510Portland Cement Concrete

510.1 Description

This Work consists of placing Po rtland Cement Concrete (PCC).

510.2 Materials

All Materials shall be tested in accordance with AASHTO and AS TM methods or other test procedures designated by the Department. The State Materi als Bureau is the final authority regarding the interpretation of test procedures. The Contractor shall correct or remove and dispose of improperly graded or segregated Material that fails to meet the requirements as directed by the Project Manager and at no addit ional cost to the Department. The Contractor shall only use the Materials listed on the appr oved mix design. The Contractor shall not substitute an approved Material or Materia l Source listed on the approved mix design without written prior approval by the State Material s Bureau. The Department will consider a Material change only a fter receiving a written reque st. The State Materials Bureau will review the request and provi de written approval once it ha s verification of the equivalency of the proposed Material.

510.2.1 Portland Cement Concrete

The Contractor shall use a portland cement concrete mixture th at has been reviewed and approved in accordance with Section 509, “Portland Cement Concr ete Mix Designs” for the freeze-thaw risk zone in whi ch the Project is located.

510.2.2 Aggregate

The Contractor shall use aggregates that are the same as those used on the approved mix design. The Contractor shall not use aggregate from a diff erent source as that shown on the approved mix design. If the concrete mixture is approved under the conventional sto ckpile procedures, the Contractor shall ensure the gradations comply with Table 509.2. 3.2.1, “Coarse Aggregate Gradation Requirements” and Table 509.2.3.3.11:1, “Fine Aggrega te Gradation Requirements.” If the concrete mixture is approved under the combined gradati on procedures, the Contractor shall ensure that the most current gradations have b een reviewed, and the Coarseness Factor and the Workability Factor comply with Sectio n 509.2.7.5.1, “Combined Gradations.”

510.2.3 Water

Water used for the production and curing of concrete shall conf orm to ASTM C1602. Water shall have a pH between six (6.0) and 8.5; sulfate or chl oride contents shall not exceed 1,000 ppm, and shall be free of oil, silt, clay, organic matter , or other Deleterious Material. Non-potable water sources shall be testing tested prior to use. Residual water, wash water, or recycled water generated by Equipment, mixer trucks, or central mixers shall not be used in concrete production.

510.3 Construction Requirements

510.3.1 Submittals

Thirty (30) Days prior to the start of concrete Work, the Contr actor shall submit the following items to the Project Manager for review and Acceptanc e. 1. NRMCA Certification to include the following: a. Plant inspection report; b. Most recent scales calibration documentation; c. Most recent liquid metering pumps calibration documentation; d. Concrete uniformity te st results, if required; 2. NRMCA truck certifications; 3. Approved mix designs for each c oncrete class used in the Pro ject; 4. Admixture(s) Manufacturer’s cut sheets; 5. Cement mill certifications; 6. SCM mill certifications; 7. Reinforcement fiber certifications; and 8. In-place strength measurement requests. Option 1 mix designs and mix desi gns developed for Project spec ific requirements shall be submitted to the Project Manager for Project specific approv al by the State Materials Bureau.

510.3.1 1 Freeze-Thaw

The Contractor shall use an approv ed concrete mix design which has been approved for use in a freeze-thaw zone of equal or greater risk than the zon e in which the Project is located.

510.3.1 2 Class Substitution

The Contractor may substitute an approved structural class of c oncrete with a higher compressive strength than that of the specified class of concre te, as long as the design slump characteristics remain the same (i.e. Class HPD for Class AA, C lass AA for Class A, and Class P for Class F). The Contractor shall not substitute Clas s A for Class AA or Class F for Class P concrete mixtures.

510.3.1 3 Alternate Batching Facilities

A request may be made to the State Materials Bureau to allow a currently approved concrete mixture to be batched out of facilities not under the direct control of the Supplier to whom the concrete mixture approval is granted. The Department will permit off-site batching of an approved concrete mixture when the following occur: 1. The Contractor shall use the same Materials as those used at the plant where the mixture is approved and as shown on the approved mix design; 2. The Contractor shall use the same admixtures as those used a t the plant where the mixture is approved and as shown on the approved mix design; 3. The Contractor shall prepare a written QC plan for the alter nate batch facilities, personnel and operations that adequately addresses how the alte rnate batch plant will assure the quality of the mixture; 4. The operations at the alternat e batch facility has confirmed compliance with the approved QC plan with other mixtures; and Section 510: Portland Ce ment Concrete Page 338 5. The Contractor shall provide concrete performance statistics that assure the same level of performance can be achieved from the alternate batch f acilities.

