323 perform any subsequent necessary mix adjustments. The details of this remote monitoring shall be outlined in the Quality Control Plan for plant operations. The Contractor shall provide a copy of the quality control test results to the Supplier of t he concrete which was tested within 48 hours of the completion of the test. Any Agency or Laboratory which tests Contractor Quality Control concrete compressive strength specimens, that may be used for acceptance by the Division, shall be evaluated by th e Cement and Concrete Reference Laboratory (CCRL) and certified by the Division as meeting all the requirements of ASTM C1077 pertaining to testing concrete cylinders, as outlined in Section 4.2 of MP 601.03.50.
601.4.3 -Acceptance Testing: Acceptance sampling and testing of Portland cement concrete is the responsibility of the Division, except for furnishing of necessary materials. Quality control sampling and testing performed by the Contractor may be utilized by the Division for acceptance. Stren gth as used in this specification, is only one indicator of the durability of the Portland cement concrete. Evaluation of structural concrete may include evaluation of the freeze -thaw durability, scaling characteristics, abrasion resistance, density and s uch other factors the
601.4.4 -Compressive Strength Tests for Acceptance: A strength test shall consist of three test specimens. Either 6” x 12” cylinders or 4” x 8” cylinders are permitted, provided the requirements of MP 7 11.03.23 are met. The size of the cylinders which the Contractor intends to use on each project shall be listed in the Contractor’s Quality Control Plan. The test shall be the average of the three specimens, except that if one specimen shows manifest evidence of improper sampling, molding, or testing, it shall be discarded and the remaining two strengths averaged. Should more than one specimen representing a given test show definite defects due to improper sampling, molding, or testing, the entire test sh all be discarded. The maximum acceptable range of compressive strengths within a set of three cylinders is 9.5%. This range is found by multiplying 9.5% times the average compressive strength of the three cylinders. If this acceptable range is exceeded, the cylinder that varies the most from the average shall be discarded, and the remaining two cylinders shall be evaluated as outlined in the following paragraph. The maximum acceptable range of compressive strengths within a set of two cylinders is 8.0%. This range is found by multiplying 8.0% times the average compressive strength of the two cylinders. If this acceptable range is exceeded, the entire test shall be discarded. Under no circumstances shall a compressive strength test consist of less than the average of two specimens. Compressive strength tests shall conform to the requirements of Table 601.3.1. Statistical analysis may indicate a percentage of production to be below nominal minimum design strength. Concrete represented by c ompressive strengths below the nominal minimum design strength of Table 601.3.1 may be removed and replaced by the Contractor. If the Contractor elects to leave the material in place, it will be evaluated as to adequacy for the use intended. All concrete evaluated as unsatisfactory for the use intended shall be removed and replaced or otherwise corrected by and at the expense of the Contractor as required in 105.3. When an evaluation indicates that the work may satisfactorily remain in place, a statistical analysis will be made of the material. If this statistical analysis indicates at least 93 percent (93%) of the material may be expected to have compressive strengths equal to or greater than that shown in Table 601.3.1 and 99.87 percent (99.87%) of the material may be expected to have compressive
324 strengths at least one standard deviation above forty percent of the design strength (0.4f'c+σ), the work will be accepted as substantially complying with the specification requirements. If this statistical an alysis indicates that less than 93 percent (93%) of the material may be expected to have compressive strengths equal to or greater than that shown in Table 601.3.1 or less than 99.87 percent (99.87%) of the material may be expected to have compressive strengths at least one standard deviation above forty percent (40%) of the design strength (0.4f' ’c+σ), the Engineer will provide for an appropriate adjustment under the provisions of
601.15
Whenever possible, the Division ’s statistical analysis will be ba sed on a minimum of 10 cylinder test results. These results may be from the concrete item being placed, the same class of concrete on the project, or the same class of concrete from the producer. All of the cylinder test results used in this evaluation, however, must be from the same mix design.
