514Roller Compacted Concrete

601.15 2, with the Design Strength being 3,500 psi.

Additionally, as outline d in Section 514.4.2.3, cores may also need to be obtained to determine the compressive strength of any areas which are found to not meet the specified density requirements. It should be noted that lot sizes for density testing (1,000 yd 2) and compressive strength acceptance testing (1,500 yd 2) are different, and will overlap throughout the project. However, only one price adjustment shall be applied to any area not meeting the specification requirements. If any lot, or portion of a lot, is determined to have compressive strengths below 3,500 psi as outlined in Section 514.4.2.3 and is also found to be deficient in strength as outlined in Section 514.4.3.1, the price adjustment to be applied to that lot, or portion of that lot, shall be the greater of eit her the price adjustments calculated accordingly. 514.4.3.2-Thickness Tests for Acceptance: The cores obtained in Section 514.4.3.1 shall be measured for thickness, in accordance with AASHTO T 148, prior to being tested for compressive strength. If the thickness of any core is found to be less than the specified design thickness, then an evaluation of the area represented by that core shall be performed by the Engineer in accordance with Section 105.12. If the Engineer allows that area of deficient thickness to remain in place, then that area shall be paid for at a reduced unit bid price as outlined in Table 514.4.3.2. TABLE 514.4.3.2 Average Value of Pavement Thickness as Represented by Acceptance Core Unit Price as Percent of Contract Unit Price 0.1 to 1.0% Less than Specified Thickness 98.0% 1.1 to 2.0 % Less than Specified Thickness 96.0% 2.1 to 3.0% Less than Specified Thickness 94.0% 3.1 to 4.0% Less than Specified Thickness 92.2% 4.1 to 5.0% Less than Specified Thickness 90.3% 5.1 to 6.0% Less than Specified Thickness 88.4% 6.1 to 7.0% Less than Specified Thickness 86.5% More than 7.0% Less than Specified Thickness, with a maximum of 0.70 inches Less than Specified Thickness Remove and Replace 514.5-EQUIPMENT AND TOOLS: Construct roller compacted concrete with any combination of equipment that will produce a completed pavement meeting the requirements for mixing, transporting, placing, comp acting, finishing, and curing as provided in this specification. 514.5.1-Field Laboratory: RCC shall be supplied by a plant which has been certified by the Division as meeting all requirements of the governing Specifications and as having the facilities necessary to ascertain and control the quality of the product in accordance therewith. A testing facility or laboratory, meeting the requirements of Section 501.5.1 shall be provided by the Contractor. 514.5.2-Mixing Plant: 514.5.2.1-General: Unless approved measures are taken to delay the setting time of the RCC, the mixing plant shall be located within a thirty-minute haul time from the point of RCC placement. Use only plants capable of producing an RCC pavement mixture in the proportions defined by the final approved mix design and within the specified tolerances. The capacity of the plant must be sufficient to produce a uniform mixture at a rate compatible with the placement equipment. The estimated production rate of the Plant shall be noted i n the Contractor’s Quality Control plan. If the plant is unable to produce material at a rate adequate to prevent unnecessary cold joints and frequent paver stoppages, the Engineer may halt production until such time that a plant of appropriate capacity i s used. The plant shall be inspected and approved by WVDOH District Materials Personnel prior to production of material under these specifications. 514.5.2.2-Pugmill Plant: Use only pugmill plants of the central plant type with a twin- shaft pugmill mixer, capable of batch or continuous mixing, equipped with synchronized metering devices and feeders to maintain the correct proportions of aggregate, cement, pozzolan, and water. These plants shall meet the requirements of AASHTO M 156. Other pugmill plant requirements are as follows: 514.5.2.2.1-Aggregate Storage: If previously blended aggregate is furnished, storage may be in a stockpile from which it is fed directly to a conveyor feeding the mixer. If aggregate is furnished in two size groups, follo w proper stockpiling techniques in accordance with section 501.7 to ensure aggregate separation. 514.5.2.2.2-Aggregate Feed Rate: Use aggregate bins with a feed rate controlled by a variable speed belt, or an operable gate calibrated to accurately deliv er any specified quantity of material. If two aggregate size stockpile sources are used, the feed rate from each bin must be readily adjustable to change aggregate proportions, when required. Feed rate controls must maintain the established proportions o f aggregate from each stockpile bin when the combined aggregate delivery is increased or decreased. 