510.3.1 4 Plastic Properties

The allowable slump range for n on-superplasticized Class AA, Cl ass HPD and Class A concrete is 3.5 inches ± one (1.0) inch. The allowable slump r ange for Class F and Class P Slip-Formed Concrete is 1.5 inches ± one (1.0) inch. All test procedures and frequencies will be performed in accordance with the Minimum Testing Requirement s. The Contractor shall measure the air content in accordance with AASHTO T 121. The a ir content determined by AASHTO T 121 will be used to confirm compliance with the specif ied air content for structural concrete. 1. Low Risk Freeze/Thaw Zone – from 4.5% to eight percent (8.0% ); 2. Medium Risk Freeze/Thaw Zone – from five percent (5.0%) to e ight percent (8.0%); or 3. High Risk Freeze/Thaw Zone – from 5.5% to eight percent (8.0 %).

510.3.1 5 Troubleshooting

If the concrete produced using approved mix design fails to mee t requirements, the Project Manager will immediately notify the Contractor and the State Concrete Engineer. The Contractor shall be responsible for notifying the Supplier and the Private Testing Laboratory (PTL) that designed the mixture. The PTL shall work with the S tate Concrete Engineer to make the necessary changes to resolve the problems. Efforts to evaluate problems with the concrete do not relieve the Contractor of the responsibility to provide a concrete mixture that meets Project requirements. If the compressive strengths do not comply with Department requ irements, the Contractor shall describe the needed adjustments. The Contractor shall su bmit a written summary of the adjustments to achieve compressi ve strength to the State Materi als Bureau for approval. The mix design approval may be suspended or revoked by the Stat e Concrete Engineer should concrete continue failing to meet requirements in accord ance with Section 509.2.7.8, “Suspension and Revocation of Mix Design Approval.” The Projec t Manager will notify the Contractor immediately should th e mix design’s approval status be under review.

510.3.2 Batching

The Contractor shall produce ready-mixed concrete and site-mixe d concrete in accordance with AASHTO M 157, Sec tions nine (9) to eleven (11).

510.3.2 1 Portland Cement Concrete Production Facilities

The concrete producti on facilities shall be certified in accord ance with the National Ready Mix Concrete Association (NRMCA ) Plant Certification Program. The Project Manager will review and Accept facilities and Equipment certifications and c alibrations before production operations begin. The concrete production facilit ies shall have clearly separated aggregate bins or stockpiles; silos for cement and SCM; weighing hoppers; and sca les. Batch plants shall be equipped to proportion aggregates, bulk cement and SCM using ca librated weighing devices. If weighing SCM on the same scale as the portland cement, the C ontractor shall weigh the cement first, then add the SCM. The Contractor shall ensure that the batch plant operator has a direct view or live video of each scale and admixture sight tube while preparing batches of concrete. The Contractor shall ensure that the batch plant is capable of: 1. Accurately weighing and batching Materials for the portland cement or portland cement/SCM concrete mixture within the tolerances specified; 2. Providing readily visible scale dials or instrumentation dev ices for admixture bottles, beam scales and load cells, even i f using a computer to prepare the batch; and 3. Using weighing hoppers of sufficient size to contain the Mat erial without loss or spillage. The Contractor shall use weighing hoppers that efficiently disc harge weighed Materials for each batch. The Contractor shall ensure that the Material charging Equipment can deliver the batch to the mixer without loss or spillage. The Contracto r shall provide scales for weighing aggregates, cement, water, and SCM in accordance with Section 109.1, “Measurement of Quantity.”

510.3.2 2 Cementitious Materials

Cementitious Materials shall be weighed bulk cementitious Mate rials using a scale that has been calibrated in accordance with NRMCA requirements excep t when continuous proportioning and mixing Equipment is used. Partially used pac kaged cementitious Materials shall be weighed prior concrete batching. Cement, and combined cementitious weights shall be within ± on e percent (1.0%) of the target weights. If the weight of cementitious Materials is exp ected to weigh less than 1,000 lb, the weighed Materials shall be within 30 lb of the target weigh t. If the Material varies from the target weight by more than ± on e percent (1.0%), the Department will immediately notify the Contractor to take corre ctive action. If the weight is no more than two percent (2.0%) above or two percent (2.0%) below the target weight, the Department may, at the Project Manager’s discretion, Accept a m aximum of five (5) loads out of the first ten (10) consecutiv e loads of concrete delivered o f any continuous placement with these weight discrepancies, regardless of whether the discrepan cies are for the same Material or for other weighed Materials. Any batches of concrete produc ed after the first ten (10) have been batched that have cement or total cementitious weights tha t are more than ± one percent (1.0%) will be rejected and not allowed to be placed on the Pro ject. The Contractor shall dispose of rejected loads at no additional cost to the Departme nt. Scales and hoppers shall be equipped with a device that indicat es the complete discharge of cement and SCM into the mixer. Bulk cement and SC M shall be stored in weather tight bins and weighing hoppers. Discharge chutes shal l not be suspended from the weighing hoppers. Discharge chutes shall be arranged so that c ement and SCM do not lodge in or leak from them. Different cementitious Materials shall be stored separately, pr otected from moisture. Different brands or types of cement, SCM, or blended cement fro m different production facilities shall be stored separately. Separate, and identifia ble storage shall be provided for blended Portland-SCM cement stor age at the Project or plant sit e.

