SECTION 411 - ULTRA-THIN ASPHALT PAVEMENT
411.01 Description. These specifications include ge neral requirements that are
applicable to Ultra-Thin Hot Mix Asphalt (UHMA) and Ultra-Thin Warm Mix Asphalt (UWMA). This work consists of the construction of on e lift of ultra-thin asphalt pavement (UTAP) in accordance with these specif ications and the specific requirements for the mixture to be produced and placed in reasonable close conformity with the lines, grades, thicknesses and typical sections shown on the plans or established by the Engineer. The asphalt mixture (UHMA or UWMA) used on this project will not be bid as an alternate pay item. The Contractor must select one of the asphalt mixtures, UHMA or UWMA, to be used throughout the entire project.
411.01.1 Definitions.
Maximum Sieve Size - Maximum sieve size is the sm allest sieve size at which 100 percent of the aggregate passes. Nominal Maximum Sieve Size - The nominal maximum sieve size is one sieve size larger than the first sieve to retain more than 10 percent of the aggregate. Maximum Density Line - The maximum density line is a straight line plot on the FHWA 0.45 power gradation char t which extends from the zero origin point of the chart through the plotted point of the combined aggregate gradation cu rve on the nominal maximum sieve size. Mechanically Fractured Face - An angular, rough, or broken surface of an aggregate particle created by crushing as determined by ASTM D 5821.
411.02 Materials.
411.02.1 Component Materials.
411.02.1 1--Aggregates. The source of aggregates shall meet the applicable requirements
of Section 703. The total amount of crushed limestone shall not exceed fifty percen t (50%) of the total aggregate by weight.
411.02.1 1.1--Coarse Aggregate Blend. Mechanically fractured faces by weight of the
combined mineral aggregate coarser than the No. 4 sieve shall be 90 percent, two faces.
411.02.1 1.2--Fine Aggregate Blend. Uncrushed natural sand shall pass the 3/8” sieve
and can be used, excluding the content in RAP, as no greater than 30 percent of the total mineral aggregate by weight.
411.02.1 1.3--Combined Aggregate Blend . The gradation requirements for Ultra-thin
asphalt pavements are provided in the following table: Sieve Size Percent Passing 1/2 inch 100 3/8 inch 95-100 No. 4 75 min No. 8 22-70 No.16 -- No. 200 4-12 The ultra-thin mixtures shall have a minimum fine aggregate angularity of 40.0 when tested on combined aggregate in accordance with ASTM C1252 Method A. The minus No. 40 fraction of the combined a ggregate shall be non-plastic when tested according to AASHTO T 90. Th e clay content shall not exceed 0.5 percent by weight of the total mineral aggregate when tested according to AASHTO T 88.
411.02.1 2--Reclaimed Asphalt Pavement. Reclaimed asphalt pavement may be used in
ultra-thin asphalt pavement and shall be no greater than 25 per cent of the total mix weight. Reclaimed asphalt pavement shall be separated into coarse and fine aggregate stockpiles using a ½” sieve as the break point.
411.02.1 3--Bituminous Materials. Bituminous materials shall meet the applicable
requirements of Section 702 for the grade specified.
411.02.1 4--Hydrated Lime. Hydrated lime shall meet th e requirements of Subsection
714.03.2 for lime used in soil stabilization.
411.02.1 5--Mineral Filler. Mineral filler shall meet the requirements of Subsection