514.5.2.2.3-Plant Scales: Plant scales, if utilized, for any weigh box or hopper must comply with Section 601.5.2.3. 514.5.2.2.4-Cement and Pozzolan Material Storage : Supply separate and independent storage silos for Portland cement and pozzolan. At plants with two or more silos in which different types of cement or cementitious materials are stored, ensure that each silo has a sign at each fill inlet to reduce the potential for loading errors. Make the sign from a durable material, with minimum two-inch high by ¼-inch wide letters that are raised, indented, or cut. Ensure that the sign clearly identifies the material that is in the silo and may be easily read even when completely coated with dust. 514.5.2.2.5-Portland Cement and Pozzolan: If using Portland cement and pozzolan (such as fly ash or slag), employ blending equipment acceptable to the WVDOH and demonstrate, with a testing plan, the ability to successfully produce a uniform blended material meeting the mix design requirements. Perform testing on at least a daily basis to ensure both uniformity and proper quantities. 514.5.2.2.6-Cement and Pozzolan Feed Unit: Provide a satisfactory means of dispensing Portland cement and pozzolan, volumetrically or by weight, to ensure a uniform and accurate quantity of cementitious material enters the mixer. 514.5.2.2.7-Water Control Unit: Use a water control unit capable of measuring the required amount of water for the approved mix by weight or volume. Ensure that the unit is equipped with an accurate metering device. Vary the amount of water to be used only with the approval of the Engineer. 514.5.2.2.8-Gob Hopper: For continuous operating pugmills, provide a gob hopper attached to the end of the final discharge belt to temporarily ho ld the RCC discharge in order to allow the plant to operate continuously. 514.5.2.3-Rotary Drum Mixer: Shall meet the requirements of Section 501.5.3 and shall provide a rotary drum batch mixer capable of producing a homogeneous mixture, uniform in color, and having all coarse aggregate coated with mortar. Equip the mixer with batching equipment to meet the following requirements: 514.5.2.3.1-Weighing Equipment: Measure the amounts of cement, pozzolan, and aggregate entering into each batch of RCC by direct weighing equipment. Use only weighing equipment that is readily adjustable in order to compensate for the moisture content of the aggregate or to change the proportionate batch weights. Include a visible dial or equally suitable device that will accurately register the scale load from zero to full capacity. The cement and pozzolan may be weighed separately or cumulatively in the same hopper on the same scale, provided the cement is weighed first. 514.5.2.3.2-Weigh Hoppers: Use only bulk cement and pozzolan weigh hoppers that are equipped with vibrators to operate automatically and continuously while weighing hoppers are being dumped. Ensure that the weigh hopper has sufficient capacity to hold not less than 10 percent (10%) in excess of the cementitious material required for one batch. 514.5.2.3.3-Water Metering: Measure the amount of water entering each batch of RCC by weight or volume. Use only equipment capable of measuring the water to within a tolerance of plus or minus one percent (1%) and equipped with an accurate gauge or dial measuring device. Vary the amount of water to be used only with the approval of the Engineer. During batching, admit water to the mixer only through the water measuring device and then only at the time of charging. 514.5.2.3.4-Mixing Time: Use only drum mixers equipped with an accurate clock or timing device, capable of being locked, for visibly indicating the time of mixing after all the materials, including the water, are in the mixer. 514.5.2.3.5-Recharging: Discharge all material in the drum before recharging. Ensure that the volume of mixed material per batch does not exceed the manufacturer’s rated capacity of the mixer. 514.5.3-Paver: Place RCC with a high-density asphalt-type paver subject to approval by the Engineer. Use only pavers equipped with compacting devices capable of producing an RCC pavement with a minimum of 90 percent (90%) of the maximum density in accordance with AASHTO T 180, Method D prior to any additional compaction. Ensure that the paver is of suitable weight and stability to spread and finish the RCC material, without segregation, to the required thickness, smoothness, surface texture, cross-section, and grade. 