SECTION_03_37_23_-_Roller-Compacted_Concrete_R1_0003.pdf

BUREAU OF INDIAN AFFAIRS OGLALA DAM SPILLWAY AND OUTLET WORKS

OGLALA DAM SPILLWAY AND OUTLET WORKS SECTION 03 37 23

JUNE 2023 ROLLER-COMPACTED CONCRETE

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SECTION 03 37 23

ROLLER-COMPACTED CONCRETE

GENERAL

1.01 SCOPE OF WORK

A. This Section specifies the requirements for all Roller-Compacted Concrete (RCC) for the spillway structure, including the following items:

Submittals and quality control and assurance.

Product requirements for RCC mix design, and miscellaneous materials.

Execution requirements for preparation for RCC placement; RCC manufacturing, handling, placing, finishing, and curing; cold and hot weather procedures; and care and repair of concrete.

1.02 REFERENCES

A. American Association of State Highway and Transportation Officials.

AASHTO M182 Burlap cloth made from jute or kenaf

B. American Concrete Institute (ACI)

ACI 207.SR Roller-Compacted Mass Concrete

ACI 309.SR Compaction of Roller-Compacted Concrete

C. ASTM International (ASTM)

ASTM A653 Standard Specification for Steel Sheet, Zinc-Coated (Galvanized) or Zinc-Iron Alloy-Coated (Galvannealed) by the Hot-Dip Process

ASTM C31 Practice for Making and Curing Concrete Test Specimens in the Field

ASTM C33 Standard Specification for Concrete Aggregates

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

ASTM C40 Test Method for Organic Impurities

ASTM C42 Test Method for Obtaining and Testing Drilled Cores and Sawed Beams of Concrete

ASTM C87 Test Method for Effect of Organic Impurities in Fine Aggregate on Strength of Mortar

ASTM C94 Standard Specification for Ready-Mixed Concrete

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ASTM C109 Test Method for Compressive Strength of Hydraulic Cement Mortars

ASTM C114 Test Methods for Chemical Analysis of Hydraulic Cement

ASTM C117 Standard Test Method for Materials finer than 75-um (No. 200) Sieve in Mineral Aggregates by Washing

ASTM C127 Standard Test Method for Density, Relative Density (Specific Gravity), and Absorption of Coarse Aggregate

ASTM C128 Standard Test Method for Relative Density (Specific Gravity) and Absorption of Fine Aggregate

ASTM C131 Test Method for Resistance to Degradation of Small Size Coarse Aggregate by Abrasion and Impact in the Los Angeles Machine

ASTM C136 Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates

ASTM C138 Test Method for Unit Weight, Yield, and Air Content (Gravimetric) of Concrete

ASTM C143 Test Method for Slump of Hydraulic Cement Concrete

ASTM C150 Standard Specification for Portland Cement

ASTM C156 Test Method for Water Retention by Concrete Curing Materials

ASTM C172 Standard Practice for Sampling Freshly Mixed Concrete

ASTM C173 Test Method for Air Content of Freshly Mixed Concrete by the Volumetric Method

ASTM C186 Test Method for Heat of Hydration of Hydraulic Cement

ASTM C192 Practice for Making and Curing Concrete Test Specimens in the Laboratory

ASTM C231 Test Method for Air Content of Freshly Mixed Concrete by the Pressure Method

ASTM C260 Specification for Air-Entraining Admixtures for Concrete

ASTM C295 Guide for Petrographic Examination of Aggregates for Concrete

ASTM C403 Standard Test Method for Time of Setting of Concrete Mixtures by Penetration Resistance

ASTM C470 Specification for Molds for Forming Concrete Test Cylinders Vertically

ASTM C494 Standard Specification for Chemical Admixtures for Concrete

ASTM C535 Test Method for Resistance to Degradation of Large Size Coarse Aggregate by Abrasion and Impact in the Los Angeles Machine

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ASTM C566 Standard Test Method for Total Evaporable Moisture Content of Aggregate by Drying

ASTM C595 Standard Specification for Blended Hydraulic Cements

ASTM C617 Practice for Capping Cylindrical Concrete Specimens

ASTM C618 Specification for Coal Fly Ash and Raw or Calcinated Natural Pozzolan for Use as a Mineral Admixture in Portland Cement Concrete

ASTM C685 Standard Specification for Concrete Made by Volumetric Batching and Continuous Mixing

ASTM C1040 Standard Test Methods for In-Place Density of Unhardened and Hardened Concrete, Including Roller Compacted Concrete, By Nuclear Methods

ASTM C1064 Standard Test Method for Temperature of Freshly Mixed Hydraulic-Cement Concrete

ASTM C1074 Standard Practice for Estimating Concrete Strength by the Maturity Method

ASTM C1170 Standard Test Method for Determining Consistency and Density of Roller-Compacted Concrete Using a Vibrating Table

ASTM C1435 Standard Practice for Molding Roller-Compacted Concrete in Cylinder Molds Using a Vibrating Hammer

ASTM D75 Standard Practice for Sampling Aggregates

ASTM D2419 Standard Test Method for Sand Equivalent Value of Soils and Fine Aggregate

ASTM D3042 Test Method for Insoluble Residue in Carbonate Aggregates

ASTM D4318 Test Method for Liquid Limit, Plastic Limit, and Plasticity Index of Soils

ASTM D4791 Test Method for Flat particles, Elongated particles, or flat and elongated particles in coarse aggregate