601.4.5 -Tests for Permeability Acceptance of Class H Concrete: The Contractor shall be required to compare the compressive strength test results obtained in Section 601.4.4, for Class H concrete, to the compre ssive strength of the approved test mix per Section 601.3. The Contractor shall also be required to fabricate six (6) rapid chloride permeability test specimens in accordance with AASHTO T 277 every time that a set of compressive strength specimens for C lass H concrete is fabricated. Chloride Permeability of the in -place concrete shall be considered acceptable if the 28 -day compressive strengths obtained in Section 601.4.4 are greater than eighty percent (80%) of the 28 -day compressive strength of the app roved test mix. Concrete represented by compressive strengths below eighty percent (80%) of the 28 -day compressive strength of the approved test mix may be removed and replaced by the Contractor. If the Contractor elects to leave the material in place, it will be evaluated as to adequacy for the use intended. All concrete evaluated as unsatisf actory for the use intended shall be removed and replaced or otherwise corrected by and at the expense of the Contractor as required in Section 105.3. The Contractor shall also be required to fabricate six rapid chloride permeability test specimens in ac cordance with AASHTO T 277 every time that a set of compressive strength specimens is fabricated. These test specimens shall be moist cured until as close to the time of test as possible. If the 28 -day compressive strength of the in -place concrete (obtai ned in Section 601.4.4) is less than or equal to eighty percent (80%) of the compressive strength of the approved test mix, these rapid chloride permeability test specimens shall be tested in accordance with AASHTO T 277, otherwise testing of these specime ns is not required. When testing of these specimens is required, two test specimens shall be tested at each of the following ages: 35, 56, and 90 days. These test results shall be used by the Engineer as the basis for evaluation as to the adequacy of the material for the use intended.
601.5 -EQUIPMENT AND TOOLS : 601.5.1 -Field Laboratory: Field laboratory provisions shall conform to the requirements prescribed in 501.5.1.
601.5.2 -Batching Plant and Equipment: 601.5.2.1 -General: The batching plant shall include bins, weigh hoppers, and scales for the fine aggregate and for each size of coarse aggregate. If cement is used in bulk, a separate bin, weight hopper, and scale for cement shall be included. The cement weight hopper sh all be properly sealed to preclude dusting during operation and shall be properly vented to prevent a build -up in pressure. The discharge chute shall not be suspended from
325 the weighing hopper and shall be so arranged that cement will not lodge in it nor l eak from it. When fly ash is used in the concrete a separate bin shall be included.
601.5.2.2 -Bins: Bins with adequate separate compartments for fine aggregate and for each size of coarse aggregate shall be provided in the batching plant.
601.5.2.3 -Scales: The scales for weighing aggregates and cement shall conform to the requirements in 109.1. Scales shall be inspected and sealed as often as the Engineer deems necessary to ensure their continued accuracy and as outlined in MP 700.00.30. The Contra ctor shall have on hand not less than ten (10) 50 lb. weights for frequent testing of all scales.
601.5.2.4 -Automatic Weighing Devices: Batching plants equipped to proportion aggregates and bulk cement by means of automatic weighing devices of an approved type may be used.
601.5.2.5 -Water Measuring Equipment: Water shall be measured by volume or by weight. The device for the measurement of the water shall be readily adjustable and, under all operating conditions, shall have an accuracy within one per cent (1%) of the quantity of water required for the batch.
601.5.2.6 -Admixture Dispenser: A positive, automatic method shall be used for adding each admixture in solution.
601.5.2.7 -Aggregate Sampling: Provisions shall be made to allow a rapid sampling of the aggregates as they pass from the storage bin to the weigh hopper or as they pass from the storage bin into the conveyor feed.