510.3.2 3 Water

Mixing water consists of free water, ice added to the batch and surface moisture on the aggregates. Prior to placement, the amount of water added by t he addition of ice shall be Section 510: Portland Ce ment Concrete Page 340 measured, recorded, and used to calculate the concrete mixture’ s water:cement ratio. The total amount of water, including water add at the Project site, shall be no more than 1.5% greater than the amount required by the approved mix design. F or truck mixers, the Contractor shall discharge the wash water before loading the ne xt batch of concrete.

510.3.2 4 Aggregates

510.3.2 4.1 Stockpiles

The Contractor shall ensure the separation of stockpiles of dif ferent sizes or from different sources. The Contractor shall stockpile aggregates s o that the coarse and fine particles do not separate. The Contractor shall provide stockp iles that can produce enough concrete for the section cons tructed during a scheduled operati on. The Contractor shall ensure that aggregates are not contaminated by Material from ad jacent stockpiles or from contact with the ground, dust, or other Deleterious Materials. The Contractor shall not use aggregates that become segregated or mixed with Deleterious Mat erial. The Contractor shall not use frozen lumps of aggregate in concrete batching. The Contractor shall ensure that a “sacrificial” layer of the s ame size aggregate at least six (6) inches deep is maintained below the bottom of the stock pile so that the front-end loader will not pick up non-complying Mate rials that would contaminate the concrete mixture.

510.3.2 4.2 Aggregate Properties and Gradations

All gradation tests performed to fulfill the requirements of th is section must be performed by TTCP certified technicians. The Project Manager may cancel concrete placements that have gr adation data that is more than seven (7) Days old. 1. The Contractor shall provide new gradation results to the Pr oject Manager in accordance with Section 906, “Mi nimum Testing Requirements.” 2. If the mixture design is approved with the Conventional Stoc kpile Procedure, the Contractor shall ensure that the stockpile gradations comply wi th the standard gradation requirements for each sieve size shown in Table 509.2 .33.2.3:1, "Coarse Aggregate Gradation Requirements," and Table 509.2.33.3.3:1, "F ine Aggregate Gradation Requirements." 3. If the mixture design is approved with the combined gradatio n procedure, it is the Contractor’s responsibility to continuously monitor the gradati o n o f e a c h o f t h e stockpiles. 4. The Contractor’s responsibilities to monitor gradations are not related to the QC/QA testing requirements. The Depar tment considers these responsib ilities to be part of the standard operation and maintenance of the batching faciliti es. 5. The Contractor shall determine if the combined gradation is within the following limits: 5.1. Coarseness factor is ± three (3) percentage points of the value in the approved mixture design; 5.2. Workability factor is ± two (2) percentage points of the v alue in the approved mixture design. 6. The aggregate batch weights shall be automatically adjusted when the gradation information determined by the Supplier is entered into the Fiel d Report form. The Supplier will be required to use the most recent gradations to determine if the Section 510: Portland Ce ment Concrete Page 341 Coarseness Factor or the Workability Factor does not comply wit h 5.1 or 5.2 above. If the Coarseness Factor or the Workability Factor does not com ply with 5.1 or 5.2 above, the mix batch weights must be adjusted to bring these fa ctors into compliance. When adjusting these fa ctors, adjust them to the t olerances in 6.1 and 6.2, below. 6.1. Coarseness factor is ± two (2) percentage points of the va lue in the approved mixture design; 6.2. Workability factor is ± 1.5 percentage points of the value in the approved mixture design. 7. If the gradation tolerances in 5.1 and 5.2 cannot be met, th e Contractor shall not place concrete until the Material is corrected to meet the spec ified gradation tolerances.

510.3.2 4.3 Batch Weights

The Contractor shall batch aggregate target weights over 1,000 lb to within ± two percent (2%) of the target weight. For target weights less than 1,000 lb, the Contractor shall batch to within ± 50 lb of the target weight. If any of the first ten (10) loads of concrete have a fine or c oarse aggregate weight that differs from the target weight by more than two percent (2%), b ut not more than ± three percent (3%), the Department may, at the Project Manager’s disc retion Accept the concrete. The Department will allow no more than five (5) loads out of th e first ten (10) consecutive loads of concrete of any continuous placement to exceed the max imum allowable weight tolerances. Any batches produc ed after the first ten (10) that differ from the target weight by more than ± two percent (2%) will be rejected from the Project and shall not be placed on the Project. The Contractor shall di spose of rejected loads at no additional cost to the Department.

