Roller-Compacted Concrete Pavements as Exposed Wearing Surface
This document provides a guideline specification useful for developing project specifications for roller compacted concrete (RCC) as an exposed RCC pavement surface, that may or may not be diamond ground for smoothness and/or texture. RCC as a base/subbase layers is not covered in this specification. The information is also not wholly applicable for non-pavement applications such as backfills, dams or liners. This guideline should not be used as a specification reference in contract documents. An owner, engineer or contractor must consider the available options and apply these guidelines to create specifications for specific local projects.
This document references appropriate material standards, test methods and specifications of American Association of State Highway and Transportation Officials (AASHTO), ASTM International (ASTM), and Canadian Standards Association (CSA). These references assume that the contractor and the engineer will use the most up-to-date and applicable standards or methods that are in effect when bids are solicited for the project. It also assumes that the specification writer will choose the standard or test most suitable for their agency/project.
Footnotes accompany many of specification provisions herein. These added details describe reasoning for certain specification features, as well as provide considerations and important information for the specification writer.
ACPA’s ROLLER-COMPACTED CONCRETE TASK FORCE
The following individuals serve on the ACPA RCC Task Force as members or friends, and have contributed their expertise, experiences and efforts to create this guideline:
|Abdo, Fares||MORGAN CORP.|
|Adaska, Wayne||PORTLAND CEMENT ASSOCIATION|
|Burwell, Brent||OKLAHOMA/ARKANSAS CHAPTER – ACPA|
|Byers, Mike||INDIANA CHAPTER – ACPA|
|Carwie, Chris||A.G. PELTZ GROUP, LLC|
|Davenport, William||AMERICAN CONCRETE PAVEMENT ASSN.|
|Delatte, Norbert||CLEVELAND STATE UNIVERSITY|
|Duit, James||DUIT CONSTRUCTION CO., INC.|
|Eaton, William (Cody)||MOMENTIVE SPECIALTY CHEMICALS|
|Edwards, John||INTERSTATE HIGHWAY CONSTRUCTION, INC. (IHC)|
|Fightmaster, Mark||BASF CONSTRUCTION CHEMICALS|
|Flynn, Matt||HOLCIM (US) INC.|
|Forrestel, Stephen||COLD SPRING CONSTRUCTION CO.|
|Friess, Steve||MILESTONE CONTRACTORS|
|Fung, Rico||CEMENT ASSOCIATION OF CANADA|
|Gray, William||A.G. PELTZ GROUP, LLC|
|Gulden, Wouter||ACPA – SOUTHEAST CHAPTER|
|Harrington, Dale||SNYDER & ASSOCIATES, INC.|
|Harris, Terry||GRACE CONSTRUCTION PRODUCTS|
|Johnson, Jim||CEI ENTERPRISES|
|Lafrenz, Jim||TIGERBRAIN ENGNEERING|
|LaTorella, Todd||MISSOURI/KANSAS CHAPTER, ACPA|
|Lennox, Frank||BUZZI UNICEM USA INC.|
|Long, Robert||ACPA, MID-ATLANTIC CHAPTER|
|Maybee, Andrew Phillip||CONCRETE PAVING ASSOCIATION OF TENNESSEE|
|Narsingh, Laikrram||WIRTGEN AMERICA INC.|
|Niederriter, Chuck||GOLDEN TRIANGLE CONSTRUCTION CO., INC.|
|Niemuth, Mark||LAFARGE NORTH AMERICA|
|Pardi, Mark||OHIO CONCRETE CONSTRUCTION ASSN.|
|Prusinski, Jan||CEMENT COUNCIL OF TEXAS|
|Render, Jim||ESSROC – ITALCEMENTI GROUP|
|Rodden, Robert||AMERICAN CONCRETE PAVEMENT ASSN.|
|Roesler, Jeff||UNIVERSITY OF ILLINOIS|
|Smith, Andrew||ROBERT SMITH, INC.|
|Surianello, Frank||SURIANELLO GENERAL CONCRETE CONTRACTOR, INC.|
|Thomas, Joe||PRIMCO, INC.|
|Thompson, Jeff||COMPLETE GENERAL CONSTR. CO.|
|Tiefenthaler, Lori||LEHIGH HANSON, INC.|
|Toedt, Chris||VINCE HAGAN CO., THE|
|Tull, Christopher||CRT CONCRETE CONSULTING, LLC|
|Van Dam, Thomas||NICHOLS CONSULTING ENGINEERS|
|Voigt, Gerald||AMERICAN CONCRETE PAVEMENT ASSN.|
|Wentland, Kevin||CEI ENTERPRISES|
This guide specification is directly applicable to roller-compacted concrete (RCC) as a pavement surface, that may or may not have diamond grinding applied to it. Available options provide the specification writer flexibility to tailor provisions specifically for an array of projects, including:
Heavy-duty applications, such as:
o Military installations
o Intermodal facilities
Light industrial applications, such as:
o Manufacturing facilities
o Commercial parking lots
o Maintenance and storage yards
Roadway applications, such as:
o Highway shoulders
o Local streets and roads
BACKGROUND ON ROLLER-COMPACTED CONCRETE
To achieve a successful project, it is important that the specification writer distinguish RCC from conventional concrete, and apply the provisions of this specification that are most appropriate for their application. RCC is essentially portland cement concrete. However, it is engineered and constructed differently than conventional concrete and requires different placement and design considerations even though it is made of the same constituent materials: aggregate, portland cement, supplementary cementitious materials, chemical admixtures and water.
Although made of similar materials, RCC pavements are unlike conventional concrete pavements in many ways, especially during production and placement. Therefore, it is important for the specification writer to be keenly aware of these differences while developing RCC specifications, including:
• RCC requires placement with asphalt-type pavers. It is not placed with typical slipform concrete paving machines.
• RCC mixtures require compaction with the use of vibratory, tamper bar screeds, and subsequently, with vibratory rollers to achieve a target density. RCC does not require the internal vibration necessary to consolidate conventional concrete.
• RCC has little to no slump. Conventional concrete paving mixes require between 1-in (0.25 mm) and 4-in (100 mm) of slump depending on placement method.
• RCC mixtures require different mixing considerations than conventional concrete mixtures. RCC mixtures are relatively dry compared to conventional concrete mixtures and depend on stability in the plastic state to support rollers for compaction.
• RCC mixtures do not usually require air entrainment for freeze/thaw durability. The experience from past projects indicate that it is not necessary, however additional study is continuing.
• Due to its dry nature, RCC pavements do not allow for or require finishing operations like conventional concrete pavement.
• RCC pavements are not surface textured in a plastic state like conventional concrete pavement, however, they can be surface textured through grinding or grooving like conventional concrete pavements.
• The surface of an RCC pavement does not resemble the surface of a conventional concrete. Rather an RCC surface is more inconsistent and typically includes minor surface tearing, checking , pitting or pockmarks. It more closely resembles an asphalt pavement surface.
