03 30 00.60.pdf

Charleroi Locks and Dam - Upper and Lower Guard Walls

SECTION TABLE OF CONTENTS

DIVISION 03 - CONCRETE

SECTION 03 30 00.60

CONCRETE: PLACEMENT REQUIREMENTS

PART 1 GENERAL

1.1 SUMMARY

1.2 RELATED WORK SPECIFIED ELSEWHERE

1.3 REFERENCES

1.4 SUBMITTALS

1.5 GENERAL REQUIREMENTS

1.5.1 Tolerances

1.6 GOVERNMENT ASSURANCE INSPECTION AND TESTING

1.6.1 Fresh Concrete

1.6.2 Hardened Concrete

1.6.3 Inspection

PART 2 PRODUCTS

2.1 EPOXY GROUT AND BONDING AGENT

2.1.1 Bonding Agent

2.1.2 Dowel Grout

2.2 CURING MATERIALS

2.2.1 Impervious-Sheet

2.2.2 Membrane-Forming Curing Compound

2.2.3 Burlap and Matting

2.2.4 Cold Weather Blankets

2.2.5 Underwater Insulation

PART 3 EXECUTION

3.1 PREPARATION FOR PLACING

3.1.1 Foundations

3.1.1.1 Concrete on Underwater Rock Foundations

3.1.2 Embedded Items

3.1.3 Construction Joint Preparation

3.1.3.1 Exposed Construction Joints

3.1.3.2 Underwater Construction Joints

3.1.3.3 Air-Water Cutting

3.1.3.4 High-Pressure Water Jet

3.1.3.5 Wet Sandblasting

3.1.3.6 Wastewater Disposal

3.1.3.7 Disposal of Concrete Debris

3.2 TRANSPORTING AND CONVEYING CONCRETE

3.3 PLACING CONCRETE

3.3.1 General

3.3.2 Ambient Conditions

3.3.3 Concrete Lifts

3.3.4 Placing Concrete Underwater

3.3.5 Placing Concrete in Congested Areas

SECTION 03 30 00.60 Page 1 W911WN-09-B-0004 Revised by Amendment No. 0002

3.3.6 Placing Tremie and Flowable Concrete

3.4 CONCRETE TEMPERATURE

3.5 PROTECTION OF CONCRETE

3.6 COLD WEATHER REQUIREMENTS

3.6.1 General

3.6.2 Cold Weather Protection

3.6.3 Determination of In-place Concrete Strength

3.7 HOT WEATHER REQUIREMENTS

3.7.1 General

3.8 JOINTS

3.8.1 General

3.8.2 Joints in Features Other then Pavement

3.8.2.1 Construction Joints

3.8.2.2 Expansion Joints

3.8.3 Dowels and Tie Bars

3.9 CONSOLIDATION

3.9.1 General

3.9.2 Vibrators

3.10 FINISHING FORMED SURFACES

3.10.1 General

3.11 FINISHING UNFORMED SURFACES

3.11.1 General

3.11.2 Broom Finish

3.11.3 Float Finish

3.12 REPAIRS

3.12.1 Dry-Pack Mortar Repair of Minor Defects

3.12.2 Repair of Major Defects

3.12.3 Mixing Epoxy-Resin Grout Components

3.12.3.1 Tools and Equipment

3.12.3.2 Health and Safety Precautions

3.13 CURING

3.13.1 Materials

3.13.2 Curing Time

3.13.2.1 Moist Curing

3.13.2.2 Membrane Forming Curing Compounds

3.13.2.3 Impervious Sheet Curing

3.13.2.4 Sealed Insulation Curing

3.13.2.5 Ponding or Immersion

3.14 CONTRACTOR QUALITY CONTROL, TESTING AND INSPECTION

3.14.1 Testing of Fresh Concrete Mixes

3.14.2 Inspection Before Placing

3.14.3 Concrete Placement Inspection

3.14.4 Vibrator Testing

3.14.5 Curing Inspection

3.14.6 Cold Weather Protection and Sealed Insulation Curing

3.14.7 Reports

-- End of Section Table of Contents --

SECTION 03 30 00.60 Page 2

SECTION 03 30 00.60

CONCRETE: PLACEMENT REQUIREMENTS

PART 1 GENERAL

1.1 SUMMARY

This section addresses the basic requirements for concrete placement to be performed under this contract. Unique placement requirements for the various concretes to be placed are specified in other sections.

1.2 RELATED WORK SPECIFIED ELSEWHERE

Section 03 11 14.00 10 CONCRETE: FORMWORK

03 15 14.00 10 EXPANSION, CONTRACTION AND CONSTRUCTION JOINTS IN CONCRETE

FOR CIVIL WORKS

Section 03 20 02 CONCRETE: STEEL BARS AND WELDED WIRE FABRIC

FOR CONCRETE REINFORCEMENT

Section 03 30 00.10 CONCRETE: GENERAL REQUIREMENTS

Section 03 30 00.20 CONCRETE: FIELD DEMONSTRATIONS

Section 03 30 00.40 CONCRETE: MIXTURE PROPORTIONING

Section 03 30 00.50 CONCRETE: PRODUCTION AND TRANSPORT

Section 03 30 00.70 CONCRETE: CAST-IN-PLACE

Section 03 31 23 CONCRETE: DRILLED SHAFTS

Section 03 37 26.10 CONCRETE: FLOWABLE

Section 03 45 33 PRECAST PRESTRESSED STRUCTURAL CONCRETE

Section 03 70 00 CONCRETE: MASS

1.3 REFERENCES

The publications listed below form a part of this specification to the extent referenced. The publications are referred to in the text by basic designation only.