514.5.4-Compactors: Use self-propelled steel drum vibratory rollers having a minimum static weight of 10 tons for primary compaction. For final compaction, use either a steel drum roller, operated in a static mode, or a rubber -tired roller of equal or greater weight. Only use walk-behind vibratory rollers or plate tampers for compacting areas inaccessible to large rollers. 514.5.5-Haul Trucks: Use trucks for hauling the RCC material from the plant to the paver with covers available to protect the material from inclement weather and excessive evaporation. To ensure adequate and continuous supply of RCC material to the paver, have a sufficient number of trucks. If the number of trucks is inadequate to prevent frequent starts and stops of the paver, cease production until additional trucks are obtained. 514.5.6-Water Trucks: Keep at least one water truck, or other similar equipment, on-site and available for use throughout the paving and curing process. Equip such equipment with a spreader pipe containing fog spray nozzles capable of evenly applying a fine spray of water to the surface of the RCC without damaging the final surface. 514.5.7-Inspection of Equipment: Before start-up, the Contractor’s equipment will be carefully inspected. Should any of the equipment fail to operate properly, cease work until the deficiencies are corrected. 514.5.8-Access for Inspection and Calibration: Provide the Engineer or WVDOH District Materials Inspector access at all times for any plant, equipment, or machinery to be used in order to check calibration, scales, controls, or operating adjustments. 514.6-PREPARATION OF GRADE AND CONDITIONING OF SUBGRADE OR BASE: Before the RCC processing begins, prepare the subgrade in accordance with Section 228 of the Specifications. 514.7-HANDLING, MEASURING, AND BATCHING MATERIALS: Handling, measuring, and batching of materials shall be in accordance with Section 501.7, except that volumetric batching shall not be permitted. 514.8-MIXING RCC: 514.8.1-Mixing Process: Use the same mixture for the entire project unless otherwise stated in the project documents. If, during production, the source of Portland cement, pozzolan, or aggregates is changed, then suspend production and submit a new mix design to the Engineer for approval. Do not exceed the manufacturer's rated capacity for dry concrete mixtures in the mixing chamber. Keep the sides of the mixer and mixer blades free of hardened RCC or other buildups. Routinely check mixer blades for wear and replace if wear is sufficient to cause inadequate mixing. 514.8.2-Mixing Time: Use a mixing time adequate to ensure a thorough and complete mixing of all materials. Do not al low the mixing time, after all materials including water are in the mixer, to be less than 1½ minutes for one cubic yard and 20 seconds for each additional cubic yard. 514.8.2.1-Mixing Time for Truck Mixers: When truck mixers are used to mix RCC, the mixer capacity shall be limited to 5 cubic yards per batch and mixing time shall be a minimum of 3 minutes. If the condition of the blades in the drum of any truck mixer, used for mixing RCC, is such that the adequacy of mixing after 3 minutes is questionabl e, or if there is any other reason to question the adequacy of the mixing, uniformity testing, in accordance with AASHTO M 157, for mass per cubic foot and coarse aggregate content, shall be performed on that truck prior to using it during production. If that truck mixer cannot produce a uniform RCC mix after 3 minutes of mixing, then the required mixing time shall be increased to the mixing time which is shown to produce a uniform mix. 514.8.3-Plant Calibration: Prior to commencement of RCC production , carry out a complete and comprehensive calibration of the plant in accordance with Section 501.5.2. Provide all scales, containers, and other items necessary to complete the calibration. After completion of the initial calibration, calibrate the plant periodically as directed by the Engineer. Plants listed on WVDOH approved list at the time of RCC production are exempt from this requirement, although the WVDOH reserves the right to require additional calibration if variation in mixture quantities are suspected. 514.8.4-Daily Reports: Supply daily plant records of production and quantities of materials used that day to the Engineer. These records may be used as a check on plant calibration. 514.8.5-Transportation: Transport the RCC pavement 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. Ensure that the trucks are dumped clean with no buildup or hanging of RCC material in the corners. Have the dump trucks 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. Dump truck delivery must be timed and scheduled so that RCC material is spread and compacted within the specified time limits. 