185 SECTION 409 DESCRIPTION
409.01.01 General. This work consists of constructing Portland cement concrete pavement on a prepared
surface. MATERIALS
409.02.01 General. Material shall conform to the following Sections:
Portland Cement Concrete ..................................................................................................................................................... Section 501 Reinforcing Steel .................................................................................................................................................................... Section 505 Portland Cement .................................................................................................................................................................... Section 701 Concrete Curing Materials and Admixtures ............................................................................................................................ Section 702 Aggregates for Portland Cement Products ............................................................................................................................. Section 706 Water ..................................................................................................................................................................................... Section 722 Concrete for Por tland cement concrete paving shall be Class PCCP conforming to Section 501 with the modifications and additional requirements specified herein. Use a three aggregate system consisting of a blend of two Coarse Aggregates from Subsection 706.03.01 and Fine Aggregate conforming to Subsection 706.03.03. Use American Concrete Institute, Manual of Concrete Practice, Guide 302.1R-04, Section 5.4.3 Combined Aggregate Grading to optimize the combined aggregate grading within the grading limits below. Submit the results with the mix design. For mix design approval and as a project control requirement, the proposed proportions of individual aggregates, combined mathematically, by volume or mass, shall produce a mixture within the grading limits for combined aggregates as follows: Grading Limits of Combined Aggregates Sieve Size Percent Passing by Mass 50 mm (2 in.) .............................................................................. 100 37.5 mm (1 1/2 in.) ....................................................................... 90-100 25 mm (1 in.) ............................................................................. 50-86 19 mm (3/4 in.) ........................................................................... 45-75 9.5 mm (3/8 in.) ........................................................................... 38-55 4.75 mm (No. 4) .......................................................................... 30-45 2.36 mm (No. 8) .......................................................................... 23- 38 1.18 mm (No. 16) ......................................................................... 15-33 600 μm (No. 30) ........................................................................... 8- 22 300 μm (No. 50) ........................................................................... 4- 13 150 μm (No. 100) ............................................................................ 1-5 75 μm (No. 200) ............................................................................ 0-3 The air range indicated is not required in Clark County. For mix design approval, testing shall demonstrate that a minimum flexural strength of 4.5 MPa (650 psi) will be achieved at 28 days. An average of 3 beams, when cured and tested according to Test Method No. Nev. T442, shall meet or exceed 4.5 MPa (650 psi) with no individual beam having a strength less than the specified strength. CONSTRUCTION
409.03.01 Equipment . (a) General. Equipment and tools necessary for handling materials and performing all
parts of the work must be approved as to design, capacity, and mechanical condition. Provide this equipment on the site, available for inspection, testing, and approval before paving operations are started. Maintain all equipment, tools, and machinery in a satisfactory working condition. Provide equipment of such capacity that the paver will operate continuously or at a constant rate of production. If any piece of equipment does not have sufficient capacity to keep pace with the other operations, the Engineer may limit the size of the batch or otherwise limit the rate of production to prevent poor workmanship, overloading of equipment, or frequent delays. 409 PORT LAND CEMENT CONCRETE PAVEMENT 186 Equipment that will be operating entirely or partially on any existing pavement shall have rubber -tired wheels in contact with the pavement. Hard tracked equipment will not be allowed to run on the pavement regardl ess of the pavement age or strength. Provide lightweight concrete saws (early entry saws) specifically designed for sawing fresh concrete without the use of water for constructing weakened plane joints in the concrete pavement. Provide vibratory equipmen t to consolidate the concrete. Cores may be taken to verify adequate consolidation of the concrete. Provide adequate internal vibrating equipment, including power, to enable the Engineer to fabricate concrete cylinders for testing purposes.
b.Batch Plant and Equipment. Provide a copy of the plant ce rtification as specified in Subsection 106.07 and receive approval prior to performing any work. For all batches with a volume of 1 m3 (1 yd3) or more, provide batching equipment conforming to o ne of the following combinations:
1.Separate boxes and separate dial or beam scales for weighing each size of aggregate.
2.Single box and dial or multiple beam type scales for all aggre gates.
3.Single box or separate boxes and automatic weighing mecha nism for all aggregates. In order to check the accuracy of batch masses, determine the gross mass and tare mass of batch trucks, truck mixers, and truck agitators, when ordered. Weigh the equipment on approved scales. Proportion aggregates and bulk cemen t by mass by means of automatic proportioning devices of approved type conforming to the requirements specified herein. Weigh bulk cement on scales separate and distinct from the ag gregate hoppers. Interlock the discharge mechanism of the bulk cement hop per against opening before the full amount of cement is in the hopper, against closing before the contents of the hopper are entirely dis charged and the scales are back in balance, and against opening when the amount of cement in the hopper is either over or under mass by more than 1% of the amount specified. Interlock the bulk cement batcher and aggregate batcher so that a new batch of cement cannot be started until all weigh hoppers are empty, the scale is at zero, and the discharge gates are closed. Equip the batch plant with a numerical printout device that will make a continuous, permanent, and accurate record of the masses of cement, gravel, and sand as well as the amount of water and additives used in each batch of concrete and the target weights. Provide the record immediately after each batch is produced. Design the discharge gate on the cement hopper so as to permit reg ulating the flow of cement into the aggregate as approved. Control material discharged from the bins by gates or by mechanical conveyors. Interlock the means of withdrawal from the bins, and of discharge from the weigh hopper, so that not more than one bin can discharge at a time, the order of discharge can be changed , and the weigh box cannot be tripped until the required quanti ty from each of the bins has been deposited therein. Should a separate weigh hopper be used for each size of aggre gate, all may be operated and discharged simultaneously. When the discharge from the bins is controlled by gates, actuate each gate automatically so that the required mass is discharged into a weigh hopper, after which the gate shall automatically close and lock. Provide a weighing device which is automat ic to the extent that the only manual operation required for proportioning the a ggregates and cement for a batch is a single operation of a switch or a starter. Provide a stable platform with canopy from which the inspector can step onto the bed of the trucks in order to take samples. Locate platform no farther than 75 m (250 ft) fro m the mixer. Provide platform with a height equal to the height of the truck beds and at least 10.7 m (35 ft) long and 2.4 m (8 ft) wide with a 2.4 m x 2.4 m x 2.4 m (8 ft x 8 ft x 8 ft) lockable insulated shed at one end for cylinder storage. Provide the platform with adequate railing and stairs with handrail down to ground level. Construct the platform of either wood or steel, and conforming to the standards contained in "Safety and Health Regulations for Construction" of the Department of Labor. Temperat ure PORTLAND CEMENT CONCRETE PAVEMENT 409 187 control the shed in order to maintain the concrete test cylinders within the temperature range required by Test Method No. Nev. T428. Supply potable running water to the platform, 110 V electrical power, suitable lights, vibrators , and outlets. Furnish radios or telephones so the inspector on the platform can communicate with the batch plant operator.