ACI INTERNATIONAL (ACI)

ACI 117 (2006) Standard Specifications for Tolerances for Concrete Construction and Materials

ACI 305R (1999; Errata 2006) Hot Weather Concreting

SECTION 03 30 00.60 Page 3

AMERICAN ASSOCIATION OF STATE HIGHWAY AND TRANSPORTATION OFFICIALS

(AASHTO)

AASHTO M 182 (2005) Standard Specification for Burlap Cloth Made from Jute or Kenaf and Cotton Mats

ASTM INTERNATIONAL (ASTM)

ASTM C 1064/C 1064M (2005) Standard Test Method for Temperature of Freshly Mixed Hydraulic-Cement Concrete

ASTM C 1074 (2004) Standard Practice for Estimating Concrete Strength by the Maturity Method

ASTM C 171 (2007) Standard Specification for Sheet Materials for Curing Concrete

ASTM C 309 (2007) Standard Specification for Liquid Membrane-Forming Compounds for Curing Concrete

ASTM C 518 (2004) Steady-State Thermal Transmission Properties by Means of the Heat Flow Meter Apparatus

ASTM C 881/C 881M (2002) Standard Specification for Epoxy-Resin-Base Bonding Systems for Concrete

ASTM C 940 (1998a; R 2003) Expansion and Bleeding of Freshly Mixed Grouts for Preplaced-Aggregate Concrete in the Laboratory

U.S. ARMY CORPS OF ENGINEERS (USACE)

COE CRD-C 400 (1963) Requirements for Water for Use in Mixing or Curing Concrete

COE CRD-C 521 (1981) Standard Test Method for Frequency and Amplitude of Vibrators for Concrete

1.4 SUBMITTALS

Government approval is required for submittals with a "G" designation;

submittals not having a "G" designation are for information only. When used, a designation following the "G" designation identifies the office that will review the submittal for the Government. Submit the following in accordance with Section 01 33 00 SUBMITTAL PROCEDURES

SD-06 Test Reports

Contractor Quality Control, Testing and Inspection

Inspection and test reports shall be submitted to the Contracting Officer in accordance with paragraph "Contractor Quality Control, Testing and Inspection".

SECTION 03 30 00.60 Page 4

SD-07 Certificates

Epoxy Grout

Certifications for these materials shall be submitted with each lot delivered.

Curing Materials

Certifications for these materials shall be submitted 30 days prior to there use.

1.5 GENERAL REQUIREMENTS

1.5.1 Tolerances

Except as otherwise specified herein, tolerances for concrete batching, mixture properties, and construction are covered in Section 03 30 00.50 CONCRETE: PRODUCTION AND TRANSPORT, Section 03 30 00.40 CONCRETE: MIXTURE PROPORTIONING, and Section 03 30 00.10CONCRETE: GENERAL REQUIREMENTS.

1.6 GOVERNMENT ASSURANCE INSPECTION AND TESTING

Day-to day inspection and testing shall be the responsibility of the Contractor Quality Control (CQC) staff. However, representatives of the Contracting Officer can and will inspect construction as considered appropriate and will monitor operations of the Contractor's CQC staff.

Government inspection or testing will not relieve the Contractor of any of his CQC responsibilities.

1.6.1 Fresh Concrete

Unless otherwise specified, fresh concrete will be sampled at the Left Bank Batch Plant and as delivered to the Point of Delivery in accordance with the requirements presented in other sections of these specifications.

1.6.2 Hardened Concrete

Tests on hardened concrete shall be performed by the Contractor, as directed by the Government, when such tests are considered necessary due to defective work.

1.6.3 Inspection

Concrete operations may be tested and inspected by the Government as the project progresses. Failure to detect defective work or material will not prevent rejection later when a defect is discovered nor will it obligate the Government for final acceptance.

PART 2 PRODUCTS

2.1 EPOXY GROUT AND BONDING AGENT

Epoxy resins shall be two component, shall contain 100% solids, and shall be moisture tolerant. The epoxy class shall be as appropriate for the existing ambient and surface temperatures.

SECTION 03 30 00.60 Page 5

2.1.1 Bonding Agent

Epoxy resins for use as a bonding agent shall conform to ASTM C 881/C 881M, Type V, Grade 1 or 2.

2.1.2 Dowel Grout

Epoxy resins used for dowel grout shall conform to ASTM C 881/C 881M, Type IV, Grade 3.

2.2 CURING MATERIALS

2.2.1 Impervious-Sheet

Impervious-sheet materials shall conform to ASTM C 171, type optional, except, that polyethylene sheet shall not be placed directly on the concrete surface.

2.2.2 Membrane-Forming Curing Compound

Membrane-forming curing compound shall conform to ASTM C 309, Type 1-D or

2. Type 2 shall not be used for surfaces exposed to view. Only a styrene acrylate or chlorinated rubber compound meeting ASTM C 309, Class B, requirements shall be used for surfaces that are to be painted or are to receive bituminous roofing, or waterproofing, or floors that are to receive adhesive applications of resilient flooring. The curing compound selected shall be compatible with any subsequent paint, roofing, waterproofing, or flooring specified. Nonpigmented compound shall contain a fugitive dye, and shall have the reflective requirements in ASTM C 309 waived.

2.2.3 Burlap and Matting

Burlap and matting used for curing shall conform to AASHTO M 182.

2.2.4 Cold Weather Blankets

Insulation blankets shall be used in addition to curing materials when required. The blankets shall have a minimum R-value of 4.0 hr-ft2-oF/BTU when tested in accordance with ASTM C 518.

2.2.5 Underwater Insulation

Cold weather protection may be used for underwater placements to facilitate early strength gain at the surface of the concrete. Insulation would allow concrete strength at the surface to develop more efficiently and expedite form removal. Insulation shall have a minimum R-value of 3.0 hr-ft2-oF/BTU and shall consist of closed-cell insulation or foam, such as insulation board or polyethylene foam sheets. Open-cell insulation and foam will not be permitted. Insulation shall be securely fastened to the forms. The insulation shall be placed on the interior of the forms so that it is protected from water flow and floating debris unless the forms are designed in such a way that exterior insulation can be securely fastened and protected from damage.