510.3.2 4.4 Moisture Control

1. For a manually operated facility or for hoppers not equipped with automatic moisture sensors, the Contractor shall measure the moisture content of e ach stockpile not monitored by automatic moisture sensors at least every four (4) hours, or as required by changing moisture c onditions within the stockpiles. 2. For plants equipped with automatic moisture probes, for each stockpile monitored by an automatic moisture probe, the Contractor shall measure mo isture content manually at least once a Day. The Contractor shall compare the manual measurement immediately before pr eparing the first concrete loa d to the measurement shown by the moisture sensing Equipment. If the me asurements differ by more than 0.5%, re-correlate the moisture probe. 2.1 For stockpiles not monitored by an automatic moisture probe , the Contractor shall follow the requirements of bullet 1 above. 3. The Contractor shall send a certificate showing the moisture content determined by manual methods in accordance with bullet 4 below, and the moist ure correlation to the Project Manager with the first load of concrete. If this i nformation is not included with the first load of concrete delivered to the Project, that load of concrete and all subsequent loads of concrete are s ubject to rejection until the information is received at the Project. 4. The Contractor shall determine the aggregate moisture conten t to the nearest 0.5% in accordance with one (1) of the following procedures: Section 510: Portland Ce ment Concrete Page 342 4.1 AASHTO T 217: The shelf life of the calcium carbide is rel atively short. Closely monitor the age of the c alcium carbide and replace it i n strict accordance with the manufacturer’s recommendations; 4.2 AASHTO T 255: The Department will allow the hot-plate or m icrowave methods for this purpose, as long as no Material is lost and th e pan is continuously agitated during the drying process. 5. The Contractor shall provide the following information on th e moisture certificate to the Project Manager: 5.1 Pan weight; 5.2 Wet weight of the pan and the sample; 5.3 First dry weight of the pan and the sample; 5.4 Second dry weight of the pan and the sample; 5.5 Third dry weight of the pan and the sample (if necessary); 5.6 Absolute moisture content of the sample; 5.7 The moisture probe reading from the tested sample (if equip ped); and 5.8 The calculated difference bet ween the actual moisture conte nt test and that shown by the moisture sensing Equipment. The Contractor shall allow washed aggregates to drain before us e. The Project Manager may require the aggregates to remain in the stockpile or storag e area for longer, if the moisture contents are excessive.

510.3.2 5 Air-Entraining and Chemical Admixtures

The Contractor shall store admix tures in separate containers to avoid contamination, evaporation, and damage. The Contractor shall protect liquid a dmixtures from freezing and from damaging temperatures. For admixtures used as suspensions in non-stable solutions, the Contractor shall provide agitating Equipment to ensure the thorough distribution of the ingredients. All admixtures listed on the approved mix design shall be included in the concrete mixture; specific admixture proportions maybe adjusted to meet Project specific conditions or requirements. All admixtures added by hand and/or at the Proje ct site will be documented by the Department on the batch tickets.

510.3.2 6 Pigment Admixtures for Integrally Colored Concrete

The Contractor shall follow the manufacturer’s instructions in handling, storing, and mixing pigments. The Contractor shall deliver pigments to job site or batch plant in original, unopened packaging. The Contractor shall store in dry conditio ns. The Contractor shall submit product data and manufacturer’s ins tructions for pigment use and submit product samples or mock-ups to the Project Manager f or approval. If required by the Contract and/or if requested by the Project Manager, the mo ck-up panels shall include samples of rubbing and patching. The Contractor shall allow 30 Days for submittal approval and 14 Days for each necessary resubmittal. The color of the a pproved samples or mock-ups shall be used as a control for the Acceptance of the installed Material. Bulk Materials for this portion of the Project should not be purchased until the Projec t Manager has approved the samples or mock-ups.

510.3.2 7 Mixing

Section 510: Portland Ce ment Concrete Page 343 The Contractor shall ensure that the uniformity of the concrete mixture complies with AASHTO M 157, Section 10.2. If using a central plant mixer it must have a rated mixing capacity of at least three (3) CY. The Contractor shall batch and deliver concrete in accordance with NRMCA Standards.

510.3.3 Transporting

The Contractor shall transport mixed concrete in non-agitating trucks only when the slump is less than two (2) inches. Revolving-drum mixer trucks shall be used to transport concrete with a slump in excess of two (2) inches. The Contrac tor shall transport concrete produced in a dry-batched concrete plant in revolving-drum mixe r trucks. Non-agitator, mixer and agitating trucks used for transporting concrete shall be an nually certified by NRMCA. Upon request, the Contractor shall provide the Project Manager documentation of current NRMCA certification for each tr ansport truck used on the Projec t.

