405.01 288 SECTION 405 – BITUMINOUS SEAL COAT
405.01 Description ................................ ................................ ................... 288
405.02 Materials ................................ ................................ ...................... 288
405.03 Equipment ................................ ................................ .................... 289
405.04 Limita tions ................................ ................................ ................... 289
405.05 Preparing the Designated Surface ................................ ................ 289
405.06 Application ................................ ................................ ................... 290
405.07 Spreading and Rolling Aggregate ................................ ................ 293
405.08 Shoulders ................................ ................................ ...................... 294
405.09 Maintenance and Protection ................................ ......................... 294
405.10 Method of Measurement ................................ .............................. 295
405.11 Basis of Payment ................................ ................................ .......... 295
DESCRIPTION
405.01 Description
This work consists of constructing a bituminous seal coat consisting of one or more applications each of bituminous material and cover aggregate. MATERIALS
405.02 Materials
Provide materials as specified in: Mineral Aggregate, Size No s. 7, 8, 78, 89 ............................. 903.13 Mineral Aggregate ................................ ................................ . 903.14 Emulsified Asphalt, CRS -2p ................................ .................. 904.03 Apply seal coat at a temperature range of 60 to 140 F. 405.03 289 EQUIPMENT
405.03 Equipment
Provide a power broom or other mechanical sweeping equipment, equipment for heating b ituminous material, a pressure distributor meeting the requirements of 402.03, two pneumatic -tire rollers, self -propelled mechanical aggregate spreading equipment that can be adjusted to spread accurately at the specified rate, and such other equipment and small tools as may be required to perform the work in a satisfactory manner. CONSTRUCTION REQUIREMENTS
405.04 Limitations
Only apply bituminous material:
1.When the designated surface is dry, firm, and properly cured;
2.Between April 15 and October 1 ; and, unless otherwise directed,
3.When the ambient temperature in the shade and away from artificial heat is 70 °F or more.
405.05 Preparing the Designated Surface
Before placing seal coat, clean all surfaces to be sealed by sweeping with a motorized broom to remove any loose material. Clean depressions and cracks not reached by the power broom using hand brooms or pressurized air. Remove pavement markers and adhesives. Abrade all types of existing pavement markings. Work shall be accomplished wit hout the pavement being gouged or damaged and in a manner which ensures the bituminous treatment will adhere in all areas applied. Work shall be performed to the satisfaction of the Engineer. Cover any utility installations to prevent adherence of the bit uminous mixture. Suitable covering includes plywood disks, sand, craft paper, roofing felt or other approved methods. Remove the protective coverings before opening the road to traffic. The cost for these adjustments shall be included in the bid price f or other items. 405.06 290 The Plans will indicate whether the surface is to be constructed on a treated or untreated subbase, a granular base, an asphalt base, or on an existing surface. The surface of the base or sub -base upon which the construction is to be placed shall meet the requirements of the applicable Section of Part 3, Bases and Subgrade Treatments, of these Specifications. Condition existing surface, if called for on the Plans, as specified in 407.10. Condition existing mineral aggregate base as specified in 310. Construct and maintain Prime Coat or Tack Coat, if shown on the Plans, as specified in 402 or 403, respectively .
405.06 Application
A.Applying Bituminous Material Have all equipment calibrated prior to starting work. The TDOT inspector shall be present during calibration to determine aggregate spread rate and distributor rates. Distributor trucks shall have proper calibration of spray equipment. Spray nozzles should be clean, properly angled, and appropriately sized for the desired application rate. Stop work if the distributor is not applying material properly, such as gaps in application or streaking. Place a 500-foot test strip for the bituminous seal coat at the beginning of the project to assure proper coverage and proper equipment calibration. The test section is to verify break time of emulsion and chip retention. The test strip shall be able to carry n ormal traffic within 3 hours. If normal traffic cannot be carried, the emulsion shall be adjusted and another test strip is required. At least 14 working days before the scheduled start of construction of any bituminous seal coat, submit a sample of aggre gate intended for use for the determination of the appropriate application rates of bituminous material and aggregate. Apply emulsified asphalt by pressure distributor at a uniform rate in accordance with Table 405 .06-1 below. The exact rate will be established by the Engineer . 405.06 291 Table 405 .06-1: Application Rates for Bituminous Material Aggregate Size (per 903.22) Aggregate Spread Rate (lb/yd2) Emulsion Shot R ate (gal/yd2) 7 25 – 30 0.30 – 0.45 78 22 – 28 0.28 – 0.38 8 20 – 25 0.20 – 0.35 89 17 – 23 0.17 – 0.28 Before beginning each spread, place building paper across the roadway surface with the forward edge exactly coinciding with the end of the preceding covered spread. Start distributors on the paper, the width of which shall allow the full force of all nozzles to be in effect before the forward edge of the paper is reached. If required by the Engineer, also stop the spread on building paper. Remove the paper immediately after its use, and dispose of properly. Immediately correct all defects in application. The length of spread of bituminous material shall not exceed that which trucks loaded with cover material can immediately cover. The spread of bituminous material shall not extend more than 6 inches wider than the width covered by the cover material. Do not allow the bituminous material to chill or otherwise impair retention of the cover material. Do not allow traffic on the bituminous mat erial until it has been covered with mineral aggregate. Treat areas that are inaccessible to the distributor with either hand sprays or pouring pots as directed by the Engineer.
