BITUMINOUS CONCRETE PAVEMENT PROJECT
Has been made bituminous concrete pavement project of an education center.
BITUMINOUS CONCRETE PAVEMENT
GENERAL REQUIREMENTS
The paving shall consist of full depth pavement section. Place the pavement as indicated.
Preconstruction Conference
A joint working conference attended by a representative of the Contracting Officer, the General Contractor, and paving subcontractor shall be held prior to actual paving operation to confirm required drainage slopes, traffic flow and control, paving work sequencing, work start and stoppage, requirements for safety signs and barricades and other construction constraints that need to be considered.
Walk-Thru
Prior to actual paving operations, a walk-thru of the entire project area by the Contracting Officer and Contractor shall be conducted to ensure the following:
(1) All compaction requests have been satisfied;
(2) All manhole and storm drainage covers have been raised to finish grade;
(3) No obstructions or stalled vehicles will impede paving operations;
(4) Required surface preparation has been accomplished and entire area is ready for bituminous surfacing.
DEFINITION OF TERMS
a. Bituminous Tack Coat: Low viscosity liquid asphaltic materials applied to new bituminous concrete binder course or on old bituminous pavements before placing a wearing course or any new layer of bituminous pavement.
b. Bituminous Concrete Wearing Course: Bituminous concrete layer to finish road pavement as top traffic bearing layer of the pavement.
c. Aggregate Base Course: Gravel or crushed stone course immediately below the bituminous concrete surface course.
d. Subgrade: Existing or borrow earth foundation upon which pavement is constructed.
SUBMITTALS
Design Data
a. Job-mix formula
Job-mix formula
Submit a job mix formula, prepared within one year of submittal, for approval by the Contracting Officer prior to preparing and placing the bituminous mixture. Design mix using procedures contained in "AASHTO Interim Guide for design of pavement structures". The formulas shall indicate the physical properties of the mix as shown by tests made by an approved commercial laboratory using materials identical to those to be used on this project. Submit all formulas with materials samples. The job mix formula for each mixture shall be in effect until modified in writing by the Contractor and approved by the Contracting Officer. Provide a new job mix formula for each source change.
Required Data
The job-mix formula shall show the following: the source and proportions (percent by weight) of each ingredient of the mixture; the required gradation (the percentage passing each sieve size listed in the specifications for the mixture to be used) for the aggregate and mineral filler from each separate source and for each different size to be used in the mixture and for the composite mixture; the amount of material passing the 0.075 UNI 2332/1 (N. 200 ASTM) sieve determined by dry sieving; the number of blows of hammer compaction per side of molded specimen; the temperature/viscosity relationship of the asphalt cement; the stability, flow, percent voids in mineral aggregate, percent air voids, unit weight; asphalt absorption by the aggregate; effective asphalt content as percent by weight of total mix; the temperature of the mixture immediately upon completion of mixing; the asphalt viscosity grade and/or penetration range; and The result of: As determined by:
Course and fine aggregate
a. Bulk specific gravity CNR BU 62-1978 CNR BU 76-1980
b. Shape coefficient CNR BU 95-1984
c. Percentage of voids CNR BU 65-1978
d. Percentage of fine aggregate CNR BU 75-1980
e. Freeze resistance CNR BU 20-1981
f. Percentage of wear CNR BU 34-1973
Asphalt
g. Consistency CNR BU 24-1971 CNR BU 35-1973
h. Brittleness CNR BU 43-1974
i. Ductility CNR BU 44-1974
j. Solubility CNR BU 50-1976
k. Density CNR BU 67-1978 Cutback asphalt
l. Viscosity CNR BU 7-1957
m. Combustion CNR BU 7-1957
Emulsified asphalt
n. Sedimentation CNR BU 3-1958
o. Viscosity CNR BU 3-1958
p. Adhesion CNR BU 3-1958 Tar
q. Viscosity CNR BU 7-1957
r. Adhesion CNR BU 3-1958 Bituminous mixture
s. Bulk specific gravity CNR BU 40-1973
t. Percentage of voids CNR BU 39-1973
u. Stability CNR BU 30-1973
v. Bitumen content CNR BU 38-1973
Charts/Graphs
Plot and submit, on a grain size distribution chart, three graphs: (1) the specified gradation band, (2) the job-mix gradation and (3) the job mix tolerance band.