D. National Ready-Mixed Concrete Association (NRMCA)

CPMB 100 Concrete Plant Standards (1990)

E. United States Army Corps of Engineers

CRD C 521 Test Method for Frequency and Amplitude of Vibrators for Concrete

CRD C 38-73 Test Method for Temperature Rise in Concrete

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1.03 DEFINITIONS

A. Roller-Compacted Concrete (RCC): RCC is a combination of crushed rock and/or natural sand, gravel, and/or soil having a controlled gradation to which cementitious materials such as cement or Supplementary Cementitious Material (SCM) includingcement and pozzolans andor ground granulated blast-furnace slag (slag) are added. The materials are blended with water to a damp consistency, which can be hauled in vehicles (where permitted) or delivered with a conveyor, spread with earth moving equipment, and compacted with a vibratory roller. Specific requirements of RCC for this project are included herein.

B. Lift Joint Maturity (LJM): A measure of the age of an exposed lift of RCC in terms of time and air temperature of exposure. Measured in degree-Fahrenheit-hours (degree-F-hrs), this time-temperature joint maturity concept is defined in ASTM C1074. Temperatures for Lift Joint Maturity shall be taken with a Forney LA-0549-15 recording thermometer, or equal located near the RCC placement area as approved by the BIA Representative.

C. Theoretical Air-Free Density of the RCC is a calculated value based on the specific gravity of the constituent materials and the proportions of each material in the RCC mix. The value will be agreed to between the CONTRACTOR and the BIA Representative as part of the RCC mix design.

D. Hot and Cold Horizontal Lift Joints

Hot Joint: A horizontal lift area of RCC that has a LJM of less than 1000 degrees F-hours.

Cold Joint: A horizontal lift area of RCC that has a LJM of more than 1000 degrees F-hours.

LJM limits may be adjusted by the BIA Representative based on the results of testing.

E. Target Compaction Density (TCD): The objective density of compacted in-place RCC.

F. Vebe: A test for RCC consistency according to ASTM C1170.

1.04 SUBMITTALS

A. Shop Drawings

General Requirements: Submit all required information within 30 days following notice to begin Work, unless otherwise noted.

RCC Schedule and Production Rates: At least 30 days before starting RCC placement for the spillway structure, submit a detailed schedule of the anticipated RCC production rates and placement area/elevation versus calendar date.

RCC Material Production Plant(s) and Equipment:

a. Submit a layout and schematic drawing of the RCC plant(s) together with a narrative description giving anticipated peak capacities and sustainable production rates.

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b. Submit detailed procedures for calibrating plant(s), maintaining NRMCA certification, and monitoring materials used during construction.

c. Submit NRMCA certifications and calibration report before initiating trial placement and each time plant is recalibrated.

d. Submit proposed sampling facilities for obtaining material samples at the plant.

e. Submit a proposed onsite spare parts inventory that will limit any down time on the concrete plant to less than two hours.

RCC Conveying, Hauling and Placement Plan:

a. Submit a conveying, hauling and placement plan at least 30 days prior to starting RCC placement for the spillway structure. The plan shall detail the planned RCC transport system, including conveyor supplier and haul truck equipment type and specifications, as appropriate. Include detailed description of anticipated methods and equipment for conveying RCC from the mixing plant to the RCC placement area. Include details showing how the delivery system will reach every portion of the RCC placement area. Include provisions for minimizing segregation in the RCC while conveying and hauling in trucks, and for minimizing lift surface contamination by trucks, if used.

b. Within 90 days following Notice to Proceed: Submit a copy of an executed contract with a an approved conveyor system supplier if external supplier is used. The contract must include a guarantee that the system will meet the specified installation dates, minimum capacity requirements, and all technical requirements of this Specification. Submit final details of the entire conveying system, including supports and how they may affect the dam structure, transfers, belt dimensions, operating speeds, maximum conveyor angle, covers, wipers, and how long the RCC will be on the belts.

RCC Mix Design Data: Submit mix proportions for minimum of three mix designs and complete test results demonstrating compliance with specified requirements.

Submit final mix proportions selected by CONTRACTOR for approval by the BIA Representative.

RCC Hauling and Placement Plan: Submit detailed description of anticipated methods and equipment for placing, spreading, and compacting RCC. Revise the RCC hauling and placement plan within 30 days following completion of all RCC test section to incorporate changes resulting from testing, as directed by the BIA Representative. The BIA Representative will review and approve the revised RCC hauling and placement plan before contractor begins placing any RCC.

Formwork: Submit detailed calculations and drawings of forming system, manufacturer's catalog, data and descriptive literature for formwork, anchors and all associated hardware. Also submit schedule and procedures of forms installation and removal, material and procedures for patching form anchor holes. Computations shall be signed and sealed by a Professional Engineer certified in the State of South Dakota.

Professional Engineer’s seal shall be clearly legible, including jurisdiction of registration, registration number, and name on seal.

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Contraction Joint Installation Plan: Submit detailed description of anticipated methods, materials, and equipment for installing contraction joints, including whether equipment has rubber tires or is track-mounted. If equipment is track-mounted, provide details regarding type of track and methods for preventing damage to RCC lift surfaces.

Horizontal Lift Joint Treatments Plan: Submit a detailed description of methods, materials, and equipment to be used for each type of lift joint treatment (Hot and Cold).

