addendum-2-rfp-des-2025-02.pdf

Little Bog Pond Dam & Lower Trio Pond Dam Reconstruction Project

Addendum #2

Please find the following ADDENDUM #2, dated August 23th, 2024, for the Little Bog Pond Dam & Lower Trio Pond Dam Reconstruction Project which is to be included as part of the Contract Documents thereof.

As per Specification Section 00200, Article 13.09 the bid shall contain an acknowledgment of receipt of this Addendum #2, (and all addenda). The number and date of which shall be filled in by filling out the information in the space provided in Section 00301 – Bid Form, Article 3 – 3.01A.

Please note bids are due Thursday, September 12, 2024, at 2:00 PM (EST). Hard copy bids may be received as stipulated in the Contract Documents. This Addendum has been issued to address clarifications in the Contract Specifications as well as address Prospective Contractor Questions after the August 7, 2024, Pre- Bid Meeting:

ITEM #1: Response to Contractor Questions

1. Can the bid date be extended. Yes, the bids due date will be extended to September 12th at 2 PM EST.

2. Response to Addendum 1 Question No. 8: If installed per the documents, should a storm in excess of the basis of design occur, is the Contractor liable. The Contractor is hereby made aware that the NHDES Dam Bureau has no control over inflows into the waterbodies. Major rainfall events and/or snowmelt may cause the level of either Little Bog Pond or Lower Trio Pond to rise rapidly and lead to potential inundation of the work site. In the event of uncontrolled increases in the Lake level, the Contractor shall undertake measures to protect existing structures and new work at no additional cost to the Bureau, up to the design requirements specified in the Contract Documents. The Contractor shall be responsible for any loss or damage to their work, equipment, or material. Costs for any mobilization(s) and demobilization(s) required by the Dam Bureau, as a result of a major rainfall event that exceeds the control of water requirements in the Design Documents, shall be paid for at a time and materials rate to be negotiated with the Dam Bureau and shall not be included in the bid. Note that no payment for mobilization(s) and demobilization(s) will be made if it is the result of the Contractor’s surface water control systems (i.e. cofferdams, diversion channels, pump/siphon systems, etc.) inadequacies under normally anticipated weather/precipitation conditions.

3. Response to Addendum 1 Question No. 11: Is the contractor required to have a trailer with a dedicated office for the RPR in addition to what the Contractor requires? Is the Contractor to furnish the office? Please clarify what is required. The Contractor is responsible to provide a dedicated workspace for the RPR in a construction trailer. At a minimum, this should include a desk, rolling office chair, two-drawer file cabinet, flat table.

4. Based upon observations made during the site walk, and dueto a lack of subsurface investigations, will NH DES revise the Bid Form to provide an item for Rock Removal, specifically buried boulders (not shown on t he design documents as stated in Specification Section 01 20 00 under General Site Demolition) and ledge.

No. This work is incidental to the excavation pay item.

5. Per Specification Section 312323 3.02B: If a mud mat is required at footings if graded gravel, cobbles, or b oulders are present at subgrade, how will this be paid for? This work is incidental to the concrete work associated with the footings.

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6. Per Specification Section 312323 3.02B: If choke stone is required at the weir and apron slab where graded gravel, cobbles, or boulders are present at subgrade, how will this be paid for? This work is incidental to the concrete work associated with the footings.

7. Should the Spillway weir wall be considered as mass concrete? Please advise. See revised Specification 03 30 00 – Cast-in-Place Concrete which provides clarity on mass concrete. The concrete pours may be considered mass concrete depending on the contractors proposed pour sequences and sizes.

Attachments:

Attachment #1 – Revised Section 03 30 00 Cast-In-Place Concrete

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NHDES – Dams Bureau Little Bog Pond and Lower Trio Pond Dam Reconstruction

SECTION 03 30 00

CAST-IN-PLACE CONCRETE

PART 1 GENERAL

1.01 WORK INCLUDES

A. Provide all layout, products, materials, equipment, tools, services, transportation, supervision, and labor to complete all the work as shown on the drawings and including the following:

1. Cast-in-place concrete required for construction of the Work shown on the drawings.

B. Related Sections:

1. Section 03 05 00: BASIC CONCRETE MATERIALS

2. Section 03 10 00: CONCRETE FORMS AND ACCESORIES

3. Section 03 20 00: CONCRETE REINFORCEMENT

4. Work Specified under other sections: Items to be embedded in concrete are as specified in the various sections of this specification. The responsibility for coordinating concrete placements with embedded items rests solely with the

CONTRACTOR.

1.02 REFERENCES

A. The following is a list of standards that may be referenced in this Section:

1. American Concrete Institute (ACI):

a. ACI 301 - Specifications for Structural Concrete

b. ACI 117 - Standard Specifications for Tolerances for Concrete Construction and Materials.

c. ACI 207.1R – Guide to Mass Concrete

d. ACI 211.1 – Standard Practice for Selecting Proportions for Normal, Heavyweight and Mass Concrete.

e. ACI 302.1R - Guide for Concrete Floor and Slab Construction.

f. ACI 304R - Guide for Measuring, Mixing, Transporting, and Placing Concrete.

g. ACI 304.2R - Placing Concrete by Pumping Methods.

h. ACI 305R - Hot Weather Concreting.

i. ACI 306R - Cold Weather Concreting.

j. ACI 306.1 - Standard Specification for Cold Weather Concreting.

k. ACI 308.1 - Standard Specification for Curing Concrete.

l. ACI 309R - Guide for Consolidating Concrete.