Specimens
CNR BU 61-1978 for the making and testing of all bituminous specimens.
a. Curves: Plot and submit curves for the wearing course to show the effect in the test properties of at least four different percentages of asphalt on the unit weight, stability, flow, air voids, and voids in mineral aggregate; each point on the curves shall represent the average of at least four specimens.
b. Cooling of Specimen: After compaction is completed, allow the specimen to cool in air to the same temperature approximately as that of the water, 25 degrees Centigrade , to be used in the specific gravity determination.
c. Selection of Optimum Asphalt Content: Base selection on percent of total mix and the average of the values at the following points on the curves for each mix:
Stability Peak
Unit Weight Peak
Percent Air Voids Median
d. Variations from Formula: Variations from the approved job-mix formula shall not exceed the following; however, in no case shall the job-mix formula, with tolerances applied, fall outside the general limits for aggregate gradation and bituminous material specified herein:
Aggregate Tolerance millimeters (Plus or Minus)
12.70 and larger 8 percent
10 and 5 7 percent
3 and 1 6 percent
0.5 and 0.3 5 percent
0.15 4 percent
0.075 3 percent
Asphalt Cement (0.3) (0.5) percent
Temperature of Mixture 9 degrees Centigrade at Discharge
Test Reports
Submit certified test reports for the following:
a. Mineral Aggregate
b. Bituminous Materials
Field Test Reports
The bituminous mixtures shall be tested for conformance with the specified asphalt content and gradation requirements without cost to the Government, and those test results submitted for approval. The size and number of samples shall be as directed and shall be furnished by the Contractor without cost to the Government. Mixtures that do not conform to the asphalt content and gradation requirements will be rejected. No payment will be made to the Contractor for mixtures rejected, or for pavements or portions of pavements removed.
a. Temperature
b. Thickness test
c. Smoothness test
d. Density test
e. Bituminous concrete job-mix test
DELIVERY AND STORAGE
Inspect each truckload of bituminous mix delivered to the site for proper temperature range and reject all loads arriving at the project site that do not meet temperature requirements. No more than one truckload of mix shall be standing by as load back-up, and temperature of the mix in the back-up truck shall be verified as meeting required limits before use. Any truckload that has been standing for an extended period as to cause the load to cool down below acceptable temperature range shall be rejected.
Paint
Provide in accordance with Specification Section, "Pavement Markings."
TRAFFIC CONTROL
Vehicular and utility vehicle traffic shall not be permitted on the pavement until the surface temperature has cooled to at least 50 degrees Centigrade and required final rolling and compaction has been achieved. Trucks and heavy equipment shall not be allowed on newly paved areas until after 95 percent of compacted density is achieved and only after 72 hours have elapsed since final rolling. Surface temperature shall be measured by approved surface thermometers. Place barricades and warning signs prominently near the beginning of the work site and around access points to the project area for alerting vehicular and pedestrian traffic of construction operations and/or obstructions. The use of bunting or multi-colored striped cloth materials, that can easily be blown by the wind, is not allowed as a barricade. Use barricades and warning signs that will withstand the weather and perform their intended function even after hours of darkness.
OPERATIONAL SAFETY AND HEALTH GUIDELINES
In addition to the requirements of the General Provision, conduct mixing and delivery of bituminous materials and paving operations in accordance with D.P.R. 27 April 1955, n. 547 and D.L. 14 August 1996, n. 494.
WEATHER LIMITATIONS
Wearing Course
Place the bituminous mixture only during dry weather and on dry surfaces. Place courses only when the surface temperature of the underlying course is greater than 7 degrees Centigrade for course thickness greater than 2.5 centimeters and 12 degrees Centigrade for course thickness of 2.5 centimeters or less.
Tack Coat
Apply the tack coat only when the surface is dry or contains moisture not in excess of the amount that will permit the uniform distribution and the desired penetration. Apply the prime coat and tack coat, only when the ambient temperature is 10 degrees Centigrade or above and when the temperature has not been below 2 degrees Centigrade for 12 hours immediately prior to application, unless otherwise directed.