510.3.3 1 Non-Agitator Trucks

The Contractor shall use only non-agitating trucks with bodies that are smooth, mortar- tight metal containers capable of d ischarging the concrete at a satisfactory controlled rate without segregation. The Contractor shall provide covers neede d for protection.

510.3.3 2 Truck Mixers and Agitators

The Contractor shall equip agitator trucks with a plate directl y attached to the truck in a readily visible location, labeled with the specific truck prope rties, including the designated drum mixing speed. Department personnel will check the water tank site tube when t he truck arrives at the Project site. If there is water missing from the tank, the Dep artment will reject the truck unless the Driver can account for the missing water.

510.3.3 3 Arrival at the Project

The Contractor shall re-mix the concrete that arrives at the Pr oject site in agitator trucks as follows: 1. For concrete mixed in a central mix plant: mix at the desig nated mixing speed for a minimum of two (2) min, before discharging; 2. For concrete mixed inside an Agitator Truck: mix at the des ignated mixing speed for a minimum of five (5) min, before discharging; and 3. If any water, water-reducing admixtures, entrained air, or o ther ingredients are added to the concrete, mix the additional Material at the desig nated mixing speed for at least five (5) min before discharging.

510.3.4 Placing

510.3.4 1 Temperature and Weather Limitations

See Section 511.3.44, "Temperature and Weather Limitations."

510.3.4 2 Mixing Time

"Mixing time" is the elapsed time from when the cement is expos ed to the aggregates until the concrete has been placed into its final location. Th e Contractor shall not use concrete mixed less than the minimum spec ified time. The maximum mixing time for concrete hauled in Section 510: Portland Ce ment Concrete Page 344 truck mixers or truck agitators is 90 min. The Contractor shal l not exceed 60 min of mixing time when: 1. The concrete temperature is 80 °F or above for Bridge decks or approach slabs, and 2. The concrete temperature is 85 °F for other concrete. When hauling the concrete in non- agitating trucks, all concrete must be placed into its final location within 45 min of i nitial mixing. If the concret e temperature is 80 °F or above, the Contractor shall, place concrete within 30 min from initial mix ing. Concrete arriving at the Project with a temperature greater tha n 90 °F shall be rejected for use on the Project.

510.3.4 2.1 Extended Mixing Time

In rural and remote areas of the State where mixing time cannot be met, the Contractor shall submit a written request to the Project Manager for addit ional time. The Contractor shall include the following information: 1. The reason for re questing additional time; 2. The additional time needed in exce ss of the specified mixing time; 3. The proposed procedures, methods, and type of Materials or a dmixtures to be used, and the ambient temperature range to be considered, so that the concrete will meet required fresh and hardened properties; and 4. Documentation to prove that the additional time will not dam age the quality of the concrete. Documentation shall include admixture technical data . This information will be forwarded to the State Concrete Engine er for review. The State Concrete Engineer will issue a written recommendation within 14 Days from receipt of the request. If the Department allows a mixing time extension, the Contracto r shall prepare a trial batch consisting of at least one (1) full load of concrete at t he designated production facility and haul to the Project site. The Contractor shall batch the c oncrete in the same quantities as anticipated for the Project. The Contractor shall place the tr ial batch in a non-critical application to assess the mixture. If dosage for the admixture used for extending mix time is found to provide an initial setting time 30 minutes or more aft er the concrete has been unloaded, then the admixture will be approved for use by the Co ntractor at the dosage determined from the trail.

