Section 346 portland cement concrete 346 1 Description




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SECTION 346

PORTLAND CEMENT CONCRETE

346 1 Description.

Use concrete composed of a mixture of portland cement, aggregate, water, and, where specified, admixtures and pozzolan. Deliver the portland cement concrete to the site of placement in a freshly mixed, unhardened state.

Meet the production and quality control of concrete provisions of this Section and the Florida Department of Transportation Standard Operating Procedures.
346 2 Materials.

346 2.1 General: Meet the following requirements:

Coarse Aggregate Section 901

Fine Aggregate* Section 902

Portland Cement Section 921

Water Section 923

Admixtures Section 924

Fly Ash, Slag** and Microsilica (Pozzolanic Materials) Section 929

*The Engineer will allow only silica sand except as provided in 902 5.2.3.

**The Engineer will allow only granulated blast furnace slag.

Use the materials containing no hardened lumps, crusts or frozen matter, and that are not contaminated with dissimilar material.



346 2.2 Types of Cement: Unless a specific type of cement is designated elsewhere, use Type I, Type IP, Type IS, Type IP(MS), Type II, or Type III cement in all classes of concrete.

Use only the types of cements designated for each environmental condition in structural concrete.



TABLE 1

BRIDGE SUPERSTRUCTURES

Component


Slightly Aggressive Environment


Moderately Aggressive Environment


Extremely Aggressive Environment


Precast Superstructure and Prestressed Elements


Type I, Type II, Type III, Type IP, Type IS, or Type IP (MS)


Type I, Type II, and Type III all with Fly Ash or Slag; Type IP, Type IS, or Type IP(MS)


Type II with Fly Ash or Type II with Slag


C.I.P. Superstructure Slabs and Barriers


Type I, Type II, Type IP, Type IS, or Type IP(MS)


Type I with Fly Ash or Slag, Type II, Type IP, Type IS, or Type IP(MS)


Type II with Fly Ash or Type II with Slag


BRIDGE SUBSTRUCTURE, DRAINAGE STRUCTURES AND OTHER STRUCTURES


Component


Slightly Aggressive Environment


Moderately Aggressive Environment


Extremely Aggressive Environment


All Structure Components


Type I, Type II, Type III, Type IP, Type IS, or Type IP (MS)


Type I with Fly Ash or Slag, Type II, Type IP, Type IP(MS), or Type IS


Type II with Fly Ash or Type II with Slag




346 2.3 Use of Fly Ash, Slag, Microsilica, and Other Pozzolanic Materials: The Contractor may use fly ash, slag, microsilica and other pozzolanic materials as a cement replacement in all classes of concrete (when Type I, Type II, or Type III cement is used) with the following limitations:

(1) When fly ash, slag or microsilica is used as a cement replacement, use it on a pound per pound [kilogram per kilogram] basis. Calculate cement replacement as shown in the example.

Example   Assume a total cementitious content of 752 pounds [341 kg]. Calculate the required microsilica for a 7.6% replacement as 752 by .076 = 57 pounds [341 by .076 = 26 kg]. Calculate the required fly ash for a 20% replacement as 752 by 0.20 = 151 pounds [341 by 0.20 = 68 kg]. Cement required is 544 pounds [247 kg].

(2) Ensure that the quantity of cementitious material replaced with fly ash in mass concrete is greater than 18% and less than 50% by weight of the total cementitious content. The minimum cementitious content for each class of concrete is shown in the Master Proportion Table (Table 3).

(3) Ensure that the quantity of cementitious material replaced with fly ash in drilled shaft concrete is 35  2% by weight of the total cementitious content.

(4) For all other concrete uses not covered in (2) and (3) above, ensure that the quantity of cementitious material replaced with fly ash is greater than 18% and less than 22% by weight of the total cementitious content.

(5) Ensure that the pozzolan constituent of Type IP(MS) is in the range of 15 to 40% by weight of the portland pozzolan cementitious material.

(6) Obtain the Engineer's approval to use pozzolanic materials other than Class F fly ash.

(7) Ensure that the quantity of cementitious material replaced with slag in drilled shaft concrete is 60  2% by weight of the total cementitious content.

(8) For all other concrete uses not covered in (7) above, ensure that the quantity of cementitious material replaced with slag is not less than 25% or greater than 70% of the total cementitious content when used in Slightly and Moderately Aggressive environments, and not less than 50% or greater than 70% of the total cementitious content when used in Extremely Aggressive environments. When used in combination with microsilica, ensure that the slag does not replace less than 50% or more than 55% of the total cementitious content.

