3-26-46 Attachment C TxDOT Specifications.pdf

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OTU

Item 8011 Dense-Graded Hot-Mix Asphalt (Small Quantity) (Materials Only)

1. DESCRIPTION

Provide a hot-mix asphalt (HMA) material composed of a dense-graded mixture of aggregate and asphalt binder mixed hot in a mixing plant. This specification is intended for small quantity (SQ) HMA projects, typically under 5,000 tons per work order.

2. MATERIALS

Furnish uncontaminated materials of uniform quality that meet the requirements of the plans and specifications.

Notify the Engineer of all material sources and before changing any material source or formulation. The Engineer will verify that the specification requirements are met when the Contractor makes a source or formulation change, and may require a new laboratory mixture design, trial batch, or both. The Engineer may sample and test project materials at any time during the project to verify specification compliance in accordance with Item 6, “Control of Materials.”

2.1. Aggregate. Furnish aggregates from sources that conform to the requirements shown in Table 1 and as specified in this Section. Aggregate requirements in this Section, including those shown in Table 1, may be modified or eliminated when shown on the plans. Additional aggregate requirements may be specified when shown on the plans. Provide aggregate stockpiles that meet the definitions in this Section for coarse, intermediate, or fine aggregate. Aggregate from reclaimed asphalt pavement (RAP) is not required to meet Table 1 requirements unless otherwise shown on the plans. Supply aggregates that meet the definitions in Tex-100-E for crushed gravel or crushed stone. The Engineer will designate the plant or the quarry as the sampling location. Provide samples from materials produced for the project. The Engineer will establish the Surface Aggregate Classification (SAC) and perform Los Angeles abrasion, magnesium sulfate soundness, and Micro-Deval tests. Perform all other aggregate quality tests listed in Table 1. Document all test results on the mixture design report. The Engineer may perform tests on independent or split samples to verify Contractor test results. Stockpile aggregates for each source and type separately. Determine aggregate gradations for mixture design and production testing based on the washed sieve analysis given in Tex-200-F, Part II.

2.1.1. Coarse Aggregate. Coarse aggregate stockpiles must have no more than 20% material passing the No. 8 sieve. Aggregates from sources listed in the Department’s Bituminous Rated Source Quality Catalog (BRSQC) are preapproved for use. Use only the rated values for hot-mix listed in the BRSQC. Rated values for surface treatment (ST) do not apply to coarse aggregate sources used in hot-mix asphalt.

For sources not listed on the Department’s BRSQC:

build an individual stockpile for each material;

request the Department test the stockpile for specification compliance; and once approved, do not add material to the stockpile unless otherwise approved.

Provide aggregate from non-listed sources only when tested by the Engineer and approved before use. Allow 30 calendar days for the Engineer to sample, test, and report results for non-listed sources.

Provide coarse aggregate with at least the minimum SAC shown on the plans. The SAC for sources on the Department’s Aggregate Quality Monitoring Program (AQMP) (Tex-499-A) is listed in the BRSQC.

http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/100-E_series/pdfs/soi100.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit200.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/400-A_series/pdfs/cnn499.pdf

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2.1.1.1. Blending Class A and Class B Aggregates. Class B aggregate meeting all other requirements in Table 1 may be blended with a Class A aggregate to meet requirements for Class A materials, unless otherwise shown on the plans. Ensure that at least 50% by weight, or volume if required, of the material retained on the No. 4 sieve comes from the Class A aggregate source when blending Class A and B aggregates to meet a Class A requirement unless otherwise shown on the plans. Blend by volume if the bulk specific gravities of the Class A and B aggregates differ by more than 0.300. Coarse aggregate from RAP will be considered as Class B aggregate for blending purposes.

The Engineer may perform tests at any time during production, when the Contractor blends Class A and B aggregates to meet a Class A requirement, to ensure that at least 50% by weight, or volume if required, of the material retained on the No. 4 sieve comes from the Class A aggregate source. The Engineer will use the Department’s mix design template, when electing to verify conformance, to calculate the percent of Class A aggregate retained on the No. 4 sieve by inputting the bin percentages shown from readouts in the control room at the time of production and stockpile gradations measured at the time of production. The Engineer may determine the gradations based on either washed or dry sieve analysis from samples obtained from individual aggregate cold feed bins or aggregate stockpiles. The Engineer may perform spot checks using the gradations supplied by the Contractor on the mixture design report as an input for the template; however, a failing spot check will require confirmation with a stockpile gradation determined by the Engineer.

2.1.2. Intermediate Aggregate. Aggregates not meeting the definition of coarse or fine aggregate will be defined as intermediate aggregate. Supply intermediate aggregates, when used that are free from organic impurities.

The Engineer may test the intermediate aggregate in accordance with Tex-408-A to verify the material is free from organic impurities. Supply intermediate aggregate from coarse aggregate sources, when used that meet the requirements shown in Table 1 unless otherwise approved.

Test the stockpile if 10% or more of the stockpile is retained on the No. 4 sieve, and verify that it meets the requirements in Table 1 for crushed face count (Tex-460-A) and flat and elongated particles (Tex-280-F).

2.1.3. Fine Aggregate. Fine aggregates consist of manufactured sands, screenings, and field sands. Fine aggregate stockpiles must meet the gradation requirements in Table 2. Supply fine aggregates that are free from organic impurities. The Engineer may test the fine aggregate in accordance with Tex-408-A to verify the material is free from organic impurities. Unless otherwise shown on the plans, up to 10% of the total aggregate may be field sand or other uncrushed fine aggregate. Use fine aggregate, with the exception of field sand, from coarse aggregate sources that meet the requirements shown in Table 1 unless otherwise approved.