100% Design Submittal, REV 1 Cast-in-Place Concrete August 2024 03 30 00-1

m. ACI 318/318R - Building Code Requirements for Structural Concrete and Commentary.

n. ACI 350 - Code Requirements for Environmental Engineering Concrete Structures and Commentary

2. American Society for Testing and Materials (ASTM):

a. ASTM A82 - Steel Wire, Plain, for Concrete Reinforcement.

b. ASTM A185 - Steel Welded Wire Fabric, Plain, for Concrete Reinforcement.

c. ASTM A615 - Deformed and Plain Billet-Steel Bars for Concrete Reinforcement.

d. ASTM C31 - Standard Practice for Making and Curing Concrete Test Specimens in the Field.

e. ASTM C33 - Concrete Aggregates.

f. ASTM C39 - Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens.

g. ASTM C94 - Ready-Mixed Concrete.

h. ASTM C114 - Standard Test Methods for Chemical Analysis of Hydraulic Cement.

i. ASTM C143 - Standard Test Method for Slump of Hydraulic Cement Concrete.

j. ASTM C150 - Portland Cement (PC).

k. ASTM C156 – Standard Test Method for Water Retention by Concrete Curing Materials.

l. ASTM C 231 - Standard Test Method for Air Content of Freshly Mixed Concrete by the Pressure Method.

m. ASTM C260 – Air Entraining Admixtures for Concrete.

n. ASTM C309 – Liquid Membrane-Forming Compounds for Curing Concrete.

o. ASTM C494 – Chemical Admixtures for Concrete.

p. ASTM C595 – Standard Specifications for Blended Hydraulic Cements (PLC – Portland Limestone Cement)

q. ASTM C618 - Standard Specification for Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use in Concrete.

r. ASTM C989 - Standard Specification for Slag Cement for Use in Concrete and Mortars.

s. ASTM C1077 - Standard Practice for Agencies Testing Concrete and Concrete Aggregates for Use in Construction and Criteria for Testing Agency Evaluation.

t. ASTM C 1315 - Standard Specification for Liquid Membrane-Forming Compounds having Special Properties for Curing and Sealing Concrete.

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u. ASTM C1602 - Standard Specification for Mixing Water Used in Production of Hydraulic Cement Concrete.

v. ASTM C1611 – Standard Test Method for Slump Flow of Self- Consolidating Concrete.

w. ASTM D 2103: Polyethylene Film and Sheeting.

x. ASTM E 329 - Standard Specification for Agencies Engaged in the Testing and/or Inspection of Materials Used in Construction.

3. American Welding Society:

a. AWS D1.4 – Structural Welding Code – Reinforcing Steel

4. U.S. Army Corps of Engineers Specifications (USACE):

a. CRD C572 PVC Waterstop.

b. EM 1110-2-2104 – Strength Design for Reinforced Concrete Hydraulic Structures.

c. INP-SL-1 – Assessment of Underwater Concrete Technologies for in- Wet Construction of Navigation Structures.

5. Other:

a. U.S. Product Standard PS 20 - American Softwood Lumber Standard.

B. Where these Specifications differ from the requirements of ACI or ASTM, the more stringent requirements shall apply.

1.03 DEFINITIONS

A. Exposed Concrete: Concrete surfaces that can be inside or outside of structures, regardless of whether concrete is above or below water, dry at all times, or can be seen when structure is drained.

B. Defective Areas: Surface defects that include honeycomb, rock pockets, indentations greater than 3/16 inch, cracks 0.005-inch wide and larger as well as any crack that leaks for liquid containment basins and below grade habitable spaces; cracks 0.010-inch wide and larger in non-fluid holding structures spalls, chips, air bubbles greater than 3/4-inch in-diameter, pinholes, bug holes, embedded debris, lift lines, sand lines, bleed lines, leakage from form joints, fins and other projections, form popouts, texture irregularities, and stains and other color variations that cannot be removed by cleaning.

C. New Concrete: Concrete less than 60-days old.

D. Design Strength: As defined in Section 03 05 00: BASIC CONCRETE MATERIALS.

E. Mass Concrete: is any concrete system that approaches a maximum temperature of 160 degrees F within the first 72 hours of placement. In addition, it includes all concrete elements with a section thickness of 3 feet or more regardless of temperature.

1.04 SUBMITTALS

A. Furnish submittals following procedures specified in applicable sections of the Contract Documents.

B. Concrete Placement Plan to include at a minimum:

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1. Procedures for control of concrete temperature during placement.

2. Laboratory and Field Testing.

3. Placement Schematic and Procedures.

4. Pour sequence(s) for all concrete work at the site.

5. Quality control procedure and responsible parties.

C. Cold Weather Concrete Placement and Insulation Plan. Develop a Cold Weather Placement and Insulation Plan in conformance to ACI 306.1. The plan shall include:

1. Temperature controls

2. Heaters

3. Thermal blankets to insulate curing concrete.

D. Warm Weather Concrete Placement and Cooling Plan. Develop a Warm Weather Concrete Placement and Cooling Plan in conformance with ACI 305.1. The plan shall include:

1. Concrete materials cooling plan to ensure delivered concrete is no hotter than 80 degrees F.

2. Placement sequence and controls to control temperatures during warm weather.

3. Thermal controls that will prevent curing concrete temperatures from exceeding 160 degrees.

E. Administrative:

1. Manufacturer’s application instructions for curing compound.

2. Statement of Qualifications:

a. CONTRACTOR’s resident superintendent for concrete placement.

3. Preinstallation Conference minutes.

F. Quality Control:

1. Concrete batch ticket for each load of concrete delivered to the site.

2. Manufacturer’s certification.

3. Test reports.

G. Shop Drawings:

1. Detailed drawings of the falsework proposed to be used. Such drawings shall be in sufficient detail to indicate the layout, sizes of members, anticipated stresses, grade of materials to be used in the falsework, and typical foundation conditions.

Falsework drawings must be designed and stamped by a professional engineer licensed in the state of New Hampshire.

