18-Attachment C - Technical Specifications.pdf

Hillsborough County Solid Waste Management Department Geosyntec Consultants Northwest Transfer Station Community Collection Center Section 03300: Cast-In-Place Concrete

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SECTION 03300

CAST-IN-PLACE CONCRETE

PART 1 GENERAL

1.01 SCOPE OF WORK

A. CONTRACTOR shall furnish all labor, materials, tools, supervision, transportation, and installation equipment necessary for the design, manufacture, storage, delivery, and installation of all cast-in-place concrete work, including high-early strength concrete, as specified herein, and as shown on the Drawings.

B. CONTRACTOR shall coordinate the installation of all cast-in-place concrete with other construction activities and subcontractors at the Site.

C. All Work shall be performed in accordance with ACI 301.

D. CONTRACTOR shall retain a Construction Quality Control (CQC) Consultant to perform the field and laboratory testing of cast-in-place concrete. The CQC Consultant must be acceptable to ENGINEER and OWNER.

E. CONTRACTOR shall not interfere with traffic entering, exchanging containers in, and exiting the portion of the Community Collection Center that is not included in the phase where Work is being completed.

1.02 QUALIFICATIONS

A. CONTRACTOR shall have prior experience installing high early strength concrete.

1.03 SUBMITTALS

A. At least 14 days prior to starting the Work of this Section, CONTRACTOR shall submit to OWNER a Plan of Execution (including a diagram) for traffic patterns entering and exiting the facility during construction activities.

B. At least 14 days prior to starting the Work of this Section, CONTRACTOR shall submit to ENGINEER Shop Drawings for all cast-in-place concrete. The Shop Drawings shall provide details for formwork, reinforcing steel, and embedded steel I-beams.

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C. At least 14 days prior to starting the Work of this Section, CONTRACTOR shall submit to ENGINEER the proposed concrete design mix. The design mix shall present the composition, quantities per cubic yard, of the concrete mix including:

1. aggregate, sand, and cement content;

2. types of admixtures; and

3. compressive strength and slump.

D. At least 14 days prior to starting the Work of this Section, CONTRACTOR shall submit to ENGINEER the methods proposed for use against low and high temperatures for protection of the concrete.

E. At least 14 days prior to starting the Work of this Section, CONTRACTOR shall submit to ENGINEER Shop Drawings for laminated rubber dock bumpers.

F. Following installation, CONTRACTOR shall submit a placement log to ENGINEER for all cast-in-place concrete items including the following information:

1. date of placement;

2. location and extent of placement;

3. design strength of concrete used;

4. time concrete batched and time sampled;

5. water added at Site (if any);

6. quantity of concrete;

7. air temperature; and

8. results of slump; and

9. results of laboratory compressive strength testing.

G. As soon as the data is available, CONTRACTOR shall submit to ENGINEER compression test data from compression test cylinders. Testing of compression test cylinders shall be performed by CONTRACTOR’s Construction Quality Control (CQC) Consultant in accordance with ASTM C 39. Cast-in-place concrete that does not meet these Specifications shall be removed and replaced at CONTRACTOR’s expense or may be subjected to a load test, also at CONTRACTOR’s expense.

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1.04 CONSTRUCTION QUALITY ASSURANCE

A. Placement of cast-in-place concrete shall be monitored by ENGINEER.

B. CONTRACTOR shall be aware of monitoring activities by ENGINEER and shall account for these activities in the construction schedule.

PART 2 PRODUCTS

2.01 CONCRETE MATERIALS

A. High-early strength concrete mix shall be ready-mixed, normal weight, with a minimum compressive strength of 6,000 psi at 28 days with a 3-day compressive strength of 75 percent of the minimum compressive strength (or 4,500psi).

B. Slump shall be less than 4 in. when measured according to ASTM C 143.

C. Cement shall conform to ASTM C 150, Type III for high-early strength applications.

D. Coarse aggregate shall conform to ASTM C 33. Maximum size of coarse aggregate shall be 3/4 in.

E. Only clean, natural sand shall be used as a fine aggregate. Artificial or manufactured sand will not be acceptable.

F. Water shall be potable.

2.02 ADMIXTURES

A. Admixtures shall be free of all chlorides.

B. Water-reducing admixtures shall conform to ASTM C 494, Type A and shall be used in accordance with the manufacturer’s recommendations. Technical assistance from the manufacturer’s representative shall be provided upon request. If using a high-range water-reducing admixture to enhance workability, then the admixture shall conform to ASTM C 494, Type F.