B.Application of Double Bituminous Surface Treatment
1.First Application Apply th e first application of emulsified asphalt using pressure distributors at a uniform rate established by the Engineer within the range of 0.30 to 0.38 gallons per square yard. Apply each spread of bituminous material to not be more than 6 inches wider than the 405.06 292 width covered by the immediate spread of cover aggregate. Each width of spread shall not be less than half the surface to be treated. Before beginning each spread, place building paper across the roadway surface with the forward edge exactly coincidin g with the end of the preceding covered spread. Start distributors on the paper, the width of which shall allow the full force of all nozzles to be in effect before the forward edge of the paper is reached. If required by the Engineer, also stop the spre ad on building paper. Remove the paper immediately after its use, and dispose of properly. Immediately correct all defects in application. Treat areas that are inaccessible to the distributor with hand sprays or pouring pots as directed by the Engineer. If treating less than the full width of the roadway, do not spread the aggregate on the inside 6 inches of either the first or second application until the adjacent lane has been treated. Immediately following each application, uniformly cover the applied bituminous material with Size No. 7 mineral aggregate that is reasonably free of surface moisture. Spread the aggregate at a rate between 24 and 30 pounds per square yard, as established by the Engineer, using a self -propelled mechanical spreader; except on short projects of ½ mile in length or less, self-propelled mechanical spreading equipment will not be required. Back the truck on the aggregate being spread, without driving on or over uncovered bituminous material. The length of bituminous material spread shall not exceed that which trucks loaded with cover material can immediately cover.
2.Second Application Apply the second application of emulsified asphalt in the same manner as the first application, at a uniform rate established by the Engineer within the range of 0.20 and 0.35 gallons per square yard. Spread mineral aggregate, Size No. 8, in the same man ner as the first spread at a rate established by the Engineer within the range of 16 to 28 pounds per square yard. 405.07 293 Immediately after each spread of cover aggregate, broom to achieve uniform coverage. Use a power source, which is independent of the drive train that propels the equipment, to power the revolving brooms of mechanical sweeping equipment. Place additional aggregate by hand on thin or bare areas.
405.07 Spreading and Rolling Aggregate
A.Spreading Immediately after bituminous material has been applied, no more than two minutes, spread and embed the mineral aggregate cover in the bituminous material. Spread the aggregate as close to the application of bituminous material as is practicable, and cover e ach distributor load applied immediately. Aggregates shall be moistened and visually damp at the time of placement. Spread the aggregate in accordance with the rates specified in Table 405.06-1. The exact rate will be established by the Engineer. Back the truck on the aggregate being spread, without driving on or over uncovered bituminous material. If treating less than the full width of roadway, do not spread the aggregate on the inside 6 inches of the bituminous spread until the adjacent lane is tr eated. Immediately after spreading the aggregate, perform hand -brooming to achieve uniform coverage. Place additional aggregate by hand on thin or bare areas. The speed of the spreader shall be such that the aggregates are not rolling over, and starting and stopping of the spreader is minimized. Use of previously used (swept) aggregates is not permitted.
B.Rolling – Bituminous Seal Coat Immediately after distributing the aggregate, roll the entire surface by moving in a l ongitudinal direction, beginning at the outer edges and progressing toward the center of the roadway, with each trip of the roller overlapping the previous trip by half the width of the rear wheel. The amount and sequence of rolling shall be as directed b y the Engineer. Complete t he initial rolling of the aggregate within 1 hour after applying the bituminous material. Use power brooms to correct i rregularities by sweeping the aggregates from areas of thick or heavy distribution to areas of thin or light distribution. Then continue rolling until the aggregate is thoroughly 405.08 294 embedded in the bituminous material. The Engineer may require additional rolling at a later date. Redistribute excess or loose aggregate that was thrown out of place. Slow moving traff ic may use the section or roadway upon which the aggregate has been spread.