601.5.3 -Mixers and Agitators: Site and central mixers, truck mixers, truck agitators, and non-agitator trucks shall conform to the requirements of AASHTO M 157, except as modified. Volumetric mixers shall conform to the requirements of AASHTO M 241, except as modified. Central mixers shall be equipped with a device w hich will automatically lock the discharge lever when the drum has been charged and release it at the end of the mixing period. The device shall be equipped with a bell or other suitable warning device adjusted to give a clearly audible signal each time t he lock is released. In case of failure of the timing device, the mixer may be used for the balance of the day while it is being repaired, providing that each batch is mixed for the specified time period. All mixers shall be cleaned at suitable intervals. The pickup and throw -over blades in the drum or drums shall be repaired or replaced when they are worn down ¾ inch or more. The Contractor shall either have available at the job site a copy of the manufacturer's design, showing dimensions and arrangem ents of blades in reference to original height and depth, or provide permanent marks on blades to show points of ¾ inch wear from new conditions. Holes of ¼ inch diameter near each end and at midpoint of each blade are recommended.
326 601.5.4 -Recording T hermometer: The Contractor shall supply a continuous recording thermometer capable of recording temperatures in the 30 -150° F range. It shall likewise provide a recording capability over a 24 -hour continuous period, minimum. The Contractor shall provide a ny ancillary equipment, supplies and labor necessary for calibration of this equipment.
601.5.5 -Bridge Deck Placing and Finishing Equipment: This shall include adequate hand tools for the placement of plastic concrete and for working down to approximately the correct level for the auger strike -off. A self -propelled finishing machine will be required to place and finish all concrete, except in areas inaccessible to the machine. The finishing machine shall be capable of forward and reverse mo tion under positive control. Provisions shall be made for raising the screeds to clear the screeded surface, if traveling in reverse. The machine shall be capable of placing full width, in one operation, the pours shown in the plans. The finishing machine shall be equipped with a vibrating device to consolidate the concrete, a power -driven strike -off auger, a power -driven finishing roller, and a pan float. The vibrating device shall vibrate at a frequency between 50 Hz and 115 Hz. A suffic ient number of suitable portable lightweight or wheeled work bridges shall be required and used behind the finishing operation for touch -up work, surface texturing and curing cover placement. Approved manual type screeds, metal plates equipped with elect ric vibrators, or handheld vibrators shall be used to consolidate and finish small inaccessible areas. The placing and finishing equipment shall be designed so that the elapsed time requirements, specified in Section 601.12.4, between discharge of the co ncrete and application of the wet burlap will be met.
601.6 -HANDLING, MEASURING, AND BATCHING OF MATERIALS : Handling, measuring, and batching of materials for ready -mix co ncrete shall conform to the requirements specified in Subsection 501.7. Handling, measuring, and batching of materials for volumetric batching and continuous mixing shall conform to the applicable requirements specified in 501.7 and AASHTO M 241. When si lica fume densified powder is used, the densified powder shall be weighed using an approved cement scale or standard 25 lb. or 50 lb. full bags may be substituted. Batching tolerance for the cement plus densified powder shall be 1.0%. Batching and mixing recommendations for bulk and bagged densified silica fume are provided in the Silica Fume User’s Manual which is available through the Silica Fume Association (Report Number FHWA -IF-05-016). These recommendations include procedures to be used when the Ready -Mix Supplier desires to add silica fume, which is supplied in repulpable bags, into the mix. If these recommendations are followed, and the Ready -Mix Supplier can satisfactorily demonstrate to the Engineer, by means of testing and wet -sieving a t rial batch (see section 7.3.6 of the Silica Fume User’s Manual), that there are no fragments of the packaging material remaining in the mix, then the restriction in section 501.7, concerning the addition of the SCM packaging material, may be waived. The a bove referenced testing and wet -sieving of the trial batch shall be done on a plant -by- plant and mix -by-mix basis. When truck -mixed concrete is used, the truck which demonstrates the greatest degree of variability in the uniformity requirements, as specif ied in AASHTO M 157, shall be the truck which is used to produce the trial batch for testing and wet -sieving purposes. If the Ready -Mix Supplier intends to use this approach, it shall be addressed in the Plant portion of the Quality Control Plan.