510.3.4 3 Concrete Sampling and Testing

The Contractor shall test for Quality Control and the Departmen t will test for Acceptance in accordance with Division 900, “Quality Criteria” and as spec ified in this Section. The Contractor Quality Control Field Technicians shall be certified by ACI or TTCP. 1. The Contractor shall test the concrete for compliance and Ac ceptance in accordance with Section 906, “Minimum Testing Requirements.” T he Contractor shall obtain representative samples of concrete being tested fo r the required properties from the point of discharge into the Structure being placed. The Department will provide test results to the Contractor after th e final compressive strength tests for each set of test specimens is completed with a copy to the Supplier on a weekly basis. Section 510: Portland Ce ment Concrete Page 345 2. The Contractor shall mold and cure concrete cylinders for co mpressive strength tests in accordance with AASHTO T 23, Making and Curing Concrete Test Specimens in the Field using four (4) inch × eight (8) inch single use plastic cylind er molds with plastic lids. The Contractor shall use cylinder mol ds that are six (6) inch × 12 inch if the nominal maximum size of the aggregate is equal to or greater than 1.5 inch. 3. The Contractor shall use a rod to consolidate the concrete f or all slump, air content and unit weight tests and all compressive strength test cylinde rs cast with normal slump concrete. For Class F and P, the Contractor shall use a vibrator to consolidate the concrete in a ll air content and unit weight tes ts and all test cylinders cast from slip form concrete. The Contractor shall not use a r od to consolidate slip- form concrete. 4. Prior to any concrete placement or multiple concrete placeme nts with differing location(s), the Contractor, Supplier and Project Manager shall agree upon in writing the location(s) of the initial curing station(s) for concrete c ylinders. If a pre-concrete placement conference is required, the location(s) of the initia l curing station(s) shall be a required item of discussion. The Project Manager will not agree to any initial curing location that will jeopardize the integrity of the test specimens during subsequent transport to the initial curing location. The curin g station may be relocated should the current loc ation cause a detrimental effec t to the Project as agreed upon by the Contractor, Supplier and Project Manager. T he new location shall be designated by the Contractor, Supplier and Project Man ager. 5. The Contractor shall provide all necessary support at the agreed upon initial curing location(s) for all testing and to maintain sufficient safe sto rage space, including but not limited to water bath container, water for initial curing o f concrete cylinders, heating or cooling as necessary, generators (and alternate powe r sources, as needed) and all vibratory Equipment and all Equipment required to operate the vibratory Equipment as required by this Section. 6. Immediately after molding, the concrete test cylinders shall be transported vertically, in a water filled container to the initial curing station. The Contractor shall begin curing of test cylinders by placing them in a water bath with a temperature of 70 °F ± ten (10) °F. The Contractor shall maintain the water-filled containers with the test cylinders undisturbed for a minimum of 21 h, but not more than 48 h, from t h e t i m e o f placement. The Contractor shall ensure that the level of water never drops below the tops of the cylinders. Water baths for both Quality Control and Acceptance testing sha ll be provided and maintained by the Contractor. Cylinders shall be appropriately marked to differentiate between Quality Control and Acceptance testing. 7. After initial curing, the Contractor shall strip the concret e cylinders and place into a standard curing tank (or moist room) in accordance with AASHTO T 23, Section 10.1.3. If the cylinders are to be shipped to an off-site Labo ratory for testing, the Contractor shall maintain the cylinders in the standard curing environment at a temperature of 73 ± three (3) °F until they are ready to be tra nsported. The Contractor shall not ship test cylinders until they are at leas t 48 h old. 8. The party that prepared the test specimens shall be responsi ble for transporting them from the initial curing station to the final curing locati on. The Contractor shall protect the test specimens from being damaged in any way. Spec ific attention will be paid to protection from sun, wind, rain, vibrations, moistur e loss and any sudden drops or impacts during transport.

510.3.4 3.1 Testing Frequency

Department personnel will perform all testing in accordance wit h the Minimum Testing Requirements as defined in Secti on 906, “Minimum Testing Requir ements.”

510.3.4 3.2 Continuous Concrete Placements

As concrete is being placed and t ested, concrete tests which a re outside the allowable concrete test ranges may be en countered and shall be immediatel y reported to the Project Manager. Continuous concrete placement shall be stopped if the slump is more than one (1) inch over the specified limits or air is more than 0.5% below t he minimum allowable air content and the remainder of the that was being placed shall be rejecte d. The next consecutive load shall then be tested for plasti c properties. In the event that two (2) consecutive trucks or any two (2) out of six (6) trucks are outside the allowable testing ranges, concrete shall not be placed in the Structure until the concrete testing is performed prior to the placement operation and the allowable concrete test ranges are shown to be in the a llowable range. Continuous concrete placement shall only resume if concrete from five (5) consecutive trucks are delivered within allowable concrete testing parameters, then th e placement and testing of concrete can once again be pe rformed concurrently. Concrete that has been placed with air content less than 0.5% b elow the minimum allowable air content or slump less than one (1) inch over the specified limits shall be subject to an additional price reduction of $50/CY. Concrete with air content more than 0.5% below the minimum allowable air content or slump greater than one (1) inch over the specified limits shall be rejected. This shall be in addition to the outcome of the final pay factors for concrete.

510.3.4 4 High Range Water Reducer

If using a high range water reducer (commonly referred to as su perplasticizers), the Contractor shall measure the initial slump before adding the hi gh range water reducer, and again immediately after the high range water reducer has been p roperly mixed into the load. The Contractor shall not exceed slump Specifications defined on the approved mixture design before introducing the high range water reducer. The Contracto r shall not exceed a slump of eight (8) inches after adding the high range water reducer. Th e Contractor shall check adjusted concrete for segregatio n before and during placement. The Contractor shall not place segregated concrete.