PART 3 EXECUTION

3.1 PREPARATION FOR PLACING

Unless otherwise specified or shown, before commencing any concrete

SECTION 03 30 00.60 Page 6 placement, the following shall be performed. Surfaces to receive concrete shall be clean and free from laitance, frost, ice, mud, and water. Forms, where used, shall be in place, cleaned, coated, and adequately supported, in accordance with Section 03 11 14.00 10 CONCRETE: FORMWORK. Reinforcing steel shall be in place, cleaned, tied, and adequately supported, in accordance with Section 03 20 02 CONCRETE: STEEL BARS AND WELDED WIRE FABRIC FOR CONCRETE REINFORCEMENT. Transporting and conveying equipment shall be in-place, ready for use, clean, and free of hardened concrete and foreign material. Equipment for consolidating concrete shall be at the placing site and in proper working order. Equipment and material for curing and for protecting concrete from weather or mechanical damage shall be at the placing site, in proper working condition and in sufficient amount for the entire placement. When hot, windy conditions during concreting appear probable, equipment and material shall be at the placing site to provide windbreaks, shading, fogging, or other action to prevent plastic shrinkage cracking or other damaging drying of the concrete.

3.1.1 Foundations

3.1.1.1 Concrete on Underwater Rock Foundations

The bottoms of drilled shafts shall be cleaned in accordance with Section 31 63 26.00 10 DRILLED SHAFTS. Exposed rock within the Upper Guard Wall Nose Cell shall be prepared in accordance with Section 35 20 23.10

UNDERWATER EXCAVATION.

3.1.2 Embedded Items

Before placing concrete, care shall be taken to determine that all embedded items are securely fastened in place as indicated in the drawings or required. Embedded items shall be free of oil and other foreign matter such as loose coatings of rust, paint, and scale. The embedding of wood in concrete will be permitted only when specifically authorized or directed.

Any air or water lines or other materials embedded in structures as authorized construction expedients shall conform to the above requirements and upon completion of their use shall be backfilled with concrete or mortar as directed. Voids in sleeves, inserts, and anchor slots shall be filled temporarily with readily removable materials to prevent the entry of concrete into voids. Welding will not be permitted on embedded or otherwise exposed metals which are in contact with concrete surfaces, except where specifically designated on the drawings. Tack welding of or to embedded items will not be permitted.

3.1.3 Construction Joint Preparation

3.1.3.1 Exposed Construction Joints

Concrete surfaces to which additional concrete is to be bonded shall be prepared for receiving the next horizontal lift by cleaning the construction joint surface with air-water cutting, sandblasting, high-pressure water jet, or other approved method. Concrete at the side of vertical construction joints shall be prepared as approved by the Contracting Officer. Air-water cutting shall not be used on formed surfaces or surfaces congested with reinforcing steel. Regardless of the method used, the resulting surfaces shall be free from all laitance and inferior concrete so that clean surfaces of well bonded coarse aggregate are exposed. The edges of the coarse aggregate shall not be undercut. The surface of horizontal construction joints shall be kept continuously wet for the first 24 hours during the 48-hour period prior to placing fresh

SECTION 03 30 00.60 Page 7 concrete and then allowed to dry until concrete is placed. The surface shall be dry and completely clean prior to placing the next lift.

3.1.3.2 Underwater Construction Joints

Preparation of underwater construction joints shall be achieved using a combination of air jetting, water jetting, air lifting and any approved methods capable of suspending and/or removing sediment, and laitance or otherwise poor quality concrete from the surface of the previously placed concrete. Mechanical methods may also be used where there is no exposed rebar or other embeds, and provided the methods do not remove or damage sound concrete. Regardless of the methods used, the previously placed concrete shall achieve adequate set and hardness to be cleaned without damaging sound concrete. Divers utilizing suitable underwater camera equipment appropriate for use in heavy sediment-laden water shall be used to confirm that all sediment and laitance or otherwise poor quality concrete are removed immediately prior to placement of subsequent concrete.

3.1.3.3 Air-Water Cutting

Air-water cutting of a construction joint shall be performed at the proper time, generally between 4 and 12 hours after placement and only on horizontal construction joints. This period may be modified if a retarder is used to prolong the setting of the cement at surface of the concrete.

The air pressure used in the jet shall be 90 to 110 psi, and the water pressure shall be just sufficient to bring the water into effective influence of the air pressure. After cutting, the surface shall be washed and rinsed until the wash water is no longer cloudy. If air-water cutting does not produce acceptable results, the surface shall be prepared by high-pressure water jet or sandblasting.

3.1.3.4 High-Pressure Water Jet

A stream of water under a pressure of not less than 3,000 psi shall be used for cutting and cleaning. Its use shall be delayed until the concrete is sufficiently hard so that only the surface skin or mortar is removed and there is no undercutting of coarse-aggregate particles. If the water jet is incapable of a satisfactory cleaning, the surface shall be cleaned by sandblasting.

3.1.3.5 Wet Sandblasting

Wet sandblasting shall be used after the concrete has reached sufficient strength to prevent undercutting of the coarse aggregate particles. The operation shall be continued until all accumulated laitance, coatings, stains, debris, and foreign materials are removed. The surface of the concrete shall then be washed thoroughly to remove all loose material.

This method may be used on both horizontal and vertical surfaces.

3.1.3.6 Wastewater Disposal

Waste water produced from concrete joint preparation operations shall be managed in accordance with paragraph PROTECTION OF WATER RESOURCES of Section 01 57 20.00 10 ENVIRONMENTAL PROTECTION.