Hot and Cold Placement Plan: Submit proposed plan for placing RCC during hot and cold weather conditions in general conformance with ACI 305 and ACI 306. Include planned equipment, controls, and procedures for heating and/or cooling materials, and protection of completed Work.

Curing and Protection Plan: Submit proposed method for curing and surface protection of all placed RCC. Include source of constant curing water, planned equipment, material, and procedures for continuously maintaining completed exposed RCC surfaces in a moist condition. This includes but is not limited to lift surfaces and exposed final sloping faces.

If equipment needs or planned procedures vary during the course of RCC production, hauling and placement, submit updates to the BIA Representative prior to beginning each planned phase of Work.

RCC Materials Plan: Submit proposed source(s) of cement, all admixtures, and SCMspozzolan or slag. Include a layout and narrative description of material storage facilities to be used. Identify a primary and a backup source for each material along with samples from each source. Also include delivery and production (where applicable) schedules for all materials. Within 60 days following Notice to Proceed, submit heat of hydration test results as required by Part 2.0102, Paragraph C MINIMUM COMPRESSIVE STRENGTH of this Section. Within 120 days following Notice to Proceed, submit mortar cube and adiabatic heat rise test results.

Bonding Grout Mix Design and Delivery: Submit a mix design for grout to be used on the foundation and between RCC lift joints for cold joints. Submit a description of the methods and equipment for delivering grout to the placement at all locations.

Water-Reducing and Retarding Admixture Dosage Rate: Perform and submit initial and final set-time testing on mortar fraction of the RCC in accordance with ASTM C403/C403M to determine recommended dosage using at least two water-reducing and retarding admixture products meeting the following criteria:

a. Initial set time: 18 hours to 24 hours.

b. Final set time: 24 hours to 45 hours.

B. Administrative

Delivery Tickets: Submit delivery tickets for cement, pozzolan and/or SCMsslag.

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Project name, and a certification that the material meets the Specification requirements.

RCC Personnel Plan: Provide an organization chart showing the names of CONTRACTOR’S project manager; project superintendent over RCC operations;

RCC Production Supervisor(s); RCC Placing Supervisor(s); Quality Control Manager(s); and the on-site person(s) who will be responsible for day-to-day set-up, maintenance, and operation of the RCC production, delivery and placing operation.

Provide the qualification for staff included in the RCC Personnel Plan. Personnel listed in the plan shall have the following qualifications, unless approved by the BIA Representative:

a. The qualifications of the Project Superintendent over RCC operations shall include experience with supervision of RCC dams and spillways with a minimum RCC quantity of 50,000 cy for each project. The project superintendent shall have experience in RCC mix design, on-site batching, transport and placement utilizing the techniques anticipated to be used in the Project.

b. The qualifications of the RCC Production Supervisor(s) and RCC Placing Supervisor(s) (one two required each for each placement shift planned) shall include experience as a field superintendent on RCC construction projects within the last 15 years and each having a minimum of 50,000 cy of RCC placed.

c. The qualifications of the RCC Quality Control Manager(s) (one required for each placement shift) shall include registration as a Professional Engineer in the State of South Dakota and experience testing and reviewing test results on RCC materials on a minimum of two construction projects within the last 5 years.

d. Supervising Technicians shall have at least 3 years of relevant experience and shall possess current technician certifications. Testing Technicians shall possess current certifications and shall be certified as an ACI Concrete Laboratory Testing Technician - Grade 1.

d.e. Project Superintendent may also serve as a RCC Placing Supervisor, but may not serve as a RCC Production Supervisor.

C. Quality Control

Record Drawings: Provide as-built drawings indicating placed lift elevations, locations of cold joints, intermediate sloping joints due to interruptions in Work, and other locations of significance, if any in accordance with Section 01 78 40 – Record Drawings.

Quality Control Plan for RCC: Submit quality control plan addressing all items Required in this Section, and any additional testing necessary to meet the requirements of the Work.

Manufacturers’ Certificates of Compliance:

a. Portland Cement or Blended Cement.

b. SCMsPozzolan.

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c. Ground Granulated Blast Furnace Slag.

d. Coarse Aggregate.

e. Fine Aggregate.

f. Admixtures.

1.05 QUALITY ASSURANCE

A. Qualifications

Mix designer shall be a Licensed Professional Engineer registered in the State of South Dakota, with a minimum of 5 years of experience in the design of RCC mixes for RCC construction projects with a minimum of 50,000 cy of RCC placed for each project.

B. Pre-installation Conference

Meeting attendees:

a. CONTRACTOR, including conveying, placing, finishing, and curing subcontractors if utilized. (Attendance mandatory.)

b. BIA Representative, including field inspection personnel. (Attendance mandatory.)

c. RCC Project Superintendent, and Production Supervisor(s) and Placement Supervisor(s). (Attendance mandatory.)

d. Quality Control Manager(s) (Attendance mandatory.) and testing and sampling personnel. (Attendance optional.)

e. COR. (Attendance optional.)

Agenda will include, as a minimum, the following topics:

a. Status of submittals.

b. RCC Mix designs; required Vebe time requirements; admixture types, dosage, performance, and RCC placement temperature requirements.

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

d. Hot and cold weather joint preparation procedures.

e. Quality control requirements and procedures.

f. Other specified items requiring coordination.

C. Quality Assurance Testing

General: COR or BIA Representative will perform quality assurance testing during construction to determine RCC compliance with the Specifications. CONTRACTOR shall provide access to all parts of the Site and provide assistance as necessary to obtain samples and perform testing of all materials used in the Work.