c.Mixers. Furnish mixing equipment conforming to Subsection 501.03.06.
d.Vibrators. Furnish internal vibrators with rigid or flexible shafts, prefe rably powered by electrical motors, capable of operating at a frequency of 7,000 vibrations per minute or greater. The outside diameter or the side dimensions of the vibrating element shall be at least 19 mm ( 0.75 in.) and not greater than 38 mm (1 .5 in.). The length of the shaft shall be at least 600 mm (24 in.). Furnish a tachometer or other suitable device for measuring and indicating the actual frequency of vibrations. Do not rest vibrators on new pavements or side forms. Connect power to the vibrators so that vibration will cease when the forward or backward motion of the machine is stopped.
e.Forms. Use equipment utilizing stationary side forms or slip -form paving equip ment. If using side forms, u se only metal side forms, weighing not less than 2 6 kg/m (18 lb/ft), without stakes. Furnish side forms of sufficient rigidity, both in the form and in the interlocking connection with the adjoining forms, so that springing will not occur under the mass of the grad ing and paving equipment or from the pr essure of the pavement when placed. Furnish straight side form sections, free from warps, bends, inden tations, or other defects. Remove defective forms from the work. Equip slip -form paving equipment with travel ing side forms of sufficient dimensions, shape, and strength to support the concrete laterally for a sufficient length of time during placement to produce pavement of the required cross section. Do not create abrupt changes in longitudinal alignment of the pavement. Do not deviate more than 30 mm (1.2 in.) horizontally from the established alignment.
f.Vibrators for Testing Purposes. Provide adequate internal vibrating equipment, including power, to enable the Engineer to perform tests . Vibrators shall conform to the requirements as specified above .
g.Fogging Machine. Provide a fogging machine capable of applying water in the form of a fine mist spray over the entire width of the concrete pavement. Create fine mist by pumping water, or a combination of air and water under high pressure in c ombination with a suitable atomizing nozzle. Adapt fogging machine for intermittent or continuous use to prevent excessive wetting of the concrete, and make it capable of repeated passes in order to prevent shrinkage cracking of the concrete.
409.03.0 2 Preparation of Grade. Place a bond breaker of white pigmented wax based curing compound on
the prepared surface. Apply bond breaker in a single application at a rate of 0.60 ± 0.10 L/m2 (2 gal/150 ft2 ± 25 ft2). Allow adequate time for the bond breaker to cure as per the manufacturer’s recommendations before placing concrete. Repair or reapply bond breaker that has been contaminated or otherwise affected and which will not perform the function as intended. Apply a fine spray of water to the bond breaker im mediately before concrete placement begins.
409.03.0 3 Setting Forms . Before placing side forms, construct the underlying materi al to the proper grade.
Place side forms with full bearing upon the founda tion throughout their length and width of base and p lace to the required grade and alignment of the edge of the finished pavement. Support forms so that they will not deviate vertically at any time more than 3 mm (0.01 ft) from the grade established. Provide stake pockets and interlocking devices that will prevent movement of the form s. Stake side forms firmly by means of steel stakes at each end of the section and at intermediate points not more than 1.5 m (5 ft) apart and design so that stakes may be driven through the base of the form. Lay side form sec tions with an expansion gap of approximately 3 mm (0.01 ft). Use stakes of sufficient length so that the side forms will be held firmly in place. Provide longer stakes if lateral movement of forms is greater than 6 mm (0.02 ft) while supporting moving equi pment. 409 PORT LAND CEMENT CONCRETE PAVEMENT 188 When a straightedge 3.6 m (12 ft) long is placed on the top of any side form , the top of the side form shall not vary more than 3 mm (0.01 ft) from the lower edge of the straightedge . When a straightedge 3.6 m (12 ft) long is placed against the inside face of any side form, the inside face of the side form shall not vary more than 6 mm (0.02 ft) from the straightedge. Immediately in advance of placing pavement and after all subgrade op erations are completed , true and maintain side forms to the r equired line and grade for a distance sufficient to prevent delay in placing the pavement. Keep side forms in place until the day after placing the pavement, and in all cases until the edge of the pavement no longer requires the pro tection of the forms. Thoroughly clean and oil side forms each time they are used.
409.03.0 4 Reinforcement. Install reinforcing steel if required.
Hold bar reinforcement accurately and firmly in position during the placing and compacting of the concrete without sagging by me ans of supporting devices to be left in place. Specifically manufacture the supports for this purpose . Design each support to hold a minimum vertical load of 90 kg (200 lb).
409.03.0 5 Mixing. Mix concrete according to Sub sections 501.03.06 and 501.03.07, and as specified herein.
Provide and maintain suitable nonresettable batch counter in proper operating order, which will correctly indicate the number of batches pro portioned at the batching plant and mixed in the mixer s. Thoroughly mix concrete to a homogeneous appearance, without lumps of sand or cement or other evidence of undispersed cement. Non -homogeneous concrete will be rejected. Mix concrete not less than 60 seconds or more than 90 seconds. The actual mixing t ime will be determined. Begin mixing time upon completion of charging of all materials into the mixing drum. Mixing time ends when mix discharge begins. Transfer time in multiple drum mixers is included in mixing time. Remove the contents of an individual mixer drum before a succeeding batch is emptied therein. Charge the batch into the drum so that a portion of the mixing water enters in advance of the cement and aggregates. Uniformly add all water in the drum by the end of the first 15 seconds of the mix ing period. Keep the throat of the drum free of such accumulations as may restrict the free f low of materials into the drum.
