00743.00 750 Section 00743 - Porous Asphalt Concrete (PAC)
Description
00743.00Scope - This Work consists of constructing one or more Courses of Porous Asphalt
Concrete (PAC) Pavement for drainage or stormwater infiltration, plant mixed into a uniformly coated mixture, placed on a prepared foundation, compacted and finished to a specified smoothness to the lines, grades, thickness, and Cross Sections shown or established.
00743.01Abbreviations :
PAC - Porous Asphalt Concrete TSR - Tensile Strength Ratio VFA - Voids Filled with Asphalt VMA - Voids in Mineral Aggregate
00743.02Definitions :
Asphalt Treated Permeable Base - A plant mixed, uniformly coated mixture of asphalt cement, open graded Aggregate and additives as required. All references to PAC will also apply to ATPB unless otherwise specified.
Porous Asphalt Concrete - A plant mixed, uniformly coated mixture of asphalt cement, open graded Aggregate and additives as required.
Wearing Course - The top Lift of PAC, regardless of thickness.
Materials
00743.10Aggregate - Furnish new Aggregates meeting the following requirements:
crushed Rock or other inert Material of similar characteristics.
No natural or uncrushed blend Sand will be allowed in PAC.
12 percent when subjected to five cycles of the soundness test using sodium sulfate solution according to AASH TO T 104.
Test Method Aggregates Test ODOT AASHTO Coarse Abrasion T 96 30.0% Degradation Passing No. 20 sieve TM 208 30.0% Sediment Height TM 208 3.0"
fractured faces as determined by AASHTO T 355 as follows:
00743.12 751 Percent of Fracture (by Weight) Material Retained on 1", 3/4", 1/2", Material Retained and No. 4 Sieve on No. 8 sieve Type of Mix (two fractured faces) (one fractured face) ATPB 75 75 PAC 90 75
Test Method Aggregates Test ODOT AASHTO Coarse Fine
Lightweight pieces T 113 1.0% Wood Particles TM 225 0.10% Elongated Pieces TM 229 10.0% (at a ratio of 5:1) Plasticity Index T 90 0 or NP Sand Equivalent T 176 45 min.
production of new PAC is optional. No more than 30 percent RAP M aterial will be allowed in the new PAC Pavement . Use RAP Aggregates in the PAC that are n o larger than the specified maximum allowable Aggregate size before entering the cold feed. Blend the RAP M aterial with new Aggregate to provide a mixture conforming to the JMF within the tolerances specified.
00743.11Asphalt Cement, Additives, and Agg regate Treatment - Furnish the following asphalt
cement and additives:
polymer modified asphalt cement is r equired in the Wearing Course. Provide asphalt cement conforming to the requirement of ODOT's publication Standard Specifications for Asphalt Materials . Copies of the publication are available from the ODOT Pavement Services Engineer ct is advertised.
are of known value for the intended purpose and approved for use on the basis of laboratory tests and capable of being thoroughly mixed. Do not use asphalt cement additives that have deleterious effects on the asphalt Material. Do not use silicones as an additive. Add the following asphalt cement additives when required by the JMF:
• Anti-stripping asphalt cement additives to prevent stripping or separation of asphalt coatings from Aggregates to satisfy the TSR specified in 00743.13. • Asphalt cement admixtures used to aid in the mixing.
00743.12Mix Type and Broadband Limits - Furnish the mix type specified in the Contract
Documents within the broadband limits acc ording to the following:
below:
00743.13 752 Sieve Size 3/8" PAC 1/2" PAC 3/4" ATPB Control Points (% passing by Weight) Control Points (% passing by Weight) Control Points (% passing by Weight) Min. Max. Min. Max. Min. Max. 1" 99 100 3/4" 99 100 85 95 1/2" 99 100 90 98 35 68 3/8" 90 100 − − − − No. 4 22 40 18 32 2 10 No. 8 5 15 3 15 0 5 No. 200 1.0 5.0 1.0 5.0 0.0 2.0 Asphalt Cement * * * * 2.5 3.5 * Per JMF
00743.13Job Mix Formula Requirements - Do not begin production of PAC for use on the Project
until the JMF is reviewed by the Engineer and written consent is provided to proceed. The JMF proposed for use on the Project will be evaluated based on the criteria identified in 00743.13(b) and the latest ODOT Contractor Mix Design Guidelines for Asphalt Concrete. For all mixes, complete TSR testing at least once per calendar year. A new JMF is required if the asphalt cement grade or source, any additives, or the source of the Aggregate change during production.
the Engineer for each mixture required at least 10 Calendar Days before the anticipated use in PAC, and according to the latest copy of the ODOT Contractor Mix Design Guidelines for Asphalt Concrete. If requested, submit material samples at least 10 Calendar Days before use.