3.1.3.7 Disposal of Concrete Debris

Disposal of milled concrete and other dry concrete debris, unless otherwise specified, shall be disposed of in accordance with Section 02 42 00

SECTION 03 30 00.60 Page 8

DISPOSAL OF MATERIALS.

3.2 TRANSPORTING AND CONVEYING CONCRETE

Concrete shall be transported/conveyed from the Points of Delivery to the point of placement in accordance with the applicable requirements of Section 03 30 00.50 CONCRETE: PRODUCTION AND TRANSPORT.

3.3 PLACING CONCRETE

3.3.1 General

Concrete shall be placed in compliance with Sections 03 30 00.70 CONCRETE:

CAST-IN-PLACE, 03 45 33 PRECAST PRESTRESSED STRUCTURAL CONCRETE, 03 70 00

CONCRETE: MASS, 03 37 26.10 CONCRETE: FLOWABLE, and 03 31 23 CONCRETE:

DRILLED SHAFTS. All methods and equipment used to place concrete shall be subject to approval by the Contracting Officer. Concrete shall be handled from the Points of Delivery to the point of placement in a continuous manner. Concrete shall be placed without permitting the material to segregate. A properly designed and sized elephant trunk connected to a rigid pipe or other approved method shall be used to prevent the free fall of concrete. Concrete shall not free fall more than 5 feet, except that placement of tremie or flowable infill concrete shall be placed through rigid pipe with no free fall of the concrete. Adequate platforms, scaffolding, ramps and walkways shall be provided so that personnel and equipment are not supported by in-place reinforcement. Placing will not be permitted when the sun, heat, wind, or limitations of facilities furnished by the Contractor prevent proper placement, consolidation, finishing and curing. During periods of precipitation, or the threat of precipitation, all batching, conveying and placement facilities shall be protected so that the concrete will not be subjected to precipitation. If the Contracting Officer determines that the concrete is inadequately protected, the Contracting Officer shall order that concrete production stop until such time as adequate protection is provided or precipitation stops. Sufficient placing capacity shall be provided so that concrete can be kept free of cold joints.

3.3.2 Ambient Conditions

Concrete placement shall not be permitted when weather conditions prevent proper placement and consolidation, or when conditions will adversely affect the quality of the concrete. Unless otherwise specified or approved, the ambient air temperature of the placement area and all surfaces to receive concrete shall be above 32 degrees F. In hot weather, forms, reinforcement, and conveying and placement equipment shall be cooled if necessary to achieve the specific concrete temperature.

Concrete exposed to air shall be maintained at a temperature above 40 degrees F for the first 7 days following placement and above 32 degrees F for the remainder of the specified curing period.

Underwater ambient conditions can not be controlled. It must be recognized that the rate at which cement and cementitious materials hydrate is highly dependent on the temperature of the concrete while it is curing, and hydration will be significantly slowed by colder temperatures.

3.3.3 Concrete Lifts

The depth of concrete placed in each lift shall be limited to 5 feet unless

SECTION 03 30 00.60 Page 9 otherwise indicated on the drawings. Lifts shall be placed in a sequence that facilitates dissipation of heat. The Contractor's placement sequence shall be arranged to make all practical efforts to optimize reduction of internal concrete temperatures. Adjacent lifts shall be staggered.

All concrete, other than tremie and flowable concrete mixes, shall be deposited in stepped progression at such a rate that the formation of cold joints, except where construction joints are permitted, will be prevented.

A minimum of three successive horizontal layers in stepped progression shall be used for each lift. Each new layer of concrete shall be placed on the oldest exposed layer. The maximum depth of a layer shall be 20 inches.

See diagram at the end of this Section of the Specifications. The minimum time period between successive lifts shall be 7 days.

3.3.4 Placing Concrete Underwater

Unless otherwise specified, all concrete deposited in water shall be placed by a tremie, using the "dry pipe" start method. The methods and equipment used shall be subject to approval as demonstrated by the field demonstrations required by Section 03 30 00.20 CONCRETE: FIELD DEMONSTRATIONS. The discharge end of the tremie pipe shall be raised off the bottom of the placement 6 inches with a fully charged pipe and hopper to initiate the flow of the concrete. The tremie pipe shall not be raised after the flow is started, unless the end of the pipe remains at least 5 feet into the previously placed concrete. The tremie pipe shall only be raised vertically and shall not be moved horizontally for any reason. If the seal between the end of the pipe and the previously placed concrete is lost during the placement, the tremie pipe shall be fully withdrawn, the cap replaced, the pipe reset into the concrete a minimum of 5 feet, and the flow of concrete shall be re-established. Concrete buckets shall not be used for underwater placement of concrete. Requirements for the tremie pipe and tremie placements shall be as specified in other related technical specification sections. Prior to placement of additional lifts of tremie or subsequent in-the-dry cast-in-place or mass concrete, all sediment, dirt, debris and laitance shall be removed to the satisfaction of the Contracting Officer.

3.3.5 Placing Concrete in Congested Areas

Special care shall be used to ensure complete filling of the forms, elimination of all voids, and complete consolidation of the concrete when placing concrete in areas congested with reinforcing bars, embedded items, waterstops and other tight spacing. The Contactor shall verify that the nominal maximum size of aggregate (NMSA) conforms to the specified criteria when evaluated for the congested area. Any violations shall be brought to the attention of the Contracting Officer. Vibrators with heads of a size appropriate for the clearances available shall be used, and the consolidation operation shall be closely supervised to ensure complete and thorough consolidation at all points. Where necessary, splices of reinforcing bars shall be alternated to reduce congestion. Where two mats of closely spaced reinforcing are required, the bars in each mat shall be placed in matching alignment to reduce congestion. Reinforcing bars may be temporarily crowded to one side during concrete placement provided they are returned to exact required location before concrete placement and consolidation are completed.