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Testing Program: Testing by the BIA Representative during both the trial placement and actual construction of the spillway shall include, but not be limited to, the following items:

a. Verification testing and inspection to determine that the RCC mix is produced and placed as intended by the Specifications. Verification testing shall include, but not be limited to, nuclear density testing, Vebe testing, aggregate testing, and RCC compressive strength testing.

1.06 DELIVERY, STORAGE, AND HANDLING

A. Cement and SCMs, Pozzolan and Slag

Transportation of Bulk Cement, Pozzolan and/or SCMsSlag: Transport cement, pozzolan and/or SCMsslag from the railhead, mill, or intermediate storage to the mixing plant in adequately designed weather-tight trucks which protect the cement, pozzolan or SCMslag from exposure to moisture.

Storage: Immediately upon receipt at the plant, store cement, pozzolan, or SCMsslag in a dry, weather-tight and properly ventilated structure. Provide access to storage facilities for inspection and identification. Maintain sufficient cement, pozzolan, and/or SCMsslag in onsite storage to meet and/or exceed the CONTRACTOR’s expected RCC production and placement rates providing materials for at least two days of placement at the typical production rate being experienced. Clearly mark material storage facilities with signs to indicate the material contained in each facility.

B. Water: Maintain sufficient water in on-site storage to meet CONTRACTOR’s expected RCC production rate and concrete curing needs. On-site water storage may be reduced or eliminated if municipal potable water is readily available.

C. Aggregates: Aggregates shall be handled in a manner that minimizes segregation.

Stockpiles shall be constructed in horizontal layers. The building of stockpiles and the removal of aggregate therefrom shall be in a manner that maintains the overall uniformity of aggregates as delivered to the RCC production facility.

D. Admixtures: Deliver admixtures to site in original manufacturer's sealed containers. Store and handle in accordance with manufacturer's printed instructions.

PRODUCTS

2.01 MATERIALS

A. General: RCC shall be composed of portland cement, SCMspozzolan or slag, fine and coarse aggregate, water, and optional admixtures.

B. Alternate Sources: Alternate material sources will not be permitted without advance approval by the BIA Representative.

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C. Cement and SCMspozzolan or slag shall conform to the requirements specified in Section 03 30 00 – Cast-in-Place Concrete.

D. Aggregates

Source: Western Construction, Inc.; Croell, Inc; or approved equal.

Fine Aggregate: Fine aggregate shall meet the requirements of Section 03 30 00 – Cast-in-Place Concrete except gradation will be as developed by CONTRACTOR mix design to meet the compaction requirements in Paragraph 3.04 COMPACTION of this Specification.

a. The sand equivalent value shall be no less than 35 when tested in accordance with ASTM D2419.

Coarse Aggregate: Coarse aggregate shall meet the requirements of Section 03 30 00 – Cast-in-Place Concrete except gradation will be as developed by CONTRACTOR mix design to meet the compaction requirements in Paragraph 3.04 COMPACTION of this Specification. Aggregate will have a maximum aggregate size of 1 ½-inches.

Combined Aggregate Gradation: Grading of combined aggregate, as delivered to the mixer shall conform to the following grading requirements.

Sieve Size Percent Finer by

Mass 1 1/2 inch 100

1 inch 75-100 3/4 inch 65-97 1/2 inch 50-85 3/8 inch 42-75

No. 4 32-52 No. 8 23-40

No. 16 15-30 No. 30 9-22 No. 50 6-15

No. 100 4-11 No. 200 3-8

Abrasion Resistance: Maximum loss of 40% in accordance with ASTM C131.

E. Water: Provide a water source meeting the requirement of Section 03 30 00 – Cast-in- Place Concrete.

F. Admixtures

Water-reducing admixture shall conform to ASTM C494, Types A or D.

Set retarding admixture shall conform to ASTM C494, Types B or D.

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G. Joint Materials: Galvanized steel (ASTM A653) metal sheeting, minimum 14 gauge thickness, or driven plastic sheeting or woven geotextile, minimum 8 ounce weight, compatible with joint placement methods.

H. Formwork: Formwork shall be used to facilitate placement of RCC to the lines and grades shown, including vertical face of the chute wall. Formwork shall be metal or wooden forms free from dents, sags, rust, cracks or other irregularities that would adversely affect the RCC lines and grades as shown on the plans.

I. Bonding Grout: Grout for bonding upstream edge of lifts and cold joints in RCC and foundation preparation shall be a neat cement grout consisting of portland cement and water having a water-cement ratio of 0.50 to 0.60, by mass.

J. Facing Concrete: Provide concrete meeting the requirements of Class B concrete of Section 03 30 00 – Cast-in-Place Concrete. Facing concrete will be used where high velocity water flows are expected, at exposed structural faces and where placement geometry is restricted limiting the ability to properly compact RCC material such as against abutments, concrete pipes and structures, and formwork. Facing concrete will be consolidated with immersion vibrators into the adjacent uncured RCC material to provide a well-integrated boundary material.

2.02 RCC MIXTURE

A. General: RCC mix proportions will be determined by CONTRACTOR using materials and equipment which are representative of those to be used in the Work.

B. Mix Proportions: CONTRACTOR will develop three laboratory mixes to evaluate potential mix designs. Water from selected water source is to be used in the development and testing of laboratory mixes. Final mix proportions will be selected by CONTRACTOR and approved by the BIA Representative prior to the start of placement based on an evaluation of the actual aggregate, cement, and SCMpozzolan or slag sources.