2. Reinforcing shop drawings, rebar bending diagrams, and placing lists for reinforcing steel. Details of reinforcing steel for fabrication and erection shall conform to ACI 315 - Details and Detailing of Concrete Reinforcement. The shop bending diagrams shall show the actual lengths of bars, to the nearest inch measured to the intersection of the extensions (tangents for bars of circular cross

August 2024 03 30 00-4 section) of the outside surface. Include bar placement diagrams which clearly indicate the dimensions of each bar splice.

3. Shop drawings showing vertical and horizontal construction joints, control joints expansion joints, Waterstops and the requirements herein.

4. Where mechanical couplers are required or permitted to be used to splice reinforcing steel, submit manufacturer's literature, which contains instructions and recommendations for installation for each type of coupler used; certified test reports, which verify the load capacity of each type and size of coupler used; and shop drawings that show the location of each coupler with details of how they are to be installed in the formwork.

H. Mix Designs: Prior to beginning the work, submit concrete mix designs, which shall show the proportions and gradations of materials proposed for each class and type of concrete as well as historical performance data showing that the mix designs will meet the requirements of these Specifications. When a water-reducing admixture is to be used, the CONTRACTOR shall furnish mix designs for concrete both with and without the admixture.

I. Delivery Tickets: Where ready-mix concrete is used, the CONTRACTOR shall furnish certified delivery tickets at the time of delivery of each load of concrete. Each ticket shall show the state-certified equipment used for measuring, and the total quantities, by weight, of cement, sand, each class of aggregate, admixtures, the amounts of water in the aggregate, and added at the batching plant. If water is added at the Site, that shall be included on the ticket. In addition, each certificate shall state the mix number, total yield in cubic yards, and the time of day to the nearest minute, corresponding to the time when the batch was dispatched, when it left the plant, when it arrived at the Site, when unloading began, and when unloading was finished.

J. Mass Concrete Thermal Control Plan. Develop a Thermal Control Plan in conformance with ACI 207 for concrete placement that exceeds 4 feet in walls or 3 feet in slabs or mats.

1. Plans and systems to monitor and control temperature during batching, transportation, and placement of concrete.

2. Plans and systems for monitoring temperature of concrete during curing using thermistors placed in middle and edges of each pour to confirm the temperature differentials are within specification limits, that the heat of hydration has reached its peak and is dissipating prior to subsequent pours.

Include description of thermistors, placement locations, plans for protection.

Include redundant thermistors.

a. Thermal controls that will prevent curing concrete temperatures from exceeding 160 degrees F and differential temperature limit between interior curing concrete and exterior curing does not exceed 35 degrees F.

3. Sequence of subsequent pours to allow the heat of the mass to dissipate and remain within the temperature limits in the specifications.

4. Plans to lower the temperature of placed concrete if temperature exceeds limits specified in the Thermal Control Plan.

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1.05 HOT AND COLD WEATHER CONDITIONS

A. Hot and Warm Weather:

1. Follow approved Warm Weather Concrete Placement and Cooling Plan.

2. Concrete temperature shall not exceed 80⁰F at placement.

3. At air temperatures of 80⁰F, water reducing, set retarding admixtures shall be used in accordance with manufacturer’s recommendations.

4. When concrete temperatures exceed 80⁰F, water reducing, set retarding admixtures shall be used in accordance with manufacturer’s recommendations.

5. Rate of evaporation from concrete surface shall not exceed 0.2 lb/ft²/h based on ACI 305R Table 2.1.5 and Figure 2.1.5. Use fog-spray or evaporation retardant to maintain evaporation at 0.2 lb/ft²/h or less.

B. Cold Weather

1. Follow approved Cold Weather Placement and Insulation Plan when the ambient air temperature is less than 40oF, or if the ambient air temperature is approaching 40oF and falling.

2. Temperature of earth, reinforcement, forms, fillers, and other materials in contact with concrete at time of placement shall not be less than 35⁰F.

3. Maintain air and forms in contact with concrete sections having minimum dimension less than 12 in. at temperature above 50⁰F for at least first 3 days and at temperature above 32⁰F for remainder of specified curing period.

4. Maintain air and forms in contact with concrete in more massive sections at temperature above 40⁰F for at least first 7 days and at temperature above 32⁰F for remainder if specified curing period.

5. Do not locally heat or dry concrete when using heating units to meet Specification requirements.

1.06 QUALITY ASSURANCE

A. Preinstallation conference:

1. Meeting attendees:

a. CONTRACTOR, including pumping, placing, finishing, and curing subcontractors. (Attendance mandatory)

b. RPR, including field inspection personnel.

c. Concrete supplier representative. (Attendance mandatory)

d. Admixture representative. (Attendance mandatory)

e. Quality control testing and sampling personnel. (Attendance mandatory)

f. OWNER’s representative.

2. Agenda shall include, as a minimum, the following topics:

a. Status of submittals.

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b. Mix designs; required slump and air content requirements; admixture types, dosage, performance, and re-dosing at site; concrete placement temperature requirements.

c. Placement methods and equipment, consolidation, finishing, curing, and protection of concrete.

d. Quality control requirements and procedures.

e. Hot and cold weather procedures.

B. Quality Control Submittals

1. Manufacturer’s Certificate of Compliance:

a. Portland Cement.

b. Admixtures.

c. Fly ash.

d. Aggregates.

e. Bonding agent.

f. Bond breaker.

g. Patching materials.

h. Admixtures: Manufacturers’ Certificate of Proper Installation.

2. Test Reports

a. Admixtures, test reports showing chemical ingredients and percentage of chloride in each admixture and fly ash.

b. Source test analyses report for fly ash, including a percentage of chloride content and loss on ignition (LOI).

c. Statement identifying reactivity of aggregates. Determine water-soluble chloride in each component of aggregates in accordance with ASTM C 1218.

d. For each trial concrete mix design and signed y a qualified mix designer;

including cylinder compressive strength test results for laboratory concrete mixes.

e. Field quality control test results.