SAMPLING AND TESTING
The Contractor shall conduct required tests on the bituminous mix for conformance with the specified asphalt content, temperature and gradation without additional cost to the Government. Mixtures that do not conform shall be rejected. No payments shall be made to the Contractor for pavements or portions of pavements removed for nonconformance and replaced with asphaltic pavements which meet the requirements of this specification.
WATER
Shall be soft, potable and free from any suspended inorganic material and chloride or sulphate compounds exceeding the percentages indicated. Water shall be slightly alkaline with PH between 6 and 8, shall not include more than 2 parts per 100, by weight, of material in suspension and not more than 15 parts per 100, by weight, of material in solution. It shall not contain organic matter either in suspension or in solution. Sulphate shall not be more than 1 part per 1000 by weight. Sea water is prohibited.
AGGREGATES
Bituminous surface treatment and construction of wearing or binder courses; shall comply with CNR BU 95-1984, CNR BU 104-1984, CNR BU 93- 1983 and CNR BU 80-1980 and shall consist of crushed stone, crushed or uncrushed gravel, screenings, sand, and mineral filler. Grade and proportion aggregates and filler so that the combined mineral aggregate conforms to the grading specified herein. The coarse and fine aggregate and mineral filler shall be so graded and of such character that when combined, a blend will be produced that will meet the requirements specified herein. Stone or gravel to be crushed shall come from eruptive or metamorphic rocks of microcrystalline structure, either siliceous or hard pure calcareous, unfreezable, free of outcrop, with high crushing strength.
Products of crushed stone or gravel shall consist of clean, sound, durable particles, shall be uniform in shape, free from adherent films of clay, dust, soft or disintegrated pieces and foreign materials. The particles shall not have more than one rounded face or shall have, at least, two fractured faces and shall be of such nature that a thorough coating of bituminous compound will not strip off under traffic load application. The moisture content shall be such that all particles will be readily coated with the bituminous compound. Drying may be required, as directed.
Coarse Aggregate
CNR BU 4-1953 and Circ. Min. 17 February 1954, n. 532. Shall be aggregate of sizes not bigger than 2.5 centimeters - 2.5 UNI 2334 sieve; and not smaller than 2 millimeters - 2 UNI 2332/1 sieve (8 ASTM C 136 sieve). Such aggregate is divided into two minor classes: the first from 2.5 centimeters to 10 millimeters called "pietrischetto" and the second from 10 millimeters to 2 millimeters called "graniglia". 75 percent by weight of the aggregate retained at 2 UNI 2332/1 (N. 8 ASTM C 136) sieve shall have two or more fractured faces. Percentage of wear (Los Angeles test) shall not exceed 40 in accordance with CNR BU 34-1973.
Fine Aggregate
CNR BU 4-1953 and Circ. Min. 17 February 1954, n. 532 shall be aggregate of sizes not bigger than 2 millimeters and not smaller than 0.075 millimeters to meet requirements for wear and soundness specified for coarse aggregate. Where necessary to obtain a gradation of aggregate blend for workability, natural sand may be used. Quantity of natural sand to be added shall be approved by the Contracting Officer and shall not exceed 15 percent of weight of coarse and fine aggregate and material passing the 0,075 UNI 2332/1 (N. 200 ASTM) sieve.
Natural Sand
CNR BU 4-1953 and Circ. Min. 17 February 1954, n. 532 shall have more than one rounded face and shall be fine, from 0,5 millimeters to 0,075 millimeters , and coarse, from 2 millimeters to 0,5 millimeters . Sand shall be well washed and absolutely free from earth, organic matter, chloride, sulphate contents and soluble salts. Shall consist of siliceous material originating from rocks having high crushing strength. The use of sea sand is prohibited.
Mineral Filler
CNR BU 4-1953 non-plastic material size 0.075 millimeters and smaller, 100% passing through 0.075 UNI 2332/1 (N.200 ASTM C 136) sieve.