• RCC pavement, unlike conventional concrete pavement, cannot be reinforced with steel nor include dowel bars to provide joint load transfer because there is no way to insert the steel during construction. Joint load transfer must rely on aggregate interlock and base support for long-term joint performance.
SCOPE OF THIS GUIDELINE
This guideline includes all of the provisions necessary to create an RCC pavement project specification. Specification language and helpful commentary cover appropriate provisions and descriptions for proportioning, mixing, placing, compacting, and curing concrete for RCC applications. Specific placement provisions ensure that an RCC pavement conforms to the lines, grades, thickness, and typical cross section details required in project plans or detail drawings. The specification writer should incorporate appropriate project details and assumptions into the project specification developed using this guideline. It is recommended to consult with your local or national ACPA representative for any advice on developing a project specification.
APPLICABLE MATERIAL AND TESTING STANDARDS
M6 Standard Specification for Fine Aggregate for Portland Cement Concrete
M80 Standard Specification for Coarse Aggregate for Hydraulic Cement Concrete
M85 Standard Specification for Portland Cement
M148 Standard Specification for Liquid Membrane-Forming Compounds for Curing Concrete
M194 Standard Specification for Chemical Admixtures for Concrete
M240 Standard Specification for Blended Hydraulic Cement
M295 Standard Specification for Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use in Concrete
M302 Standard Specification for Slag Cement for Use in Concrete and Mortars
T26 Standard Method of Test for Quality of Water to Be Used in Concrete
T99 Standard Method of Test for Moisture-Density Relations of Soils Using a 2.5-kg (5.5-lb) Rammer and a 305-mm (12-in.) Drop
T180 Standard Method of Test for Moisture-Density Relations of Soils Using a 4.54-kg (10-lb) Rammer and a 457-mm (18-in.) Drop
214 Evaluation of Strength Test Results of Concrete
C31 Practice for Making and Curing Concrete Test Specimens in the Field
C33 Standard Specification for Concrete Aggregates
C39 Test Method for Compressive Strength of Cylindrical Concrete Specimens
C42 Test Method for Obtaining and Testing Drilled Cores and Sawed Beams of Concrete
C78 Test Method for Flexural Strength of Concrete (Using Simple Beam with 3rd Point Loading)
C94 Standard Specification for Ready-Mixed Concrete
C150 Standard Specification for Portland Cement
C171 Standard Specification for Sheet Materials for Curing Concrete
C309 Standard Specification for Liquid Membrane-Forming Compounds for Curing Concrete
C494 Standard Specification for Chemical Admixtures for Concrete
C496 Test Method for Splitting Tensile Strength of Cylindrical Concrete Specimens
C566 Test Method for Total Evaporable Moisture content of Aggregate by Drying
C595 Standard Specification for Blended Hydraulic Cements
C618 Standard Specification for Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use in Concrete
C685 Standard Specification for Concrete Made by Volumetric Batching and Continuous Mixing
C989 Standard Specification for Slag Cement for Use in Concrete and Mortars
C1040 Test Method for Density of Unhardened and Hardened Concrete in Place by Nuclear Methods
C1077 Standard Practice for Agencies Testing Concrete and Concrete Aggregates for Use in Construction and Criteria for Testing Agency Evaluation
C1170 Standard Test Method for Determining Consistency and Density of Roller-Compacted Concrete Using a Vibrating Table
C1157 Standard Performance Specification for Hydraulic Cement
C1176 Standard Practice for Making Roller-Compacted Concrete in Cylinder Molds Using a Vibrating Table
C1240 Standard Specification for Silica Fume Used in Cementitious Mixtures
C1435 Practice for Molding Roller-Compacted Concrete in Cylinder Molds Using a Vibrating Hammer
C1602 Standard Specification for Mixing Water Used in the Production of Hydraulic Cement Concrete
D698 Standard Method of Test for Moisture-Density elations of Soils Using a 2.5-kg (5.5-lb) Rammer and 305-mm (12-in.) Drop.
D977 Standard Specification for Emulsified Asphalt
D1557 Test Method for Laboratory Compaction Characteristics of Soil Using Modified Effort
E329 Standards of Recommended Practice for Inspection and Testing Agencies for Concrete, Steel, and Bituminous Materials as Used in Construction.
CSA A23.1/A23.2 Concrete Materials and Methods of Concrete Construction/Test Methods and Standard Practices for Concrete
CSA A3001 Cementitious Materials for Use in Concrete
Approval: Written authorization or acceptance from the Engineer prior to starting an activity.
Construction Stakes, Lines, and Grades: The Engineer positions construction stakes to establish lines and grades for street work and for structures; the Engineer stakes the centerline and furnishes bench marks necessary to correctly lay out the pavement. The contractor maintains these lines, grades, and bench marks and uses them to lay out the work under the contract. The contractor must carefully preserve stakes and bench marks.
Contractor: The contracted construction firm or its subcontractor hired to perform all or part of the work under the contract specifications and drawings.
Design Strength: The strength used by the designer in the thickness design method or software to determine the RCC Plan thickness. (The design strength should be the expected average field strength, which is necessarily higher than the minimum specified strength.)
Engineer: The owner or an agent of the owner that issues drawings and specifications, or administers the work under contract specifications and drawings, or both.
Intent of the Contract: For the contractor to build the pavement in accordance with the specification and in reasonably close conformity with the lines, grades, thickness, and typical cross sections shown in the project plans or as established by the engineer/owner. Construction methods are generally left to the discretion of the contractor, as long as progress and workmanship are satisfactory.
Lot: Term used for acceptance testing, representing the pavement/material placed in a maximum area or volume specified for quality assurance testing; placed in one day; placed with one construction method; or with one unique mixture.
Maximum Dry Density (MDD): The maximum unit weight (density) of an RCC mixture corresponding to the optimum moisture content typically determined per ASTM D1557.
Optimal Moisture Content (OMC): The water content at which the maximum dry unit weight (density) is achieved for a specific compaction effort, typically determined per ASTM D1557.
Plan Thickness: The nominal pavement layer thickness shown in the Plans.
Reference Wet Density (RWD): The unit weight density calculated by multiplying the Maximum Dry Density (MDD) by 1 + Optimum Moisture Content (OMC), where the MDD and OMC are determined in the laboratory in accordance with ASTM D1557. [Example: assume an RCC mix has a Modified Proctor MDD of 142 lb/ft3 (2,275 kg/m3) and the OMC = 6%. The calculated RWD = 142 · (1+(0.06)) = 150.5 lb/ft3 or in SI Units: RWD = 2,275 · (1+(0.06)) = 2,412 kg/m3].
Sublot: The volume, area or lineal quantity requiring a sample test(s) for acceptance.