510.3.5 Acceptance

510.3.5 1 Concrete Strength

The Department will determine the compressive strength for comp liance by averaging two (2) or more concrete cylinder test results from the same co ncrete sample and tested at the specified age. The Department will make, handle, and store cyl inders in accordance with AASHTO T 23 and test in accordance with AASHTO T 22. The Depar tment will consider the result from a single cylinder only as an indicator. It will no t be considered an actual strength measurement. Any on-site storage facilities shall be provided by the Contractor.

510.3.5 1.1 Individual Strength Test

Unless otherwise specified, the Department will verify complian ce with the Specifications by determining the concrete strength at the age specified in Se ction 509.2.7.1, “Concrete Classifications.” The cylinders tested at the specified age wi ll be used to determine the Individual Strength Test result. The Department will make four (4) cylinders for each test set. The first cylinder shall be tested at seven (7) Days. Two (2) cylinders shall be tested at the specified age. The forth cylinder will be held in reserve for testing if the Within-Test- Section 510: Portland Ce ment Concrete Page 347 Coefficient-of-Variation exceeds five percent (5%), as determin ed in accordance with ACI

214.3.4 1.

If the forth cylinder is tested, the Department will average al l of the cylinders tested at that age to determine the Individual Strength Test, unless any of th e following conditions exist: 1. There is a visible cylinder defect or a defect in the cappin g. 2. A significant irregularity occurred while loading the test s pecimen to failure, such as a sudden load burst, cyclic or pu lsating loads, or a loading ra te not in accordance with AASHTO T 22.

510.3.5 2 In-Place Concrete Strength Measurements

If the Contractor requests measurement of in-place concrete str ength for construction- related purposes, the Contractor shall provide testing Equipmen t and perform strength tests at no additional cost to the Department. Field cured test cylinde rs shall be tested by a PTL approved by the State Materials Bureau. The Contractor may use one of the following procedures to determine the in-place concrete strength. Prior to using any of the procedures listed in this Section, and no later than 30 Days prior to conc rete placement, the Contractor shall submit an In-Place Concrete Strength Measurement Plan, co mplete supporting documentation, and procedures for the proposed method to the Pr oject Manager for approval by the State Materials Bureau. 1. AASHTO T 23 – Cure molded cylinders in accordance with T 23 - Section 10.2.1; 2. ASTM C805 – Rebound Number of Hardened Concrete (Rebound Met hod): As modified herein. This procedure shall be performed in accordan ce with directions from the State Concrete Engineer. At a minimum, a test shall c onsist of at least 14 credible rebounds obtained from an area approximately 18 inches in diameter. The highest two (2) and the lowest two (2) rebounds will be deleted and the remaining ten (10) rebound results averaged to determine the rebound numb er from the test location; 3. ASTM C873 – Compressive Strength of Concrete Cylinders Cast In-Place in Cylindrical Molds; 4. ASTM C900 – Pullout Strength of Hardened Concrete; 5. ASTM C1074 – Estimating Concrete Strength by the Maturity Me thod. The maturity curve shall be developed on site during the first curing period of the first concrete placement on the Project. This shall be performed each concret e class and/or concrete mix design used on the Project for which the Maturity Method will used; or 6. Match-Cure Method – Places a dditional molded cylinders into a specially controlled chamber that maintains the temperature of the cylinders to that of the concrete represented. In-place strength measurement will not be used for Final Accept ance or to determine the pay factor. The Contractor shall not use ASTM C805, C873 or C9 00 for in-place strength measurements of concrete contained in Bridge decks, prestressed members, approach slabs, or the top slabs of CBCs that are defined as Bridges. The Depa rtment will not allow any samples to be taken from Bridge decks, prestressed members or a pproach slabs.