C. All admixtures shall be approved by the ENGINEER and shall be added to the concrete in strict accordance with the recommendation of the manufacturer.

2.03 CONCRETE MIXING

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A. Mix proportions for all concrete, unless otherwise specified, shall be selected preferably based on field experience. In the case where sufficient or suitable strength test data is not available, concrete shall be proportioned based on laboratory trial mix design.

B. The concrete shall have adequate workability and proper consistency to allow it to be readily worked into the forms and around reinforcement without excessive segregation or bleeding.

C. Ready Mix Concrete shall comply with the requirements of ASTM C 94 for mixing time and water addition. Total mixing time for concrete shall be determined in accordance with ASTM C 94 for the type of mixing equipment used.

D. Concrete that has been in a truck for more than 1½ hours after addition of water, or had more than 300 revolutions, or concrete that has become hard or non-plastic, shall not be used and shall be rejected by CQC Consultant or ENGINEER.

E. When concrete arrives at the Site having a slump below that specified herein, water may be added only if neither the maximum specified water/cement ratio nor the maximum specified slump is exceeded. At no time shall more than 10 gallons of water be added to any one truckload. The additional water should be incorporated into the mix by increasing the mixing time at least 1½ times the total mixing time required by ASTM C 94. However, CONTRACTOR shall bear total responsibility for the effects of adding water on the quality and strength of the concrete.

F. During hot weather, or under conditions contributing to rapid setting of concrete, a shorter mixing time than specified in ASTM C 94 may be required.

PART 3 EXECUTION

3.01 FAMILIARIZATION

A. Prior to implementing any of the Work described in this Section, CONTRACTOR shall become thoroughly familiar with all portions of the Work falling within this Section.

B. Work described in this Section will be completed in three construction phases, as shown on the Drawings. Prior to implementing any of the Work in this Section, CONTRACTOR shall carefully inspect the installed Work for all other phases and verify that all Work is complete to the point that the installation of this phase may

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properly commence without adverse impact and that operations can resume on the previously completed phase.

3.02 EXAMINATION AND PREPARATION

A. ENGINEER shall examine formwork, sleeves, and joint materials prior to placement of concrete. Defective material shall be removed and replaced with new material at no cost to OWNER.

B. CONTRACTOR shall clean all formwork and structural excavations of foreign matter, debris, loose material, and water.

C. ENGINEER shall be notified at least two working days in advance of a scheduled delivery to allow time for adequate observation of the Site.

3.03 PLACING CONCRETE

A. Concrete shall not be placed until the forms and other conditions are approved by

ENGINEER.

B. Water shall be removed from the space to be occupied by concrete, and any continuous flows of water shall be diverted to a sump or removed by pumping.

C. Concrete placement practices shall comply with ASTM C 94 and the following:

1. Concrete shall be conveyed from the mixer to the place of final deposit by methods that will prevent segregation or loss of materials.

2. Conveying equipment shall be capable of providing a supply of concrete at the placement site without interruptions sufficient to permit loss of plasticity between successive increments.

3. Concrete shall be placed as near as practicable to its final position to avoid segregation due to re-handling or flowing.

4. Concrete placement shall be performed at such a rate that the concrete is plastic at all times and readily flows into the forms.

5. Concrete placement shall be performed at such a rate to assure that lifts below have not taken initial set before fresh concrete is placed.

6. Consolidate concrete by vibrating. Use a vibrator with a minimum frequency of 4,500 impulses per minute with sufficient intensity and duration to cause complete consolidation of the concrete without causing segregation of the materials. For vibrating thin, heavily reinforced sections, use heads of such size to secure proper vibration of the concrete without disturbance of either the

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reinforcing bars or the forms. Use vibrators to consolidate properly placed concrete. Do not use them to move concrete about in the forms.

7. Concrete that has partially set shall not be re-tempered; it shall be discarded.

8. No concrete that has hardened or has been contaminated by foreign materials shall be placed, nor shall re-tempered concrete or concrete that has been re-mixed after initial set be used, unless approved by ENGINEER.

D. In the event of rain during concrete placement, the placement shall be terminated as soon as practicable at a point approved by ENGINEER and freshly placed concrete shall be protected with a waterproof covering that shall prevent marring or damage of surfaces.

E. Concrete shall not be placed without consent of ENGINEER when the temperature is 50°F or less, or when there is reason to expect a drop in temperature to below 50°F within 12 hours of the conclusion of the pour. Concrete placed at air temperature below 40°F shall have a minimum temperature of 60°F. When the air temperature is below 40°F or near 40°F and falling, the water and aggregates shall be heated before mixing. Accelerating chemicals shall not be used to prevent freezing.