Supplementary Cementitious Materials: Mineral admixtures consisting of powdered or pulverized materials which are added to concrete before or during mixing to improve or change some of the plastic or hardened properties of concrete. Materials are generally natural or by-products of other manufacturing processes, such as fly ash, silica fume, metakaolin, or ground-granulated blast-furnace slag that reacts pozzolanically or hydraulically.
Testing Laboratory: An organization that measures, examines, performs tests, or otherwise determines the characteristics or performance of materials or products. This may include organizations that offer commercial testing services, an in-house quality control function, or other organization providing the required testing services. These firms must meet requirements of ASTM C1077, “Standard Practice for Laboratories Testing Concrete and Concrete Aggregates for Use in Construction and Criteria for Laboratory Evaluation.”
Testing Technician: Person or persons that are either engineers, engineering technicians, or experienced craftsman with qualifications to perform tests.
The Plans: The drawings, diagrams, details or standards describing the dimension, elevation, form, location or size of the pavement or any of its components, including the foundation and any existing infrastructure.
1. Subgrades and Subbases for Concrete Pavements” EB204P, American Concrete Pavement Association, Rosemont, IL, 2007.
2. Guide for Roller-Compacted Concrete Pavements, SN298, National Concrete Pavement Technology Center, Ames, IA, August 2010.
3. Guide Specification for Construction of Roller-Compacted Concrete Pavements, IS009, Portland Cement Association, Skokie, IL, June 2004.
4. Report on Roller Compacted Concrete Pavements, 325.10R-95, American Concrete Institute, Farmington Hills, MI, 1995.
5. Guide to Evaluation of Strength Test Results of Concrete, ACI 214R-11, American Concrete Institute, Farmington Hills, MI, April 2011.
6. RCC Specification, Georgia Department of Transportation
7. RCC Specification, Kansas Department of Transportation
8. RCC Specification, Kentucky Transportation Cabinet
9. The Indiana Local Technical Assistance Program Roller Compacted Concrete Pavement Manual For Local Government Agencies, TR-2-2010, Indiana LTAP Center, Purdue University School of Civil Engineering, Nov. 2010.
10. Supplemental Specification 1523 Roller Compacted Concrete Pavements (RCC), City of Columbus, Columbus, OH, Feb. 2009.
11. Suggested Specification for Roller Compacted Concrete Paving For Municipal and Industrial Applications, Tennessee Ready Mixed Concrete Association.
12. RCC Specification, City of Edmonton, Alberta, Canada, October 2009.
13. Specification for Roller Compacted Concrete (RCC) Pavements, City of Burrton, Kansas
14. “Utility Cuts in Concrete Pavements,” IS235P, American Concrete Pavement Association, Rosemont, IL, 2009.
RCC-1.01 Description of Work. This work consists of constructing roller compacted concrete pavement as an exposed pavement surface on a prepared base or subgrade layer. The final surface may or may not be diamond ground, milled or grooved depending on the application, and smoothness and texture requirements. 1
RCC-1.02 Prequalification2. Submit the information required in RCC-1.02.1 to RCC 1.02.2 for prequalification to perform the work on this project.
1.02.1 Completed Project Listing. Provide evidence of successful installation of RCC pavement on <insert number3> prior projects of comparable size and application. Include a brief project description for each project as well as the final contract amount, the owners name and contact information, and the design engineer’s name and contact information for each project listed.
1.02.2 Proposed Installation Equipment. For prequalification, supply a list of the proposed installation equipment, including mixing plant, paving equipment, and compaction equipment. Include the make, model, and equipment specification sheet for each piece of equipment with the prequalification submittal. Make the equipment available for inspection by the Engineer upon request.
RCC-2.01 Material Requirements. Furnish materials conforming to the latest version of the standard material specifications in Table RCC-1, as appropriate. Only furnish materials from sources approved by the Engineer.
RCC-2.02 Material Approval. Prior to use, obtain the Engineer’s approval on all materials for RCC construction based on certifications and, where required, laboratory tests of representative samples of the materials that will be used in the actual construction.
RCC-2.03 Aggregate Gradation. Use a blend of fine and coarse fractions that in combination conform to the sieve size ranges listed in Table RCC-2, or size ranges approved by the Engineer.5 Obtain all aggregates from qualified sources for concrete pavement appearing on the <insert state DOT or provincial ministry> qualified products listing, as well as conforming to requirements in Table RCC-1. Do not use an aggregate with a plasticity index exceeding five.
3.0 Quality Management Plan
RCC-3.01 Quality Management Plan. Submit a quality management plan to the Engineer at least 30 days prior to start of paving operations. As a minimum include the following information in the quality management plan: 7
1) Organizational chart that identifies the key individuals assigned to production and placement operations. As applicable, include a project manager, RCC consultant, project superintendent, RCC production supervisor and quality control manager, or other positions as appropriate given the application. Include all appropriate contact data and the chain of command for decision-making.
2) List of subcontractors, including proposed job site personnel, for any construction operations.
3) Identification of the independent testing firm and qualifications of testing personnel.
4) Construction schedule for all RCC work.
5) List of all mixing, hauling, placing, compaction, curing and sawing equipment with manufacturer’s data, specifications and certifications.
6) Outline of procedures for calibrating the mixing plant and monitoring materials during construction.
7) Plan for locating the mixing plant, required haul times to the furthest location of the placement, and use of set-retarding admixtures, if required to faciliate the delivery logistics.
8) Proposal for:
a. Lift thicknesses (if multiple lifts are necessary).
b. Paving width and staging plan.
c. Direction of paving operation.
d. Daily production, including trucking, placement and production rates.
e. Planned longitudinal and transverse cold joint locations.
f. Horizontal cold joint cleaning and preparation procedures.
g. Location and operation of mixing plant, including proposed mixing cycle time, drum capacity targeted per batch if using a drum-type mixing plant, cement and aggregate storage, and water supply on or off site.
9) Certification for aggregate source, quality and sizing as required by the appropriate material specification.
10) Certification of all cementitious materials and chemical admixtures as required by the appropriate material specification.
11) Outline of procedures and methods for curing and weather protection for cold [less than 40°F (4.5°C)], hot [more than 90°F (32°C)]8 and rainy conditions.
12) Mixture design as outlined in Section 4.0.
RCC-3.02 Pre-Construction Meeting. General contractor representative/consultant, site work contractor, RCC paving contractor, RCC plant manager, and construction testing laboratory representative. 9 Schedule a pre-construction meeting with the Engineer after submitting the quality management plan and prior to installation of a test section or the start of construction. Include project personnel identified in the quality management plan in the meeting, including but not limited to: g
RCC-3.03 Records. Maintain records of all certifications, tests, construction reports, material tickets, and remedial actions taken on the work. Supply the Engineer with all records upon request.