C. Minimum Compressive Strength: The mixture will be designed to produce an average cylinder compressive strength of at least 2,000 psi at 28 days when tested in accordance with ASTM C39.

D. Water Content: The water content of the RCC shall be based on aggregates in a saturated surface-dry condition. The amount of water added to the RCC mixture shall be that which produces a Vebe time of 9 +/- 3 seconds, as deposited and spread, when tested in accordance with ASTM C1170, Procedure B.

E. Admixture Dosage: Admixture dosage shall be as required to meet consistency, and initial and final set times as per the approved mix design and as tested in accordance with ASTM C1170 and ASTM C403.

F. Water Adjustments: Frequent changes to the batch water quantities shall be considered usual and can be expected to occur during the course of each day's placement to assure

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batch-to-batch uniformity depending on such variables as humidity, wind velocity, temperature, cloud cover, and changes in aggregate moisture contents. Such changes shall be made by CONTRACTOR as required to achieve the desired consistency as measured by the Vebe time. Changes shall be based on visual examination of the RCC during the spreading and compaction process; on the Vebe time, when it varies outside the range considered ideal for compaction; and when the density tests in accordance with ASTM C1040 varies outside of the range considered suitable for compaction.

G. Test Section for Mixture and Equipment Evaluation: Prior to the start of RCC placement, a test section shall be constructed to evaluate characteristics and performance of the RCC mix and spreading and compaction equipment. The test section shall consist of 4-6 layers of RCC of a minimum of 16 feet wide and 30 feet long. RCC shall be deposited by loader or other suitable method, spread, and compacted with the actual equipment to be used in the Work. Density test by ASTM C1040 shall be made on each layer. Placement of the test section will also be required to demonstrate 10 foot minimum lengths of vertical and stepped (minimum of two 2-foot tall step sections) face treatments including the placement of CVC material, and sloped face treatments. Placement of the test section will also be required to demonstrate a contraction joint placement and interior stepped corner. Test section may be used for form anchor pullout testing. Two representative full depth vertical cores and 2 full height horizontal samples exposing vertical sections through the placement oriented perpendicular to and extending through the CVC facing by sawcut methods are to be taken from the test section. Cores and samples are to be evaluated visually for RCC placement, including segregation, and RCC to CVC facing element interface characteristics. Strength testing may be conducted on the cores for verification. Upon completion of testing and inspection, the test section material shall be removed to the designated waste area unless otherwise approved by the BIA Representative. The initial TCD value shall be determined during placement of the test section. Methodology for testing included in Paragraph 3.04F COMPACTION of this Specification. Test section to be located within CONTRACTOR staging area unless otherwise approved by COR.

H. Mix Validation: Prior to the start of RCC placement during the Test Section, prepare five sets of 6 inch by 12 inch RCC cylinders for testing according to ASTM C39. The five sets shall be determined by the BIA Representative. Two cylinders shall be prepared for each mix for testing at 7, 28, 90, 180 and 365 days, plus two additional cylinders to be tested as directed.

2.03 EQUIPMENT

A. General: Provide sufficient equipment that has been demonstrated through use on other similar projects with similar mixes and production rates to be suitable for production and placement of RCC as described by the Contract Documents.

B. Equipment Changes: After equipment is demonstrated as suitable for production and placement, as indicated by CONTRACTOR submittals, calibration report(s), production uniformity test results, and the trial placement, no change of equipment will be permitted without prior written approval by the COR.

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C. Concrete Plant(s) for RCC

The concrete plant(s) shall be stationary and conform to the requirements of ASTM C94 or ASTM C685. Provide the concrete plant(s) at the site, in-place, in operating condition, and calibrated before the start of the test section. Do not initiate the test section until written calibration reports have been submitted to the BIA Representative and approved by COR. Provide plant(s) capable of routinely and consistently producing well-mixed RCC of the type to be used on this Project and with demonstrated satisfactory performance with similar mixes. The plant(s) shall meet the CPMB standards.

Plant Control System: All plant(s) shall be automatic, computer controlled. The system shall be capable of immediate aggregate and water batch weight adjustments to compensate for changes in aggregate moisture content. Plant(s) shall be capable of wasting material that is improperly batched or mixed. The control system shall be capable of recording all production information which shall be submitted to the BIA Representative on a daily basis.

Mixer and Mixing Time: Continuous type plants, shall be equipped with horizontal shaft compulsory mixer(s). The minimum mix time for these mixers shall be 30 seconds but sufficient to produce a uniform mixture. RCC produced by volumetric batching shall be mixed in a pug mill of appropriate size. The RCC, as discharged from the mixing plant, shall be uniform in composition and consistency and with no segregation. The plant’s transfer systems must be capable of charging and discharging the constituents and the mixed product without bridging or choking. The mixing plant will be routinely inspected by CONTRACTOR for changes in condition due to accumulation of hardened concrete or mortar, or wear of paddles. If directed by the COR, the adequacy of mixing will be determined by CONTRACTOR using mixer uniformity tests.