409.03.06 Test Strip. Prior to performing concrete pavement placement, construct a test strip of at least 50 m
(150 ft) in length and to a width that will be common to the majority of production placement. Construct the test strip with the equipment and mix design that will be used throughout the concrete paving operation. Should a change in the equipment or mix design occur at any time during the concrete paving operation, an additional test strip may be required. The test strip shall be constructed under the same conditions that will occur during production. These conditions are to include anticipated working shift an d atmospheric and surface temperatures. Suspend concrete pavement placement operations for 10 working days. The test strip will be evaluated to ensure conformance wit h the plans and specifications. Remove test strips not conforming to the requirements of the plans and specifications from the roadway and dispose of according to Subsection 107.14 . Construct additional test strips until approval is given to begin the production of concrete pavement placement. Test strips conforming to the plans and specificat ions will be considered as permanent concrete pavement and will be measured for payment as specified in Subsection
409.04.01 Acceptance of the test strip shall not relieve the Contractor of responsibility to complete the remainder of
work in accordance wi th the plans and specifications.
409.03.07 Placing Concrete. Do not place concrete when the surface temperature is less than 0 °C (32 °F) or
greater than 32 °C (90 °F). Do not place concrete while the atmospheric temperature is below 2 °C (35 °F) unless adequate means are employed to heat the aggregates and water, and satisfactory provisions made for protecting the work. Do not place concrete where ponded water, snow, or other foreign debris is on the surface . If necessary, the surface of the base may be c ooled by watering sufficiently in advance of concrete placement. In the event of rainfall, s top placing concrete before the quantity of rainfall is sufficient to cause a flow or wash the surface or as directed . After the concrete has been batched and del ivered to the project, only one attempt may be made, by adding approved admixtures, to bring the slump and air content into specification. Do not make any adjustments to the mix PORTLAND CEMENT CONCRETE PAVEMENT 409 189 if more than 10% of the originally batched concrete has been discharged from t he delivery vehicle. Do not use concrete showing improper proportions of materials, including water. Remove and dispose of any such unsatisfactory concrete. Equipment that damages the base course will be prohibited from traveling thereon. Prevent delay in delivery and placing of the concrete. An in terval of more than 45 minutes between placing of any 2 consecu tive batches or loads will constitute cause for stopping paving operations. If so ordered to shut down, make a contact joint at the location and of the type directed, in the concrete already placed. Place concrete pavement in 3.6 m (12 ft) traffic lane widths separated by contact joints, or place monolithically 2 or more lanes wide without a contact joint, but with a longitudi nal weakened plane j oint at each traffic lane line. Protect freshly placed pavement , previously constructed pavement , and existing pavements from damage by any cause. Repair all damage. Protect expansion joint material while depositing fresh concrete adjacent thereto. Adeq uately barricade concrete work area in all directions to protect the work.
409.03.08 Spreading, Compacting, and Shaping. (a) Side Form Construction. Distribute the concrete
uniformly with a mechanical spreader. Vibrate and screed the spread concrete by a machine or machines. Vibrate the concrete, for the full paving width, by means of surface vibrators with internal vibrators adjacent to each longitudinal edge or by some other method of vibration that produces equivalent results without segregation. Vibrate at a rate of not less than 3,500 vibrations per minute for surface vibrators and 5,000 vibrations per minute for internal vibrators. Operate the amplitude of vibration to be perceptible on the surface of the concrete more than 300 mm (12 i n.) from the vibrating element. Furnish adequate machines to perform the work required at a rate equal to the progress of the mixer. Any delay in excess of 15 minutes in vibrating and screeding will constitute cause for stopping the mixer until the machines performin g such work are again in prope r position in the paving train. Perform screeding by making at least 2 complete passes over the entire area of the pavement. Adjust the screed to an elevation slightly above grade so that when properly consolidated and finish ed, the completed surface of the pave ment will be at the established grade, true to the cross section shown on the plans, and free from porous areas. Keep the tops of the forms or the adjacent pavement and the contact surface of the crawler tracks or whee ls clean by effective devices attached to the machine. Maintain the travel of the machine true without lift, wobble, or other variation tending to affect precision screeding. During each pass of the machine, maintain a roll of concrete ahead of the front s creed for the entire width of pavement being placed and , except when mak ing an expansion joint, do not operate the machine beyond that point where the roll of concrete can be maintained. Use equipment to produce a surface requiring minimum cutting during the floating and final finishing process as specified in Subsection 409.03.1 1. Submit a written proposal for approval, detailing the equipment, materials , and procedures to be used for concrete widths less than one traffic lane.
b.Slip -Form Construction. References at reasonable intervals on both sides of the roadway, for line and grade control of the placing operations will be established. Furnish, place, maintain, remove, and dispose of such supports, wire devices, and materia ls as may be required to provide continuous line and grade reference controls to the placing machine or paver. Equip the slip -form paver with a control system which will automatically sense and simultaneously control the laying and trimming of the material s to the specified longitudinal and lateral grade, from both sides of the roadway. Automatically actuate the control systems from independent line and grade control references through a system of mechanical sensors or sensor directed devices which will mai ntain the equipment at the proper transverse slope and at the proper elevation to obtain the required thickness and surface. Deliver the fresh concrete to the front of the paver by means of a belt feeding device or other device that is capable of loading concrete onto the dowel bar baskets and in front of the paver without causing the misalignment of the dowel bars as the paver passes. 409 PORT LAND CEMENT CONCRETE PAVEMENT 190 Spread, consolidate, screed, and float -finish the freshly placed concrete with slip -form paving equipment in such a manner that a minimum of finishing with a hand float will be required. Distribute the concrete uniformly into final position by the slip-form paver without delay. Effectively consolidate the concrete, for the full paving width, by internal vibration with trans verse vibrating units or a series of equally spaced longitudinal vibrating units. If a series of longitudinal vibrating units are used, equally space them at intervals not to exceed 0.75 m (2.5 ft) measured center to center. Vibrate at a rate of not less t han 3,500 vibrations per minute for surface vibrators and 5,000 vibrations per minute for internal vibrators. Operate the amplitude of vibration to be perceptible on the surface of the concrete more than 300 mm (12 in.) from the vibrating element. The ter m "internal vibration" used above shall mean vibration by means of vibrating units located within the spec ified thickness of pavement section and a minimum distance ahead of the screed e qual to the pavement thickness. At locations inaccessible to slip -form paving equipment, place concrete pavement according to the requirements for placing concrete in widths less than a traffic lane as specified above for side form construction . At such locations, use stationary side forms conforming to Subsection 409.03.0 1 (e). Finish locations inaccessible to the slip -form paving equipment by the hand float method and equipment specified in Subsection 409.03.1 1 (b).
