipment on site for checking grout workability (flow cone), temperatures, and other spec ified tests. Use grouting equipment that can operate continuous ly with little variation of pressure, which also includes a system for recirculating the grout while actual grouting is not in progress. Use grouting equipment that can maintain a pressure on c ompletely grouted ducts and id fitted with a valve that can be locked off without loss of pressure in the duct. Provide written certification that ingredients used in the grout meet the ASTM requirements contained in PTI, Guide Specification for Grouting of Post -Tensioned Structures . Include the following:
(1)Cement mill test reports;
(2)Mineral additives test reports;
(3)Chemical admixtures reports; and
(4)Test reports for other ingredients used in the grout. For prepackaged grouts, provide the manufacturer’s current certified mill test reports for the product. Do not use compressed air to aid in the pumping of grout. Provide grout pumps of a positive displacement type, that can provide a continuous flow of grout and maintain an outlet pressure of at least 150 pounds per square inch and has a pressure gauge with a full - scale reading of no more than 300 pounds per square inch. Grout only when the efflux time of a grout sample immediately after mixing is between 11 and 30 seconds according to ASTM C939. When hot weather conditions may cause quick setting of the grout, cool the grout by approved methods, as necessary, to prevent blockages during pumping operations. When freezing weather conditions are possible during and following placement of grout, protect the grout from damage by freezing according to PTI, Guide Specification for Grouting of Post - Tensioned Structures . Provide a supply of potable water and standby flushing equipment that can develop a pumping pressure of 250 pounds per square inch with sufficient capacity to flush out partially grouted ducts. Clean ducts of material that would impair bonding of the grout or interfere with grouting procedures. Blow out each duct with compressed, oil- free air. Check inlets and outlets for their capacity to accept injection of grout by blowing compressed, oil -free air through the system and proving each inlet and outlet in turn. Pass grout through a screen with ⅛- inch maximum clear openings before entering the grout pump. Open grout vents before the start of grouting. Completely fill the duct by injecting grout from the lowest end of the tendon in an uphill direction. Pump grout continuously through the duct and waste at the outlet until no visible slugs of water or air are ejected, and the efflux time of ejected grout is between 11 and 30 seconds. Maintain a continuous, one-way flow of grout within a grouting stage. Close outlets in a similar manner one after the other in the direction of the flow. Close outlets placed a short distance downstream from a high point before the associated high point outlet. Increase the grouting pressure at the injection end to at least 100 pounds per square inch and hold for at least 10 seconds. Do not remove or open valves and caps until the grout has set. Abrasive blast clean the concrete surface of recessed anchorage assemblies. Fill anchor recesses with concrete conforming to the requirements for the structure and finish flush. Remove ends of vents 1 inch below the roadway surface after grouting has been completed. Permanently seal recess areas. Do not release the falsework under the bottom slab supporting the superstructure until at least 48 hours after grouting the post -tension prestressing steel or until the grout strength is obtained.
553.11Coating Steel. Use a wire brush or abrasive blast to remove dirt and residue not firmly bonded to the metal or concrete surfaces. Clean and coat the exposed ends of the prestress ing steel, post -tensioned anchor head assemblies, and a 1 -inch strip of adjoining concrete. Mix zinc- rich coating material conforming to MIL -DTL -24441. Work the coating material into voids in the prestressing tendons. Apply one thick coat to surfaces that will be covered with concrete. Apply two coats to surfaces not covered with concrete.
553.12Continuity of Prestressed Girders. Construct continuity diaphragms between precast girders at least 90 days after girders have been prestressed. Submit supporting calculations conforming to AASHTO, LRFD Bridge Design Specifications when establishing co ntinuity less than 90 days after girders have been prestressed.
553.13Acceptance. See Tables 552 -10 and 553-3 for sampling, testing, and acceptance requirements. Prestressing steel, anchor devices, an d material for concrete and grout will be evaluated under Subsections 106.02 and 106.03. Provide production certifications with each shipment of hydraulic cement and prestressing steel. Grouting will be evaluated under Subsections 106.02 and 106.04. Concrete will be evaluated u nder Section 552. Concrete repairs will be evaluated under Section 572. Reinforcing steel will be evaluated under Section 554. Temporary works will be evaluated under Section 562.
Measurement
553.14Measure the Section 553 pay items listed in the bid schedule according to Subsection 109.02 .
Payment
553.15The accepted quantities will be paid at the contract price per unit of measurement for the Section 553 pay items listed in the bid schedule. Payment will be full compensation for the work prescribed in this Section. See Subsection 109.05 . Table 553-3 Sampling, Testing, and Acceptance Requirements
Material or
Product
(Subsection) Type of
Acceptance
(Subsection) Characteristic Category Test Methods
Specifications Sampling
Frequency Point of
Sampling Split
Sample Reporting
Time Remarks
Mix Design
Concrete
composition Measured & tested for conformance (106.04) All − Subsection
552.031 per mix design Source of material If requested Before producing −
Production
Concrete
(552.03 )(1) Process control (153.03 ) Density − AASHTO T 121 1 per load after 0.25 yd3 minimum is discharged(4) Point of discharge at truck No Upon completing tests − Air content − AASHTO T 152 or T 196 " " " " − Slump(5) − AASHTO T 119 " " " " − Slump flow(6) − ASTM C1611 " " " " For SCC mixes only Temperature − ASTM C1064 " " " " − Table 553-3 (continued) Sampling, Testing, and Acceptance Requirements
Material or
Product
(Subsection) Type of
Acceptance
(Subsection) Characteristic Category Test Methods
Specifications Sampling
Frequency Point of
Sampling Split
Sample Reporting
Time Remarks
Production (continued)
Concrete
(552.03 )(1) Measured & tested for conformance (106.04 ) Density − AASHTO T 121 1 per load after 0.25 yd3 minimum is discharged(4) Discharge at point of placement No Upon completing tests − Air content − AASHTO T 152 or T 196 " " " " − Slump(5) − AASHTO T 119 " " " " − Slump flow(6) − ASTM C1611 " " " " For SCC mixes only Temperature − ASTM C1064 " " " " −
Concrete
(552.03 )(1) Measured & tested for conformance (106.04) Compressive strength(2),(3) − AASHTO R 100 & T 22 1 per 30 yd³ Discharge stream at point of placement No Upon completing tests − Grout(7) Measured & tested for conformance (106.04) Compressive strength − ASTM C109 1 set of 3 per day Grout plant No Upon completing tests −
(1)Sample according to AASHTO R 60, except composite samples are not required.
(2)Cast at least four compressive strength test cylinders for 6 - by 12 -inch specimens or six compressive strength cylinders for 4- by 8-inch specimens and transport the cylinders to the job site curing facility. In addition to the test cylinders required to determin e 28-day strength, cast two release cylinders for each concrete member. Cure the release- strength cylind ers with the concrete member that they represent
(3)A single compressive strength test result is the average result from two 6 - by 12 -inch or three 4 - by 8-inch cylinders cast from the same load.
(4)If three successive samples are tested and compliance w ith the specifications is indicated, screening tests may be reduced to an approved frequency. Resume testing frequency if a test shows a failing temperature, air content, or slump, or if directed.
(5)If a hydration stabilizer is used, limit slump loss to 2 inches as compared to slump recorded at the batch plant.
(6)Use ASTM C1611 instead of AASHTO T 119 for SCC mixes.
(7)Sample and test according to PTI, Guide Specification for Grouting of Post- Tensioned Structure s.