RCC-3.04 Independent Testing Firm. Only use an independent testing laboratory meeting the requirements of ASTM C107710 for preparing, handling, coring, storing and testing concrete specimens, who have the testing equipment necessary to carry out all proposed testing methods, and who can demonstrate adequate knowledge of the testing methods prescribed. Obtain the written qualifications of the testing firm, indicating their compliance with ASTM E329.11 Obtain the most recent certificates of calibration for testing equipment, showing that the equipment has been calibrated at a minimum 12-month interval by devices of accuracy traceable to either National Bureau of Standards or an established value. Submit all certification records from the testing firm and equipment to the Engineer. Provide testing personnel access to the paving and plant sites for inspection and sampling of the RCC layer and constituent materials.
RCC-3.05 Quality Control at Mixing Plant. Conduct quality control testing at the mixing plant in accordance with the requirements in Table RCC-3. Obtain specimens, as required, for post-construction testing.
Table RCC-3: Quality Control Requirements at Mixing Plant
RCC-3.06 Quality Control at Placement Site. Conduct quality control testing during placing operations to ensure the RCC material is placed, compacted, finished and cured in accordance with the requirements in Table RCC-4. Obtain specimens, as required, for post-construction testing.
9 Commentary – The purpose of the pre-construction meeting is to review the information in the quality management plan and discuss the means, methods, sequences, techniques, communication protocol and procedures for installing the RCC pavement. A representative of the owner and the Engineer should participate in the meeting, along with relevant personnel, including the RCC consultant and subcontractors.
10 Note to specification writer – In Canada use CSA A23.2-12C Making, Curing and Testing Compression Test Specimens of No-Slump Concrete.
11 Note to Specification writer – In Canada use CSA A283-06(R2011) Qualification Code for Concrete Testing Laboratories.
Table RCC-4: Quality Control Requirements at Placement Site12
12 Note to specification writer – Lot sizes are based on length, volume or area depending on the item being tested and local practice. The recommendations in Table RCC-4 apply to typical medium-sized projects. Consider varying the lot sizes or including sublots depending on the size of the project. Sublots (4 sublots per lot) may be beneficial when larger projects are being constructed. Typical lots sizes are:
• Length based lots range from 250 to 1000 ft (75 to 300 m); typically 500 ft (150 m);
• Area based lots range from 500 to 1500 yd2 (420 to 1250 m2); typically 1000 yd2 (850 m2);
• Volume based lots range from 100 to 500 yd3 (75 to 380 m3); typically 300 yd3 (850 m3);
13 Note to specification writer – In Canada use CSA A23.2-12C for ASTM C31 and C39; CSA A23.2-14C for ASTM C42.
14 Note to specification writer – For density testing, it is critical in RCC to use the direct transmission test method (with a probe) and not the backscatter test method. The critical density location for RCC is at the bottom of the RCC layer and only the direct transmission test method can assess the density at this location.
15 Note to specification writer – Other specifications may refer to the Maximum Wet Density (MWD) to calculate the percent compaction achieved in the field. However, in practice the Reference Wet Density is preferred. For most RCC mixtures, the MWD occurs at the optimum moisture content (OMC) plus 1 to 3 percentage points. However, if an RCC mix is placed at a moisture content more than 1 to 1.5 percent above the OMC, it can be too wet, not properly support vibratory rollers, and not reach its strength potential. The formula to calculate the Reference Wet Density is defined in Terminology (page 5).
16 Note to specification writer – While ASTM C1040 requires edge testing at 9 in. (225 mm) from the edge, ACPA recommends testing no closer than 12 in. (300 mm) so the testing does not damage the edge. For confined edges, testing can be done as close as 6 in. (150 mm).
17 Note to specification writer – ACPA suggests making three cylinders for each lot or sublot, and using at least two for strength acceptance. Each cylinder should be visually observed for uniformity, with special attention to paste formation as explained in ASTM C1435. A testing technican may also need to roughen the surface between lifts to mimic bond where two lifts are made. To make sure cylinders are square it is important to that they are capped properly.
18 Note to specification writer – The owner may allow for modification to ASTM C1435 to allow five-lift molding. Based on field experience, it has been suggested that this better represents field compaction.
19 Note to specification writer – In addition to determining thickness, the cores should be visually inspected to ensure that compaction at the bottom of the lift is obtained. If significant honeycombing or other signs of lower density are evident, check the cores for strength. On RCC projects with multiple lifts, these cores may also be used to ensure that the 2-lifts are bonded together.
4.0 RCC Mixture Design
RCC-4.01 Mixture Design and Submittal.20 Proportion one or more mixtures complying with requirements in Sections RCC-2.02 and RCC-2.03. Submit certified test data for each proposed mixture in accordance with the quality management plan from the declared independent testing laboratory. Do not submit mix designs unless they meet the requirements outlined in Sections RCC-4.02 to RCC-4.04.
Include the following information for each mix design: 1) manufacturer certifications of material compliance with requirements listed in Table RCC-1; 2) quantity and gradation of each aggregate, as well as combined gradation; 3) quantity and types of each cementitious material; 4) type(s) of chemical admixtures and range of dosages; 5) optimum moisture content and reference wet density; and 6) strength results.21
RCC-4.02 Cementitious Materials Content.22 Report the portland cement content in pounds per cubic yard (kilograms per cubic meter) as part of the mixture design. Replacing portland cement with supplementary cementitious materials (SCMs) is allowable to a maximum of 50% of the portland cement with ground granulated blast furnace slag or 25% of the portland cement with fly ash, or a combination of both, with fly ash not exceeding 25%.
RCC-4.03 Minimum Compressive Strength. The proposed laboratory mix design(s) shall meet the following minimum compressive strength (tested according to ASTM C39) based on test results of cylinders prepared according to ASTM C143523:
• 4000 psi (28 MPa) at 28 days for RCC mixtures in areas without freeze-thaw conditions.
• 4500 psi (31 MPa) at 28 days for RCC mixtures in areas exposed to freeze-thaw conditions.24
RCC-4.04 Alternative or Additional Strength Requirements. As an option, use alternative or additional strength testing to Section RCC-4.03 with the Engineer’s approval.
RCC-5.01 General. Furnish equipment matching those listed in the quality control plan and approved by the Engineer before starting work.
RCC-5.02 Mixing Plant. Obtain the Engineer’s approval of the mixing plant before starting RCC production. Use a mixing plant capable of producing a homogeneous RCC mixture in the proportions25 defined in the approved mixture design and conforming to the tolerances specified in ASTM C9426 for batch mixing plants or ASTM C68527 for continuous mixing plants.
Use a plant with production capacity sufficient to produce a uniform RCC mixture at a rate compatible with the placement operation. The Engineer can halt operations if the plant is unable to produce the RCC mixture sufficiently in quality or quantity, until operations are adjusted or a plant meeting all requirements is obtained. 28
5.02.1 Pugmill Plant. Pugmill plants shall be central plant type with a twin-shaft pugmill mixer, capable of continuous mixing.