Plant access and Sampling Facilities: Provide adequate and safe stairways to the mixing chamber platform and guarded ladders to other plant units, where required, for accessibility to all plant operations. Provide access to the COR and BIA Representative at all times to all parts of the plant and the construction site for checking adequacy of equipment in-use, operation of plant, and verification of weights or proportions and character of materials. The layout of the plant shall be such that the mixing chamber of each plant can be observed from a safe location that can be reached from the plant control station. Provide safe areas where the COR and BIA Representative can observe RCC in the receiving hopper(s) or conveyors as it exits the mixing chamber.

Conveyors: If used, any conveyor belt system must be designed, operated, and maintained by experienced personnel. The conveyor system shall demonstrate the successful delivery of RCC of the type to be used on this Project at the required speeds and size to meet Contractor’s production rates, and quantities.

Provide conveyors and transfer components designed for low maintenance, and continuous operation with clean return belt surfaces and without segregation or excessive loss of material. Cover all belts with covers or shields to prevent drying by

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the wind and sun, and over-wetting from rain. Conveyors must be covered throughout the entire length of all sections where the covers do not interfere with the routine operation of the conveyor system. Equip all hoppers, if used, with vibrators or linings as necessary to prevent material from building up on the sides, choking, or bridging.

D. Haul Vehicles: If used, the following requirements apply to the operation of haul vehicles used within the placement areas to be covered by RCC.

Haul vehicles that will be placing RCC shall be capable of handling and dumping concrete without causing excessive segregation.

Thoroughly wash the tires of vehicles regardless of function before moving onto the surface that will be covered with RCC.

As much as possible keep equipment used for RCC hauling, placement and compaction located on the RCC surface, except during fueling, maintenance and relocations.

Minimize impact of haul vehicles on the previously placed lift surface. Substantial permanent damage to the lift surface shall not be allowed, including deep tire rutting, vibratory drum roller rutting, cracking the RCC lift surface, and pumping excessive mortar to the surface as a result of vehicular traffic. If such damage occurs, it shall be repaired while the RCC is still fresh and before placing the next lift of RCC.

Control segregation of RCC material during loading of haul trucks. The BIA Representative may stop all RCC placing operations if excessive material segregation is observed at any location throughout the RCC delivery system. RCC placing operations may not restart until the material handling procedure is modified to mitigate segregation, as approved by the COR.

E. Chutes and Drop-Tubes: Unless specifically authorized in writing, chutes or drop-tubes exceeding 200-feet will not be permitted. Adjustment of the drop-tube diameter shall be made to minimize segregation.

F. Spreading Equipment: Provide tracked equipment for spreading compatible with the capacity of the plant, delivery systems, and size of the Work area. Provide dozers with controls to hydraulically adjust blade tilt and angle. Quip dozers with a laser target mounted on the blade with a level indicator to indicate to the operator when the lift elevation is within the specified tolerance. The dozers shall be equipped with well-maintained grousers having a maximum of 1 ½-inch cleats. The dozer blade shall be an adjustable angle "U" shaped blade.

G. Compaction Equipment

Primary Rollers: Use single drum self-propelled vibratory rollers that transmit a dynamic impact to the surface through a smooth steel drum by means of revolving weights, eccentric shafts, or other equivalent methods. Use compactors with gross weights of not more than 21,000 pounds and a minimum dynamic force of at least 120 pounds per inch of drum width. The drum shall have a minimum diameter of 55-inches. The compactors shall have variable amplitude, and a minimum vibrating

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frequency of 25 Hz. The engine driving the eccentric mass shall have a rating of at least 100 Hp. Operate rollers at speeds not exceeding 120 feet per minute. The rollers shall not remain stationary on the RCC with the vibratory mechanism operating.

Within the range of operational capability of the equipment, variations to the frequency and speed of operation, which result in maximum density at the fastest production rate, will be allowed. Provide a sufficient number of fully operable, self-propelled vibratory rollers on the placement area at all times during production to meet CONTRACTOR’s placing rate. Provide standby replacement equipment available for functional operation on the placement within 30 minutes.

Plate Compactors: Provide reversible vibratory plate compactors for use along the slopes, along the formwork if used, and other areas where the large vibratory rollers specified above cannot maneuver. Use plate compactors with an operating weight between 130 and 300 pounds, a dynamic force between 2,000 and 6,000 pounds, and an operating frequency between 5,000 and 6,000 vibrations per minute. Provide a sufficient number of fully operable plate compactors on the placement area at all times during RCC placement to meet the placing rate. Provide standby replacement equipment available for functional operation on the placement within 30 minutes.

Small Vibratory Rollers: Small vibratory rollers which can operate within a few inches of a vertical face can be used in lieu of plate compactors along the formwork, and at areas where the larger primary vibratory rollers cannot maneuver. Provide rollers with a dynamic force of at least 600 pounds per inch of drum width. Provide a sufficient number of fully operable small vibratory rollers on the placement area at all times during RCC placement to meet placing rate. Provide standby replacement equipment available for functional operation on the placement within 30 minutes.

The number of passes and lift thickness required shall be whatever is necessary for the particular equipment to provide the same degree of compaction as would be attained with the primary vibratory rollers.

H. Vacuum Truck: CONTRACTOR shall provide as many vacuum trucks with size necessary to complete final foundation and RCC lift cleanups needed to meet their RCC placement rates. The Vacuum truck shall be tested during the RCC trial placement.

I. Grout Plant: CONTRACTOR shall provide a grout plant dedicated to RCC construction including high-speed colloidal mixing, agitating tanks, and delivery system for grout for bonding layers and elsewhere as approved.