3.3.6 Placing Tremie and Flowable Concrete

Extreme care shall be used in conveying and placing the concrete to avoid

SECTION 03 30 00.60 Page 10 segregation. No relaxation of requirements to accommodate flowable concrete will be permitted.

3.4 CONCRETE TEMPERATURE

Temperature of specific classes and types of concrete to be placed under this contract, unless otherwise specified, shall be as listed below when measured in accordance with ASTM C 1064/C 1064M:

Maximum Temperature Concrete/Location (At Placement)

Tremie Concrete 65 degrees F

Mass Concrete 65 degrees F

Flowable Concrete 65 degrees F

Precast Concrete 85 degrees F

Ready-mix Concrete 85 degrees F

The minimum placement temperature shall be 40 degrees F unless otherwise specified.

3.5 PROTECTION OF CONCRETE

No fire or excessive heat shall be permitted near or in direct contact with concrete at any time. No pile-driving equipment shall be operated within 20 feet horizontally of concrete, or 14 feet clear distance for shafts, that has not achieved a minimum, in-place compressive strength of 2000 psi. The in-place compressive strength of the concrete is defined as the strength of the placed concrete, not the strength of 6 x 12 cylinders cured in the field under like conditions or in the lab. Field cylinder compressive strength testing alone is not adequate to assure that the in-place strength of the placed concrete is accurately represented. The in-place concrete compressive strength shall be verified in accordance with, Paragraph "Determination of In-place Concrete Strength" and in accordance with ASTM C 1074. The surface of the concrete shall be protected from rain, snow, and extreme temperatures during placing.

3.6 COLD WEATHER REQUIREMENTS

3.6.1 General

Special protection measures, approved by the Contracting Officer, shall be used if freezing temperatures are anticipated before the expiration of the specified curing period and as otherwise specified. The ambient temperature of the air where concrete is to be placed and the temperature of surfaces to receive concrete shall be above 32 degrees F. The temperature of the concrete when placed shall be not less than 50 degrees F nor more than 70 degrees F. for structural concrete, and not less than 40 degrees F nor more than 60 degrees F for tremie, flowable or mass concrete.

Heating of the mixing water and/or fine and coarse aggregates will be required to regulate the concrete placing temperature. The heating of mixing water and/or aggregates shall be closely regulated so that the concrete temperature meets these requirements. Materials entering the mixer shall be free from ice, snow, or frozen lumps. Salt, chemicals or other materials shall not be incorporated in the concrete to prevent

SECTION 03 30 00.60 Page 11 freezing.

The rate at which cement and cementitious materials hydrate is highly dependent on the temperature of the concrete while it is curing. Form removal and other construction sequencing events require the in-place concrete to achieve certain strength requirements. Cold ambient conditions will make it more difficult to determine the in-place strength. Forms shall not be removed until the concrete has gained adequate strength so that form removal does not damage the concrete. The concrete shall also have gained adequate strength so that exposure to cold ambient conditions while the forms are removed does not cause damage to the concrete. After forms are removed, the insulation shall be immediately replaced on all concrete surfaces exposed to the air. The procedures used to remove initial insulation and the forms, and then to reinstall the insulation, shall be selected to minimize the exposure of the concrete to cold.

Construction sequencing events shall be as stated in other sections of the specifications.

The Contractor is responsible for establishing procedures in the field for determining when the concrete has achieved adequate strength. Methods shall be in accordance with the paragraph "Determination of In-place Concrete Strength". If such methods are not established, the time required before forms can be removed will be determined by the Contracting Officer.

This time will be established based on the conservative estimates that assure the concrete has achieved adequate strength. Regardless of what criteria is used to govern form removal and construction sequencing, the contractor shall be responsible for other temperature monitoring requirements set forth in paragraph "Cold Weather Protection".

3.6.2 Cold Weather Protection

When the daily ambient low temperature is less than 32 degrees F the temperature of the concrete shall be maintained above 40 degrees F for the first seven days after placing. The temperature differential between the surface of the concrete and the interior concrete at a depth of 2 inches shall be maintained at less than 25 degrees F, 1) For a minimum of 28 days after concrete placement, 2) during protection and removal, and 3) for 24 hours after protection removal. If necessary, the air temperature adjacent to the concrete surface shall be controlled so as not to exceed the 25 degree F temperature differential. The Contractor shall supply suitable equipment for monitoring the concrete temperature adjacent to the concrete surface and 2 inches inside the concrete. The Contractor shall monitor the temperature at least continuously for the duration of the entire curing period and until the in-place strength of the concrete has achieved its design strength when extreme conditions are anticipated. Equipment for monitoring the temperature within the concrete shall consist of digital, un-interruptible and non-alterable data loggers cast into the concrete.

The equipment shall be as furnished by Engius Constructive Intelligence, IntelliRock Data Logging System (phone number 216-272-5801), or an approved equal. In addition to adequate remote readers for all placements being monitored, the contractor shall provide 2 hand held data readers. Remote reading devices and hand held recorders shall be provided to the Concrete QC Manager and the Government Materials Technician. The equipment and methods for monitoring concrete temperature shall be included in the Contractor's submittal for Cold Weather Requirements.

All exposed concrete surfaces shall be insulated for a minimum of 28 days after placement during the insulation period from October 15 to April 15, regardless of ambient temperatures. Any concrete that is less than 14 days

SECTION 03 30 00.60 Page 12 old at the start of the insulation period shall be insulated until the concrete is a minimum of 28 days old. In addition, insulation shall be placed on any newly placed concrete when the ambient temperature is expected to be less than 32 degrees F. Insulation shall be installed as soon as the concrete has sufficiently set as not to be disturbed by the insulation. No insulation shall be removed when the actual air temperature is below the anticipated daily mean temperature, or when the difference between the concrete surface temperature and the air temperature is forecasted to be greater than 25 degrees F for a 24-hour period after insulation removal.