409.03.09 Joints. (a) General. Joints in pavement will be designated as longitudinal and transverse contac t
joints, transverse expansion joints, and longi tudinal and transverse weakened plane joints. Construct transverse joints at the angle to the centerline of the pavement shown on the plans. Construct faces of both transverse and longitudinal joints normal to the surface of the pavement. Keep sawed joints clean and free of all foreign material after com pletion of shoulder work and bef ore acceptance of the contract. Use tie bars for all longitudinal contact joints and longitudinal weakened plane joints. Place straight tie bars mechanically by an approved method. Do not place tie bars closer to adjacent dowel bars than allowed in the Standard Plans. Use tie bars conforming to AASHTO M31 Grade 300 (40) or Grade 420 (60) steel and epoxy coat as specified in Section 505. Tie bars may be bent at right angles against the form of the first lane constructed and straightened into final position before the concrete of the ad jacent lane is placed. If an "S" shaped bend is formed in straightening the bar, do not all ow the offset from a straight line to be more than 30 mm (1.2 in.). In lieu of bent tie bars, approved 2 piece connec tors may be used. Dowel bars are required for all transverse weakened plane joints and transverse contact joints as shown on the plans. Place the dowel bars within 25 mm (1 in.) of the planned transverse and depth location and within 50 mm (2 in.) of the planned longitudinal location. Place the dowel bars parallel to the pavement surface and centerline within a tolerance of 12.5 mm in 450 mm (0.5 in. in 18 in.). Do not interrupt the forward movement of the finishing beam or screed by the inserting of the dowel bars. Provide an approved method of marking the locations of the transverse joints. Dowel bars shall be plain, round, smooth, coa ted bars, free from burrs or other deformations detrimental to free movement of the bars in the concrete. Provide dowel bars of the size and length shown on the plans and with at least one end sawed. Dowel bars shall be Corrosion Resistant Dowel Bars meeti ng the requirements of AASHTO M254, Type B, except the core material shall be of steel meeting the requirements of AASHTO M31, Grade 300 (40) or Grade 420 (60), or the equivalent, except that the bend test will not be required. The coating material shall m eet the coating material requirements of AASHTO M284. Coat the cut ends of the dowel bars . Uniformly apply an approved bond breaker to the coated bar before insertion in the concrete. Use the type of bond breaker as recommended by the coating manufacturer. Submit certified test results showing compliance with all requirements of AASHTO M254 for approval. In particular, see the Pull -Out Test requirement of AASHTO M254. Perform this test on bars to which the propose d bond breaker has been applied. The test re port shall identify the type of bond breaker used. PORTLAND CEMENT CONCRETE PAVEMENT 409 191 Place dowel bars by one of the following methods:
1.Automatic Dowel Bar Inserter Method. The automatic dowel bar inserter shall have a successful performance history. Submit documentation regarding perfo rmance history of the dowel bar inserter for approval. Place and consolidate the pavement to full depth before insertion of the dowel bars. Insert the dowel bars into the concrete ahead of the finishing beam or screed.
2.Wire Basket Method. Use wire ba sket type supports specifically manufactured for this purpose. Determine the type of dowel supporting baskets as well as the method of anchoring. Dowel bars may be tack welded at alternating ends, to the basket assemblies, to prevent slippage. No portion o f the dowel support assembly shall cross the transverse joint. Securely anchor and construct dowel bar assemblies to firmly hold all the dowel bars at the specified depth and alignment. Cut and remove all tie wires or shipping support wires prior to concr ete placement. Do not start paving until the approved assemblies are in place at least 60 m (200 ft) in advance of the paving. Stop paving at any time that approved assemblies are not in place at least 60 m (200 ft) in advance of the concrete placement op eration. This requirement may be waived, upon written request and approval, in areas where access is restricted or other construction limitations are encountered. Approval of the initial placement of basket assemblies shall not constitute acceptance of the final position of the dowel bars. Consolidate the concrete around the dowel bars such that no voids exist. Do not supplement consolidation by the use of hand held vibrators. Dowel bar location will be verified for acceptance on all dowel bars placed. If there is a dispute with the results of verification , perform coring at the locations of the bars in question. Cores shall be a nominal 100 mm (4 in.) in diameter and one core shall be taken at each end of the do wel bar. Once measurements are complete, fill all core holes with an approved patching material. Control the positioning of dowels in a manner such that dowels meet the specified tolerances. If at any time dowels are found to be installed improperly, the paving operations will be suspended and operations shall not begin until it is demonstrated that the problem which caused the improper dowel positioning has been corrected. Concrete pavement containing improper dowel positioning will be subject to the pro visions of Subsection 105.03.
b.Contact Joints. Contact joints are those made by placing fresh concrete against hardened concrete at planned locations. Connect concrete on both sides of longitudinal contact joints with tie bars as shown on the plans. Connect concrete on both sides of transverse contact joints with dowel bars as shown on the plans. When the plans require the construction of keyways, construct the grooved portion of the keyway as part of the pavement width being placed.