Gradation of Aggregate
CNR BU 23-1971. The aggregate, as finally selected for use in the work, shall have a gradation within the limits designated in Table I and II and shall not vary from the low limit on one sieve to the high limit on the adjacent sieve or vice versa, but grade uniformly from coarse to fine. The following Tables are based on aggregates of uniform specific gravity and the percentages passing the various sieves are subject to appropriate correction when aggregates of varying specific gravities are used. When materials of different specific gravities are used, the Contractor shall make satisfactory arrangements for separate stock piles, controlled distribution, and other operations necessary to maintain the specific gravity of the mixture constant and uniform.
Table I is based on Italian sieve sizes as specified in UNI 2332/1 and UNI 2334. UNI 2334 "crivello" type are rounded hole sieves and shall be used for coarse aggregate. UNI 2332/1 "setaccio" type are square mesh sieves and shall be used for fine aggregate. Table II is based on US standard sieves sizes as specified in ASTM E 11 and shall be square mesh sieves only. Table III shows the equivalency between the two systems. Section 02741 117
Mineral Aggregate Properties:
a. Apparent Specific Gravity of non Compacted Mineral Aggregate Mix: CNR BU 62-1978, 1.5 kilograms per cubic decimeter .
b. Apparent Specific Gravity of Compacted Mineral Aggregate Mix: CNR BU 76-1980.
c. Shape Coefficient: CNR BU 95-1984, percentage of long particles on short particles.
d. Index of Voids: CNR BU 65-1978, for binder and wearing courses shall not exceed 0.80 - 0.85
e. Percentage of Voids: CNR BU 65-1978 voids/total volume ratio.
f. Percentage of fine aggregate: CNR BU 75-1980.
g. Sand equivalent "E.S.": CNR BU 4-1953, for road construction.
h. Freezing Resistance: CNR BU 20-1981.
i. Percentage of Wear: CNR BU 34-1973. For wearing courses percentage shall be less than or equal to 20, for binder courses shall be less than or equal to 24.
j. Crushing Index: CNR BU 4-1953: Shall be determined for the coarse aggregate "graniglia". For binder courses shall be 140, for wearing courses shall be 100.
BITUMINOUS MATERIALS
CNR BU 24-1971 and CNR BU 68-1978. Bitumen for road construction shall be organic compound made of hydrocarbon mixtures, completely soluble in carbon disulfide, capable of binding graded mineral aggregate to which it shall adhere in a permanent way so as to form a stable and flexible bituminous concrete for road pavement construction. All bituminous materials shall be made of bitumen manufactured from natural petroleum and shall be semisolid bitumens (asphalts), liquid bitumens (cutback asphalts) and bituminous emulsions (emulsified asphalts). Asphalt cement shall be produced by grinding natural asphaltic rocks. Tar shall be produced by distillation of bituminous natural coal.
Asphalt (Semisolid bitumen)
CNR BU 68-1978. Asphalt shall be class B 50/70 where "B" is the abbreviation for bitumen and the two numbers indicate the range of penetration admitted for that class measured in decimillimeters during the penetration test. Asphalt shall also comply with Circ. Min. 21 January 1952, n. 179 and requirements of CNR BU 24-1971 Penetration test, CNR BU 35-1973 Consistency test, CNR BU 43-1974 Brittleness test, CNR BU 48-1975 solubility test, CNR BU 50-1976 volatility test, CNR BU 66-1978 Paraffin content test, CNR BU 67-1978 Density test, CNR BU 44-1974 Ductility test in relation to the type of bituminous concrete layer for which it shall be employed.
Cutback Asphalt (liquid bitumen)
CNR BU 7-1957, cutback asphalt, produced by adding either petroleum oil or tar oil to solid bitumen, shall be class BL 150/300 where "BL" is the abbreviation for liquid bitumen and the two numbers indicate the range of viscosity, admitted for that class, measured in seconds at 25 degrees Centigrade temperature for the viscosity test. Cutback asphalt shall also comply with Circ. Min. 30 September 1957, n. 2759 and requirements of CNR BU 7-1957 for viscosity test (Redwood method), combustion test (Marcusson method), and fractionated distillation test, in relation to the type of bituminous concrete layer for which it shall be employed. No classification as per US Customary Standard such as RC, MC or SC Cutback Asphalt, respectively Rapid Curing, Medium Curing or Slow Curing Cutback Asphalt, shall be used in this specification.