C. Testing of Reinforcing Steel:

1. If requested by NHDES or RPR, the CONTRACTOR shall furnish samples from each heat of reinforcing steel in a quantity adequate for testing.

D. Testing of Concrete Materials:

1. Testing for aggregate shall include sieve analysis, sand equivalence, clay and friable content, light weight particles and organic impurities content, alkali-silica reactivity, abrasion resistance, and soundness in accordance with ASTM C33 - Concrete Aggregates.

2. The cost of laboratory tests on cement, aggregates, and concrete, will be paid by the CONTRACTOR. The laboratory will meet or exceed the requirements of

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ASTM C1077 - Standard Practice for Agencies Testing Concrete and Concrete Aggregates for Use in Construction and Criteria for Testing Agency Evaluation.

3. Field Sampling and Testing

a. Concrete samples for pumped concrete will be taken from the placement (discharge) end of the pumping line.

b. Compressive Strength

1) Frequency: Compression test specimens shall be taken during construction from the first daily delivery and placement of each class of concrete herein and at 50 cubic yard intervals thereafter as selected by NHDES or RPR to ensure continued compliance with these Specifications.

a) Each set of test specimens will be a minimum of six (6) cylinders.

b) One additional test cylinder will be taken during cold weather and be cured on site under same conditions as concrete it represents.

2) Cylinder Preparation: Compression test specimens for concrete will be made in accordance with Section 9.2 of ASTM C31 - Standard Practice for Making and Curing Concrete Test Specimens in the Field.

a) Specimens will be 6-inch-diameter by 12-inch-high cylinders.

3) Test Procedure: Compression tests will be performed in accordance with ASTM C39 - Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens at the following intervals:

a) One (1) test cylinder will be tested at three (3) days,

b) One (1) test cylinder will be tested at seven (7) days,

c) one (1) test cylinder will be tested at fourteen (14) days,

d) two (2) test cylinders will be tested at twenty-eight days (28), and

e) one (1) test cylinder will be retained for additional testing as needed.

c. Slump

1) Test Procedure: Tests for determining slump will be in accordance with the requirements of ASTM C143 - Standard Test Method for Slump of Hydraulic Cement Concrete

2) Frequency: One (1) test for each 50 cubic yards or one for each concrete pour.

d. Air Entrainment

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1) Test Procedure: Tests for air entrainment in accordance with the requirements of ASTM C231 - Air Content of Freshly Mixed Concrete by the Pressure Method

2) Frequency: One (1) test for each 50 cubic yards or one for each concrete pour.

e. Temperature:

1) Frequency: One (1) test for each 50 cubic yards or one for each concrete pour.

2) Measure temperature immediately prior to placement.

f. Concrete for NHDES QA testing shall be furnished by the CONTRACTOR at no cost to NHDES. The CONTRACTOR shall assist RPR in obtaining samples and disposal and cleanup of excess material.

E. Evaluation and Acceptance of Concrete:

1. Evaluation and acceptance of the compressive strength of concrete will be according to the requirements of ACI 318 - Building Code Requirements for Reinforced Concrete, Chapter 5 "Concrete Quality", and as indicated herein.

2. If any concrete fails to meet these requirements, immediate corrective action shall be taken to increase the compressive strength for subsequent batches of the type of concrete affected.

3. Concrete that fails to meet the ACI requirements and these Specifications is subject to removal and replacement as part of the Work.

F. Construction Tolerances:

1. The CONTRACTOR shall set and maintain concrete forms and perform finishing operations so that the concrete is within the tolerances herein. Surface defects and irregularities are defined as finishes and are to be distinguished from tolerances. Tolerance is the permissible variation from lines, grades, or dimensions indicated.

2. Where tolerances are not indicated, permissible deviations will be in accordance with ACI 117 - Standard Tolerance for Concrete Construction and Materials.

Unless otherwise specified, the variation from required lines or grades shall not exceed 1/4 inch in 10 feet and there shall be no offsets or visible waviness in the finished surface.

G. Concrete curing shall conform to requirements of ACI 301 and ACI 308.

PART 2 PRODUCTS

2.01 FORM AND FALSEWORK MATERIALS

A. Refer to specification Section 03 10 00: CONCRETE FORMS AND ACCESORIES.

2.02 FORM TIES

A. Refer to specification Section 03 10 00: CONCRETE FORMS AND ACCESORIES.

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2.03 CONCRETE MATERIALS

A. Materials shall be delivered, stored, and handled to prevent damage by water or breakage.

Only one brand of cement shall be used. Cement reclaimed from cleaning bags or leaking containers shall not be used. Cement shall be used in the sequence of receipt of shipments.

B. Materials for the Work shall comply with the requirements of Sections 201, 203, and 204 of ACI 301- Structural Concrete for Buildings, as applicable.

C. Storage of materials shall conform to the requirements of Section 205 of ACI 301.

D. Materials for concrete shall conform to the following NHDOT requirements:

1. Cement shall be Portland Cement (PC) conforming to ASTM C150 - Portland Cement, Type I/II, Type II, or a Portland Limestone Cement (PLC) conforming to ASTM C595 – Standard Specifications for Blended Hydraulic Cements (PLC

– Portland Limestone Cement) Type 1L.

2. Where Portland Cement or Portland Limestone Cement plus a pozzolan is used the pozzolan shall not constitute more than 20% by weight of the total cementitious materials, unless otherwise specified. Pozzolan shall meet the requirements of ASTM C618 for Class N or F with the following additional requirements:

a. The maximum percentage of sulfur trioxide shall be 4.0 percent for Class F.

b. The maximum percentage loss on ignition shall be 8.0 percent for Class N and 2.5 percent for Class F.

c. The pozzolanic activity index with lime shall be determined using 2-inch cubes and the minimum strength at seven (7) days shall be 900 pounds per square inch.

d. Unless the CONTRACTOR selects aggregates that are not potentially alkali-reactive, pozzolan shall be tested for reduction of mortar expansion at fourteen (14) days as specified for Class N pozzolan under the optional physical requirements in Table 2A of ANSI/ASTM C618.