c.Weakened Plane Joints. Space transverse weakened plane joints 4.5 m (15 ft) on center and perpendicular to centerline. Cut longitudinal weakened plane joints on all lane lines and shoulder lines. Where the combined width of the Portland cement concrete pavement shoulder and adjacent lane is 4.9 m (16 ft) or less, omit the longitudinal joint between the shoulder and the lane. Saw weakened p lane joints by cutting the pavement with a power driven early entry saw designed for sawing fresh concrete without the use of water . Cut joints when sawcutting equipment can be placed on the surface without raveling, tearing, spalling, or causing any other damage to the newly placed concrete pavement. Determin e the exact time to saw joints. 409 PORT LAND CEMENT CONCRETE PAVEMENT 192 Saw transverse weakened pl ane joints to a width of 3 mm (1/8 in .) and to a depth of 1/4 of the planned pavement thickness. Saw longitudinal weakened plane joints to a width of 3 mm (1/8 in.) and to a depth of 1/ 3 of the planned pavement thickness. After the joint is sawed, clean the saw cut and adjacent concrete surface with a dry vacuum. Immediately revise any procedure used to saw joints which results in uncontrolled random cracking. Repair portions of curing seal which are disturbed by sawing operations by spray ing the areas with additional curing seal. Keep a standby power saw on the project at all times when concrete paving operations are under way.
d.Repair of Spalls, Raveling, and Tearing. Repair spalls, raveling , and tearing at joints before opening the pavement to p ublic traffic. Submit repair products and procedures for approval. Repair sawed joints with excessive raveling or tearing. Prepare by removing all weak fractured concrete and cleaning surfaces to receive the patch. Following cleaning of the excavated are a and before placement of the concrete patch, apply a prime coat of epoxy conforming to AASHTO M235 (ASTM C881), Type V, to the entire surface to be patched. Immediately apply a patch material conforming to Subsection 502.03.15 following the application of the prime coat. Use an insert, or other means, to prevent bonding both sides of planned joints together.
409.03.10 Pavement Cracks. Pavement cracks shall be classified as either plastic shrinkage cracks or random
cracks based on the definitions herein. Plastic shrinkage cracks are generally tight -hairline cracks less than 0.80 mm (1/32 in.) which do not usually penetrate the depth of the slab, and are not structural in nature. They may appear either as irregular “map cracking” or as short irregular crack s roughly parallel to each other. The crack length is generally 50 to 600 mm (2 to 24 in.) and cracks are usually spaced from 50 to 600 mm (2 to 24 in.) apart. They are normally caused by rapid evaporation of water from the surface. They occur soon after t he concrete has been placed. Repair plastic shrinkage cracks unless the cracking exceeds 50% of the slab area, in which case the slab will be considered unacceptable and shall be remove d and replace d. Repair plastic shrinkage cracks with crack sealant according to Section 646. Random cracks are normally located approximately parallel to a sawed joint and may extend the full width or length of the slab and usually penetrate the full depth of the slab. Slabs containing random cracks are unacceptable and sha ll be r emove d and replace d. Remove and replace slabs as directed.
409.03 11 Finishing. (a) General. Provide adequate lighting facilities if required for finishing operations.
At the start of each day's work, mark the edge of the new pavement, nearest the outside shoulder, at 15 m (50 ft) from the beginning joint, with an approved stamp. The stamp shall contain the Contractor's name, the month, day, and year the section is placed, and the Engineer's station at the beginning joint. Make the stamp approxi mately 300 mm x 600 mm (12 in. x 24 in.) in size. In case fine cracks or hair checks appear in newly placed concrete before it is thoroughly set, apply water in the form of a fine fog mist above the concrete surface until the finishing operations are comp leted and the curing is applied. Apply the fog mist to the area between the finishing machine and the tining machine. If the combination of fogging and curing compound application are not or will not be effective in preventing plastic shrinkage cracking, stop paving operations until environmental conditions improve substantially or until other preventative measures are approved in writing.
b.Oscillating Screed . Provide a free floating oscillating screed device attached to the slipform paver, behind the conforming pan, which is capable of performing final finishing on the concrete surface. PORTLAND CEMENT CONCRETE PAVEMENT 409 193 The machine shall have a lightweight aluminum float 300 mm (12 in.) wide and a minimum of 3.6 m (12 ft) long, which oscillates fore and aft in the direction of traffic. Provide a float with the ability to traverse the entire concrete slab from edge to edge. Connect the float in such a way that it is driven (oscillated), yet it is free floating on the surface of the concrete. Adjust and set the movements of the float ac cording to concrete surface conditions and forward speed of the paver. Hand finishing will only be allowed when mechanical finishing equipment breaks down (only for that concrete already deposited on the grade) , for narrow or irregular areas , or where use of mechanical equipment would be impractical. Insure that floats are in good working condition. Discontinue use of equipment that leaves ridges, indentations, or other objectionable marks in the surface. Do not add water or chemicals to the pavement surfa ce to aid in finishing. Operate floats to smooth and fill in the open textured surface areas . Keep hand finishing to a minimum . Do not overwork the concrete.
c.Final Finish. After the preliminary finishing has been completed, round the edges of an initial pavement lane to a 13 mm (1/2 in.) radius. Round transverse contact joints, expansion joints, and joints adjacent to an existing pavement to a 6 mm (1/4 in.) radius. In advance of the curing operations, o r as directed, texture the pavement with a drag strip of burlap or other device which will produce scoring parallel to the centerline. The burlap drag shall consist of one or more pieces of burlap fastened to a cross member riding on the subgrade or side f orms by means of wheels or skids to form a continuous strip of burlap the full width of the pavement. Keep drags clean and free from encrusted mortar. Discard drags that cannot be cleaned and substitute new drags.
d.Surface Tining. In advance of curing operations, use a mechanical steel tine device to form grooves parallel to the centerline. Do not perform tining too early, where by the grooves may close up. Make tines of rectangular cross section and of sufficient thickness and resilience to result in g rooves spaced 19 mm (3/4 in.) on center, 2 mm to 3 mm (3/32 in. to 1/8 in.) wide and 3 mm to 5 mm (1/8 in. to 3/16 in.) deep in the finished concrete pavement. Operate the tine machine at a speed that keeps up with the paving machine. Tine the pavement w ithin 75 mm (3 in.), but no closer than 50 mm (2 in.) , of pavement edges . Tine the pavement within 75 mm (3 in.), but no closer than 50 mm (2 in.), of the centerline of longitudinal weakened plane joints. Omit tining at this location for a total width of 100 mm (4 in.) to 150 mm (6 in.). Maintain the tining device clean and free of encrusted mortar and debris to ensure uniform groove dimensions. Do not tine pavement which has set, whereas the operation is lifting aggregate out of, or tearing, or causing excessive roughness to the pavement surface. In such case, groove the pavement as directed . Grind and groove pavement surfaces that do not meet tining requirements. Perform grinding and grooving to meet the tining requirements as directed.