5.02.1.a: Synchronized metering devices and feeders. Provide synchronized metering devices and feeders to dispense the correct proportions of aggregate, cement, supplementary cementing materials, and water for continuous mixing within the tolerance requirements of ASTM C685 depending on plant type.
5.02.1.b Surge Hopper. Provide a surge or gob hopper attached to the final discharge belt to temporarily hold the mixed RCC, in order to minimize segregation when loading into haul trucks, and to allow the plant to operate continuously.
5.02.2 Central Mix Batch Plant. Central Mix Batch plants shall be Tilt Drum Rotary or Horizontal Shaft Mixers. Use a mixer capable of producing a homogeneous mixture, uniform in texture and meeting the requirements of ASTM C94. Equip the mixer with batching equipment to meet the following requirements:
5.02.2.a Weigh Hoppers. Provide sufficient capacity to hold at least 10 percent more cementitious material than required for one batch, and equipped with vibrators to operate automatically and continuously while being dumped.
5.02.2.b Timing Device. Provide an accurate measure and visible indication of mixing time after all the materials, including the water, enter the mixer.
RCC-5.02.3 Alternate Mixing Equipment. Obtain the Engineer’s approval before using alternative mixing equipment, including portable pugmill mixers for dry batch plants conforming to ASTM C685, or truck mixers conforming to ASTM C94. Demonstrate that the mixing equipment has the ability to produce a consistent, well-blended, non-segregated, homogeneous RCC mixture in the proportions defined in the approved mixture design, and within the capacity and tolerance limits specified in Section 5.02.1 or Section 5.02.2, as appropriate. Demonstrate that the equipment meets hourly production rates proposed in the Quality Management Plan.
5.02.4 Cementitious Material Storage Silos. Provide separate and independent storage silos to store and supply portland cement, blended cement and individual supplementary cementitious materials. Label each silo clearly near the fill inlet to prevent loading errors.
RCC-5.04 Paving Machine. Obtain the Engineer’s approval of the paving equipment before starting RCC placement. Furnish a paving machine equipped with a high density29 screed capable of placing the RCC material to a minimum of 90% of the reference wet density in accordance with ASTM D1557 or equivalent test method, prior to any additional compaction. Ensure that the paver is of suitable weight and stability, equipped to spread, compact, and place the RCC mixture to the required thickness , cross slope, edge and surface texture . Do not us graders , bulldozers, or any equipment that does not provide compaction during paving, except as required for areas inaccessible to a paving machine or requiring odd-shapes.
RCC-5.05 Compaction Equipment. Furnish self-propelled vibratory dual steel drum and/or pneumatic rollers capable of providing primary and final compaction efforts necessary to meet in the place, wet density requirements of Table RCC-4, as appropriate, and in a manner comparable to the test strip demonstration. Furnish each drum on steel drum vibratory rollers with a properly operating scraper and brush. Only operate steel drum vibratory rollers in static mode for final compaction. Never operate a roller or paver in vibratory mode when equipment is not in motion.. Furnish walk-behind vibratory rollers or plate tampers only for compacting areas in accessible to larger rollers.
RCC-5.06 Haul trucks. Furnish trucks for transporting the RCC material form the plant to the paver. On long hauls, equip open-bed haul trucks with retractable protective covers to protect the RCC material from rain, evaporation, heat and other detrimental weather conditions. Provide a sufficient number of trucks to ensure adequate and continuous supply of RCC material to the paver.
RCC -5.7 Water Truck. Furnish a water truck, or similar equipment, on-site and available for use throughout the paving and curing process. Equip the truck or device with a spray bar capable of evenly applying a fine spray of water to the RCC subgrade or subbase surface without damage.
RCC – 5.8 Concrete Saws. Furnish concrete saws that are capable of sawing new RCC for crack control with minimal raveling and to the depth shown on the plans. Equip all saws with blade guards or devices to control alignment and depth.
Commentary – The achievable density behind any type of paver depends upon the mixture. In some cases even a seemingly good compactable mixture may come out the back a high-density screed at less than 90% density and require more compaction effort with rollers. RCC density, especially at the bottom of the RCC layer, is ultimately the key to good long term pavement performance. It is important that contractors choose from among allowable methods carefully.
RCC-6.01 Proof Rolling. Prior to placing RCC pavement, check for any soft or yielding subgrade or subbase areas by proof rolling with a loaded dump truck or pneumatic-tired roller over the entire area to be paved. Correct and make stable any soft or yielding subgrade areas prior to RCC layer construction.33 Remove any unsuitable soil or material and replace with acceptable material.
RCC-6.02 Test Section.34 Construct a <consider: 50 to 100-ft (15 to 30 m)35> long test section no less than 7-days prior to starting construction.36 Construct the test section using the proposed mixture design, and with the materials and equipment listed in the quality management plan and approved by the Engineer. If the placement requires more than one pass of the paver, construct the test section a minimum of two paver widths wide. If the pavement placement requires more than one lift, construct the test section to the required number of lifts. Place the test section in a location approved by the Engineer. It is acceptable to place and leave the test section as part of the completed pavement if it complies with all acceptance testing criteria.
The Engineer shall evaluate the following criteria from the test section:
• Adequacy of mixing plant to meet productivity requirements and produce consistent material.
• Maximum density directly behind the paver prior to roller compaction.
• Suitability of the proposed lift thickness.
• Sequence of primary/ secondary roller passes (with and without vibration).
• Maximum density following roller compaction.
• Texture and surface finish acceptability.
• Integrity of both fresh and cold joints (vertical and horizontal).
• RCC compressive strength based on cylinders and extracted cores tested at 7 days. 37
RCC-6.03 Producing RCC. Conform to applicable sections of ASTM C94 and ASTM C685, and the following requirements.
6.03.1 Storing and Handling Material General. Store and handle all material in a manner that prevents cross contamination. Do not use any material that has been stored for a period exceeding the manufacturer’s recommended shelf life. Do not use cement or supplementary cementitious materials containing evidence of moisture contamination. Where recommended by the manufacturer, agitate chemical admixtures to ensure consistency during use.
6.03.2 Storing and Handling Aggregate. Place aggregate stockpiles on paved pads or 12 inch (300 mm) sacrificial layers of the aggregate to prevent accidental contamination by stockpile loader operators. Store and handle aggregate in a manner that ensures reasonably uniform moisture content at the time of batching.
6.03.3 Mixing RCC. Mix the RCC material following the approved mixture proportions and within the tolerances in ASTM C94 for central mixed concrete and ASTM C685 for volumetric batching and continuous mixed concrete. For a new or additional mixture, submit a revised mixture design for approval by the Engineer before making any changes in supply sources or character of the materials. Follow the guidelines of 4.0 RCC Mixture design. Do not use unapproved RCC mixtures.