327 601.7 -MIXING : Concrete may be central -mixed, truck -mixed, or shrink -mixed as defined in AASHTO M 157 and will be designated as ready -mixed concrete. The production of ready -mixed concrete shall meet the applicable requir ements of AASHTO M 157, paragraphs ten and eleven, except as otherwise specified. Concrete for incidental construction items may be made by volumetric batching and continuous mixing as designated in ASTM C685, except as otherwise specified. Concrete produced by this method will not be permitted in bridge, box culvert, pavement, or retaining wall construction. When a truck mixer or agitator is used for transporting concrete, the concrete shall be delivered to the site of work and discharge completed withi n one and one -half hours after the addition of the cement to the aggregates. Each batch of the concrete delivered at the job site shall be accompanied by a batch ticket that contains complete batching information, including the batch weights (or batch vol ume, in the case of water) of all materials in that batch of concrete. In adverse weather or under other conditions contributing to quick stiffening of the concrete, or when the temperature of the concrete is 85°F or above, the time between the introducti on of the cement to the aggregates and the discharge shall not exceed one hour. When a truck mixer is used for the complete mixing of the concrete, the mixing operation shall begin within one hour after the cement has been added to the aggregate. When placing concrete at remote locations, due to excessive haul time to the site of work from the closest approved batch plant, and when discharge of the concrete within the time limits specified in the previous paragraph is not possible, or in other circ umstances when approved by the Engineer, a concrete mix that includes a hydration control stabilizing admixture may be used to extend the allowable concrete discharge time. The subject concrete mix containing this admixture must be approved in accordance with section 601.3.1, and the hydration control stabilizing admixture must be approved in accordance with section 707.15. When conditions are such that a hydration control stabilizing admixture is used, the allowable time between the introduction of the c ement to the aggregates and discharge of the concrete shall be increased to three hours. The limit of 300 maximum revolutions (pertaining to truck mixers or agitators) specified in AASHTO M 157 may be waived when hydration control stabilizing admixtures a re used, provided that no additional water is added prior to discharge of the concrete. A single batch of concrete containing a hydration control stabilizing admixture may not be discharged on more than one project. When a mix, containing a hydration control stabilizing admixture is used, and that mix has been approved for the three -hour discharge time, the reduced discharge time required when concrete temperatures are 85°F or above, and specified in the third paragra ph of this sub - section, shall not apply, provided that the concrete supplier has adjusted the hydration control stabilizing admixture dosage rate to account for that higher concrete temperature. The addition of water after completion of initial mixing wi ll not be permitted, except that when concrete is delivered in truck mixers, additional water may be added to adjust to a specified consistency. In this event, a minimum of 20 additional revolutions of the truck mixer drum at mixing speed shall be required before discharge of any concrete; the maximum allowable time between the addition of the cement to the aggregates and the discharge of the batch shall not be exceeded. Concrete that is not within the specified consistency limits at the time of placements hall not be used. When superplasticizer is used to adjust the consistency of a mix at the job site, as outlined in Section 601.3.2.1, water may still be used to adjust the consistency of the mix prior to the job site addition of superplasticizer, but no ad ditional consistency adjustment of that mix with water shall be permitted after the job site addition of superplasticizer. The additional consistency
328 testing required in Section 601.3.2.1 applies each time that superplasticizer is added at the job site. When superplasticizer is used to adjust the consistency of a mix at the batch plant, but not at the job site, as outlined in Section 601.3.2.1, additional consistency adjustment of that mix with water at the job site shall still be permitted. For all cl asses of concrete except Class H and concrete for specialized overlays, the total amount of water in a concrete mix, including any water added at the job site, shall not be more than the amount which would cause the water -cement ratio (w/c) of that concret e mix to exceed the w/c which corresponds to the Mix Design Approved Strength, as outlined in Section 5.4 of MP 711.03.23. The maximum water amount shall also be shown in Attachment 4 or 5 of MP 711.03.23 for all approved concrete mix designs. However, u nder no circumstances shall the w/c in Table 601.3.1A be exceeded. Shrink -mixed concrete is a ready -mixed concrete which is initially and partially mixed in a central mix plant and lastly mixed to completion in a truck mixer while in transit to or after arrival at the job site. Shrink -mixed concrete will be allowed for use in the work if specified in the Contract.