However, the cement used in the test shall be low-alkali. For the pozzolan to be acceptable, it shall result in an expansion reduction of zero percent or greater when compared to the control test.

e. Pozzolan shall not decrease the sulfate resistance of concrete. Before a Class N pozzolan is used, it shall be shown by test and experience not to detract from the sulfate resistance. Before a Class F pozzolan is used, it shall be shown to have an “R” factor of less than 2.5, determined in accordance with ASTM C114.

3. Granulated blast furnace slag shall conform with ASTM C989 Grade 100 and contain less than 0.1% by weight free carbon or steel slag.

4. Water shall be potable, clean, and free from objectionable quantities of silty organic matter, alkali, salts, and other impurities. The water shall be considered potable, for the purposes of this Section only, if it meets local drinking water standards. Agricultural water with high total dissolved solids (over 1000 mg/l TDS) shall not be used.

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NHDES – Dams Bureau

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Little Bog Pond and Lower Trio Pond Dam Reconstruction

Aggregates shall be obtained from pits acceptable to NHDES and RPR, shall be non-reactive, and shall conform to ASTM C33, and meet the durability requirements of the NHDOT. Lightweight sand for fine aggregate will not be permitted. Sand shall not exceed 40% of the total aggregates.

a. Coarse Aggregate Size: Maximum size of coarse aggregate shall not exceed the following requirements but in no case larger than ¾ inches.

1) One-fifth narrowest dimension between sides of forms within which concrete is to be cast.

2) Three-fourths of the minimum clear spacing between reinforcing bars.

3) One-third the slab thickness for unreinforced slabs.

4) Reduced aggregate concrete containing aggregate with particle size not less than 1/8 inch nor more than 1/2 inch in any dimension and a maximum of 5 percent of particles passing a No. 8 sieve (for use in metal pan stairs only).

5) Three-fourths of the minimum clear spacing between waterstop and reinforcing steel.

6) Self-Consolidating Concrete shall have a maximum size of coarse aggregate not exceeding ½ inch.

Ready-mixed concrete shall conform to the requirements of ASTM C94 – Ready-Mixed Concrete.

Air-entraining agent meeting the requirements of ASTM C260 - Air Entraining Admixtures for Concrete shall be used. Sufficient air-entraining agent shall be used to provide the specified air content. NHDES and RPR reserves the right, at any time, to sample and test the air-entraining agent. The air-entraining agent shall be added to the batch as specified by the manufacturer. Air content shall be tested at the point of placement. Air entraining agent shall be Micro-Air by Master Builders, Daravair by Grace Construction Products, Sika AEA-15 by Sika Corporation, or equal.

Admixtures: The CONTRACTOR may propose the addition of admixtures to control the set, affect water reduction, and increase workability. The use of an admixture shall be subject to acceptance by NHDES and RPR. In any case, the addition of an admixture shall be at the CONTRACTOR 's expense. Concrete containing an admixture shall be first placed at a location determined by RPR, in a test pour if so directed; such a test pour shall be at the CONTRACTOR’s expense. If the use of an admixture is producing an inferior result, the CONTRACTOR shall discontinue use of the admixture. Admixtures shall conform to the requirements of ASTM C494 - Chemical Admixtures for Concrete. The required quantity of cement shall be used in the mix regardless of whether an admixture is used. Admixtures shall contain no free chloride ions, shall be non-toxic after 30 days, and shall be compatible with and made by the same manufacturer as the air entraining admixture.

a. All chemical admixtures shall be from the same manufacturer.

b. Concrete shall not contain more than one water-reducing admixture.

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NHDES – Dams Bureau c.

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Little Bog Pond and Lower Trio Pond Dam Reconstruction

Provide admixtures produced and serviced by established, reputable manufacturers and use in compliance with manufacturer's recommendations.

Admixtures used for all cast-in-place concrete shall conform to the requirements of ANSI/NSF 61.

Air-Entraining Admixture: Use a product conforming to requirements of ASTM C 260. Acceptable Manufacturers:

AEA-92; The Euclid Chemical Company.

Sika Air; Sika Corporation.

Micro Air; BASF.

Or approved equal.

Water-Reducing Admixture: Use a product conforming to requirements of ASTM C 494 Type A. (Required for all concrete except where an alternate water reducing admixture type as listed below is used).

Acceptable Manufacturers:

Eucon WR-91; The Euclid Chemical Company PolyHeed 997; BASF.

Or approved equal.

Water-Reducing and Retarding Admixture: Use a product conforming to requirements of ASTM C 494, Type D. Acceptable Manufacturers:

Eucon Retarder-75; The Euclid Chemical Company.

Plastiment; Sika Corporation.

Pozzolith 200N; BASF.

Or Approved Equal.

High-Range Water Reducing Admixture: Use a product conforming to requirements of ASTM C 494, Types A and F. Acceptable Manufacturers:

Eucon 37; The Euclid Chemical Company.

Sika ViscoCrete 2100; Sika Corporation.

Glenium 7700; BASF.

Or approved equal.

Water-Reducing, and Acceleration Admixture: Use a product conforming to requirements of ASTM C 494, Types C or E. Not permitted for use in concrete for water retaining structures. Acceptable Manufacturers:

Accelguard 80; The Euclid Chemical Company.

Pozzutec 20; BASF.

Plastocrete 161 FL, Sika Rapid-1, or Sikaset series; Sika

Corporation.