411.02.2 Composition of Mixtures.
411.02.2 1--General. Unless otherwise specified or permitted, the UTAP shall consist of
a uniform mixture of asphalt, aggregate, mineral filler, hydrated lime and, when required or necessary to obtain desired properties, antistripping agent and/or other materials. Hydrated lime shall be used in all UTAP at the rate of one percent (1%) by weight of the total dry aggregate. The ag gregate, prior to the addition of the hydrated lime, shall contain sufficient surface moisture. The Contractor shall obtain a shipping ticke t for each shipment of hydrated lime. The Contractor shall provide the District Materi als Engineer with a copy of each shipping ticket from the supplier, including the date, time and weight of hydrated lime shipped. Mixtures will require the addition of an antistripping agent when the Tensile Strength Ratio (MT-63) and/or the Boiling Water Test (MT-59) fail to meet the following criteria. Tensile Strength Ratio (TSR - MT-63) Wet Strength / Dry Streng th ................................ 85 percent minimum Interior Face Coating ........................................... 95 percent minimum Boiling Water Test (MT-59) Particle Coating ................................................... 95 percent minimum
411.02.2 2--Mixture Properties. Ultra-thin asphalt pavement shall be designed at N
design of 50 revolutions of the gyratory compactor. Mixtures shall be designed such that the percent of maximum specific gravity (Gmm) shall be between 94.0 and 96.0. There will not be voids in mineral aggregate (VMA) requirement for ultra-thin asphalt. However, the specified volume of effective binder (the difference between total air voids and VMA) shall be a minimum of 12 percent. Dust/Binder Ratio (Percent Passing No. 200 / Effective Binder Content) for ultra-thin asphalt pavement shall be between 1.0 and 2.0.
411.02.2 3--Job Mix Formula. At least 10 working days prior to the proposed use of
each mixture, the Contractor shall submit in writing to the Engineer a proposed job-mix formula or request the transfer of a verified job-mix formula as set forth in the latest edition of MDOT’s Field Manual for HMA. The job-mix formula shall be signed by a Certified Mixture Design Technician (CMDT). The Department will perform the tests necessary for review of a proposed job-mix formula for each required mixture free of charge one time only. A charge will be made for additional job-mix formulas submitted by the Contractor for review. The mixture shall conform thereto within the range of tolerances specified for the UTAP mixture. No change in properties or proportion of any component of the job-mix formula shall be made without permission of the Engineer. The job-mix formula for each mixture shall be in effect until revised in writing by the Engineer. A job-mix formula may be transferred to other contracts in accordance with conditions set forth in the Department's Field Manual for HMA. The Contractor shall not place any UTAP pr ior to receiving “tentative” approval and a MDOT design number from the Central Laboratory. When a change in source of materials, unsa tisfactory mixture production results such as segregation, bleeding, shoving, rutting over 1/8 inch, raveling & cracking, or changed conditions make it necessary, a new job-mix formula will be required. The conditions set out herein for the original job-mix formula are applicable to the new job-mix formula.
411.02.2 4--Single Lift Laying Thickness. The minimum lift thickness for ultra-thin
asphalt pavement shall be 1/2 inch and the maximum lift thickness shall not exceed one inch (1”).
411.02.2 5--UWMA Products and Processes. The Department will maintain a list of
qualified UWMA products and processes. No product or process shall be used unless it appears on this list. The Contractor may propose other products or processes for approval by the Product Evaluation Committee. Documentation shall be provided to demonstrate laboratory performance, field performance, and construction experience.
411.02.3 Contractor’s Quality Management Program.
411.02.3 1--General. The Contractor shall have full responsibility for quality
management and maintain a quality control system that will furnish reasonable assurance that the mixtures and all component materials incorporated in the work conform to contract requirements. The Contractor shall have responsibility for the initial determination and all subsequent adjustments in proportioning materials used to produce the specified mixture. Adjustments to pl ant operation and spreading and compaction procedures shall be made immediately when results indicate that they are necessary. Mixture produced by the Contractor without the required testing or personnel on the project shall be subject to removal and repl acement by the Contractor at no additional cost to the State.