Other Equipment: All other equipment necessary for use on the RCC trial and actual placement area, but not previously discussed within these Specifications or determined to be necessary during the course of the Work, shall be proposed by CONTRACTOR subject to approval of the COR before and during actual use. This shall include but not be limited to equipment used to install the transverse contraction joints and to deliver grout.

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EXECUTION

3.01 FOUNDATION PREPARATION

A. General

Do not cover any foundation with Bonding Grout, concrete or RCC until cleanup has been completed and the area has been inspected by the BIA Representative and approved by the COR.

Foundation preparation to be in accordance with Specification 31 23 13 – Subgrade Preparation. All surfaces shall be cleaned and free of mud and silt accumulations, vegetation, grease, spilled oils; frozen materials, standing water; puddles or ponds of free surface water; mortar; and other detrimental materials prior to material placement.

Prior to placement of RCC, rock surfaces shall be covered with Bonding Grout spread to 1/16 to 3/16 inches thick. The Bonding Grout shall be placed and manually spread using serrated rakes or other approved methods. RCC shall be spread onto the fresh Bonding Grout within 30 minutes of bonding grout placement.

Do not place RCC or grout on or against any surface with a temperature that is less than 35 degrees F or conditions in which the ambient air temperature is less than 35 degrees F.

A clean sound surface is required prior to placing RCC. CONTRACTOR is required to have adequate equipment available for necessary air jetting, air/water jetting, pressure water jetting, and vacuuming of the foundation before grout, conventional concrete, or RCC placement.

B. Dewatering

Groundwater Control: During the period of RCC preparation and placement, maintain foundations in a dewatered condition. Install dewatering systems that result in a slightly damp foundation surface, if needed.

Surface Water Control: Before preparing the area for RCC placement, install facilities to divert surface waters from the Work area. Maintain facilities until all RCC placements and curing is complete.

C. Shaping and Filling Rock Surfaces

Fill depressions as specified in Section 31 23 13 – Subsurface Subgrade Preparation, or as directed by the BIA Representative. The fill material shall be dental concrete.

Dental concrete may require rough face forming. Continuously moist cure dental until covered with additional RCC or for a minimum of seven days.

D. Final Cleanup

Remove loose material and clean by using air blowing, high-volume water washing, and/or air/water jetting with equipment normally designed for this purpose and used in large scale foundation cleanups. In addition, use the vacuum truck or other high

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performance vacuum systems for low areas or pockets in the foundation where water, soil and/or rock fragments accumulate.

Roughen hardened surfaces of existing concrete surfaces with a minimum of 10,000 psi water pressure to produce 1/2 inch minimum surface irregularities and pressure wash previously hydro- demolished concrete surfaces with a minimum of 5,000 psi water pressure before grout and RCC placement. CONTRACTOR’s means and methods may require higher water pressure and/or longer durations to meet RCC production and placement rates.

Moisture condition hardened conventional concrete and prepared foundation rock surfaces by maintaining surface in a continuous moist condition for a minimum period of two hours immediately before grout, conventional concrete, or RCC placement.

Allow surfaces to dry to a saturated-surface dry condition immediately before RCC related concrete operations.

3.02 CONVEYING AND TRANSPORTING

A. General: Deliver RCC from the mixer(s) to the placement area with conveyors, cranes (with buckets) or haul trucks. Once on the lift surface, haul vehicles may be used to move RCC to the point of placement. Conveying, hauling and placement plan approval shall be based on continued satisfactory performance, and may be subject to additional restrictions as determined by the COR.

B. Convey RCC from the mixer to the placement area as rapidly as practicable, by methods that control segregation, contamination, drying, and spillage. If necessary, provide baffles at the end of conveyors and within hoppers to limit free falls, and at other locations that otherwise cause excessive segregation as determined by the BIA Representative. Use vibrators or other methods to prevent plugging at transfer locations including belt transfers and any interim bins or hoppers. No equipment (haul, service, or other) will be allowed to track mud, spilled petroleum products or other contamination onto previously placed RCC.

This includes, but is not limited to using clean crushed rock on haul roads, washing tires of vehicles before driving onto RCC, and other special measures as directed by the COR.

Contamination on the RCC surface shall be cleaned, and may require Bonding Grout, or may be required to be removed, as determined by the BIA Representative, from the RCC before placing the next lift. If a surface is damaged by vehicle operation due to tight turns, driving over a wet area that pumps, or other reasons, clean the damaged surface and/or remove the damaged material as directed.

3.03 PLACING AND SPREADING

A. Placing

General: The placing of RCC shall follow the general guidelines and recommendations in ACI 207.5R and the trial placement, except as specified.

Lift Thickness: Each RCC layer (12 inches after compaction) shall be placed and compacted prior to the placement of the subsequent layer. CONTRACTOR shall place

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and compact RCC as rapidly as possible. No maximum production rate is specified.

RCC shall be placed in approximately horizontal layers; however, CONTRACTOR may place the RCC layers at a maximum slope of two (2) percent cross slope dipping upstream to facilitate drainage in the event of rain.

