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90-4.02 MATERIALS


You may use Type III portland cement in PC concrete.

The specifications for SCM content in section 90-1.02B(3) do not apply to PC concrete.

For PC concrete, the SCM content must comply with one of the following:

1. Any combination of portland cement and SCM satisfying the following equation:


Equation 1:
[(25 x UF) + (12 x FA) + (10 x FB) + (6 x SL)]/TCX
where:

UF = silica fume, metakaolin, or UFFA, including the quantity in blended cement, lb/cu yd

FA = natural pozzolan or fly ash complying with AASHTO M 295, Class F or N, with a CaO content of up to 10 percent, including the quantity in blended cement, lb/cu yd

FB = natural pozzolan or fly ash complying with AASHTO M 295, Class F or N, with a CaO content of greater than 10 percent and up to 15 percent, including the quantity in blended cement, lb/cu yd

SL = GGBFS, including the quantity in blended cement, lb/cu yd

TC = total quantity of cementitious material, lb/cu yd

X = 0.0 for innocuous aggregate, 3.0 for all other aggregate
2. 15 percent Class F fly ash with at least 48 oz of LiNO3 solution added per 100 lb of portland cement. The CaO content of the fly ash must not exceed 15 percent.

3. Any combination of SCM and portland cement for which the expansion of cementitious material and aggregate does not exceed 0.10 percent when tested under ASTM C1567. Submit test data with each mix design. Test data authorized by the Department no more than 3 years before the 1st day of the Contract is authorized for the entire Contract. The test data must be for the same concrete mix and must use the same materials and material sources to be used on the Contract.


If municipally supplied potable water is used for PC concrete, the testing specified in section 90-1.02D is waived unless requested.

Portland cement based repair material must be on the Authorized Material List for precast Portland cement based repair material.


90-4.03 CONSTRUCTION


Cure PC concrete using steam curing or any of the methods specified in section 90-1.03B. Cure for the minimum time specified for each method or until the concrete reaches its design strength, whichever is less.

Steam curing must comply with the following:

1. After placing the concrete, hold it for a 4-hour minimum presteaming period. If the ambient air temperature is below 50 degrees F, apply steam during the presteaming period to hold the air surrounding the concrete at a temperature of 50 to 90 degrees F.

2. To prevent moisture loss on the exposed surfaces during the presteaming period, cover the concrete as soon as possible after casting or keep the exposed surfaces wet by fog spray, curing compound, or wet blankets.

3. Enclosures for steam curing must allow free circulation of steam around the concrete and must be constructed to contain the live steam with a minimum moisture loss. The use of tarpaulins or similar flexible covers is allowed if they are kept in good repair and secured in such a way that prevents the loss of steam and moisture.

4. Steam at the jets must be at low pressure and in a saturated condition. Steam jets must not impinge directly on the concrete, test cylinders, or forms. During application of the steam, the temperature rise within the enclosure must not exceed 40 degrees F per hour. The curing temperature throughout the enclosure must not exceed 150 degrees F and must be maintained at a constant level for the time necessary to develop the required transfer strength. Cover control cylinders to prevent moisture loss and place them in a location where the temperature is representative of the average enclosure temperature.

5. Use a minimum of 1 temperature recording device per 200 feet of continuous bed length for checking the temperature. Temperature recording devices must provide an accurate, continuous, permanent record of the curing temperature.

6. Detension the concrete in pretension beds immediately after the steam curing is completed while the concrete and forms are still warm, or maintain the temperature under the enclosure above 60 degrees F until the stress is transferred to the concrete.

7. Curing is complete at the end of the steam curing cycle.
For dimensional tolerances of PC concrete members, comply with the Precast/Prestressed Concrete Institute's Tolerance Manual for Precast and Prestressed Concrete Construction, MNL 135-00.

For tier 1 and tier 2 PC concrete members, apply curing compound using power-operated spraying equipment. You may request application by hand spraying for small quantities of PC concrete members. For tier 3 and tier 4 PC concrete members, the application of curing compound may be hand sprayed.


90-4.04 PAYMENT


Not Used

90-5 SELF-CONSOLIDATING CONCRETE


90-5.01 GENERAL

90-5.01A Summary


Section 90-5 includes specifications for furnishing SCC.

Section 90-5 applies only where the specifications allow the use of SCC.

You may use SCC for PC concrete.