H. Hot weather placement of concrete shall comply with ACI 305R.

I. Cold weather placement of concrete shall comply with ACI 306R.

3.04 CONCRETE CURING

A. Freshly placed concrete shall be protected from premature drying and excessive cold or hot temperatures.

B. Curing procedures shall begin immediately after placement in accordance with ACI 308R procedures to provide continuous moist curing above 50°F for at least seven

(7) days.

C. Curing of concrete shall be performed by moist curing and by moisture retaining cover curing, as herein specified. Moisture curing shall be provided by one of the following methods: covering with water, sprinkling with water, continuous water fog spray, and covering concrete surface with specified absorptive cover, thoroughly saturating cover with water, and keeping continuously wet. No salt, manure, or other chemicals shall be used for protection.

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3.05 FINISH AND JOINT SEALANT

A. The concrete slab shall initially be struck off with a vibrating metal screed.

Afterwards, a metal float shall be used to obtain a reasonably smooth surface.

CONTRACTOR shall take care not to overwork the surface. No further finishing is required.

B. Crafco® RoadSaver Silicone SL (or similar) joint filler for saw-cut joints, transition from concrete to asphalt, and top of expansion joints shall be one part silicone (no primer), cold-applied, and self-leveling in accordance with ASTM D5893. Apply joint filler only after concrete has cured a minimum of 4 days and after receiving approval from Engineer. Install joint filler for the full depth of the saw-cut joint. Before the sealant is applied, the joints should be dry and clean of all scale, concrete dust, dirt, and other foreign materials.

3.06 PROTECTION OF COMPLETED WORK

A. Concrete shall be protected from damaging mechanical disturbances, water flow, loading, shock, and vibration during the entire curing period.

B. Concrete surfaces shall be kept free from all foot and vehicular traffic and all other sources of abrasion for not less than 72 hours after finishing.

C. Any protective coverings shall be maintained continuously during entire curing period, and damage to coverings shall be repaired immediately at no additional expense to OWNER.

D. Finished surfaces and slabs shall be protected from the direct rays of the sun to prevent checking and crazing.

3.07 REPAIRS

A. Repair of rock pockets, honeycombs, and sand streaks shall be accomplished by:

1. cutting and removing concrete to at least 1-in. deep with sides perpendicular to surface;

2. flushing with clean water;

3. coating with neat cement paste;

4. filling with cement drypack mix;

5. curing as specified for concrete; and

6. grinding smooth and flush with adjacent surfaces.

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3.08 FIELD QUALITY CONTROL

A. CONTRACTOR’s CQC Consultant shall perform tests and submit test reports as defined in this Section.

B. CONTRACTOR’s CQC Consultant shall be currently accredited by one or more of the following:

1. Concrete Materials Engineering Council; and

2. other accreditation authority of equivalent standing to the above, on the basis if its compliance with the requirements of ASTM C 1077.

C. Sampling fresh concrete shall be performed in accordance with ASTM C 172, except modified for slump to comply with ASTM C 94:

1. Slump test according to ASTM C 143 shall be measured as follows:

a. one test at point of discharge for each set of compression cylinders taken;

b. additional tests when concrete consistency appears to have changed; and

c. one test on each truck load of concrete delivered to the site.

2. Molded concrete compression cylinders shall be sampled in accordance with ASTM C 172, processed and cured in accordance with ASTM C 31, and prepared and tested in accordance with ASTM C 39:

a. one set of eight (8) cylinders shall be obtained for each 50 cubic yards, or fraction thereof, for each day’s placement of each mix design;

b. two cylinders shall be tested at three (3) days, two cylinders shall be tested at seven (7) days, two cylinders shall be cured and held for testing at 28 days, and two cylinders held if the 28-day test indicated deficient results (i.e., compressive strength less than required in Part 2.01.A of this Section), or kept as spares in case of cylinder damage.

D. If sampling of fresh concrete for slump falls outside the limits specified under Part

2.01.B of this Section, CONTRACTOR’s CQC Consultant shall immediately test another portion of the same sample. If the results fall outside the limits specified herein again, then the sample fails and the concrete will be rejected.

3.09 PRODUCT PROTECTION

A. CONTRACTOR shall use all means necessary to protect all prior Work, including all materials and completed Work of other Sections.

B. In the event of damage to prior Work or Work specified in this Section, CONTRACTOR shall immediately make all repairs and replacements necessary to the approval of OWNER or ENGINEER and at no cost to OWNER.

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