514.9-PLACING RCC: 514.9.1-Subbase Condition: Prior to RCC placement, ensure that the surface of the subbase is clean and free of foreign material, ponded water, and frost. Ensure that the subbase is uniformly moist at the time of RCC placement. If sprinkling of water is required to remoisten certain areas, ensure that the method of sprinkling will not form mud or pools of freestanding water. Correct soft or yielding subbase areas prior to placement of RCC as specified in Section 6.1 above. 514.9.2-Adverse Weather Conditions: 514.9.2.1-Cold Weather Precautions: Employ cold weather precautions as detailed in Section 601.9.1 of the Specifications. Stop placement operations when the air temperature falls below 40°F and is declining. Start operations only if the air temperature rises above 35°F and is elevating. If the air temperature is expected to fall below 40°F at some time during construction, and if the Contractor plans to place RCC during that time, the Contractor shall advise the Division of his plans for cold weather curing and protecting the RCC. The Division may, at any time, require the Contractor to provide additional protection to cause the provisions of this specification to be met. 514.9.2.2-Hot Weather Precautions: Employ hot weather precautions as detailed in Section 601.9.2 of t he Specification. During periods of hot weather or windy conditions, take special precautions to minimize moisture loss due to evaporation. Cooling of aggregate stockpiles by shading or the use of a fine mist may be required. Protective covers may be req uired on dump trucks. Keep the surface of the newly placed RCC pavement continuously moist. The Engineer may decrease the allowable time, specified in Section 514.10.1, between mixing and the completion of compaction when the ambient temperature exceed s 90°F or during windy conditions. In no event shall RCC be placed when its temperature at any time after the completion of mixing exceeds 90°F. 514.9.2.3-Rain Limitations: Conduct no placement of RCC pavement during rain conditions sufficient to be detrimental to the finished product. Placement may continue during light rain or mists provided the surface of the RCC pavement is not eroded or damaged in any way. Use dump truck covers during these periods. The WVDOH may terminate paving at any time when, in the WVDOH judgment, the rain is detrimental to the finished product. 514.9.3-Paver Requirements : Place all RCC with an approved paver as specified in 514.9.3.1-Filling the Paver: Do not allow the quantity of RCC material in the paver to approach empty between loads. Maintain the material above the auger at all times during paving. 514.9.3.2-Stopping the Paver: Ensure that the paver proceeds in a steady, continuous operation with minimal starts and stops, except to begin a new lane. Maximum paver speed during laydown is ten (10) feet per minute. Higher paver speeds may be allowed at the discretion of the WVDOH if the higher speeds may be obtained without distress to the final product or cause additional starts and stops. 514.9.3.3-Surface Condition: Ensure that the surface of the RCC pavement is smooth, uniform, and continuous without excessive tears, rid ges, or aggregate segregation once it leaves the paver. 514.9.4-Inaccessible Areas: Pave all areas inaccessible to either roller or paver with cast- in-place concrete meeting the requirements of Section 501. 514.9.5-Adjacent Lane Pavement: Place adjacent paving lanes within 60 minutes. If more than 60 minutes elapses between placement of adjacent lanes, the vertical joint must be considered a cold joint and prepared in accordance with Section 514.1 1. At the discretion of the Engineer, this time may be increased or decreased depending on ambient conditions of temperature, wind, and humidity. Multiple pavers may be used in tandem to reduce the occurrence of cold joints. 514.9.6-Hand Spreading: Broadcasting or fanning the RCC material across areas being compacted is not permissible. Such additions of materials may only be done immediately behind the paver and before any compaction has taken place. Any segregated coarse aggregate shall be removed from the surface before rolling. 514.9.7-Segregation: If segregation occurs in the RCC during paving operations, placement shall cease until the cause is determined and corrected to the satisfaction of the Engineer. If the segregation is judged by the Engineer to be severe, remove and replace the segregated area at no additional cost to the Department.