6.03.4 Plant Calibration. Prior to RCC material production, conduct a complete and comprehensive calibration of the plant in accordance with the manufacturer’s recommended practice. Provide all scales, containers, and other items necessary to complete the calibration. Calibrate the plant at the times specified in Table RCC-3.
To maintain accuracy, keep the sides of the mixer and mixer blades free of hardened RCC material or other buildups. Routinely check mixer blades for wear and replace if wear is sufficient to cause inadequate mixing per manufacturer’s recommendations.
6.03.5 Charging the Mixer. For plants conforming to ASTM C94 ensure that the volume of mixed material per batch does not exceed the manufacturer’s rated capacity of the mixer.38 For batch mixers, discharge all material in the mixing chamber before recharging.
6.03.6 Mixing Time. Mix the materials a sufficient length of time in the mixer to ensure thorough and complete blending of all ingredients. For plants conforming to ASTM C94, mix each batch for the minimum time recommended by the plant’s manufacturer.39
6.03.7 Daily Reports. Produce and maintain records of production and quantities of materials used in the plant. Supply these reports to the Engineer daily.
RCC-6.04 Transporting RCC. Transport the RCC material from the plant to the areas to be paved in dump trucks equipped with retractable protective covers for protection from rain or excessive evaporation, as necessary for the weather conditions. Do not exceed a <insert time40> minute haul time. The Engineer may increase or decrease the time requirement depending upon the ambient conditions and approved use of set retarding admixtures in the mixture. To minimize segregation during loading, load trucks uniformly across the entire bed of the truck.41 Ensure that the trucks are dumped clean with no buildup of RCC material in the corners.
RCC-6.05 Placing RCC. Deposit the RCC material directly into the hopper of the paver or into a secondary material distribution system that deposits the material into the paver hopper. Time the delivery and placement so that RCC material is spread with minimum stops and compacted within the time limits specified in Section 6.09.1. Place the RCC mixture without segregation.42
When using dual lift construction, feed the RCC material to the paver by an approved material transfer device that possesses the following characteristics:
• The ability to feed the paver at a rate which allows for continuous forward motion of the paving machine.
• The ability to feed the paving machine from an offset position which is outside of the initial lift of RCC pavement.
If RCC material is left in the paving machine past the delivery and placement time limits specified in Section 6.09.1, pull the paving machine off the placement and construct a cold joint in accordance with Section 6.10.2. The Engineer may increase or decrease the placement time requirement depending upon the ambient conditions and approved use of set retarding admixtures in the mixture.s.
RCC-6.06 Subbase Condition for Placement. Do not place RCC material on frozen ground or in standing water. Prior to proof rolling the grade and placing RCC material, ensure that the surface of the subgrade/subbase is clean and free of foreign material, ponded water, and frost. Ensure that the subgrade/subbase is uniformly moist at the time of RCC material placement. If moistening certain areas is necessary, ensure that the method of sprinkling will not form mud or pools of free standing water.
RCC-6.07 Weather Conditions.
6.07.1 Cold Weather Precautions. Stop placement operations when the air temperature falls below 40°F (5°C) and is declining. Start operations only if the air temperature is at least 35°F (2°C) and is rising.
If the air temperature is expected to fall below 40°F (5°C) at some time during placement operations, apply the cold weather procedures outlined in the quality management plan and approved by the Engineer. Provide a sufficient supply of protective material on site. RCC paved during cold weather is subject to the quality requirements outlined in Sections RCC-4.01 to RCC-4.04 and Table RCC-4.
6.07.2 Hot Weather Precautions. Take special precautions to minimize moisture loss due to evaporation during periods of hot weather [more than 90°F (32°C)]43 or windy conditions, including but not limited to the following options: cooling of aggregate stockpiles by shading or the use of a fine misting, covering haul truck beds, cooling RCC mix water, and decreasing the allowable time between mixing and final compaction. Keep the surface of the newly placed RCC layer continuously moist with mist sprayers until applying curing compound.
6.07.3 Rain Limitations. Stop placement operations when it is raining hard enough to be detrimental to the finished product. Placement is acceptable during light rain or mist provided the surface of the RCC layer does not erode, scab or damage. Cover dump truck beds during these periods to protect material during transport.
RCC-6.08 Paving. Only place RCC material with equipment listed in the quality management plan and meeting the requirements of Section RCC-5.04, including subsections.
6.08.1 Lift Thickness Range. Place RCC in lifts generally between 4 in. (100 mm) and 10 in. (250 mm) thick. The Engineer may approve placing lifts at thicknesses at 10 in. (250 mm) or greater with successful demonstration that the proposed method meets all requirements of Table RCC-4, Sections 5.04, 6.02 and 7.04, including ASTM C 1040 density testing using direct transmission test method (with a probe) at multiple locations throughout the entire lift thickness range.
6.08.2 Adjacent Lane Placement. Place adjacent paving lanes within 60 minutes. Keep the fresh edge44 (fresh vertical joint) from drying out until the adjacent lane is placed either by increasing productivity with tandem paving, spraying the joint surface with a light water mist, applying wet burlap cover, or by using a set-retarding admixture in the RCC mixture with proper approval.
If more than 60 minutes elapses between placements of adjacent lanes, consider the fresh vertical joint a cold vertical joint and prepare it in accordance with Section 6.10.2. The Engineer may increase or decrease the 60 minute adjacent lane placement requirement depending upon the ambient conditions and approved use of set retarding admixtures in the mixture.
6.08.3 Multiple Lift Placement. For multiple lift placements, compact the bottom lift to the specified minimum wet density before placing the next lift. Place and compact the top lift within 60 minutes of the completion of the bottom lift. Keep the surface of the bottom lift clean of debris, and prevent it from drying prior to placing the subsequent lift by increasing productivity with tandem paving, spraying the bottom lift surface with a light water mist or by using a set-retarding admixture in the RCC mixture with proper approval.
If more than 60 minutes elapses between lift placements, consider the interface between the top and bottom lifts as a cold joint and prepare the bottom lift surface in accordance with Section 6.10.4. The Engineer may increase or decrease the 60 minute lift placement requirement depending upon the ambient conditions and approved use of set retarding admixtures in the mixture.
6.08.4 Hand Spreading. Do not broadcast or spread RCC material across areas being compacted. Hand repair of small, isolated surface locations is permissible only immediately behind the paver and before any roller compaction operations begin in the area. Use only fresh RCC material from in front of the paver as repair material.45
RCC-6.09 Compaction. Only compact RCC material with approved equipment listed in the quality management plan, and that meets the requirements of Section RCC-5.05, including subsections.
6.09.1 Compaction Timing. Begin compaction as soon as practical after paver placement and complete all compaction operations within 60 minutes of the RCC material being mixed. The Engineer may increase or decrease this time depending on use of set retarding admixtures or the ambient conditions of temperature, wind, and humidity. Do not delay rolling operations from the timing approved in the quality management plan and validated in test strip construction unless approved by the Engineer.