C.Rolling and Curing – Double Bituminous Seal Coat Immediately after spreading and brooming the cover aggregate, roll the entire surface, b eginning at the edges and progressing to the center. Begin rolling within 30 minutes after spreading the aggregate. The amount and sequence of rolling shall be as directed by the Engineer. Allow the first application of bituminous material and aggregate to cure for as long as deemed necessary by the Engineer before beginning the second application. For the second application of bituminous material and cover aggregate, repeat the same rolling and curing procedures as required for the first application. The Contractor may allow slow -moving traffic to use sections of the roadway where the bituminous material has been covered with mineral aggregate.
405.08 Shoulders
Restore shoulders that have been disturbed by the Contractor’s construction operations at no cost to the Department. Remove all objectionable material placed on the shoulders by the Contractor as directed by the Engineer. Construct shoulders, when specified, as provided for under 208.
405.09 Maintenance and Protection
Maintain in a satisfactory condition each completed section of seal coat until the entire Project is complete. Maintenance shall include making repai rs where failures occur, and maintaining the seal coat in a smooth uniform condition; and brooming, dragging, and rolling when required. 405.10 295 After the final application, maintain the work in a satisfactory condition for at least 10 calendar days. If all other requirements of the Contract have been fulfilled, the Department will not charge working time during the 10 -day maintenance period against the Contract time. For final cleanup, sweep up all excessive quantities of loose, dislodged cover aggregate that may have collected along the edge of the completed seal coat, and dispose of this material as directed by the Engineer. COMPENSATION
405.10 Method of Measurement
The Department will measure Mineral Aggregate and Bituminous Material by the ton in accordance with 109. The Department may use net certified weights as a basis of measurement for mineral aggregate, subject to correction for aggregate that is lost, wasted, or otherwise not incorporated into the Work.
405.11 Basis of Payment
A.General The Department will pay for accepted quantities of Bituminous Seal Coat, complete in place, at the contract prices as follows: Item Pay Unit Bituminous Material Ton Mineral Aggregate Ton The Department will measure and pay for the work required to prepare the designated surface, as provided for under 405.05, in accordance with the applicable Section or Subsection under wh ich the work is performed.
B.Adjustments Specific Gravity. In cases where the Bulk SSD specific gravity of the mineral aggregate exceeds 2.80, the Department will adjust the tonnage of mineral aggregate for payment by multiplying the tonnage of mineral aggregate used by a specific gravity of 2.80 and dividing by the higher specific gravity 407.01 296 SECTION 407 – BITUMINOUS PLANT MIX PAVEMENTS (GENERAL)
407.01 Description ................................ ................................ ................... 296
407.02 Materials ................................ ................................ ...................... 297
407.03 Composition of Mixtures ................................ ............................. 298
407.04 Bituminous Mixing Plant ................................ ............................. 312
407.05 Hauling Equipment ................................ ................................ ...... 323
407.06 Bituminous Pavers and Material Transfer Devices ...................... 323
407.07 Rollers ................................ ................................ .......................... 325
407.08 Small Tools ................................ ................................ .................. 326
407.09 Weather Limitations ................................ ................................ ..... 326
407.10 Conditioning the Existing Surface ................................ ............... 328
407.11 Preparing the Bituminous Material ................................ .............. 328
407.12 Preparation of Aggregates ................................ ............................ 330
407.13 Mixing ................................ ................................ .......................... 330
407.14 Spreading and Finishing ................................ ............................... 331
407.15 Compaction ................................ ................................ .................. 333
407.16 Joints ................................ ................................ ............................ 338
407.17 Pavement S amples ................................ ................................ ....... 338
407.18 Surface Requirements ................................ ................................ .. 339
407.19 Method of Measurement ................................ .............................. 339
407.20 Basis of Payment ................................ ................................ .......... 341
DESCRIPTION
407.01 Description
This Section 407 is applicable to all types of bituminous pavements of the asphalt plant mix type as described in 307, 313, and 411. Deviations from these general requirements will be indicated in the specific requirements for each pavement type. This work consists of constructing one or more courses of bituminous mixture on a prepared foundation in accordance with this Section 407 and the specific requirements of the pavement type under contract .
Source: Tennessee Standard Specifications for Road and Bridge Construction, 2021 Edition. Pages 297–304 of 1,072.