411.02.3 2--Personnel Requirements. The Contractor shall provide at least one Certified
Asphalt Technician-I (CAT-I) full-time during UTAP production at each plant site used to furnish material to the project. Sampling shall be conducted by a certified technician or by plant personnel under the direct observation of a certified technician. All testing, data analysis and data posting will be performed by the CAT-I or by an assistant under the direct supervision of the CAT-I. The Contractor shall have a Certified Asphalt Technician-II (CAT-II) available to make any necessary proces s adjustments. An organizational chart, including names, telephone numbers and current certification, of all those responsible for the quality control program shall be posted in the contractor's laboratory while the UTAP paving work is in progress
411.02.3 3--Testing Requirements. As a minimum, the Contractor's quality management
program shall include the following:
a.Bituminous Material. Provide Engineer with samples in a sealed one-quart metal container at the frequency given in MDOT SOP TMD-20-04-00-000.
b.Mechanically Fractured Face. Determ ine mechanically fractured face content of aggregates retained on the No. 4 siev e, at a minimum of one test per day of production.
c.Mixture Gradation. Conduct extraction tests for gradation determination on the mixture. Sample according to the frequency in paragraph (i) and test according to Mississippi Test Method MT-31.
d.Total Voids and V be. Determine total voids and volume of effective binder (Vbe), at N Design, from the results of bulk specific gravity tests on laboratory compacted specimens. Sample according to the sampling frequency in paragraph (h) and test according to the latest edition of MDOT’s Field Manual for HMA.
e.Asphalt Content. Sample according to the sampling frequency in paragraph (i), and determine the asphalt content using one of the following procedures.
1.Nuclear gauge. (Missi ssippi Test Method MT-6)
2.Incinerator oven. (AASHTO T 308, Method A)
f.Stripping Tests. Conduct a minimum of one stripping test at the beginning of each job-mix production and thereafter, at least once per each two weeks of production according to Mississippi Test Method: MT-63 and one stripping test per day of production according to Mississippi Test Method: MT-59. Should either the TSR (MT-63) or the boiling water (MT-59) stripping tests fail, a new antistrip additive or rate shall be established or other changes made immediately that will result in a mixture which conforms to the specifications; otherwise, production shall be suspended until corrections are made.
g.Quality Control Charts. Plot the individual test data, the average of the last four tests and the control limits for the following items as a minimum: Mixture Gradation (Percent Passing) Sieves: 1/2-in, 3/8-in, No. 4, No. 8, No. 30, and No. 200. Asphalt Content, Percent Maximum Specific Gravity Total Voids @ N Design, Percent V be @ NDesign, Percent Keep charts up-to-date and posted in a readily observable location. Charts may be kept on a computer; however, the charts shall be printed out a minimum of once each production day and displayed in the laboratory. Note any process changes or adjustments on the Air Voids chart.
h.Sampling Frequency. Conduct those tests as required above at the following frequency for each mixture produced based on the estimated plant tonnage at the beginning of the day. Total Estimated Production, tons Number of Tests 0-500 1 501-1000 2 1001-1500 3 1501-2000 4 2001+ 5
i.Sample Requirements. Obtain the asphalt mixture samples from trucks at the plant. Obtain aggregate samples from cold feed bins or aggregate stockpile. Save a split portion of all mixture samples at the laboratory site in a dry and protected location for 14 calendar days. At the completion of the project, the remaining samples may be disposed of with the approval of the Engineer. The above testing frequencies are for the estimated plant production for the day. If production is discontinued or interrupted, the tests will be conducted at the previously established sample tonnage points for the materials that are actually produced. If the production exceeds the estimated tonnage, sampling and testing will continue at the testing increments previously established for the day. A testing increment is defined as the estimated daily tonnage divided by the required number of tests from the table in Subsection 411.02.3.3 paragraph (h). In addition to the above program, aggregate stockpile gradation tests (AASHTO T-11 and T-27) shall be conducted every other production day. Fine aggregate angularity tests (ASTM C 1252, Method A) shall be conducted on the first day of production and once for every eight production samples thereafter, with a minimum of one test per production week.