The insulation shall be maintained in such a condition that the R value does not diminish during the period of protection. Edges and corners of the placement shall be protected with a double layer of the insulation specified above for a minimum distance of 2 feet in all directions. Forms shall be insulated in such a manner that the combined form-insulation system shall have a thermal resistance (R value) not less than that specified. The form system shall remain in place for at least 5 days after placement of the concrete and insulation continued as required. After 5 days, forms and insulation on vertical surfaces may be removed for periods not to exceed 4 hours in a 24 hour period to allow forms to be moved, and insulation on horizontal surfaces may be removed for periods not to exceed 8 hours in a 24 hour period to allow reinforcement to be installed, insulation to be installed, lift joints to be prepared, etc. provided that suitable precautions are taken to prevent the concrete from being subjected at any time to ambient temperatures of 32 degrees F or below. The first 6 feet of all steel protruding from insulated concrete shall be insulated with material having an R value as stated. All form bolts and metal ribs on the forms shall be insulated in a like manner. During the period of protection there shall be no holes or openings in the insulation or between the insulation and concrete which permit ambient air to penetrate the insulation except as noted for construction purposes. Special attention shall be given to seams, corners, and edges to prevent holes or openings in the insulation.

All equipment and materials for insulating the concrete shall be at the work site well in advance of expected freezing temperatures. All joints in the insulation shall be sealed to prevent moisture loss during the curing period. Waterproof paper or polyethylene-coated burlap shall not be acceptable as insulation from October 15 to April 15. Insulation shall have a minimum R-value of 4.0 hr-ft2-oF/Btu.

3.6.3 Determination of In-place Concrete Strength

Form removal and some construction sequencing events are based on the in-place compressive strength of the concrete. The contractor shall establish procedures for determining the in-place strength of concrete. The procedures shall be part of the Concrete Plan and Cold Weather Concrete, and therefore shall be subject to approval of the Contracting Officer.

Concrete cylinder breaks alone are not considered adequate for this determination. The Contractor shall establish procedures such as the Maturity Method in accordance with ASTM C 1074, or other methods approved by the Contracting Officer to be adequate for this determination. Any methods used shall be developed by a specialist in determining in-place concrete strength. The specialist shall be present during the testing to develop the strength relationships, and shall be present during initial application of these methods.

Equipment for monitoring the Maturity Factor of the in-place concrete shall

SECTION 03 30 00.60 Page 13 consist of digital, un-interruptible and non-alterable data loggers cast into the concrete. A minimum of 6 data loggers shall be provided for each lift of concrete placed. Additional data loggers will be required for temperature monitoring during periods of cold weather protection and monitoring. The equipment shall be as furnished by Engius Constructive Intelligence, IntelliRock Data Logging System (phone number 216-272-5801) or an approved equal. In addition to adequate remote readers for all placements being monitored, the contractor shall provide 2 hand held data readers. Remote reading devices and hand held recorders shall be provided to the Concrete QC manager and the Government Materials Technician.

In addition, the Contractor shall demonstrate that the method can adequately determine the in-place strength. Demonstration trial placements shall be made and tested to verify that the relationship applies to field conditions. The trial placements shall be made using at least 3 temperatures that cover the anticipated ambient annual cycle. Any temperature monitoring shall be by an automated digital recording system.

If the maturity method is used, the contractor shall provide a comparison of the two maturity functions and determine which function is more accurate.

Regardless of method used, the monitoring and testing data used for the strength determination shall be included in the CQC plan and concrete reports. The set-up and operation of any instrumentation and data collection shall be included in the Concrete Plan. The instrumentation installation shall provide adequate protection for any instruments, cables and equipment required as part of the monitoring system. The test ages for correlation of cylinder breaks shall at a minimum include 1, 3, 7, 10, 14, 21 and 28 days. Additional cylinders shall be made in the event that additional ages may need to be investigated.

3.7 HOT WEATHER REQUIREMENTS

3.7.1 General

When the ambient temperature during concrete placing is expected to exceed 85 degrees F, the concrete shall be placed and finished with procedures previously submitted and as specified herein. The concrete temperature at time of delivery to the forms shall not exceed the temperature shown in the paragraph "Concrete Temperature," when measured in accordance with ASTM C 1064/C 1064M. Cooling of the mixing water and aggregates, and placing concrete in the cooler part of the day or night may be required to obtain an adequate placing temperature. A retarder may be used in accordance with Section 03 30 00.30 CONCRETE: MATERIALS, paragraph "Retarding Admixture," to facilitate placing and finishing. Steel forms and reinforcements shall be cooled as approved prior to concrete placement when steel temperatures are greater than 120 degrees F. Conveying and placing equipment shall be cooled if necessary to maintain proper concrete-placing temperature.

3.8 JOINTS

3.8.1 General

Joints shall be located and constructed as indicated or approved. Joints not indicated on the drawings shall be located and constructed to minimize the impact on the strength of the structure. Joints shall be perpendicular to the main reinforcement. All reinforcement shall be continued across joints; except that reinforcement or other fixed metal items shall not be continuous through expansion joints, or through construction or contraction

SECTION 03 30 00.60 Page 14 joints in slabs on grade. Unless otherwise shown, reinforcement shall be 2 inches clear from each joint. Joints shall be constructed as shown and in accordance with Section 03 15 14.00 10 CONCRETE: EXPANSION JOINTS, CONTRACTION JOINTS, AND WATERSTOPS.