3/8" and 1/2" PAC 3/4" ATPB
Design Method ODOT ODOT Air Voids, % 16.0 - 20.0 − Draindown, % 70 - 80 − TSR *, % minimum 80 − Coating, % minimum − 90 VFA, % 30 - 50 −
* Run the TSR for open graded mixtures on a surrogate dense graded mixture. If a dense graded JMF has been prepared for the same material sources in the last year, the results for the most recent TSR may be applied to the porous asphalt mixture. If not, prepare the TSR test samples for a dense graded mix using the equivalent top size stone and materials from the same sources, which will represent the porous asphalt mixture.
00743.17 753 00743.14 Tolerances and Limits - Produce and pl ace PAC within the following JMF tolerances and limits:
Gradation Constituent PAC Type 1/2" 3/8" ATPB 1" 99 - 100% 3/4" 99 - 100% 85 - 95% 1/2" 90 - 98% 99-100% 35 - 68% 3/8" − 90-100% − No. 4 JMF ± 5% JMF ± 5% JMF ± 5% No. 8 JMF ± 4% JMF ± 4% JMF ± 4% No. 30 JMF ± 4% JMF ± 4% − No. 200 JMF ± 2.0% JMF ± 2.0% JMF ± 2.0%
Constituent of Mixture PAC All Types Asphalt Cement - ODOT TM 321 (Cold Feed/Meter) JMF ± 0.20% Asphalt Cement - AASHTO T 308 (Ignition) and ODOT TM 323 JMF ± 0.50% RAP Content - ODOT TM 321 JMF ± 2.0% Moisture content at time of discharge from the mixing plant - AASHTO T 329* 1.10% max. * Does not apply to 3/4" ATPB
When a JMF tolerance applies to a constituent, full tolerance will be given even if it exceeds the control points established in 00743.12(b).
00743.16Sampling and Testing - Provide sampling, testing, and quality control according to
Provide test results to the Engineer by the middle of the following work shift.
If less than three samples are obtained on a Project , the Contractor may supplement test results with the Engineer's approval by:
• Accelerating testing. • Provide test results from other projects with the same JMF within the past 120 Days of first date of JMF production. • Test back up samples. Provide a minimum of three test results. Provide samples or split samples to the Engineer when requested.
00743.17Acceptance - If the average for each mix gradation constituent and asphalt content is
within the Specification limits, the Material will be accepted. If the average asphalt content or one or more gradation constituents is not within the Specification limits, the Material that is not within the Specification limits will be accepted according to 00150.25.
00743.20 754 Equipment
00743.20Pavers - Provide pavers specifically designed to spread and finish asphalt concrete
Pavement to a uniform texture in the widths, thicknesses, lines, grades, and C ross Sections specified. When approved, alternate E quipment may be used for areas where the use of a paver is impractica ble.
00743.21Compactors - Provide self -propelled steel -wheeled rollers specifically designed to
compact asphalt concrete Pavement and capable of reversing without backlash. Provide a sufficient number of appropriately weighted rollers to compact the mixture.
Labor
00743.30Quality Control Personnel - Provide technicians having CAT -I, CMDT, and CAgT
technical certifications.
Construction
00743.40Season and Temperature Limitations - Place PAC when the temperature of the surface
that is to be paved is not less than 50 °F.
00743.41Prepaving Confere nce - Have a prepaving conference with all Contractor Supervisory
personnel, all Subcontractors who are to be involved in the paving Work , and the Engineer. Meet at a mutually agreed time to discuss all methods of accomplishing all phases of the paving Work .
00743.42Preparation of Underlying Surfaces - All Bases and foundations on which the Pavement
is to be constructed shall meet the applicable Specifications and be approved before beginning paving operations. Recondition existing Bases and foundations according to Section 00610. Trim broken or ragged edges to firm material when directed.
The Pavement surface shall be dry before the preparation Work and paving.