90-5.01B Definitions


self-consolidating concrete (SCC): Flowing concrete that is capable of spreading to a level state without segregation and without the use of internal or external vibrators.

90-5.01C Submittals


Submit the following before placing SCC:

1. Mix design and placement procedures.

2. Trial batch test report, including test results for the tests specified in section 90-5.01D(2)(c).

3. If a mock-up is specified:

3.1. Details and placement procedures for the mock-up

3.2. Test samples and test results from the mock-up


Submit test results for slump flow and visual stability index.

If the Engineer rejects the SCC for slump flow and visual stability index, make corrective changes and resubmit the SCC mix design or placement procedures.

Submit the aggregate gradation as an informational submittal.

90-5.01D Quality Assurance

90-5.01D(1) General


Reserved

90-5.01D(2) Quality Control

90-5.01D(2)(a) General

Reserved
90-5.01D(2)(b) Compressive Strength

Prepare SCC specimens for compressive strength testing under California Test 540, except fabricate test specimens as follows:

1. Place the test molds on a firm, flat surface to prevent distortion of the bottom surface.

2. If more than 1 specimen is to be made from the same batch, make all the specimens simultaneously.

3. Fill the mold in 1 lift, pouring the concrete from a larger container.

4. Pat the sides of the mold lightly by hand or jig by rocking the mold from side to side.

5. Strike off the surface of the concrete even with the top edge of the mold.

6. Wipe the sides of the mold free of excess concrete and press the lid on.

90-5.01D(2)(c) Prequalification of Mix Design

Prequalify the SCC mix design with a trial batch using the same materials, mix proportions, mixing equipment, procedures, and batch size to be used in SCC production.

The SCC trial batch must comply with the requirements for the quality characteristics shown in the following table:



SCC Mix Design Requirements

Quality characteristic

Test method

Requirement

Slump flow (min, inches)

ASTM C1611

20

Flow rate, T50 (seconds)

ASTM C1611

2–7

Visual stability index (max)

ASTM C1611

1

J-Ring flowa (max, inches)

ASTM C1621

2

Column segregation, static (max, %)

ASTM C1610

15

Bleeding capacity (max, %)

ASTM C232

2.5

Compressive strengthb,c (min, psi)

California Test 521

strength described

Compressive strengthc (min, psi, average of 5 cylinders)

California Test 521

≥ 600 + strength described

aDifference between J-ring flow and slump flow

bFor an individual test cylinder

cAt the maximum age specified or allowed


90-5.01D(2)(d) Mock-up

If the construction of a mock-up is specified in the special provisions, construct a mock-up before placing the SCC.

The mock-up must demonstrate that the SCC will:

1. Flow for the distance required by the proposed construction procedure

2. Completely fill the forms

3. Encapsulate the reinforcement and embedments
Prequalify the SCC mix design before constructing the mock-up.

The mock-up forms must be similar to those used for the production elements. Include in the mock-up the concrete, reinforcement, and concrete embedments shown, except the reinforcement and embedments must stop 12 inches from both longitudinal ends of the mock-up.

The mock-up must simulate the flow of concrete for the maximum distance anticipated during production or for a minimum of 10 feet if the anticipated flow travel is less than 10 feet.

Place the SCC in the mock-up in the Engineer's presence.

Take a test sample of at least 100 lb of concrete from within the forms at the discharge point and at the point farthest from the discharge point. Determine the coarse aggregate content of each test sample under California Test 529. The coarse aggregate content of the test samples must not differ from each other by more than 8 pounds of aggregate per cubic foot of concrete.

Saw-cut the mock-up full-depth in the transverse direction approximately 2 feet from the end of the pour. Voids or honeycombing in the SCC or between the concrete and embedded elements are not acceptable.

If the Engineer rejects the SCC placed in the mock-up, construct additional mock-ups until the SCC is accepted by the Engineer.

Dispose of the mock-up.


90-5.01D(2)(e) Field Quality Control
90-5.01D(2)(e)(i) General

Reserved
90-5.01D(2)(e)(ii) Fine Aggregate Moisture Content

Determine the fine aggregate moisture content for each batch of SCC.
90-5.01D(2)(e)(iii) Slump Flow and Visual Stability Index

At the start of SCC placement and whenever a set of concrete cylinders is prepared, determine the slump flow and the visual stability index under ASTM C1611.

90-5.01D(3) Department Acceptance


Reserved


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