514.10 Compaction:

514.10.1 Time to Compaction Start: Ensure that compaction begins with the placement

process and is completed within 60 minutes of the start of the mixing at the plant. The time may be increased or decreased at the discretion of the WVDOH depending on ambient conditions of temperature and humidity. Do not permit delays in rolling unless approved by the Engineer. Plan operations and supply sufficient equipment to ensure that these criteria are met.

514.10.2 Rolling: Determine the sequence and number of passes by vibratory and non -

vibratory rollers to obtain the specified density and surface finish. Only operate rollers in the vibratory mode while in motion. Rubber -tire rollers may be used for final compaction. Use additional rollers if specific density requirements are not obtained or if placing operations get ahead of the rolling operations.

514.10.3 Rolling Longitudinal and Transverse Joints: Do not operate the roller within

two (2) feet of the edge of a freshly placed lane until the adjacent lane is placed. Then, roll both edges of the two lanes together within the allowable time. If a cold joint is planned, then roll the complete lane and follow cold joint procedures as specified in Section 514.11.

514.10.4 Inaccessible Areas: Compact areas inaccessible to large rollers using walk -

behind rollers or hand tampers. Cast -in-place, meeting the requirements of Section 501, may be used in these areas as a replacement for RCC.

514.11 Joints:

514.11.1 Fresh Vertical Joints: A joint is considered a fresh joint when an adjacent RCC

lane is placed within 60 minutes of placing the previous lane or as specified by the Engineer based on ambient conditions. Fresh joints do not require special treatment.

514.11.2 Cold Vertical Joints: Any planned or unplanned construction joints that do not

qualify as fresh joints are considered cold joints. Prior to placing fresh RCC mixture against a compacted cold vertical joint, thoroughly clean the cold joint of loose or foreign material. Wet the vertical joint face and maintain it in a moist condition immediately prior to placement of the adjacent lane.

514.11.2 1-Sawing Cold Vertical Joints: For uncompacted surfaces or slopes more

than 15 degrees from the vertical, cut the joint vertically for the full depth. Within 2 hours of final compaction, the edge of a cold joint may be cut with approved mechanical equipment. For edges cut after 2 ho urs, sawcut to the full depth of the pavement. Demonstrate any modification or substitution of the sawcutting procedure to the WVDOH for approval prior to use. In no case allow cutting of the edge to cause raveling or tearing of the surface. Moisten the cut edge immediately prior to placement of the adjacent lane.

514.11.3 RCC Pavement Joints at Structures: Line structures such as manholes, valves,

or concrete curb and gutter with joint filler as defined in Section 708 of the Specifications.

514.11.4 Control Joints: Construct transverse contraction joints in the RCC pavement by

sawing. At the option of the Contractor, soft-cut or green-cut saws may be utilized as soon as possible behind the rolling operation and set to manufacturer's recommendati ons. Conventional cut saws must be used as soon as the sawing operation will not result in raveling or other damage to the RCC pavement, but not more than 18 hours after RCC placement. Cut all joints to 1/4 the depth of the RCC pavement to a single saw b lade width. Joints should be spaced at intervals not to exceed 24 times the nominal pavement thickness unless otherwise indicated on the Plans or directed by the WVDOH. (For example, for an eight (8) inch RCC pavement, cut joints at sixteen (16) foot intervals.). In areas where RCC is placed adjacent to existing concrete pavement, such as in shoulder areas, the Contractor shall adjust the joint spacing to align with the joints in the existing adjacent concrete pavement. In these areas, in order to wor k out a joint spacing which aligns with the joints in the existing pavement, the joints in the RCC may be spaced at intervals up to 24 times the nominal RCC pavement thickness, plus 10 percent (10%) of that distance. (For example, for an eight (8) inch RCC pavement, cut joints at a maximum spacing of 17.6 -foot intervals).