601.8 -FORMS : 601.8.1 -General: Forms shall be of wood, metal or other approved material and shall be mortar tight and sufficiently rigid to prevent distortion due to pressure of the concrete and other loads incidental to the construction operations including vibration. Wood forms shall be constructed and maintained so as to prevent the opening of joints due to shrinkage of the lumber. All falsework shall be designed and constructed to provide the necessary rigidity and to support the loads without appreciable settlement or deformation. Suitable jacks, wedges or other approved devices shall be used to maintain the forms at correct elevation and to permit lowering the centers gradually and uniformly without injury to the structure. Deck slab overhang forms shall be supported from the bottom flange of fascia girders or stringers. The Contractor shalls ubmit forming plans and supporting calculations for the overhang to the Engineer for approval prior to erecting the formwork. A "Telltale" or other approved type of indicator shall be attached to the forms and arranged in such a manner that any settlemen t or movement in the forms or falsework is indicated. Forms shall be filleted and chamfered as shown on the Plans and shall be given a bevel or draft in the case of all projections to assure easy removal. All field welding shall be performed by a certif ied welder. Welding of form ties and supports to the beam will not be permitted. Welding of screed rail supports will not be permitted in the top flange in tension zone.
601.8.2 -Form Lumber: Form lumber for all exposed concrete surfaces shall be dres sed at least on one side and two edges.
601.8.3 -Metal Ties: Metal ties or anchorages within the forms shall be constructed to permit their removal to a depth of at least one ( 1) inch from the face without injury to the concrete. Only rods shall be used for internal ties. The cavities shall be filled with cement mortar and the surface left sound, smooth, even, and uniform in color.
601.8.4 -Cleanouts: Where the bottom of the form is inaccessible, the lower form area shall be left loose or other provisions made so that extraneous material may be removed from the forms immediately before placing the concrete.
329 601.8.5 -Surface Treatment: Forms shall be treated with oil in such manner as to prevent contamination of reinforcing steel. Oil which will adhere to or discolor the concrete shall not be used.
601.8.6 -Metal Forms: The metal used for the forms shall be of such thickness that the forms will re main true to shape. All bolts and rivet heads shall be countersunk. Clamps, pins, and other connecting devices shall be designed to hold the forms rigidly together and to allow removal without injury to the concrete. Metal forms which do not present a s mooth surface or do not line up properly shall not be used. Metal forms shall be kept free of rust, grease, or other foreign matter.
601.8.7 -Removal of Forms and Construction of Superimposed Elements: The forms for any portion of the structure shall n ot be removed until the concrete is strong enough to prevent damage. Methods of form removal likely to cause overstressing of the concrete shall not be used. The minimum requirements for removal of forms or supports and the construction of superimposed elements shall be as specified in Table 601.8.7. Due to continuity of reinforcement between placements and other issues, adjacent bridge deck placements shall be considered superimposed elements and must meet the minimum strength requirement in Table 601.8.7 before an adjacent placement in the sequence may be placed. In lieu of field cured cylinders for the determination of compressive strength required for from removal and construction of superimposed elements, the Contractor may use the Matur ity Method for the estimation of concrete strength as outlined in MP 601.04.21.