(9) Ensure that the quantity of cementitious material replaced with microsilica is not less than 7% or greater than 9%. Use high range water reducing admixtures in concrete mixes incorporating microsilica.

346 2.4 Coarse Aggregate Gradation: Produce all concrete using Size No. 57 or Size No. 67 coarse aggregate except as follows:

(1) With the Engineer's approval, the Contractor may use Size No. 8 or Size No. 89 either alone or blended with Size No. 57 or Size No. 67 for concrete construction that is heavily reinforced or for barrier wall or curb construction using slip forms.

(2) The Engineer may approve other gradations of aggregates. The Engineer will consider requests for approval of other gradations individually and will require the Contractor to submit sufficient statistical data to establish production quality and uniformity of the subject aggregates, and to establish the quality and uniformity of the resultant concrete. Furnish aggregate gradations sized larger than nominal maximum size of 1.5 inch [37.5 mm] as two components.

(3) Select the maximum coarse aggregate size so as not to violate the reinforcement spacing provisions given for reinforced concrete in the AASHTO Standard Specifications for Highway Bridges.



346 2.5 Admixture Requirements:

346 2.5.1 Chemical Admixtures: Use concrete containing a water reducing admixture (Type A) or water reducing and retarding admixture (Type D). Use a dosage rate that is generally in accordance with the manufacturer's recommended dosage rate. When necessary, adjust the dosage rate.

The Engineer may approve the use of other admixtures. The Engineer will require the Contractor to submit statistical evidence supporting successful laboratory and field trial mixes which demonstrate improved concrete quality or handling characteristics.

The Engineer will not allow chemical admixtures or additives containing calcium chloride (either in the raw materials or introduced during the manufacturing process) in reinforced concrete.

346 2.5.2 Air Entrainment Admixtures: Ensure that all concrete except counterweight concrete contains an air entraining admixture. Establish dosage rates by trial mixes, and adjust them to meet field conditions.

346 2.5.3 High Range Water Reducing Admixtures: Use high range water reducing admixtures in concrete mixes incorporating microsilica. The Contractor may propose the use of an approved High Range Water Reducer (HRWR) admixture, either Type F or Type G. In a proposal to use HRWR for precast items, include a list of precast items for which it is proposed. The Contractor may also propose the use of HRWR for cast in place concrete, except for concrete used in drilled shafts. In a proposal to use HRWR for cast in place items, include a detailed listing of the areas, locations, elements, etc. for which its use is proposed and the anticipated benefits to be derived from the use of HRWR in each instance.

Perform all testing for plastic concrete properties after the HRWR has been added to the concrete mix.

The Department will not consider Value Engineering credits or other price adjustments for proposals to utilize HRWR in order to reduce the specified minimum cementitious requirements for the various classes of concrete.

In a proposal to use HRWR in concrete, include the following:

A certification from the HRWR supplier that the HRWR admixture proposed meets the requirements of ASTM C 494, Type F or G. Ensure that the certificate states that the one year tests representing the admixture to be supplied have been performed by an independent laboratory approved by the Cement and Concrete Reference Laboratory (CCRL) and that the records of such tests will be furnished to the Department on request. Ensure that the certification also includes an additional statement from the HRWR supplier or an approved independent testing laboratory that the proposed HRWR admixture is compatible with all other admixtures to be included in the concrete design mix.

When a HRWR admixture is proposed for use in the design mix, propose a target slump value. Ensure that the target slump does not exceed 7 inches [180 mm]. Meet the other control requirements and ranges as specified herein.

Include with the confirming data all details of the design mix ingredients, all required certificates from the supplier and independent testing laboratory, and a certificate from the Witnessing Department Engineer. Ensure that the certificate states that the Contractor has demonstrated through production and placement of the required number of batches that concrete containing HRWR has been produced meeting all test requirements, that the HRWR concrete has been satisfactorily mixed in accordance with the Contractor's proposed methods and sequences, and that the concrete was acceptably placed, consolidated and cured.

Before the Engineer approves any design mix, demonstrate through production of at least three batches (3 yd3 [2.3 m3] minimum size each) of concrete containing the HRWR that the concrete plant can produce concrete consistently meeting specified slump, air content, and compressive strength requirements. Also demonstrate to the Witnessing Department Engineer that the concrete containing the HRWR admixture in accordance with the proposed design mixes can be placed, consolidated and finished under conditions existing for the proposed uses. Obtain the Engineer's approval before using HRWR concrete design mixes.