Or Approved Equal

Set controlling admixture may be either with or without water-reducing properties. Where the air temperature at the time of placement is expected to be consistently over 80 degrees F, a set retarding admixture such as Sika Corporation Plastocrete 161MR, Master Builder Pozzolith, August 2024 03 30 00-12

Daratard 17 by Grace Construction Products, EUCON Retarder 100 by Euclid, or equal shall be used. Where the air temperature at the time of placement is expected to be consistently under 40 degrees, a set accelerating admixture such as Sika Corporation Plastocrete 161 FL, Polarset by Grace Construction Products, or equal shall be used.

k. Normal range water reducer shall conform to ASTM C494, Type A. It shall be WRDA 79 by Grace Construction Products, Plastocrete 161 by Sika Corporation, EUCON 37 by Euclid Chemical, or equal. The quantity of admixture used, and the method of mixing shall be in accordance with the manufacturer's instructions and recommendations.

l. Anti-Washout admixture such as MasterMatrix UW 450 by Master Builder, EUCON AWA by Euclid Chemical or equal.

9. Calcium Chloride: Calcium chloride will not be permitted in concrete.

10. Alumina: Alumina will not be permitted in concrete.

2.04 CURING COMPOUNDS AND MATERIALS

A. Compounds for curing concrete shall conform to the following requirements and ASTM C309 - Liquid Membrane-Forming Compounds for Curing Concrete. Curing compounds must be from the same manufacture as the concrete admixtures. Curing compounds shall either be approved for potable water use per NSF 61 or removed after curing.

1. Curing compounds shall be white-pigmented and resin-based. Sodium silicate compounds shall not be allowed. Concrete curing compound shall be Kurez VOX White Pigmented by Euclid Chemical Company, Cure R-2 by L&M Construction Chemicals, 1200-White by W.R. Meadows, or equal. When curing compound must be removed for finishes or grouting, curing compounds shall be Kurez DR VOX by Euclid Chemical Company, L&M Cure R by L&M Construction Chemicals, 1100-Clear by WR Meadows, or equal. Curing compounds shall meet local VOC requirements.

B. Materials for curing concrete shall be:

1. Saturated burlap blankets with drip lines conforming to AASHTO M 182.

2. Polyethylene sheet for use as concrete curing blanket shall be white and shall have a nominal thickness of 6 mils. The loss of moisture when determined in accordance with the requirements of ASTM C156 - Standard Test Method for Water Retention by Concrete Curing Materials, shall not exceed 0.055 grams per square centimeter of surface.

3. Sheet Materials: Material conforming to ASTM C 171.

1. Water: Meet the standard chemical requirements for ready mix concrete as established in ASTM C 94, “Standard Specification for Ready-Mixed Concrete.”

2.05 PVC WATERSTOP

A. Fabricated from a compound of which the basic resin shall be prime virgin polyvinyl chloride (PVC). Compound shall not contain scrapped material, reclaimed material, or pigment.

B. Conform to performance requirements of USACE CRD C572 –PVC Waterstop.

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C. Type – Flat Ribbed waterstop and hydrohilic swelling waterstops.

D. Specific Gravity – Not more than 1.4.

E. Shore Durometer Type A Hardness – Not less than 60.

F. PVC waterstops shall be designated as follows:

1. Type 1 Waterstop: Flat Ribbed waterstop shall be Greenstreak 679 or approved equal. Minimum 6-inches wide, 3/8-inch thick.

2. Type 2 Waterstop: Sika Swellstop, 3/4-inch thick.

G. Acceptable Manufacturers:

1. Sika Greensteak

2. Vinylex corporation

3. W.R. Meadows

4. Or Approved Equal

2.06 MISCELLANEOUS MATERIALS

A. Epoxy grout for grouting reinforcing bars shall be HIT-RE 500V3 two-component adhesive or approved equal. Adhesive shall be rated for use with deformed rebar in cracked and uncracked concrete under wet or dry installation and service conditions.

B. Joint filler: Conforming to ASTM D 1752; pre-molded sponge rubber fully compressible with recovery rate of minimum 95 percent.

C. Joint sealant: Polyurethane-based elastomeric sealant - Sikaflex -2c NS by Sika Corporation or approved equal.

D. Form Release Agent: Provide a Form Release Agent product that does not bond with, stain, or adversely affect concrete surfaces and does not impair subsequent treatments of concrete surfaces. Provide form release agent that does not contain diesel fuel, petroleum-based lubricating oils, waxes, or kerosene.

2.07 CONCRETE MIX DESIGN REQUIREMENTS

A. General:

1. Concrete shall be composed of cement, admixtures, aggregates, and water of the qualities indicated. In general, the mix shall be designed to produce a concrete capable of being deposited to obtain maximum density and minimum shrinkage, and where deposited in forms, to have good consolidation properties and maximum smoothness of surface. The proportions shall be changed whenever necessary or desirable to meet the required results at no additional cost to NHDES. Mix changes shall be subject to review by NHDES and RPR.

2. The CONTRACTOR is cautioned that the limiting parameters below are NOT a mix design. Admixtures may be required to achieve workability required by the CONTRACTOR 's construction methods and aggregates. The CONTRACTOR is responsible for providing concrete with the required workability.

B. Standard Classes of Concrete:

1. Structural Concrete: Proportion normal weight concrete as follows:

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a. Minimum Compressive Strength: 4,000 psi at 28 days.

b. Maximum Water-Cementitious Materials Ratio: 0.45.

c. Slump Limits: 4 to 8 inches according to ASTM C143 - Standard Test Method for Slump of Hydraulic Cement Concrete. At no time shall water be added to concrete mix on-site. If higher slump is required a water reducing agent shall be added by the concrete supplier.

d. Air Content: 6%, plus or minus 1.0 percent at point of delivery for 3/4 -inch nominal maximum aggregate size.

e. The temperature of concrete upon delivery from the truck shall not exceed 80°F.

2. Mud Mat:

f. Minimum Compressive Strength: 1500 psi at 7 days.

g. Slump Range at Placement: 2 to 4 inches.

h. Maximum Water-Cementitious Material Ratio: 0.50.

i. Air Content Range: 5 to 8 percent.