Weather: If unusual adverse weather such as heavy rain, severe heat, high winds, snow, etc. occurs or is forecast to occur during placement, the placing operations shall be suspended until conditions improve. If a combination of high ambient temperatures and wind dries the uncompacted RCC, take preventive measures such as decreasing the area of uncompacted RCC or use of fog spray. RCC shall not be placed during rainfall or snowfall of more than 0.1 inches per hour or 0.015 inches in six (6) minutes as defined by the U.S. Weather Bureau Glossary of Meteorology. RCC that has been deposited and spread can be compacted before operations are suspended provided mortar or grout is not picked up on the roller drum. If excessive mortar or grout has been worked up to the surface by rolling, the layer surface shall be treated by brooming before the layer is covered by the next layer. Production shall be suspended when free surface water begins to accumulate on the compacted RCC, when excessive pumping, tracking, or other unacceptable damage begins to develop.

Placing Procedures:

a. General: Placement shall proceed across the fill by advancing the face of uncompacted RCC in a uniform manner. Material shall be deposited on previously placed uncompacted material and then spread in a forward direction onto the previous compacted layer from the dumped pile. Placement of uncompacted material continues from uncompacted surface onto compacted layer until an entire lift of uncompacted material is placed onto the previous compacted layer. Material shall not be placed in consecutive or consistent lanes unless otherwise approved by the BIA Representative but shall be spread in a fan type manner. Rollers shall not roll down the leading edge of the layer unless it is necessary to make an intermediate sloping joint due to termination of placing operations.

b. Cold Joints within Lift: Whenever it is necessary to discontinue lift placement and produce a cold joint within the lift, it shall be located at least 1030 feet from the location of other cold joints located within a lift that may have previously occurred in the same direction in any of the previous 10 layers. All edges of the cold joint shall be rolled down and firmly compacted. Prior to resumption of RCC placement, the cold and sloping joints shall be prepared as required in Paragraph 3.065 JOINTS.

c. Time Limits: RCC shall be placed and level within 45 minutes and final compaction shall be within 90 minutes of mixing.

Spreading:

a. No RCC shall be placed on a previous layer which does not meet Specification requirements. Unacceptable material shall be removed unless otherwise approved by the COR.

b. RCC shall be deposited on previously placed and compacted RCC. The RCC shall then be worked by dozer action to knock down piles and provide remixing

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as the RCC layer is spread onto the previous compacted layer. Dozers or other spreading equipment shall be of appropriate size for the Work. Additional equipment should be considered as the RCC footprint decreases in size.

c. The RCC shall be spread in uncompacted, unsegregated layers. The layer surface shall receive at least two complete passes with the dozer. The dozer(s) shall be operated continuously during the placing and spreading even if this action results in more than two passes.

d. Under no conditions shall a dozer or other tracked vehicle be operated on other than fresh uncompacted RCC. When necessary to remove the tracked vehicle from the fill or move the dozer from one location to another, such movements shall be made using techniques that do not damage the compacted surface. Any marks made on the RCC surface will be rolled out. The equipment shall not leak or drip oil, grease or other visible contaminates on the layer surface.

3.04 COMPACTION

A. General: The compaction of RCC shall follow the general guidelines and recommendations in ACI 207.5R, except as specified.

B. Compaction equipment and its operation shall generally follow guidelines in ACI 309.5R.

After spreading the top surface of each layer of RCC shall be compacted with a self-propelled smooth drum vibratory roller. Compaction shall continue until at least 98 percent of the Target Compaction Density (TCD) has been achieved unless otherwise approved.

C. A round trip over the same material shall count as two passes for a single drum vibratory roller and four passes for a double drum vibratory roller (i.e., from point A to point B and return to point A by the same route is two passes for a single drum roller).

D. When necessary to discontinue RCC placement for more than 12 hours, the layer surface shall be left in a smooth condition with minimum of roller and tire marks and differential offsets in the joint surface so that subsequent joint cleaning work will be minimized.

E. Rollers shall not be operated in the vibratory mode while stationary.

F. Density

All RCC shall be compacted to a minimum of 98 percent of the target compaction wet density (TCD) value except that material within three feet of the outside edge of an uncompacted sloping surface. CONTRACTOR shall calculate the Theoretical Air- Free Density (TAFD) for the final mix design.

The anticipated TCD for compacted RCC will be estimated from laboratory data. The TCD will be determined during placement of the test section using RCC and equipment provided by CONTRACTOR. Wet density shall be measured using a nuclear density gage in accordance with ASTM C1040.

Because material properties, proportions, and quality may change within Specification limits, maximum attainable wet density may also change. The TCD method will be

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used to determine the performance requirements for minimum wet density. TCD determinations shall be performed by CONTRACTOR in the presence of the BIA Representative. The TCD will be invalid if material proportions, including water, are outside the designated range. TCD compaction shall commence no later than 10 minutes of mixing the RCC.

The initial TCD value shall be determined during placement of the test section. The wet density of the RCC shall be determined for every one or two passes of compaction equipment. Wet density testing shall be concurrently on the same test strip in two locations. Compaction shall continue until the density decreases significantly. When all voids are filled and additional rolling causes the surface to undulate or pump, rolling shall be stopped. The TCD shall be the average maximum recorded wet density. A variation in TCD from the two locations of more than 8.5 pounds per cubic yard shall invalidate the test and require that another test section be performed. The number of roller passes to achieve TCD shall be a guide to the equipment operators of the required compaction necessary to achieve TCD.

As RCC placement progresses, subsequent TCD testing shall be performed at the placement site, initially at least once every 24 shifts or one test every two weeks, whichever is more frequent. The frequency of testing may be reduced by the COR if results show a consistent TCD value.

Nuclear density readings shall be made by CONTRACTOR throughout the course of the RCC placement to determine whether the…