The Engineer may approve proposed HRWR mixes for concrete, centrally mixed at the placement site, without the production of demonstration batches providing you meet the requirements of 346 6.2, and:

(1) A previously approved HRWR mix of the same class has demonstrated satisfactory performance under the proposed job placing conditions with a minimum of 15 consecutive Department acceptance tests which met all plastic and hardened concrete test requirements.

(2) The cement and water reducing admixtures used in the proposed mix are the same materials from the same source used in the previously approved mix (Item (1) above), and the other materials and mix proportions are approved as similar by the Engineer.

Dispose of concrete produced for demonstration purposes at no expense to the Department. Subject to the Engineer's approval, the Contractor may incorporate this concrete into unreinforced concrete items.

Include with each design mix a description of methods, sequences, times and places that the HRWR will be introduced into the concrete mix for each proposed use. Adjust methods, sequences, times and places for introduction of the HRWR to suit the requirements for each proposed use and condition. The Contractor may transfer design mixes including a HRWR based on demonstrated ability of the mix to perform its intended function.

The Engineer will consider design mixes submitted for approval upon receiving certification from the Witnessing Department Engineer that the Contractor has demonstrated the ability to produce concrete containing a HRWR admixture in accordance with the proposed design mixes, meeting minimum strength requirements within specified ranges for slump and air, and which can be placed, consolidated and finished under conditions existing for the proposed uses. In addition, the Witnessing Department Engineer will include in the certification the test values of the slump, air and 28 day strength tests for all demonstration batches of concrete, and an evaluation and description of the Contractor's actual sequences, methods and time required for the placement and consolidation of each batch of concrete. Also include in the certification, the Witnessing Department Engineer's evaluation of the appearance, apparent consolidation and finish texture after form removal of each item cast.

Except for casting unreinforced concrete items as approved by the Engineer, do not produce or place demonstration concrete containing a HRWR admixture for payment under Contract pay items until design mixes containing the HRWR have been approved. To qualify for payment under Contract pay items, ensure that unreinforced demonstration concrete, cast with the approval of the Engineer, meets minimum strength and entrained air requirements contained in these Specifications, and that the slump is within 1.5 inch [40 mm] of the target slump proposed by the Contractor.

346 2.5.4 Corrosion Inhibitor Admixture: Ensure that concrete containing a corrosion inhibitor admixture also contains cementitious materials consisting of Type II cement and Class F fly ash. The Contractor may use ground granulated blast furnace slag in lieu of fly ash.

Ensure that concrete containing a corrosion inhibitor admixture also contains a water reducing retardant admixture (Type D). The Contractor may also need to use a high range water reducer Type F (or Type G) to provide the required workability and to normalize the setting time of concrete. Ensure that all admixtures are compatible with the corrosion inhibitor admixture.



346 2.6 Mixing Different Coarse Aggregates: The Engineer may allow the substitution of coarse aggregate of the same type from a different source in an approved concrete mix when the aggregate to be substituted is also from an approved source and has similar physical and chemical properties. If unsatisfactory results are obtained with the different source aggregate, return to the aggregate from the originally approved aggregate source of supply.
346 3 Classification, Strength, Slump, and Air Content.

346 3.1 General: The separate classifications of concrete covered by this Section are designated as Class I, Class II, Class III, Class IV, Class V, and Class VI. Strength, slump, and air content of each class are specified in the following (Table 2):

TABLE 2

Class of Concrete

Specified Minimum Strength (28 day) (psi) [(MPa)]


Target Slump (inches) [(mm)](d)


Air Content Range (%)


STRUCTURAL CONCRETE


I (Pavement) (b)


3,000 [21]


2 [50]

1 to 6

I (Special) (a)


3,000 [21]


3 [75]

1 to 6

II (a)

3,400 [23]

3 [75] (c)


1 to 6

II (Bridge Deck)

4,500 [31]


3 [75] (c)


1 to 6

III

5,000 [35]


3 [75] (c)


1 to 6

III (Seal)

3,000 [21]


8 [200]

1 to 6

IV

5,500 [38]

3 [75] (c)


1 to 6

IV (Drilled Shaft)

4,000 [28]


8 [200]

0 to 6

V (Special)


6,000 [41]


3 [75] (c) (e)


1 to 5

V

6,500 [45]


3 [75] (c)


1 to 5

VI

8,500 [59]


3 [75] (c)


1 to 5

(a) The Contractor may use concrete meeting the requirements of ASTM C 478 (4,000 psi) [ASTM C 478M (30 MPa)] in lieu of Class I or Class II concrete in precast items manufactured in plants which meet the Department's Standard Operating Procedures for Precast Drainage products. Apply the chloride content limits specified in 346 4.2 to all precast or cast in place box culverts.