3.8.2 Joints in Features Other then Pavement

Joints in features other than pavement shall be in accordance with the following requirements:

3.8.2.1 Construction Joints

Construction joints shall be located as indicated or approved. Fresh concrete shall not be placed against adjacent hardened concrete until it has achieved a minimum strength of 500 psi. Where concrete work is interrupted by weather, end of work shift or other similar type of delay, location and type of construction joint shall be subject to approval of the Contracting Officer. Unless otherwise indicated and except for slabs on grade, reinforcing steel shall extend through construction joints.

Construction joints in slabs on grade shall be keyed or doweled as shown.

In walls having door or window openings, lifts shall terminate at the top and bottom of the opening. Other lifts shall terminate at such levels as to conform to structural requirements or architectural details. Where horizontal construction joints in walls or columns are required, or where a "dummy" horizontal construction joint is desired for aesthetic purposes, a strip of 1 inch chamfer lumber, beveled and oiled to facilitate removal, shall be tacked to the inside of the forms at the construction joint.

Concrete shall be placed to the midpoint of a double chamfer for visible joints or to the bottom side of a single rectangular strip for hidden joints. Prior to placing additional concrete, horizontal construction joints shall be prepared as specified in paragraph "Construction Joint Preparation."

3.8.2.2 Expansion Joints

Installation of expansion joints and sealing of these joints shall conform to the requirements of Section 03 15 14.00 10 CONCRETE: EXPANSION JOINTS, CONTRACTION JOINTS, AND WATERSTOPS.

3.8.3 Dowels and Tie Bars

Dowels and tie bars shall be installed at the locations shown on the drawings and to the details shown, using materials and procedures specified in Section 03 20 02 CONCRETE: STEEL BARS AND WELDED WIRE FABRIC FOR CONCRETE REINFORCEMENT and herein. "Structural" type deformed bar dowels, or tie bars, shall be installed to meet the specified tolerances. Care shall be taken during placing adjacent to and around dowels and tie bars to ensure there is no displacement of the dowel or tie bar and that the concrete completely embeds the dowel or tie bar and is thoroughly consolidated.

3.9 CONSOLIDATION

3.9.1 General

Unless otherwise specified, each layer of concrete shall be consolidated immediately after placing. Consolidation shall be accomplished by internal vibrators, except for slabs 4 inches thick or less. Slabs 4 inches and less in thickness shall be consolidated by properly designed vibrating

SECTION 03 30 00.60 Page 15 screeds or other approved technique. Vibrators shall be inserted vertically at uniform spacing over the area of placement. The distance between insertions shall be approximately 1-1/2 times the radius of action of the vibrator so that the area being vibrated will overlap the adjacent just-vibrated area by a reasonable amount. The vibrator shall penetrate rapidly to the bottom of the layer and at least 6 inches into the preceding layer if there is such. Vibrators shall be held stationary until the concrete is consolidated and then vertically withdrawn slowly while operating. Form vibrators shall not be used unless specifically approved and unless forms are constructed to withstand their use. Magnetic base form vibrators shall be used to place concrete between the emptying valve precast concrete culvert and the steel liner. Vibrators shall not be used to move concrete within the forms. Hand spading may be used if necessary together with internal vibration along formed surfaces permanently exposed to view. Excessive vibration of lightweight concrete resulting in segregation or flotation of coarse aggregate shall be prevented. Grate tampers ("jitterbugs") shall not be used.

3.9.2 Vibrators

An adequate number of vibrators shall be on hand to meet placing requirements, and spare vibrators shall be available to maintain production in the event of breakdown. There shall be adequate air pressure available for air vibrators and adequate voltage for electric vibrators. Vibrators of the proper size, frequency, and amplitude shall be used for the type of work being performed in conformance with the following requirements:

HEAD DIAMETER FREQUENCY AMPLITUDE

APPLICATION INCHES VPM INCHES

Thin walls, beams, etc. 1-1/4 - 2-1/2 9,000 - 13,500 0.020 - 0.04 General construction 2 - 3-1/2 8,000 - 12,000 0.025 - 0.05 Heavy sections 3 - 6 7,000 - 10,500 0.030 - 0.06 Mass concrete 5 - 7 5,500 - 8,500 0.040 - 0.08

The frequency and amplitude shall be within the range indicated in the tabulation, as determined in accordance with paragraph CONTRACTOR QUALITY

CONTROL, TESTING AND INSPECTION.

3.10 FINISHING FORMED SURFACES

3.10.1 General

Forms, form materials, and form construction and classes of concrete shall be as specified in Section 03 11 14.00 10 CONCRETE: FORMWORK. Finishing of formed surfaces shall be as specified herein. Unless another type of architectural or special finish is specified, surfaces shall be left with the texture imparted by the forms except that defective surfaces shall be repaired. Unless painting of surfaces is required, uniform color of the concrete shall be maintained by use of only one mixture without changes in materials or proportions for any structure or portion of structure that requires a Class A or B finish.

After removal of forms, all ridges, lips, and bulges on surfaces permanently exposed shall be removed. Except for major defects, as defined hereinafter, surface defects shall be repaired as specified herein within 24 hours after forms are removed. Repairs of the so-called "plaster-type"

SECTION 03 30 00.60 Page 16 will not be permitted in any location. Tolerances of formed surfaces shall conform to the requirements of ACI 117. These tolerances apply to the finished concrete surface, not to the forms themselves; forms shall be set true to line and grade and in accordance with Section 03 30 00.10 CONCRETE:

GENERAL REQUIREMENTS.