TABLE 601.8.7 Requirements for Removal of Forms and Construction of Superimposed Elements Structural Element Removal of Forms Placing Concrete In Superimposed Elements Compressive Strength -psi Compressive Strength -psi Bridge Decks 2000 3000 Columns 2000 2000 Walls & Beams 2000 2000 Footings 500 2000 Components Supported By Falsework 3000 3000 Parapets 2000 (See 601.11) -------------
601.8.8 -Slip Forming: Slip forming and related methods of placing concrete may be used. At the Contractor's option, parapet wall joints and median barrier on the bridge may be sawed in lieu of formed open joints and the joints shall be spaced as shown on the Plans and shall be 1/4 inch 1/16 inch wide. Joints shall be sawed full width from the top of the wall to the upper break point in the wall. From the upper break point to the bottom of the wall a two ( 2) inches minimum depth saw cut shall be made along the face and bac k of the wall. Joints shall be sealed in accordance with Section 501.16.1. The face of the back -up material shall be ½ inch minimum from the concrete surface.
330 Initial sawing of joints shall commence as soon as the concrete has hardened sufficiently to permit sawing without excess raveling, usually 4 to 24 hours. All joints shall be initially sawed before uncontrolled shrinkage cracking takes place, but no later than 24 hours after placement of concrete.
601.8.9 -Stay-in-Place Fabricated Metal Forms f or Concrete Bridge Decks: All concrete bridge decks shall be constructed with a stay -in-place fabricated metal forming system per the requirements shown in this specification unless otherwise noted in the plans.
601.8.9.1 -General: Stay-in-place fabricated metal forms for concrete deck slabs of bridges shall be used on all interior bays of beams. For overhangs and where longitudinal expansion joints are located between stringers removable forms shall be used. The design and material of the forms, in the judgment of the Engineer, shall be such as to give an expected maintenance free service life equal to the service life of the concrete slab. The stay - in-place fabricated metal forms shall be crimped at each end. Unless otherwise spe cified in the plans, the weight of stay -in-place fabricated metal forms plus concrete in the form flutes used in the design is 15 psf. The contractor shall submit revised computations if the proposed forming system is heavier than 15 psf. The cost of the revised computations shall be at no additional cost to the Division.
601.8.9.2 -Material: Stay-in-place fabricated metal forms for concrete decks slabs and exposed material for supports shall be zinc -coated (galvanized) steel sheet conforming to ASTM A6 53, Designation SS, Grades 33 through 80, with a G165 Coating Designation. The stay -in-place fabricated metal forms shall be designed on the basis of dead load of the forms, reinforcement, and the plastic concrete plus 50 psf for construction loads. Unit working stresses shall be in accordance with the AASHTO LRFD Bridge Design Specifications for construction loads and the unit stress in the steel sheet shall be not more than 0.725 of the specified minimum yield strength of the material furnished but not to exceed 36,000 psi. Maximum deflection under weight of plastic concrete, reinforcement and form shall not exceed 1/180 of the form span or ½ inches , whichever is less. Maximum deflection under 60 psf of live loads shall not exceed 1/360 of the form spa n or ¼ inches , whichever is less. The form span for design and deflection shall be the clear distance between the flanges of the supporting beams less two ( 2) inches, measured parallel to the form flutes. All stay -in-place fabricated metal forms shall ha ve a minimum thickness of 22 gage. Physical design properties shall be computed in accordance with requirements of American Iron and Steel Institute Specification for the Design of Cold -Formed Steel Structural members, latest published edition. All reinf orcing bars in the bottom layer of the deck slab reinforcement shall have a minimum concrete cover of 1”. The distance from the top of the slab to the bottom layer of deck slab reinforcement shall not be less than that shown on the plans.
601.8.9.3 -Installation: All forms shall be installed in accordance with detailed fabrication plans submitted to the Engineer for approval. The fabrication plans shall clearly indicate locations where the forms are supported by steel beam flanges. Forms heets shall not be permitted to rest directly on the top of the stringer or floor beam flanges. Sheets shall be securely fastened to form supports and shall have a minimum bearing length of 1” at each end. Form supports shall be placed in direct contact with the flange of