e.Grind Rumb le Strips. Mill or grind the rumble strips to the dimensions shown o n the plans. Use a milling or grinding machine that produces a reasonably smooth cut surface with 2 mm (1/16 in.) maximum differentials between peaks and valleys. The alignment of the edg e of the ground pattern will be randomly checked. Locate the rumble strips as shown on the plans. Re-cut rumble strip s which are misaligned. Some of the shoulders designated for receiving the rumble strips may have widths of approximately 1.2 m (4 ft) from the shoulder stripe to a vertical obstruction of concrete barrier rail or guardrail. Use milling or grinding machine s capable of constructing rumble strips at these locations. Demonstrate on an initial 150 m (500 ft) test section that the equipment and method s will provide the desired ground rumble strip and surface inside each depression without cracking or spalling the remaining concrete pavement. If the desired results are not being achieved , provide new equipment, new method s, or make necessary adjus tments to obtain the desired results. If the initial 150 m (500 ft) test section is unacceptable, repair the surface as directed, make necessary adjustments , and retest. 409 PORT LAND CEMENT CONCRETE PAVEMENT 194 Use a power broom or sweeper/vacuum to remove waste material resulting from the operation each day. Recover and dispose of waste material according to Subsection 107.14. Protect adjacent permanent striping from damage. Replace permanent striping damaged by the milling or brooming operations.
409.03 12 Riding Tolerances. Produce fini shed pavement surfacing which conforms to the surface tolerance
requirements specified herein.
a.Straightedge Measurement. The Engineer will perform this measurement. When a straightedge 3.6 m (12 ft) long is laid on the finished surface and parallel wi th the centerline of the highway, the surface shall not vary more than 3 mm (0.01 ft) from the lower edge of the straightedge. When a straightedge 3.6 m (12 ft) long is laid on the finished surface and at right angles with the centerline and extending from edge to edge of traffic lane, the surface shall not vary more than 3 mm (0.01 ft) from the lower edge of the straightedge. Use abrasive means to remove any points that are high in excess of the straightedge tolerances.
b.Profilograph Measurement. Furni sh and operate a profilograph, as specified in Subsection 402.03.03, at the time and date ordered. Measure two profiles in each lane at 1 m (3 ft) from and parallel to the traffic lane lines. Measure profiles for the entire length of each traffic lane. The average of the two profiles per lane will be used to calculate the profile index. Pavement within 10 m (30 ft) of a bridge deck or approach slab shall meet the profile requirements set forth in Subsection 502.03.16. Complete initial runs of the profil ograph before opening the new pavement to public traffic whenever practical. Submit the profile graphs immediately thereafter for evaluation. A profile index will be calculated for each 0.1 km (0.1 mi) of traffic lane measured according to Test Method No. Nev. T446. Only flagging costs for traffic control required for the initial running of the profilograph will be paid for according to Section 624. The finished surface shall have a profile index of 80 mm/km (5 in./mi) or less, and not more than 8 mm/0.1 k m (0.5 in./0.1 mi), as measured and calculated according to Test Method No. Nev. T446. Should the profile index exceed the allowable indexes, discontinue the paving operations until other means and equipment are proposed for trial and are approved. Grind areas exceeding the profile index requirements and areas representing high points on the profiles having deviations in excess of 7.5 mm (0.3 in.) as measured according to Test Method No. Nev. T446. Re-measure ground areas for conformance with the profile i ndex and for high points in excess of 7.5 mm (0.3 in.). Perform additional grinding as necessary to extend the ground area laterally to the nearest lane line or edge of pavement and longitudinally to lines normal to the pavement centerline. Use grinding machines that are power driven, self -propelled and specifically designed to remove, profile, smooth, and texture concrete pavement. The grinding machine shall have a wheel base of not less than 3.6 m (12 ft.), equipped with a rotating powered mandrel drum with diamond grinding blades of the appropriate bond hardness and a cutting head of not less than 0.9 m (3 ft.) wide. The grinding machine shall provide a surface with a parallel corduroy -type texture consisting of grooves between 2.3 mm (0.10 in.) and 3.3 mm (0.13 in.) wide. The land area shall be 2.0 mm (0.08 in.) wide and 1.5 mm (0.06 in.) higher than the bottoms of the grooves. There shall be between 170 and 190 grooves per meter (52 and 62 grooves per foot). Equip the grinding machine with an effective means of controlling dust and other particulate matter. Do not cause strain or damage to the underlying surface of the pavement with the grinding machine. Do not use grinding and texturing eq uipment that causes ravels, aggregate fractures, spalls, or disturbance of joints. Perform grinding in a longitudinal direction. Satisfactorily grind to produce a uniform textured surface over the surface areas designated for grinding. Re-groove ground a reas as directed to meet the tining requirements of Subsection 409.03.11 (d). PORTLAND CEMENT CONCRETE PAVEMENT 409 195 Pick up water and materials produced from grinding and grooving operations and dispose of according to Subsection 107.14.