6.09.2 Compaction Process. Apply the sequence and number of passes by vibratory and non-vibratory rolling to obtain the specified density proposed in the quality management plan and verified on the test section. Do not operate rollers in the vibratory mode while stopped. Use steel drum rollers in static mode and/or rubber-tire rollers for final compaction.
6.09.3 Compacting Longitudinal and Transverse Joints. Do not operate a roller within 2 ft (0.6 m) of the edge of a freshly placed lane until the adjacent lane is placed. Then, roll both edges of the two lanes simultaneously within the allowable time. If a cold joint is planned, roll the complete lane and follow the cold joint requirements specified in Section 6.10.2. For freshly placed RCC next to an existing cold joint, roll the complete lane, taking extreme care not to bridge the roller drum between the new unconsolidated fresh material and a previous cold joint edge. Such bridging of roller drum over cold joint edges, especially in vibratory mode, can significantly degrade the cold joint edge.46
6.09.4 Compacting Areas Inaccessible to Larger Rollers. Compact any areas inaccessible to a large roller using a small drum roller, a walk-behind vibratory roller or a plate tamper. Cast-in-place, conventional concrete meeting the same strength requirements in Table RCC-4 may be used in these areas as a replacement for RCC with prior approval of the Engineer.
6.09.5 Density Requirements. Perform in-place density tests in accordance with the requirements of Table RCC-4.
6.10.1 Fresh Vertical Joints. A vertical joint is considered fresh only when a subsequent RCC lane is placed within 60 minutes or the time limit approved by the Engineer. See Section 6.08.2 for allowable procedures to keep a fresh edge from drying out. If more than 60 minutes or the time limit approved by the Engineer elapses between placements of adjacent lanes, consider the fresh vertical joint a cold vertical joint and prepare it in accordance with Section 6.10.2.
6.10.2 Cold Vertical Joints. Consider any planned or unplanned vertical construction joint that does not qualify as fresh vertical joint as a cold vertical joint. Prior to placing fresh RCC material against a compacted cold vertical joint, thoroughly clean the cold vertical joint of loose or foreign material. Wet the cold vertical joint face and maintain it in a moist condition immediately prior to placement of the new lane.
Remove a minimum of 6 in. (150 mm) full-depth from the exposed longitudinal edge of any cold vertical joint that does not meet the minimum joint density requirements in Table RCC-4. Do not perform this operation any sooner than 2 hours after final compaction. Demonstrate to the Engineer that saw cutting will not cause significant edge raveling and remove all slurry and excess material from the cutting operation.
The Engineer may approve the use of an edge shoe for vertical cold joint construction with successful demonstration that the proposed alternate meets the minimum joint density requirements in Table RCC-4, and the edge shoe produces a face with no more than an angle of 15 degrees from vertical.
6.10.3 Horizontal Joints. A horizontal joint is considered fresh only when a subsequent RCC lift is placed within 60 minutes or the time limit approved by the Engineer. 48 See Section 6.08.3 for allowable procedures to keep the surface of the bottom lift continuously moist and clean of all loose material prior to placing the subsequent lift.49, 50
If more than 60 minutes elapses between lift placements, consider the interface between the top and bottom lifts as a cold horizontal joint and prepare the bottom lift surface in the manner demonstrated and approved on the test section to ensure that bond occurs between layers. The Engineer may increase or decrease the 60 minute lift placement requirement depending upon the ambient conditions and approved use of set retarding admixtures in the mixture.
6.10.4 Crack Control Joints.51 If required on the plans, construct transverse contraction or crack control joints in the RCC layer by sawing with approved equipment listed in the quality management plan, and that meets the requirements of Section RCC-5.08. Saw crack control joints to the interval, depth and width specified on the plans. Extend all crack control joints the entire width of paving. When sawing crack control joints, begin as soon as the RCC cuts without excessive raveling along the saw cut and finish before conditions induce uncontrolled cracking, regardless of the time or weather.
DO NOT require wax-based or other curing compounds on bottom lifts, which may impede bonding of subsequent lifts. When cleaning a lower lift surface, care must be taken to expose the fine aggregate enough to promote bonding, without undercutting the coarse aggregate. Acceptable cleaning can include water blasting, blowing with compressed air, or a combination of water and compressed air. The type of equipment that will be most effective will depend on the strength of the RCC at the time of cleaning.
6.10.5 Isolation Joints. Line the perimeter of fixed structures such as building foundation slabs, manholes, valves, trench drains, and concrete curbs and gutters with strips of fiberboard or other approved isolation joint material, as noted in the plan details, prior to paving.
6.10.6 Expansion Joints. Install expansion joints to the details, dimensions and locations shown on the Plans. If the plans do not include details and conditions warrant expansion joints, propose a plan and install expansion joints in the pavement, with approval of the Engineer. Include width, filler, sealing material, location and/or spacing recommendations in the expansion joint plan, considering thermal effects, regional climatic conditions, RCC coefficient of thermal expansion and expected daily temperature ranges at the time of placement.
RCC-6.11 Curing. Immediately after final rolling and compaction tests, keep the surface of the RCC layer continuously moist for a minimum of five days or until an approved curing method outlined in the quality management plan is applied.
6.11.1 Water Cure. Apply water cure using water trucks equipped with misting spray nozzles, soaking hoses, sprinkler system or other means that will ensure a uniform moist condition to the RCC layer surface without damage. Apply misting spray in a manner that will not erode or damage the surface of the finished RCC layer.
6.11.2 Curing Compound. Use a concrete curing compound conforming to Table RCC-1 requirements. Apply the curing compound at a minimum application rate of 150 ft2/gal (3.7 m2/liter) 52 on the surface and edges of the RCC layer no later than one hour after completion of finishing operations.53
6.11.3 Sheet Materials. Use sheet curing materials conforming to Table RCC-1 requirements. Ensure coverings are held securely in place and weighted to maintain a close contact with the RCC layer surface throughout the entire curing period. Overlap the edges of adjoining sheets and hold in place with sand bags, planking, or similar method, as approved by the Engineer.
6.11.5 Opening to Traffic. Protect the RCC layer from vehicular traffic during the early curing period until the surface can withstand turning movements without marring or displacing RCC surface aggregates. In addition, do not place vehicular traffic on the pavement until the RCC attains the minimum strength required for structural consideration per Table RCC 5. Non-truck mounted curing equipment or saw-cutting equipment, necessary for proper construction and to meet other provisions of this specification, are allowable using techniques to prevent marring or displacing RCC surface aggregates.
7.0 Acceptance Criteria
RCC-7.01 Thickness Requirements.