Emulsified asphalt (Bituminous emulsion)
CNR BU 3-1958 emulsified asphalt shall be alkaline or acid emulsion of bitumen and water. Alkaline emulsified asphalt shall be used with basic mineral aggregate. Acid emulsified asphalt shall be used with acid mineral aggregate. Basic emulsified asphalt shall be class ER 50, ER 55 rapid setting, in accordance with CNR BU 3-1958 requirements. Acid emulsified asphalt shall be class ECR 55, ECR 65 rapid setting, in accordance with ASTM D 244 requirements. Emulsified asphalt shall also comply with Circ. Min. 2 April 1954, n. 852 and requirements of CNR BU 3-1958 for sedimentation test, Stability test, Viscosity tests (Engler method), and adhesion test in relation to the type of construction or repair of pavement for which it shall be employed.
Asphalt Cement
CNR BU 6-1956 asphalt cement shall be obtained from Sicilian soft calcareous rocks containing a small percentage of bitumen or from Abruzzi hard calcareous rocks containing a larger percentage of bitumen. Shall be class II-A or II-S where "A" and "S" are the abbreviation for Abruzzi and Sicily Regions respectively. Asphalt cement shall not have less than 7 percent by weight of bitumen, not more than 2 percent by weight of materials not soluble in HCL solution, shall have more than 95 percent by weight of particles passing through 2 UNI 2332/1 (N. 8 ASTM) sieve and more than 60 percent retained by 0.18 UNI 2332/1 (N. 100 ASTM) sieve. Bitumen extracted from cement shall comply with requirements as per asphalt test and asphaltic rocks, from which the asphalt cement is extracted with requirements of Circ. Min. 17 July 1956, n. 1916.
Tar
CNR BU 1-1951 tar shall be class C 40/125 where "C" is the abbreviation for tar and the two numbers indicate the range of viscosity admitted for that class, measured in seconds at 30 degrees Centigrade . Shall also comply with Circ. Min. 21 January 1952, n. 179 and requirements of CNR BU 7-1957 viscosity test (modified Redwood method) and CNR BU 3-1958 Adhesion test.
Recycled Asphalt Material
The bituminous concrete mix may contain a maximum of 25 percent (by weight of total aggregate material) reclaimed asphalt pavement (RAP). The mix design shall meet the requirements for the type of bituminous concrete specified. Clearly state the viscosity of the reclaimed asphalt cement, the grade of the new asphalt cement, the properties of the recycling agent (if used) and the percentage of each in the mix. Combine the asphalts and recycling agents to achieve a viscosity of 2000 plus or minus 400 poises at 60 degrees Centigrade. Furnish a new job mix formula for each change in the percentage of RAP material used.
Quantity of Bituminous Material
CNR BU 38-1973 bituminous materials shall be mixed with aggregates of corresponding mixes in the range of percentages by weight of total mix as indicated below:
PERCENTAGE OF BITUMINOUS MATERIALS (BY WEIGHT)
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Bituminous Materials Wearing
Course
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Asphalt 6-8
Cutback asphalt 6-8
Emulsified asphalt 6-8
Asphalt cement 5-10
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PAINT MARKINGS
Provide in accordance with Section 02761, "Pavement Markings."
CONSTRUCTION EQUIPMENT
Provide equipment dependable and adequate for the purpose intended and properly maintained in satisfactory and safe operating condition at all times. Calibrated equipment such as asphalt distributors, scales, batching equipment, spreaders and similar equipment, shall have been recalibrated by an approved calibration laboratory within 12 months prior to commencing work (and every 12 months thereafter, by such laboratory from the date of recalibration, during the term of the contract).
Spreading Equipment
Self-propelled electronically controlled type, unless other equipment is authorized by the Contracting Officer, equipped with hoppers, tamping or vibrating devices, distributing screws, electronically adjustable screeds, and equalizing devices. Capable of spreading hot bituminous mixtures without tearing, shoving or gouging and to produce a finished surface of the required grade and smoothness. Operate spreader, when laying mixture, at variable speeds between 1.5 and 15 meters per minute.