409.03.1 3 Curing. (a) General. Cure Portland cement c oncrete pavement by either method specified in this
Subsection. In case of low temperatures, increase the curing period according to the provisions of Subsection
501.03.09 (b).
b.Curing Compound Method . Do not apply the curing compound until all patchin g and surface finishing, except grinding, has been completed. When directed during periods of hot weather, continue fogging of the concrete with water after curing compound is applied until it is no longer required. Such fogging after the application of th e curing compound will be paid for as extra work as provided in Subsection 104.03. Cure Portland cement concrete pavement with a white pigmented curing compound applied in 2 approximately equal applications. Apply the second application in the opposite lo ngitudinal direction as the first and within 30 minutes after the first application. Uniformly spray surfaces of the concrete pavement which are exposed to the air so as to obtain total coverage of the concrete surfaces. The rate of each application of curing compound at any point shall be 0.30 ± 0.10 L/m2 (1 gal/150 ft2 ± 50 ft2) and the average rate of each application shall be 0.30 ± 0.05 L/m2 (1 gal/150 ft2 ± 25 ft2). Equip power operated spraying equipment for application of curing compound with an operational pressure gage and means of controlling the pressure. Apply the compound immediately after the moisture sheen begins to disappear from the surface, but before any drying shrinkage or craze cracks begin to appear. In the event of any delay in th e application of curing compound, continuously fog with an atomizing nozzle as specified in Subsection 501.03. 08, and continue until the application of the compound. Immediately repair any damaged portions of the compound film with additional compound befo re the expiration of 72 hours after the concret e is placed. After the completion of the curing period, remove the wax -based curing compound from the pavement surface by sand blasting in those areas intended to receive permanent pavement marking.
c.Wate rproof Membrane Method. Cure by use of waterproof membrane material as specified in Subsection
501.03.08 (b).
409.03.1 4 Protection of Pavement. Protect concrete from freezing or frost for a period of 5 days after placing.
Do not allow the temperature of t he surface of the concrete to drop below 4 °C (40 °F) for this period of 5 days. Unless directed , do not permit traffic or equipment on the pavement before a period of 10 days after the concrete has been placed, nor before the concrete has developed a modulus of rupture of at least 3.8 MPa (550 psi), as determined by Test Method No. Nev. T442. Motor graders used to shape the shoulder material adjacent to the new pavement may be permitted to ride upon one edge of the previously placed concrete at the end of 72 hours, provided that no damage is done on the pavement edge by reason of such operation. Repair damage to the pavement resulting from such operations. Request in writing to place the tracks of the p aving equipment on the pavement after a period of 3 days after the concrete was placed, and the concrete has developed a modulus of rupture of at least 3.4 MPa (490 psi). Do not locate any part of the track closer than 300 mm (12 in.) from the edge of pave ment. Do not exert more than 138 kPa (20 psi) pressure on the pavement by the paver track. In case of visible cracking or other damage to the pavement, immediately discontinue operation of the paving equipment on the pavement . Repair damage to the pavement resulting from such operations. Replace concrete which has been damaged and in the opinion of the Engineer cannot be repaired satisfactorily. METHOD OF MEASUREMENT
409.04.01 Measurement. Concrete pavement will be measured by the square meter (square ya rd).
Saw transverse and longitudinal weakened plane joints will be measured by the linear meter (linear foot). Portland cement concrete pavement curing compound for the bond breaker and for curing the pavement surface will be measured by the liter (gallo n). Grind rumble strips will be measured by the kilometer (mile) longitudinally along each ground shoulder. 409 PORT LAND CEMENT CONCRETE PAVEMENT 196 409.04.02 Pavement Thickness. Construct concrete pavement according to the thickness requirements of the plans and specifications. Do not construe the tolerances allowed for subgrade construction and other specification provisions which may affect thickness to modify such thickness requirements. The thickness of the pavement will be determined according to ASTM C174. The primary unit of pavement will be the area of pavement placed in each day’s paving operations. Within each primary unit of pavement, there may be an area or areas which have been determined to be a secondary unit or units of pavement, as provided in Subsection 409.04.02 (b). In suc h case, the primary unit area will be reduced by the secondary unit area included therein. After requirements of Subsection 409.03.1 4 have been met, thickness measurements will be made in each primary unit of pavement at the rate of not less than one meas urement for each 300 m (1,000 ft), or fraction thereof, of pavement placed in each traffic lane, auxiliary lane or shoulder. The exact location and number of thickness measurements within each primary unit, both longitudinally and transversely, will be det ermined. Thickness measurements will be made at approximately uniform intervals throughout each primary unit of pavement. If required, secondary thickness measurements will be made as provided in Subsection 409.04.02 (b). Pavement thickness variation, if any, from the thickness requirements of the plans and specifications will be determined. Such variation will be determined as either excess or deficient thickness.
a.Thickness Deficiency of Not More Than 15 mm (0.6 in.). If the thickness measurements i n a primary unit are deficient in thickness by not more than 15 mm (0.6 in.), thickness variations in such unit will be averaged, algebraically, to determine the average thickness deficiency, if any, in said primary unit. For the purpose of determining the average thickness deficiency, an excess thickness variation of more than 5 mm (0.2 in.) greater than the thickness specified will be considered to be 5 mm (0.2 in.) greater than the specified thickness. For each primary unit of pavement which is deficien t in average thickness, pay to the Department as liquidated damages, or at the Department’s option, have deducted from any money due, or to become due from the Department, an amount set forth in the following schedule: Average Thickness Deficiency Liquidated Damages mm (in.) % of bid price 0.0-5.0 (0.0 -0.20) ................................ ................................ ............. 0 5.1-7.5 (0.21 -0.30) ................................ ................................ ........... 10 7.6-10.0 (0.31 -0.40) ................................ ................................ .......... 15 10.1-12.5 (0.41 -0.50) ................................ ................................ ......... 25 12.6-15.0 (0.51 -0.60) ................................ ................................ ......... 30
b.Thickness Deficiency of More Than 15 mm (0.6 in.). If the thickness measur ement made in a primary unit is deficient in thickness by more than 15 mm (0.6 in.), secondary thickness measurements and dimensions of the secondary unit area where the apparent thickness deficiency is more than 15 mm (0.6 in.) will be determined. The determination of the limits of said secondary unit area will be made by making secondary thickness measurements in each panel of pavement adjacent to the panel in which the original measurement in the primary unit was made. This procedure will continue, regar dless of unit boundaries, until such secondary unit area is bounded by panels in which the secondary measurement is deficient in thickness by 15 mm (0.6 in.) or less. Panels are the areas bounded by longitudinal and transv erse joints and pavement edges. After eliminating the secondary unit area, or areas, and the thickness measurements therein from consideration, the average thickness deficiency, if any, of the remainder of primary unit areas will be determined as provided in Subsection 409.04.02 (a). Sec ondary thickness measurements made outside of a secondary unit area may be used to determine average thickness deficiency, if any, in the remaining primary unit area in which they are taken. Each panel in which secondary thickness measurements are made wi ll be deemed to be of the thickness shown by such measurement. After determining the limits of the secondary unit area, determination will be made of which panels, within such area, if any, will be required to be removed and replaced according to procedur e 1, below, and the panels, if any, which will remain in place according to procedure 2, below. PORTLAND CEMENT CONCRETE PAVEMENT 409 197 1. Remove and replace the concrete pavement in such panels with concrete pavement meeting the thickness and all other requirements of the contract documents. If the area to be removed is not bounded by longitudinal or transverse joints, saw and seal weakened plane joints at the designated locations. Lower subgrade as necessary to meet the full thickness requirements.