00743.43Mixing and Placement Temperatures - Establish the allowable mixing and placement
temperature ranges by the JMF. Measure the mixture temperature at the discharge of the mixer. Measure the placement temperature behi nd the paver. The maximum mixture temperature of the PAC at the mixer is 350 °F. The minimum placement temperature of the PAC behind the paver is 205 °F
00743.44Hauling, Depositing, and Placing - Haul, deposit, and place PAC according to the
following:
and placement.
If excessive stopping of the paving machine occurs during paving operations, the Engineer may suspend paving operations until the mixture delivery rate matches the paving machine operation.
for each Lift and Course, as shown. Place each Course in one Lift unless otherwise specified. Do not exceed a compacted thickness of 4 inches for any Lift unless approved. Limit the minimum Lift thickness to twice the maximum Aggregate size in the mix.
00743.60 755 Uncompacted mixture behind the paver with temperatures below the minimum specified in 00743.43 will be rejected unless otherwise allowed by the Engineer.
Do not place PAC during rain or other adverse weather conditions, unless allowed by the Engineer. PAC in transit at the time adverse conditions occur may be placed i f:
• It has been covered during transit. • The PAC temperature is satisfactory. • It is placed on a foundation free from pools or flow of water.
00743.45Longitudinal Joints - At longitudinal joints, bond, compact and finish the PAC equal to the
Pavement against which it is placed.
minimum. Offset the longitudinal joints in one Panel by at least 6 inches from the longitudinal joints in the Panel immediately below.
or within 12 inches of the center of a lane, except in irregular areas, unless otherwise shown.
Construct longitudinal joints at either skip lines or fog lines unless approved. On Median lanes and on Shoulder areas construct longitudinal joints only at lane lines or at points of change in the transverse slopes, as shown or as directed.
• Provide warning signs and markings according to Sections 00221, 00222, 00224 and 00225 where abrupt or sloped edge drop-offs greater than 1 inch in height occur. • Protect edges from being broken down.
00743.49Compaction - After the PAC has been spread, struck off, and surface irregularities and
other defects remedied, roll it uniformly until compacted. Compaction of PAC to a specified densi ty will not be required. Continue the breakdown and intermediate rolling until the entire surface has been compacted with at least four Coverages by the rollers. Perform additional Coverages to complete finish rolling of the PAC.
Maintenance
00743.60Correction of Defects - Correct all defects in Material and Work , as directed, at no
additional cost to the Agency, according to the following:
successive Lifts of mixture.
fresh mixture. If problems with boils and slicks continu e to occur, stop production until a plan for eliminating the boils and slicks is approved by the Engineer.
or by other means approved by the Engineer.
00743.70 756 Finis hing and Cleaning Up
00743.70Pavement Smoothness - Furnish a 12 -foot straightedge and test as specified. Additional
testing may be required. Mark areas not meeting the surface tolerance.
and perpendicular to the centerline, as directed. The Pavement surface shall not vary by more than 1/4 inch.
tolerances of 00743.70(a) apply. If the Utility appurtenances are adjusted by others, these tolerances do not apply.
Shoulders, paved Medians, parking lanes, and parking lots is not required.
00743.71Correction of Pavement Roughness - Correct Equipment or paving operation
procedures when tests show the Pavement smoothness does not comply with 00743.70. In addition, do the following:
of the following methods as approved by the Engineer:
• Remove and replace the wearing surface Lift . • Profile to a maximum depth of 0.3 inch with abrasive grinders equipped with a cutting head comprised of multiple diamond blades.
completion of paving.
00743.72Opening to Traffic - Allow PAC to cure at least 72 hours before opening to traffic, unless
otherwise directed.
Measurement
00743.80Measurement - The quantities of PAC will be measured on the weight basis
No deductions will be made for asphalt cement, mineral filler, lime, anti -strip, or any other additive used in the mixture.
Payment
00743.90Payment - The accepted quantities of PAC incorporated into the Project, whether or not
recycled Materials are used, will be paid for at the Contract unit price, per Ton, for the item "____ Mixture".
The types of PAC (1/2 inch PAC, 3/8 inch PAC, 3/4 inch ATPB) will be inserted in the blank.
Payment will be payment in full for furnishing and placing all Mate rials, and for furnishing all Equipment , labor, and Incidentals necessary to complete the Work as specified.
No separate or additional payment will be made for Leveling Work , QC testing, asphalt cement, mineral filler, lime, anti -stripping or other additi ves.