411.02.3 4--Documentation. The Contractor shall document all observations, records of
inspection, adjustments to the mixture, and test results on a daily basis. All tests conducted by the Contractor in accordance with Subsection 411.02.3.3 (g) shall be included in the running average calculations. If single tests are performed as a check on individual UTAP properties, between regular samples, without performing all tests required in Subsection 411.02.3.3 (g), the results of those individual tests shall not be included in the running average calculations for that particular property. The Contractor shall record the results of observations and records of inspection as they occur in a permanent field record. The Contractor shall record all process adjustments and job mix formula (JMF) changes on the air void charts. The Contractor shall provide copies of all test data sheets and the daily summary reports on the appropriate Mississippi DOT forms to the Engineer on a daily basis. The Contractor shall provide a written description of any process change, including blend proportions, to the Engineer as they occur. Information provided to the District Materials Engineer must be received in the Engineer’s office by no later than 9:00 AM the day after the UTAP is produced. Upon completion of the placement of all UTAP on the project, the Contractor shall provide the Engineer with the original test reports and control charts in a neat and orderly manner.
411.02.3 5--Control Limits. The following control limits for the job mix formula (JMF)
and warning limits are based on a running average of the last four data points. Sieve - % Passing JMF Limits Warning Limits 1/2-in ± 5.5 ± 4.0 3/8-in ± 5.5 ± 4.0 No. 4 ± 4.0 ± 3.0 No. 8 ± 4.0 ± 3.0 No. 30 ± 4.0 ± 3.0 No. 200 ± 2.0 ± 1.5 Asphalt Content, % -0.3 to +0.5 -0.2 to +0.4 Design Total Voids ± 1.3 ± 1.0 @N Design, % Vbe @ N Design, % – 1.5 – 1.0
411.02.3 6--Warning Bands. Warning bands are defined as the area between the JMF
limits and the warning limits.
411.02.3 7--Job Mix Formula Adjustments. A request for a JMF adjustment signed by
a CAT-II may be made to the Engineer by the Contractor. Submit sufficient testing data with the request to justify the change. The requested change will be reviewed by the State Materials Engineer for the Department. If current production values meet the mixture design requirements, a revised JMF will be issued. Adjustments to the JMF shall conform to the latest edition of MDOT’s Field Manual for HMA. Adjustments to the JMF to conform to actual production shall not exceed the tolerances specified for the JMF limits. Regardless of such tolerances, any adjusted JMF gradation shall be within the range given in Subsection 411.02.1.1.3 for the mixture specified. The JMF asphalt content may only be reduced if the production Vbe meets or exceeds the minimum design Vbe requirements for the mixture being produced.
411.02.3 8--Actions and Adjustments. Actions and adjustments shall be in accordance
with Subsection 401.02.5.8.
411.02.4 Standards of Acceptance.
411.02.4 1--General. Acceptance for mixture quality (Vbe and total voids @ N Design,
gradation, and asphalt content) will be based on random samples tested in accordance with the latest edition of MDOT’s Field Manual for HMA. Smoothness will be accepted by lots as set out in Subsection 411.02.4.3.
411.02.4 2--Assurance Program for Mixture Quality. The Engineer will conduct a
quality assurance program in accordance with Subsection 401.02.6.2.
411.02.4 3--Acceptance Procedure for Mixture Quality. All obviously defective
material or mixture will be subject to rejection by the Engineer. Such defective material or mixture shall not be incorporated into the finished work. If the defective material has already been placed in the work, the material shall be removed and replaced at no additional cost to the State. The Engineer will base final acceptance of the asphalt mixture production on the results of the Contractor's testing for total voids and Vbe @ N Design, gradation, and asphalt content as verified by the Engineer in the manner hereinbefore described and the uniformity and condition of the completed pavement. Areas of pavement that exhibit nonuniformity or failures (materials or construction related) such as but not limited to segregation, bleeding, shoving, rutting over 1/8 inch, raveling, slippage, or cracking will not be accepted. Such areas will be removed and replaced at no additional cost to the State. Bituminous mixture placed prior to correction for deficiencies in Vbe and total voids @ N Design, gradation, or asphalt content, as required in Subsection 411.02.3.8 and determined by the Engineer satisfactory to remain in place will be paid for in accordance with the following pay factors times the contract unit price per ton. Pay Factor for Mixture Quality * Item Produced in Warning Bands Produced Outside JMF Limits (Allowed to Remain in Place) Gradation 0.90 0.75 Asphalt Content 0.85 0.75 Total Voids @ NDesign 0.70 0.50 Vbe @ N Design 0.90 0.75 * The minimum single payment will apply.