3.11 FINISHING UNFORMED SURFACES

3.11.1 General

Grate tampers or "jitterbugs" shall not be used for any surfaces. The dusting of surfaces with dry cement or other materials or the addition of any water during finishing shall not be permitted. If bleed water is present prior to finishing, the excess water shall be carefully dragged off or removed by absorption with porous materials such as burlap. During finishing operations, extreme care shall be taken to prevent over finishing or working water into the surface; this can cause "crazing" (surface shrinkage cracks which appear after hardening) of the surface. Any slabs with surfaces which exhibit significant crazing shall be removed and replaced. During finishing operations, surfaces shall be checked with a 10 foot straightedge, applied in both directions at regular intervals while the concrete is still plastic, to detect high or low areas.

The ambient temperature of spaces adjacent to surfaces being finished shall be not less than 40 degrees F. In hot weather when the rate of evaporation of surface moisture, as determined by use of Figure 2.1.5 of ACI 305R, may reasonably be expected to exceed 0.2 pounds per square foot per hour, provisions for windbreaks, shading, or fog spraying shall be made in advance of placement to prevent plastic shrinkage cracks, and such protective measures shall be taken before, during, and immediately after finishing as operations require. All unformed surfaces of concrete that are not to be covered by additional concrete or backfill shall be finished as specified below, and shall be true to elevation as shown on the drawings. Surfaces to receive additional concrete or backfill shall be brought to the elevation shown and left true and regular. Exterior surfaces shall be sloped for drainage unless otherwise shown in the drawing or directed. Joints shall be carefully made with a jointing or edging tool. The finished surfaces shall be protected from stains or abrasions.

The concrete shall be thoroughly consolidated before finishing operations commence or before leaving it for future concrete or backfill placement.

3.11.2 Broom Finish

The top surface of horizontal traffic bearing surfaces shall be given a broom finish. The screeding shall be followed immediately by bull floating before bleeding water is present, to bring the surface to a true, even plane with no coarse aggregate visible. Then, after the concrete has stiffened so that it will withstand a man's weight without imprint of more than 1/4 inch and the water sheen has disappeared, the surface shall be broomed or brushed with a broom or fiber bristle brush in a direction transverse to that of the main traffic or at right angles to the slope of the slab or as otherwise directed. After the end of the curing period, the surface shall be vigorously broomed with a coarse fiber broom to remove all loose or semi-detached particles.

3.11.3 Float Finish

Unformed surfaces that will not be subjected to traffic shall receive a float finish. The concrete receiving a float finish shall be screeded and

SECTION 03 30 00.60 Page 17 darbied or bullfloated to bring the surface to the required finish level with no coarse aggregate visible. No water, cement, or mortar shall be added to the surface during the finishing operation. Floating may then be performed by use of suitable hand floats or power-driven equipment.

Floats, hand or power driven, shall be made of magnesium. After the water sheen has disappeared, the concrete, while still green but sufficiently hardened to bear a man's weight without deep imprint, shall be floated to a true even plane.

3.12 REPAIRS

3.12.1 Dry-Pack Mortar Repair of Minor Defects

Metal tools shall not be used to finish repairs in Class A surfaces.

Surfaces to have classes A and B finishes shall have surface defects repaired as follows: defective areas, voids, and honeycombs smaller than 16 square inches in area and less than 1/2 inches deep; bug holes exceeding 1/2 inch in diameter shall be chipped and filled with dry-packed mortar;

holes left by removal of tie rods shall be reamed and filled with dry-pack mortar. Surfaces to have Class D Finish shall have defects repaired as follows: defective areas, voids, and honeycombs smaller than 48 square inches and less than 2 inches deep; bug holes exceeding 1-1/2 inches in diameter shall be chipped and filled with dry-packed mortar; and holes left by removal of the tie rods shall be reamed and filled with dry-packed mortar. The void shall then be thoroughly cleaned and dried, and the prepared area shall be brush-coated with an epoxy resin meeting the requirements specified in paragraph EPOXY GROUT AND BONDING AGENT.

The cement used in the dry-packed mortar shall be a blend of the portland cement and white portland cement properly proportioned so that the final color of the mortar or concrete will match adjacent concrete. Trial batches shall be used to determine the proportions required to match the color of the surrounding concrete. Mortar shall be thoroughly compacted into the prepared void by tamping, rodding, ramming, etc. and struck off to match adjacent concrete. Mortar shall be a stiff mix of 1 part portland cement to 2 parts fine aggregate and minimum amount of water. Fine aggregate shall be that used for production of the project concrete and sieved so that only material passing the No. 16 mesh is used. Only sufficient water shall be used to produce a mortar which, when used, will stick together on being molded into a ball by a slight pressure of the hands and will not exude water but will leave the hands damp. Mortar shall be mixed and allowed to stand for 30 to 45 minutes before use with remixing performed immediately prior to use. Holes passing entirely through walls shall be completely filled from the inside face by forcing mortar through to the outside face. All holes shall be packed full. Dry-pack repairs shall be moist cured for at least 48 hours.

3.12.2 Repair of Major Defects

Major defects are considered to be those repairs that are larger than the repairs to receive dry-pack mortar or that are otherwise so identified by the Contracting Officer. Such defects shall be repaired as specified herein or directed, except that defects which affect the strength of the structure shall not be repaired and that portion of the structure shall be completely removed and replaced. Deep and large defects shall be repaired by procedures approved in advance including forming and placing special concrete using applied pressure during hardening. Preparation of the repair area shall be as specified. Defective areas shall be outlined by a 1 inch deep cut. All saw cuts shall be straight lines in a rectangular

SECTION 03 30 00.60 Page 18 pattern in line with the formwork panels and shall angled be approximately 20 degrees to form a dovetailed recess. Removal required deeper than the sawcut shall be achieved by chipping or grinding. Approved equipment and procedures which will not cause cracking or microcracking of the sound concrete shall be used. If reinforcement is encountered, concrete shall be removed so as to expose the reinforcement for at least 2 inches around the reinforcing steel. After concrete removal, the surface shall be thoroughly cleaned by high pressure washing to remove all loose material.