7.01.1 Thickness Verification by Cores. Determine the pavement thickness from cores by average caliper measurements in accordance with ASTM C174.55 Extract one core for each lot of RCC pavement per Table RCC-4. For pavement placement units consisting of less than one lot of RCC pavement, include the pavement with the previous or next placement unit.
7.01.2 Thickness Verification by Non-Destructive Device. The Engineer may approve a non-destructive method for thickness verification with successful demonstration that the proposed alternate is sufficiently accurate to satisfy the requirements of Table RCC-4.
7.01.3 Defective Area Correction for Pavement Thickness. The thickness after compaction shall be no less than 0.25 in. (6 mm) under the RCC thickness, as specified on the Plans or drawings. Full payment shall be made for pavement represented by verification tests meeting this requirement. Pavement that has been purposely warped to meet fixtures (manholes, drainage inlets, and catch basins), existing curb and gutter, or cross- and side-roads are exempt from thickness measurement.56
Pavement represented by any thickness verification test that is outside of the tolerance is subject to further evaluation. Take two additional tests, about 30 ft (10 m) on either side of the deficient test in the direction paving (within the same placement unit). The work is subject to full payment if the average thickness of the three tests is no less than the Plan thickness minus 0.125 in. (3 mm). Define the limits of thickness deficiency through additional tests as needed. For areas defined by the limits of testing to be deficient, propose a solution (either removal and replacement, repair method or adjusted contract unit price) to the Engineer/Owner. The proposed solution shall provide an as-built condition structurally equivalent to or greater than the design, or compensate for reduced value through a unit price adjustment, to the approval of the Engineer and at no expense to the Owner.
RCC-7.02 Density Requirements.
7.02.1 In-Place Wet Mat Density Determination. Determine the In-place Wet Mat Density on pavement at least 24 in. (610 mm) from any joint in accordance with ASTM C1040 direct transmission mode for each lot per Table RCC-4. For pavement placements of less than the size of one lot, include the pavement with the previous or next lot.
7.02.2 In-Place Wet Joint Density Determination. Determine the In-place Wet Joint Density on joints at distance 12 in. (305 mm) or greater from a free edge and 6 in. (150 mm) or greater from a confined edge accordance with ASTM C1040 direct transmission mode for each lot per Table RCC-4. For pavement placements of less than the size of one lot, include the pavement with the previous or next lot.
7.02.3 Correction for Density. For in-place wet mat and joint density, full payment shall be made for pavement based on the acceptance criteria in Table RCC-4. Lots that have a density measurement that is less than the required density requirement are subject to further evaluation. Take an additional test within a 5 to 8 ft (1.5 to 2.5 m) radius of the original test (within the same placement unit). If the additional test result is below the acceptance criteria in Table RCC-4, apply additional roller passes across the full lane width between the last testing location that produced an acceptable reading and the paver. If the additional rolling does not correct the problem, or causes the density to decrease, discontinue paving until corrections are made to assure the Engineer that the minimum density is achieved.
RCC-7.03 Strength Requirements.
7.03.1 Strength Determination. Determine the compressive strength of cylinders based on the acceptance criteria in Table RCC-4. For pavement placements of less than the size of one lot, include the pavement with the previous or next lot.
7.03.2 Remedial Action for Deficient Strength. Full payment shall be made for cylinder tests if the average strength is equal to 100% of the specified strength in Sections RCC-4.03 and 4.04, with no single result below 90%.
Pavement lots that have an average strength less than the required strength in Sections RCC-4.03 and 4.04 are subject to further evaluation.57 Extract three cores at random locations in the suspect area once the pavement is 28 days old. Remove,handle and test the compressive strength of the cores according to ASTM C42.58
Determine the average and standard deviation of the compressive strength of the three cores. If the average of the three cores exceeds85% of the minimum specified compressive strength in Sections RCC-4.03 and 4.04,theRCCin the sublot is acceptable and is subject to full payment and acceptance. If the average strength of the three cores is less than85% of the specified compressive strength in SectionsRCC-4.03 and 4.04, the RCC is not acceptable and requires removal per Section 7.03.3
7.03.3 Removal and Replacement. Areas determined to have strength deficiencies that are not resolved through referee testing (Section 7.03.2) require removal and replacement without additional payment. After the referee period or at least seven days, remove the hardened RCC material by saw cutting the perimeter of the deficient area full depth. Repair the area using an air-entrained cast in place concrete meeting the strength requirement of Table RCC-3 or as directed by the Engineer. If the repair is prepared using conventional concrete, drill and grout dowels in the sawed, butt-faced transverse perimeter joints per table RCC-6.
RCC-7.04 Surface Requirements.
7.04.1 Smoothness for RCC Pavements. Ensure that the finished surface, when tested with a 10 foot (3m) straightedge, does not vary from the straightedge or template by more than 0.375in (9mm) at any one point. In addition, the finished surface shall be within 0.625in (16mm) of the specified finished grade. Pavement surfaces that have been purposely warped to meet fixtures (manholes, drainage, inlets, and catch basins), existing curb and gutter, or cross and side road are exempt from straightedge measurements. Correct surface irregularities outside of these tolerances per the requirement of Section 7.04.2
7.04.2 Correction for Smoothness. Correct smoothness deficiencies from 7.04.1 using an approved grinding device without additional pavement. After correction, verify the corrective work by measuring the smoothness according to 7.04.1
7.04.3 Surface Texture. The final surface texture after rolling and curing shall be smooth and uniform over the entire area of pavement and shall reasonably match the surface condition of the test strip without rips. tears , cracking, segregation, rock pockets, or areas of loose aggregate.
7.04.4 Correction for Surface Texture. Correct surface texture deficiencies from Section 7.04.3 using an approved grinding device without additional pavement, or removal and replacement per Section 7.03.3 With the engineers approval, defective surface areas may remain in place.
RCC-7.05 Responsibility Prior to Acceptance of Work.
7.05.1 Maintenance and Care. Maintain the RCC pavement in good condition until all work is completed and accepted.
7.05.2 Snow and Ice Removal. Do not apply any de-icing agents to the RCC surface for at least 60 days after placement.
8.0 Measurement and Payment
RCC-8.01 Measurement. The quantity measured for payment under this specification shall be the number square yards (square meters) of RCC pavement completed and accepted, as measured in place. RCC material placed outside of the area designated to be paved under the contract shall not be included in computing the number of square yards (square meters). Construction of joints and correction of defective placement is included in the total square yard (square meters) basis and no direct payment will be made for this work.
RCC-8.02 Basis of Payment. The are unit price shall provide compensation for furnishing all labor, equipment, and materials to place, finish , texture, cure and saw joints, in accordance with the Plans and these specifications, including compensation for furnishing all raw material, and for proportioning, mixing and delivering concrete to the paving machine. All pavement accepted by the Engineer shall be paid at the contract price per unit for the pay items shown on the bid schedule or approved estimate, exept for lots requiring price adjustments for deficiencies.