C. All concrete shall be air-entrained. Air content at the point of placement shall conform to the requirements of ACI 301.

D. Fly ash may constitute up to 20 percent by weight of the total cementitious content.

E. Use set-retarding admixtures during hot weather only when approved by RPR.

2.08 MEASUREMENT OF MATERIALS

A. The amount of cement and of each separate size of aggregate entering into each batch of concrete shall be determined by direct weighing equipment furnished by the CONTRACTOR and acceptable to NHDES and RPR; provided that, where batches are so proportioned as to contain an integral number of conventional sacks of cement and the cement is delivered at the mixer in the original unbroken sacks, the weight of the cement contained in each sack may be taken without weighing as 94 pounds.

B. The quantity of water entering the mixer shall be measured by a suitable water meter or other measuring device of a type acceptable to NHDES and RPR and capable of measuring the water in variable amounts within a tolerance of one percent.

2.09 READY-MIXED CONCRETE

A. At the CONTRACTOR 's option, ready-mixed concrete may be used if it meets the requirements as to materials, batching, mixing, transporting, placing, the supplementary requirements as required herein, and is in accordance with ASTM C94 – Ready-Mixed Concrete.

B. Ready-mixed concrete shall be delivered to the Work, and discharge shall be completed within 90 minutes after the addition of water to the cement and aggregates or before the drum has been revolved 250 revolutions, whichever comes first.

C. Truck mixers shall be equipped with electrically actuated counters by which the number of revolutions of the drum or blades may be readily verified. The counter shall be of the resettable, recording type, and shall be mounted in the driver's cab. The counter shall be actuated at the time of starting the mixer at mixing speed. Materials including mixing

August 2024 03 30 00-15 water shall be in the mixer drum before actuating the revolution counter for determining the number of revolutions of mixing.

D. Each batch of ready-mixed concrete delivered to the Work shall be accompanied by a delivery ticket furnished to RPR.

E. The use of non-agitating equipment for transporting ready-mixed concrete will not be permitted. Combination truck and trailer equipment for transporting ready-mixed concrete will not be permitted.

F. The quality and quantity of materials used in ready-mixed concrete and in batch aggregates shall be subject to continuous inspection at the batching plant by NHDES or

RPR.

PART 3 EXECUTION

3.01 GENERAL

A. Conform to ACI 301 and ACI 304R, except as modified by these Specifications.

B. Notify RPR a minimum of 24 hours prior to commencement of concreting operations.

C. Inspect work to receive cast-in-place concrete for deficiencies that would prevent proper execution of the finished work. Do not proceed with placing concrete until such deficiencies are corrected to the satisfaction of the RPR.

D. Should the RPR’s inspections identify quality control issues or other quality control issues arise during construction of the cast-in-place concrete, the RPR may require the CONTRACTOR to develop a quality control checklist to be submitted to the RPR for review and approval prior to each cast-in-place concrete placement.

3.02 WATERSTOPS

A. Installed to form a continuous watertight diaphragm in both horizontal and vertical joint intersections unless otherwise shown.

B. Installed PVC waterstop with one-half of the width of the waterstop embedded in the concrete on each side of the joint.

C. Provide a minimum of 2 1/2 inches of concrete cover over Waterstops. When structure has 2 layers of reinforcing steel, locate centered between layers of steel or as otherwise shown on the Drawings.

D. Secure waterstop in correct position. Tie PVC waterstop to reinforcing steel using grommets “hog rings,” or tie wire at maximum spacing of 12 inches.

E. Do not displace waterstop during placement of concrete.

F. Ensure that concrete around waterstop is properly consolidated to ensure complete embedment of the waterstop in the concrete.

G. Splice in accordance with manufacturer’s recommendations.

H. Only straight butt splices using heat welding shall be permitted in the field for PVC waterstop. All intersections, transitions, and changes of direction shall be factory fabricated.

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3.03 STEEL REINFORCEMENT

A. General Requirements: Reinforcement steel, welded wire fabric, couplers, and other appurtenances shall be fabricated and placed in accordance with the requirements of the Building Code and the supplementary requirements indicated herein.

B. Fabrication:

1. Reinforcement steel shall be accurately formed to the dimensions and shapes indicated, and the fabricating details shall be prepared in accordance with ACI 315 - Details and Detailing of Concrete Reinforcement and ACI 318, except as modified by the Drawings.

2. The CONTRACTOR shall fabricate reinforcement bars for structures in accordance with bending diagrams, placing lists, and placing drawings. Said drawings, diagrams, and lists shall be prepared by the CONTRACTOR.

3. Unless otherwise indicated, dowels shall match the size and spacing of the spliced bar.

B. Bending or Straightening: Reinforcement shall not be straightened or re-bent in a manner that will injure the material. Field bending of reinforcing bars will not be allowed Do not field cut reinforcing bars unless approved by RPR.

C. No bars partially embedded in concrete shall be field bent except as indicated or specifically permitted by RPR.

D. Placing:

1. Reinforcement steel shall be accurately positioned as indicated and shall be supported and wired together to prevent displacement, using annealed iron wire ties or suitable clips at intersections. Reinforcement steel shall be supported by concrete, plastic or metal supports, spacers or metal hangers that are strong and rigid enough to prevent any displacement of the reinforcement steel.

a. For concrete over formwork, the CONTRACTOR shall provide concrete, metal, plastic, or other acceptable bar chairs and spacers.

b. Where concrete is to be placed on the ground, supporting concrete blocks (or dobies) may be used in sufficient numbers to support the bars without settlement, but in no case shall such support be continuous. Concrete blocks used to support reinforcement steel shall be tied to the steel with wire ties which are embedded in the blocks.

2. Tie wires shall be bent away from the forms or exposed surface.

3. Bars additional to those indicated which may be found necessary or desirable by the CONTRACTOR for the purpose of securing reinforcement in position shall be provided by the CONTRACTOR as part of the Work.