514.12 Finishing:

Ensure that the finished surface of the RCC pavement, when tested with a ten (10) foot straightedge or crown surface template, does not vary from the straightedge or template by more than 1/4 inch at any one point and shall be within 5/8 inch of the specified finished grade. When surface irregularities are outside these tolerances, or other smoothness requirements spec ified in the plans, diamond-grind the surface to meet the tolerance at no additional cost to the WVDOH.

514.13 Curing:

Immediately after final rolling and compaction testing, keep the surface of the RCC pavement continuously moist until an approved curing compound, a suitable prime coat, or a layer of asphalt concrete is applied or for 72 hours after placement, whichever comes first. Until the RCC has achieved the required strength for opening to traffic, the surface temperature of the RCC shall not be allowed to fall below freezing. The Contractor shall be responsible for the quality of the RCC placed and cured during cold weather. Any RCC injured by frost action shall be removed and replaced at the Contractor’s expense.

514.13.1 Water Cure: Apply water cure by water trucks equipped with fog spray nozzles,

soaking hoses, sprinkling system, or other means such that a uniform moist condition on the surface of the RCC is ensured. Apply this moisture in a manner that will not erode or damage the surface of the finished RCC pavement.

514.13.2 Curing Compound: Do not use curing compounds when the RCC material is to

be promptly covered with asphalt. Apply curing compound as indicated in Section 707.9 of the Specifications, except that the minimum rate of curing compound application is 11 square yards per gallon unless a higher rate is specified by the curing compound manufacturer.

514.14 Opening To Traffic:

Protect the RCC from vehicular traffic during the curing period. Do not place vehicular traffic, except for curing equipment or sawcutting equipment, on the RCC pavement until the RCC material achieves a minimum compressive strength of 3,000 psi as demons trated in Section 514.4.2.2.

514.15 Maintenance:

Maintain the RCC pavement in good condition until all work is completed and accepted. Perform such maintenance at no additional cost to the Engineer.

514.16 Method of Measurement:

The quantity of RCC placement to be paid for will be the number of square yards complete in place and accepted. The width for measurement will be the width of th e pavement or overlay shown on the typical cross section of the Plans and additional widening where called for or as otherwise directed in writing by the Engineer. The length will be measured on the surface along the centerline of the roadway or roadway ramp. Construction of control joints will not be measured separately and no direct payment will be made for this work.

514.17 Basis of Payment:

The quantities, determined as provided above, will be paid for at the contract unit prices less adjustments referred to below and shall constitute full compensation for furnishing and preparing of all materials, equipment, tools, labor, and incidentals nec essary to satisfactorily complete the work.

514.17.1 Thickness: Any sampling units found to be deficient in thickness, and which are

allowed to remain in place by the Engineer, shall be paid for at a reduced Contract Unit Bid Price as outlined in Tab le 514.4.3.2. No compensation will be allowed for the materials or labor involved in the removal of defective material.

514.17.2 Strength: Determination of RCC strength shall be in accordance with Section

514.4.3.1. Any sampling units found to be def icient in strength, and which are allowed to remain in place by the Engineer, shall be paid for at a reduced Contract Unit Bid Price as outlined in Section 514.4.3.1. No compensation will be allowed for the materials or labor involved in the removal of defective material.

514.17.3 Density: Determination of RCC density shall be in accordance with Section

514.4.2.3. Any sampling units found to be deficient in density, shall be handled in accordance with Sections 514.4.2.3 and 514.4.3.1.

514.18 Pay Item:

ITEM DESCRIPTION UNIT 514001-* “thickness” Roller Compacted Concrete Square Yard * Sequence number

Division 600

INCIDENTAL CONSTRUCTION