411.02.4 4--Acceptance Procedure for Density. The density requirement for UTAP
shall be roll to refusal. Refusal is defined as the number of roller passes to maximize the in-place unit weight of the mixture. On the first day of production and every three production days thereafter, a 500-foot test strip shall be evaluated to determine the required number of roller passes. Three random sites within the test strip shall be selected and monitored with the nuclear density gauge to determine refusal.
411.02.4 5--Acceptance Procedure for Pavement Smoothness. Prior to placement of
UTAP, the Contractor shall determine the existing surface Mean Roughness Index at no additional cost to the State. The finished UTAP lift shall have a mean roughness index no greater than that of the existing surface.
411.02.5 High Speed Inertial Profiling System. The high speed inertial profiling
system shall meet the applicable requirements of Subsection 401.02.6.9.
411.02.6 Surface Correction. In the event surface correction is needed it shall be
accomplished by removal and replacement in accordance with Subsection 403.03.4. All such corrections shall be at no additional cost to the State. The finished pavement surface will be measured for riding quality.
411.03 Construction Requirements. Mississippi DOT has adopted the “Hot-Mix
Asphalt Paving Handbook” as the guideline for acceptable UTAP construction practices.
411.03.1 Weather Limitations. The mixture shall not be placed when weather
conditions prevent the proper handling and finishing or the surface on which it is to be placed is wet or frozen. At the time of placement, the air and pavement surface temperature limitations shall be equal to or exceed 55°F for UHMA and 40°F for UWMA, regardless of the compacted lift thickness. When paving operations are discontinued because of rain, the mixture in transit shall be protected until the rain ceases. The surface on which the mixture is to be placed shall be swept to remove as much moisture as possible and the mixture may then be placed subject to removal and replacement at no additional cost to the State if contract requirements are not met.
411.03.2 Tack Coat. Tack coat shall meet the requirements of Subsection 401.03.1.2.
411.03.3 Bituminous Mixing Plants. Bituminous mixing plants shall meet the
applicable requirements of Subsection 410.03.2.
411.03.4 Hauling Equipment. Hauling equipment shall meet the requirements of
Subsection 401.03.3. Truck scales shall meet the requirements of Subsection
401.03.2 1.11.
411.03.5 Bituminous Pavers. Bituminous pavers shall meet the requirements of
Subsection 401.03.4.
411.03.6 Rollers. All rollers shall meet the requirements of Subsection 401.03.5.
411.03.7 Preparation of Grade. The foundation upon which UTAP pavement is to be
placed shall be prepared in accordance with Subsection 401.03.6.
411.03.8 Preparation of Mixture. The temperature of the mixture, when discharged
from the mixer, shall not exceed 340°F for UHMA and 280°F for UWMA.
411.03.9 Spreading and Finishing. Spreading and finishing of UTAP shall be in
accordance with Subsection 401.03.10.
411.03.10 Joints. Joints shall be constructed in accordance with Subsection 401.03.12.
411.04 Method of Measurement. Ultra-thin asphalt pavement will be measured by the
ton. Tack coat will be measured and paid as set out in Section 407.
411.05 Basis of Payment. Ultra-thin asphalt pavement, measured as prescribed above,
will be paid for at the contract unit price per ton, which price shall be full compensation for completing the work. Payment will be made under the following items: 411-A: Ultra-Thin Asphalt Pavement -per ton
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Source: Standard Specifications for Road and Bridge Construction, 2017 Edition. Pages 334–342 of 1,113. View official source ↗