510.3.5 3 Compressive Strength of Concrete Based on Cylinders f or Payment

The Department will Accept for payment purpose concrete based o n the compressive strength cylinder tests when the compliance tests equal or exce ed the specified strength. If Section 510: Portland Ce ment Concrete Page 348 the compliance test is less than the specified strength, the te st will be consider ed Acceptable if both of the following requirements are met: 1. The running average of three ( 3) consecutive individual stre ngth tests, as determined by the Department’s Performance Data Sheet for the c oncrete used on the Project, which meets or exc eeds the specified strength; and 2. No Individual Strength Test as defined in Section 510.3.5.1. 1, “Individual Strength Test” falls below the specified strength by more than 15%. If the compliance tests are not 100% or more of the specified s trength, the Department will review the tests and notify the Contractor whether the con crete will be Accepted at a reduced price, or if it has been “rejected.” The Department wi ll only allow rejected concrete to remain in place based on an engi neering analysis. Concrete tha t is rejected shall be removed and replaced at the Contractor’s expense and time. 510.3.5.4 Investigation of Low Strength Cylinder Test Results The Contractor shall not use the following test procedures as a substitute for the compliance test program in Section 510.3.4.3, "Concrete Samplin g and Testing." If problems with low strength cylinder tests persist, the Depar tment may suspend the Project at no additional cost or time to the Department and req uire the Contractor to comply with Section 510.3.1.5, “Troubleshooting.” If the corrective a ctions taken by the Contractor are insufficient, the Department may suspend Work again, at no addi tional cost or time to the Department, until the Project Manager determines Acceptable act ion as proposed by the Contractor. Should the Contractor elect to investigate low strength cylinde r test results, the Contractor shall submit a Low Strength Investigation Plan no la ter than 35 Days (28 Days for Class F or Class P concrete) after the date of placement to the Project Manager for permission to use the selected method. The Low Strength Invest igation Plan will be reviewed for Acceptance by the State Materials Bureau and returned to th e Contractor within seven (7) Days of receipt. The Contractor shall not proceed until receip t of written approval from the State Materials Bureau. The Contractor shall complete the low strength investigation no later than 56 Days after the date of concrete placement. The Contrac tor will Accept and not dispute the test results of low strength cylinders if the Low Strength Investigation Plan is not submitted within the allotted time. The Contractor may use any of the in-place strength test method s listed below to investigate areas of concern if normal Acceptance tests do not comply with Section 510.3.5.3, "Compressive Strength Compliance of Concrete Based on Cylinders ." 1. AASHTO T 24 – Obtaining and Testing Drilled Concrete Cores a nd Sawed: Perform in accordance with Section 510.3.5.4, "Investigation of Low Strength Cylinder Test Results;" 2. ASTM C803 – Penetration Resistance of Hardened Concrete (Win dsor Probe); 3. ASTM C805 – Rebound Number of Hardened Concrete (Rebound Met hod): As modified herein. This procedure must be performed in accordanc e with directions from the State Concrete Engineer. At a minimum, a test shall c onsist of at least 14 credible rebounds obtained from an area approximately 18 inches in diameter. The highest two (2) and the lowest two (2) rebounds will be deleted and the remaining ten (10) rebound results averaged to determine the rebound numb er from the test location. Section 510: Portland Ce ment Concrete Page 349 ASTM C803 and C805 will not be us ed for Final Acceptance or to determining pay factors. For Bridge concrete, test cores shall not be taken fr om Bridge decks, prestressed members, approach slabs, or the top slabs of CBCs that are defi ned as Bridges unless specifically approved by the State Bridge Engineer. For all ot her Bridge concrete with low strength test results, the Bridge Design Section will develop a Coring Plan within seven (7) Days of receipt of the Low Strength Investigation Plan. The St ate Materials Bureau may consider Contractor requests to use other industry accepted inv estigation methods not listed in this Section for investigation of low strength cylinder test re sults and Final Acceptance purposes.

510.3.5 4.1 Testing Cores

If the Contractor requests to use cores to determine in-place c ompressive strength, the cores shall obtained in accordance with AASHTO T 24. The Contr actor shall complete coring no later than 49 Days after the date of concrete placement. The Contractor shall take three

510.3.5 5 Price Adjustments

Concrete that is less than 100%, but is greater than 85% of the specified strength shall have the reduced in price in accordance with Table 510.3.5.5:1, “Pay Factors Based on % of Specified Strength.” If the compliance strength test is 85% or more of the specified strength then the Contractor may request to have a Hardened Air Content Test on a core obtained from the concrete in question. The Contractor shall obtain the core in accordance with AASHTO T 24 and immediately seal it in a plastic bag. The Department will take immediate possession of the core, for evaluation by a Department approved Petrographer in accordance with ASTM C457, linear traverse method. If the result of the hardened ai r content analysis meets the requirements below, the concrete will be paid for at full price : 1. A minimum air content of five percent (5.0%); 2. A specific surface greater than 600 inches -1; and Table 510.3.5.5:1 Pay Factors Based on % of Specified Strength Specified Strength, % Pay Factor, % 97 - 99 98 94 - 96 96 91 - 93 92 88 - 90 84 85 - 87 75 Less than 85% RejectA AThe Department will only allow re jected concrete to remain in p lace based on an engineering analysis Accepted by the Department. A 50% pay factor will be applied to rejected Material that is allowed to remain in place. Otherwise, rejected Materi al shall be removed and replaced at no additional expense to the Department. Section 510: Portland Ce ment Concrete Page 350 3. A spacing factor less than 0.008 inch.

510.4 Method of Measurement

The Department will measure concre te or concrete items in accor dance with the section of these Standard Specifications f or which the concrete is used .

510.5 Basis of Payment

The Department will pay for concrete in accordance with the Sec tion of these Standard Specifications for whic h the concrete is used. Section 511: Concrete Structures Page 351