Spreader shall be designed with a quick and efficient steering device, a forward and reverse traveling speed, and automatic devices to adjust to grade and confine the edges of the mixture to true lines. The use of a spreader that leaves indented areas or other objectionable irregularities in the fresh laid mix during operations will not be permitted.
Rolling Equipment
Power rollers shall be self-propelled three-wheeled and tandem type weighing not less than 9500 kilograms . The three-wheel rollers shall have a minimum weight of 55 kilograms per centimeter of width of the rear wheels. The wheels shall have adjustable scrapers, water tanks and sprinkling apparatus to keep the wheels wet and thus prevent the bituminous mixtures from sticking to the wheels. The roller's shall be capable of reversing without backlash and shall be free from worn parts. The roller's wheels shall not have flat or pitted areas or projections that leave marks in the pavement.
Hand Tampers
Minimum weight of 12 kilograms with a tamping face of not more than 300 square centimeters; shall be used in areas not accessible to rolling equipment.
Mechanical Hand Tampers
Commercial type, operated by pressure.
PREPARATION OF SURFACE
Damaged Pavement Repair
Areas or portion of existing pavement showing deteriorations and softened spots shall be cleaned from all unsatisfactory materials up to the sound road foundation grade, and shall be filled and accurately compacted up to the required grade prior tack coat application.
Pavement Repair
Repair pavement, as indicated. Do not repair pavement until trench or pit has been backfilled and compacted and only after all the required tests have been satisfactorily completed, witnessed and approved by the Contracting Officer. Existing pavement thickness may vary at different locations, throughout the project site.
a. Joining Pavement: Carefully make joints between old and new pavements or between successive days work made in such a manner as to ensure a continuous bond between old and new sections of the course. Expose and clean edges of existing pavement. Cut edge to straight, vertical surfaces. Paint all joints with a uniform coat of tack coat material before the fresh bituminous concrete is placed.
b. Finishing at Edges of Trench: Place top layer of bituminous concrete material such that the final compacted thickness shall be level with the existing adjacent pavement. Finish grade surface of bituminous concrete pavement shall be smooth, free from waves, irregularities, and high and low spots, or soft yielding areas and in the same elevation or slope as the existing pavement.
c. Protection of Pavement: After final rolling of bituminous concrete, no vehicular traffic of any kind shall be permitted on the pavement until it has cooled and hardened for a minimum period of six hours.
d. Pavement Marking: Where existing pavement markings were affected, obliterated, or damaged by Contractor construction operations, such pavement markings shall be restored by Contractor and repainted to their original color and lane width or markings, utilizing paints designed specifically for pavement markings.
Grinding of bituminous concrete pavement
The existing bituminous concrete pavement that shall be restored, shall be grinded by means of grinding machine. Pavement thickness to be grinded is shown on drawings. Grinded area shall have an homogeneous surface, slightly roughened to allow perfect bonding with the new bituminous concrete course that shall be placed. Edges of the grinded area shall be vertically saw cut. Prior bituminous concrete placement the existing pavement shall be perfectly cleaned and 1 kilogram per square meter bituminous tack coat shall be applied.
MIXING AND TRANSPORTATION
Mixing
Produce bituminous mixture in a plant within 30 minutes hauling distance from the project site.
Transportation of Bituminous Mixtures
Transport bituminous material from the mixing plant to the paving site in trucks having tight, clean, smooth beds that have been coated with a minimum amount of concentrated solution of hydrated lime and water or other approved coating to prevent adhesion of the mixture to the truck bodies. If haul time is greater than 30 minutes, cover each load with canvas or other approved material of ample size to protect the mixture from the loss of heat.
Make deliveries so that the spreading and rolling of all the mixture prepared for one day's run can be completed during daylight, unless adequate approved lighting is provided. Deliver mixture to the area to be paved in such a manner that the temperature at the time of dumping into the spreader will be higher than 120 degrees Centigrade . Reject any loads that are below minimum temperature, that have crusts of cold unworkable material, or that have been wet excessively by rain. Hauling over freshly laid material is not permitted.