4. Unless otherwise indicated, reinforcement placing tolerances and minimum spacing requirements shall be as specified in ACI 318 - Building Code Requirements for Reinforced Concrete and USACE EM 1110-2-2104.

5. Welded wire fabric reinforcement placed over horizontal forms shall be supported on slab bolsters having gray, plastic-coated standard type legs. Slab bolsters shall be spaced not more than 30 inches on centers, shall extend continuously across the entire width of the reinforcing mat, and shall support the reinforcing mat in the plane indicated.

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6. Welded wire fabric placed over the ground shall be supported on wired concrete blocks (dobies) spaced not more than 3 feet on centers in any direction. The practice of placing welded wire fabric on the ground and hooking into place in the freshly placed concrete shall not be used.

E. Cleaning and Protection:

1. Reinforcement steel shall always be protected from conditions conductive to corrosion until concrete is placed around it.

1. The surfaces of reinforcement steel and other metalwork to be in contact with concrete shall be thoroughly cleaned of dirt, grease, loose scale and rust, grout, mortar, and other foreign substances immediately before the concrete is placed.

Where there is delay in depositing concrete, reinforcing shall be reinspected and, if necessary recleaned.

3.04 CONCRETE PROPORTIONING AND MIXING

A. Proportioning of the concrete mix shall conform to the requirements of Section

4.2.3 "Proportioning" of ACI 301 – Specifications for Concrete Construction.

B. Mixing of concrete shall conform to the requirements of Section 4.3.1 “Measuring, batching, and mixing” of ACI 301.

C. Retempering of concrete or mortar which has partially hardened shall not be permitted.

D. Mixing of materials shall be done in accordance with AASHTO M 157 (ASTM C94).

Concrete shall be mixed in stationary mixers, in a central mix plant, in truck mixers, or in self-contained mobile mixers. Mixing time shall be measured from the time all materials, except water, are in the drum.

Admixtures listed in the mix design, or admixtures approved by the RPR and water may be added at the project site.

1. Mixing General. Concrete shall be deposited in place within 90 minutes after batching when concrete is delivered in truck mixers or agitating trucks, and within 60 minutes when delivered in non-agitating trucks.

2. The 90-minute time limit for a mixer or agitating trucks may be extended to 180 minutes if:

a. No water is added after 90 minutes.

b. The concrete temperature prior to placement is less than 90 °F. The approved concrete mix contains an approved retarding admixture.

3. The 90-minute time limit for a mixer or agitating trucks may be extended to 180 minutes if:

a. No water is added after 90 minutes.

b. The concrete temperature prior to placement is less than 90 °F.

c. The approved concrete mix contains an approved retarding admixture.

4. The 90-minute time limit for a mixer or agitating trucks may be extended longer than 180 minutes if:

a. An Extended Set Control Admixture (ESCA) is added at the time of batching. Procedures and doses shall be in accordance with

August 2024 03 30 00-18 manufacturer’s recommendations. The ESCA shall be on the approved products list.

b. The concrete temperature prior to placement is less than 90 °F.

c. Each load of concrete shall be sampled and tested by the CONTRACTOR for air content according to CP 61.

d. The Department will cast three additional acceptance cylinders. If the acceptance cylinders tested at 28 days do not meet design strength, the additional cylinders will be tested at 56 days for acceptance.

3.05 PREPARATION

A. Verify that anchors, seats, plates, reinforcement, and other items to be cast into concrete are accurately placed, held securely, and will not cause hardship in placing concrete.

Refer to Section 03 15 50: CONCRETE JOINTS, and Section 03 20 00 CONCRETE REINFORCEMENT, for additional requirements.

B. Remove debris and standing water from placement area. Dampen all earth and wood surfaces against which concrete will be placed. Keep surfaces moist until concrete is placed.

C. Do not place concrete until all formwork, reinforcement, and embedded items are properly placed and secured.

D. Supply concrete placement checkout cards satisfactory to RPR, and a watertight container for the cards at a convenient location near each placement site. List on the checkout cards all the various work items required prior to concrete placement. Each work item for the respective placement shall be completed and the card signed by CONTRACTOR.

Each work item shall then be inspected, and the card signed by RPR. Concrete placement may commence when all work items have been completed, inspected, and signed by both CONTRACTOR and RPR. The use of placement checkout cards may be waived by RPR where their use is judged to be impracticable.

E. Have all necessary placing equipment on site prior to ordering concrete.

F. Anchoring Reinforcement Dowels into Existing Concrete:

1. Drill holes for each dowel to the size and depth indicated on the Drawings with carbide tip bit or star bit. Core drilling will not be permitted. Do not drill into or cut or otherwise damage existing reinforcement bars. If existing reinforcement bars are encountered during the drilling operation, relocate the hole to clear the existing reinforcement as directed by the RPR.

2. Blow clean each finished hole with an oil free air jet and then flush with a jet of clean water.

3. Immediately prior to the grouting operation, remove all water from the hole and from the walls of the hole.

4. Pump dispensing gun for proper mixture. Insert nozzle and pump epoxy adhesive into the hole and insert reinforcement dowels. Do not retemper grout that has begun to stiffen; discard such grout. Comply with manufacturer's specified time limit within which the material must be placed after mixing.

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3.06 PLACING CONCRETE

A. Place concrete in as nearly a continuous operation as practical.

B. Place concrete in near horizontal layers. Use spreading equipment that prevents segregation and that produces layers of widths and thickness appropriate for proper consolidation. Place each successive layer as soon as practicable after the preceding layer is completed.

C. Use delivery and placement methods that do not cause segregation. The maximum free-fall drop height allowed for concrete placement shall be 4 feet.

D. Do not disturb reinforcement, inserts, embedded items, or formed joints.

E. Do not break or interrupt successive placements…