2.Leave such panels of pavement in place without payment. The cost of secondary thickness measurements made by the provisions in this Subsection, including filling of any necessary holes with concrete, will be deducted from any money due, or that may become due, under the contract. No additiona l compensation or extension of time will be granted due to any of the provisions in this Subsection. No additional compensation will be allowed for any pavement constructed in excess of the thickness requirements of the contract documents. Additional thi ckness measurements may be requested in secondary unit areas if the numbers are insufficient to fairly indicate the actual thickness of pavement placed. Such additional measurements will be used in determining the average thickness variation. The location of all such additional thickness measurements will be as determined. The cost of all such additional measurements made, including filling of any necessary holes with concrete, will be deducted from any money due, or that may become due, under the contract.
409.04.03 Compressive Strength. If concrete placed is shown by test to be below the specified 28 day
compressive strength, a determination will be made as to whether the concrete shall be removed and replaced or allowed to remain in place. If after revie w, the concrete is allowed to remain in place, liquidated damages will be determined according to Subsection 502.04.01. Price adjustments for strength and thickness will be determined separately. BASIS OF PAYMENT
409.05.01 Payment. The accepted quantities, measured and adjusted as provided above, will be paid for at the
contract price per unit of measurement for the pay items listed below that are shown in the proposal. Payment will be full compensation for the work prescribed in this Section. Reinforcement, except tie bars and dowel bars, will be paid for as provided in Section 505. Payment will be made under: Pay Item Pay Unit Portland Cement Concrete Pavement (thickness) ................................ ................................ ........................ Square Meter (Square Yard) Saw Transverse Weakened Plane Joints ................................ ................................ ................................ ......... Linear Meter (Linear Foot) Saw Longitudinal Weakened Plane Joints ................................ ................................ ................................ ........ Linear Meter (Linear Foot) PCCP Curing Compound, Wax Base ................................ ................................ ................................ ................................ ... Liter (Gallon) Grind Rumble Strips ................................ ................................ ................................ ................................ ......................... Kilometer (Mile) 199 SECTION 410 CONCRETE PAVEMENT RESURFACING DESCRIPTION
410.01.01 General. This work consists of rubblizing and compacting existing Portland cement concrete
pavement for full width and full depth. This work also consists of cracking and seating existing Portland cement concrete pavement for full width and full depth. MATERIALS
410.02.01 General. Material shall conform to the following Sections and Subsection:
Bituminous Materials .............................................................................................................................................................. Section 703 Base Aggregates ................................................................................................................................................................... Section 704 Aggregates for Bituminous Courses ....................................................................................................................................... Section 705 Commercial Mineral Filler ........................................................................................................................................ Subsection 705.03.03 CONSTRUCTION
410.03.01 Equipment. (a) Rubblizing Equipment. Use equipment that is capable of rubblizing the existing
concrete pavement into particles conforming to the following sieve requirements: Sieve Size Percent Passing by Mass 225 mm (9 in.) ............................................................................. 100 150 mm (6 in.) ........................................................................... 85-100 Equip the rubblizing unit with a water system to suppress dust generated by the rubblizing operation.
b.Crack and Seating Equipment. Provide an impact hammer of the guillotine type capable of impacting the pavement with a variable force which can be controlled in force and point of impact in order to produce continuous full depth cracking while maintaining aggregate interlock between pieces. Do not use equipment that will cause extensive surface spalling along the crack, that will punch holes in the pavement, or cause shattering of the pavement or base. Spalling over 25 mm (1 in.) in depth will be considered extensive surface spalling. Unguided free falling weights such as “headache” or “wrecking” balls will not be permitted.
410.03.02 Rubblizing. Before beginning the rubblizing operations, the Engineer will designate a 30 m (100 ft)
long test strip location full width of one lane and adjacent shoulder. Rubblize the concrete pavement in the test strip until the material conforms to the specified size requirements for the full depth of the pavement. Excavate a section of the test strip to assure that full depth rubblizing is being achieved. Excavate full depth approximately 1 m x 4 m (3 ft x 13 ft) in size. Use the equipment and operation approved in the test strip for the remainder of the work. During rubblizing operations, excavate one additional 1 m x 4 m (3 ft x 13 ft) section per day of the rubblizing operation, and any locations so designated, to assure that full depth rubblizing is being achieved. Repeat this excavation procedure whenever the equipment, rubblizing pattern, or breaking force is changed. Backfill excavated areas with Type 1 Class B aggregate base in accordance with Section 302 at own expense. Provide a positive means of protecting passing traffic from flying debris during the rubblizing operations. Restrict the rubblizing equipment to within 600 mm (24 in.) of the existing joint filler next to approach slabs. Provide equipment suitable for rubblizing these small restricted areas adjacent to the approach slabs. Remove all visible joint material after rubblizing operations. Compact the rubblized pavement prior to placing the leveling course using vibratory steel wheel and pneumatic tired rollers in the following sequence: 1.One complete coverage with a vibratory roller. 2.Two complete coverages with a pneumatic tired roller. 3.Two complete coverages with a vibratory roller; the last coverage just prior to placing the prime coat and bituminous leveling course.
Source: Nevada Standard Specifications for Road and Bridge Construction, 2014 Edition. Pages 191–204 of 610.