WEARING COURSE APPLICATION
General
Provide a bituminous surface wearing course that will result in a minimum overall compacted thickness of as indicated. Provide for storm water drainage by increasing the minimum thickness as necessary to achieve desired slope.
Placing
The range of temperature of the bituminous mix at the time of spreading shall be between 120 and 150 degrees Centigrade . Bituminous concrete having temperatures less than minimum spreading temperature when dumped into the spreader shall be rejected. Adjust spreader and regulate the speed so that the surface of the course is smooth and continuous without tears and pulling, and a surface which conforms with the design cross section and grade. Place mixture as nearly continuous as possible, and adjust the speed of placing as directed, to permit proper rolling.
Shoveling, Raking, and Tamping after Machine- Spreading A sufficient number of shovelers and rakers shall follow the spreading machine adding or removing hot mixture and raking the mixture as required to obtain a course, that when completed, will conform to the design requirements. Broadcasting or fanning of mixture over areas being compacted shall not be permitted. When segregation occurs in the mixture during placing, suspend spreading operation until the cause is determined and corrected. Correct any irregularities in alignment left by the spreader by trimming directly behind the machine. Immediately after trimming, compact edges of the course by tamping laterally.
COMPACTION
Effect compaction by rolling using either a three-wheel-tripod or a twowheel- tandem type steel wheel roller. Begin breakdown rolling as soon as placement of the mixture will bear the rollers without undue displacement. Delays in rolling freshly spread mixture shall not be tolerated. Start rolling longitudinally at the extreme sides of the lanes and proceed toward the center of the pavement, or toward the high side of the pavement with a one-way slope. Operate rollers so that each trip will overlap the previous adjacent strip by at least 30 centimeters.
Alternate trips of the roller shall be of slightly different lengths. Test for conformity with the specified slope, grade and smoothness shall be made by the Contractor immediately after initial rolling. Before continuing the rolling, correct variations by removing or adding bituminous materials as necessary. The speed of the rollers shall be slow enough to avoid displacement of the hot mixture. Provide as many number of passes with the rollers as necessary to achieve a 95 percent compacted density, but in no case shall the number of passes over any area be less than six passes. Correct any displacement of the mixture at once by the use of rakes and fresh mixture, or remove and replace mixture as directed.
Continue rolling until all roller marks are eliminated and the course has a density of at least 95 percent. During rolling, moisten wheels of the rollers to prevent adhesion of the mixture to the wheels, but excess water use will not be permitted. Operation of rollers shall be by competent and experienced operators. In all places not accessible to the rollers, compact mixture thoroughly with hand-held mechanical tampers.
Skin compaction of an area after compaction is not permitted. Remove any mixture that becomes mixed with foreign material or is defective, replace with fresh mixture, and compact to the density of the surrounding area. The roller shall pass over the unprotected edge of the course only when the laying of the course is to be discontinued for such length of time as to permit the mixture to become cold. After final rolling, do not permit tracked vehicles or heavy equipment of any kind on the pavement until it has cooled and hardened, and in no case less than 24 hours.
JOINTS
All joints shall present the same texture, density, and smoothness as other portions of the course. Carefully make joints between old and new pavement or within new pavements in a manner as to ensure a thorough and continuous bond between old and new sections of the course. Paint all vertical contact surfaces of previously constructed sections with a thin uniform coat of emulsion or other approved bituminous material just before the fresh mixture is placed.
Transverse
The roller shall pass over the unprotected end of the freshly laid mixture only when the laying of the course is to be discontinued. Except when an approved bulkhead is used, cut back the edge of the previously laid course to expose an even, vertical surface for the full thickness of the course. When required, rake fresh mixture against the joints, thoroughly tamp with hot tampers, smooth with hot smoothers, and roll. In all cases, transverse joints in adjacent lanes shall be offset a minimum of 60 centimeters.
Longitudinal Joints
Place joints so that they will not coincide with those of existing pavement or previously placed courses with an offset of at least 30 centimeters . When the edges of the longitudinal joints are irregular, honeycombed, or poorly compacted, cut back all unsatisfactory sections of joint to expose an even vertical surface for the full thickness of the course. When required, rake fresh mixture against the joint, thoroughly tamp with hot tampers, smooth with hot smoothers, and roll while hot.