(b) Ensure that consistency of the concrete is such that the edges of the pavement surface consistently meet the surface requirements in Section 350.

(c) The Engineer may allow higher target slump, not to exceed 7 inches [180 mm], when a high range water reducer is used.

(d) The Engineer may approve a reduction in the target slump for slipformed or prestressed elements.

(e) When the use of microsilica is required as a pozzolan in Class V (Special) concrete, ensure that the concrete does not exceed a permeability of 1,000 coulombs at 28 days when tested per AASHTO T 277. Submit 2, 4-inch [102 mm] diameter by 8 inch [203 mm] length cylindrical test specimens to the Engineer for permeability testing prior to mix design approval. The permeability of the concrete will be taken as the average of two tests. The Engineer may require permeability tests during production.

346 3.2 Drilled Shaft Concrete: When drilled shaft concrete is specified or required in the Contract Documents and is to be placed in any wet shaft, provide concrete in accordance with the following specified slump loss requirements. When concrete is placed in a dry excavation, do not test for slump loss, except where a temporary removable casing is required.

Ensure that drilled shaft concrete has a slump between 7 inches and 9 inches [180 mm and 230 mm] when placed and maintains a slump of 4 inches [100 mm] or more throughout the drilled shaft concrete elapsed time. Ensure that the slump loss is gradual as evidenced by slump loss tests described below. The concrete elapsed time is the sum of the mixing and transit time, the placement time and the time required for removal of any temporary casing that causes or could cause the concrete to flow into the space previously occupied by the temporary casing.

Provide slump loss tests before drilled shaft concrete operations begin, demonstrating that the drilled shaft concrete maintains a slump of at least 4 inches [100 mm] throughout the concrete elapsed time. Inform the Engineer at least 48 hours prior to performing such tests in order to allow arrangements to be made for a Department representative to witness the mixing and testing required. Perform slump loss testing of the drilled shaft mix using a laboratory acceptable to the Engineer. Use a laboratory that (1) has been inspected by the CCRL on a regular basis, with all deficiencies corrected, and under the supervision of a Specialty Engineer, or (2) meets all the requirements of ASTM C 1077.

Perform the following procedures for slump loss tests:

(1) Perform a test for time of setting of concrete mixtures by penetration resistance (FM 1 T 197).

(2) Prepare the mix for the slump loss test at a temperature consistent with the highest ambient and concrete temperatures expected during actual concrete placement. Obtain the Engineer's approval of the test temperature.

(3) Ensure that the mix is at least 3 yd3 [2.3 m3] and is mixed in a mixer truck.

(4) After initial mixing, determine the slump, concrete temperature, ambient temperature and air content. Ensure that the concrete properties are within the required specification limits. Initiate the time of setting test (FM 1 T 197) at this time.

(5) Mix the concrete intermittently for 30 seconds every five minutes at the mixing speed of the mixer.

(6) Determine slump, concrete temperature, ambient temperature and air content at 30 minute intervals until the slump is 2 inches [50 mm] or less. Remix the mix for one minute at the mixing speed of the mixer before these tests are run.

(7) Begin all elapsed times when water is initially introduced into the mix.

(8) Ensure that the concrete maintains a slump of at least 4 inches [100 mm] for the anticipated elapsed time.

(9) Obtain the Engineer's approval of slump loss test results in terms of elapsed time prior to concrete placements.

346 3.3 Mass Concrete: When mass concrete is designated in the Contract Documents, provide an analysis of the anticipated thermal developments in the mass concrete elements for all expected project temperature ranges using the proposed mix design, casting procedures, and materials. Additionally, describe the measures and procedures intended for use to maintain a temperature differential of 35F [20C] or less between the interior and exterior portions of the designated mass concrete elements during curing. Submit both the mass concrete mix design and the proposed plan to monitor and control the temperature differential concurrently to the Engineer for approval a minimum of ten working days prior to concrete placement. Provide temperature monitoring devices approved by the Engineer to record temperature development between the interior and exterior portions of the elements at points approved by the Engineer. Read the monitoring devices and record the readings at not greater than 6 hour intervals, as approved by the Engineer, beginning when casting is complete and continuing until the maximum temperature differential is reached and begins dropping. If monitoring indicates the 35F [20C] differential has been exceeded, take immediate action to retard further growth in the temperature differential and make the necessary revisions to the approved plan to maintain the 35F [20C] or less differential on any remaining placements. Obtain the Engineer's approval of revisions to the approved plan prior to implementation.

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