Cold Longitudinal Joints
Asphalt finishing equipment shall be kept on a straight predetermined longitudinal path of travel with variation on the surface- course lane edges of not more than 4 centimeters . After the first lane is placed and rolled, place adjacent lane so that it uniformly overlaps the first lane by 3 to 5 centimeters . Push back overlapping materials onto the hot lane so that the roller can "crowd" this excess asphalt mix into the hot side of the joint. When overlap is excessive remove excess material as necessary to maintain the "roll" reasonably uniform.
Abutting Pavement
Where new pavement abuts existing flexible pavement, cut back the existing surface course along uniform lines approximately 30 centimeters from the edges. Make a vertical saw cut and extend cut to full depth of the surface course. Prior to placing the wearing course, paint the exposed edges of cold joints with a thin layer of asphalt cement.
Protection of Pavement
After final rolling, do not permit tracked vehicles or heavy equipment of any kind on the pavement until it has cooled and hardened, and in no case less than 24 hours.
PAVEMENT MARKING
Refer to Section 02761, "Pavement Markings."
FIELD QUALITY CONTROL
Tests
Perform the following minimum number of tests to ensure compliance with the temperature, thickness, and density requirements of the bituminous layers, and job-mix requirements for bituminous concrete. Furnish all tools, labor and material for samples and for satisfactory replacement of pavement. Take samples and test at not less than the frequency required for each day's work as a minimum; and at each change in the mix or equipment. Perform the following tests:
a. Temperature: Take temperature readings for each truckload of bituminous mix delivered to the site, tabulate and submit daily logs of all deliveries with the "Daily Report to Inspector".
b. Thickness Test: Determine thickness of the wearing course. One test for each 420 square meters or fraction thereof. The maximum allowable deficiency at any point shall not exceed 6 millimeters of the required thickness. The Contractor shall correct areas found deficient by removing the pavement in question and replacing with new pavement.
c. Smoothness Test: Straightedge test the compacted surface of the wearing course as the work progresses. Apply straightedge parallel with and at right angles to the centerline after final rolling. Variations in the wearing course shall not vary more than 3 millimeters in 3.0 meters . Correct any portion of the pavement showing irregularities greater than that specified.
d. Density Test: One laboratory test for the project and one field test for each 840 square meters or fraction thereof of each lift.
e. Bituminous Concrete Job-Mix: One test for each metric ton or fraction thereof of each mix to determine gradation and bitumen content.
Test Result
Results of each test shall be forwarded as part of "Daily Report of Inspector". Total number of tons of bituminous mix actually incorporated into the project shall also be included as part of the daily report, including number of truckloads or quantity of bituminous mix utilized on the job per work day.
FINISHED GRADE
The finish grades of each course placed shall not vary from the finish elevations, profiles and cross section indicated on the drawings by more than 12 millimeters . The finished surface of the final wearing course will be tested (by the Contracting Officer) by running lines of levels at intervals of 7.50 meters or less longitudinally and transversely to determine elevations of completed pavement. Within 45 days after completion of final placement, the Contractor shall perform a level survey at the specified grid spacing and plot the results on a plan drawn to the same scale as the drawings. Elevations not in conformance with the specified tolerance shall be noted on the plan in an approved manner.
The survey shall be performed by a registered land surveyor. The Contracting Officer will inform the Contractor in writing of all paved areas that fail to meet the final grades indicated within the specified tolerance. The Contractor shall correct deficient paved areas by removing existing work and replacing with new materials meeting the specifications without additional cost to the Government. Skin patching for correcting low areas will not be permitted.
PROTECTION
Keep all traffic off surfaces which are freshly treated with bituminous material. Provide sufficient warning signs and barricades so that traffic will not travel over freshly treated surfaces. Protect the treated areas from traffic for at least 24 hours after final application of bituminous material and aggregate, or for such time as necessary to prevent picking up. Immediately prior to opening to traffic, roll the entire treated area with a self-propelled pneumatic-tired roller.