Test the stockpile if 10% or more of the stockpile is retained on the No. 4 sieve, and verify that it meets the requirements in Table 1 for crushed face count (Tex-460-A) and flat and elongated particles (Tex-280-F).

http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/400-A_series/pdfs/cnn408.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/400-A_series/pdfs/cnn460.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit280.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/400-A_series/pdfs/cnn408.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/400-A_series/pdfs/cnn460.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit280.pdf

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Table 1 Aggregate Quality Requirements

Property Test Method Requirement Coarse Aggregate

SAC Tex-499-A (AQMP) As shown on the plans Deleterious material, %, Max Tex-217-F, Part I 1.5 Decantation, %, Max Tex-217-F, Part II 1.5 Micro-Deval abrasion, % Tex-461-A Note 1 Los Angeles abrasion, %, Max Tex-410-A 40 Magnesium sulfate soundness, 5 cycles, %, Max Tex-411-A 30 Crushed face count,2 %, Min Tex-460-A, Part I 85 Flat and elongated particles @ 5:1, %, Max Tex-280-F 10

Fine Aggregate Linear shrinkage, %, Max Tex-107-E 3 Sand equivalent %, Min Tex-203-F 45

1. Not used for acceptance purposes. Optional test used by the Engineer as an indicator of the need for further investigation.

2. Only applies to crushed gravel.

Table 2

Gradation Requirements for Fine Aggregate Sieve Size % Passing by Weight or Volume

3/8″ 100 #8 70–100

#200 0–30

2.2. Mineral Filler. Mineral filler consists of finely divided mineral matter such as agricultural lime, crusher fines, hydrated lime, or fly ash. Mineral filler is allowed unless otherwise shown on the plans. Use no more than 2% hydrated lime or fly ash unless otherwise shown on the plans. Use no more than 1% hydrated lime if a substitute binder is used unless otherwise shown on the plans or allowed. Test all mineral fillers except hydrated lime and fly ash in accordance with Tex-107-E to ensure specification compliance. The plans may require or disallow specific mineral fillers. Provide mineral filler, when used, that:

is sufficiently dry, free-flowing, and free from clumps and foreign matter as determined by the Engineer;

does not exceed 3% linear shrinkage when tested in accordance with Tex-107-E; and meets the gradation requirements in Table 3, unless otherwise shown on the plans.

Table 3

Gradation Requirements for Mineral Filler Sieve Size % Passing by Weight or Volume

#8 100 #200 55–100

2.3. Baghouse Fines. Fines collected by the baghouse or other dust-collecting equipment may be reintroduced into the mixing drum.

2.4. Asphalt Binder. Furnish the type and grade of performance-graded (PG) asphalt specified on the plans.

2.5. Additives. Use the type and rate of additive specified when shown on the plans. Additives that facilitate mixing, compaction, or improve the quality of the mixture are allowed when approved. Provide the Engineer with documentation, such as the bill of lading, showing the quantity of additives used in the HMAC unless otherwise directed.

2.5.1. Lime and Liquid Antistripping Agent. When lime or a liquid antistripping agent is used, add in accordance with Item 301, “Asphalt Antistripping Agents.” Do not add lime directly into the mixing drum of any plant where lime is removed through the exhaust stream unless the plant has a baghouse or dust collection system that reintroduces the lime into the drum.

2.6. Compaction Aid. Compaction Aid is defined as a department-approved chemical warm mix additive that is used to produce an asphalt mixture at a discharge temperature greater than 275°F.

http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/400-A_series/pdfs/cnn499.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit217.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit217.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/400-A_series/pdfs/cnn461.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/400-A_series/pdfs/cnn410.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/400-A_series/pdfs/cnn411.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/400-A_series/pdfs/cnn460.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit280.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/100-E_series/pdfs/soi107.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit203.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/100-E_series/pdfs/soi107.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/100-E_series/pdfs/soi107.pdf

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A compaction aid may be used to facilitate mixing and compaction of HMA produced at target discharge temperatures greater than 275°F. Compaction Aid is allowed for use on all projects and is required when shown on the plans.

2.7. Recycled Materials. Use of RAP is permitted unless otherwise shown on the plans. Do not exceed the maximum allowable percentage of RAP shown in Table 4. The allowable percentage shown in Table 4 may be decreased or increased when shown on the plans. Determine the asphalt binder content and gradation of the RAP stockpiles for mixture design purposes in accordance with Tex-236-F, Part I. The Engineer may verify the asphalt binder content of the stockpiles at any time during production. Perform other tests on RAP when shown on the plans. Asphalt binder from RAP is designated as recycled asphalt binder. Calculate and ensure that the ratio of the recycled asphalt binder to total binder does not exceed the percentages shown in Table 5 during mixture design and HMA production when RAP is used. Use a separate cold feed bin for each stockpile of RAP during HMA production.

Surface, intermediate, and base mixes referenced in Tables 4 and 5 are defined as follows:

Surface. The final HMA lift placed at the top of the pavement structure or placed directly below mixtures produced in accordance with Items 316, 342, 347, or 348;

Intermediate. Mixtures placed below an HMA surface mix and less than or equal to 8.0 in. from the riding surface; and Base. Mixtures placed greater than 8.0 in. from the riding surface. Unless otherwise shown on the plans, mixtures used for bond breaker are defined as base mixtures.

2.7.1. RAP. RAP is salvaged, milled, pulverized, broken, or crushed asphalt pavement. Fractionated RAP is defined as a RAP stockpile that contains RAP material with a minimum of 95.0% passing the 3/8-in. or ½-in.

sieve, before burning in the ignition oven, unless otherwise approved. The Engineer may allow the Contractor to use an alternate to the 3/8-in. or ½-in. screen to fractionate the RAP.

Use of Contractor-owned RAP, including HMA plant waste, is permitted unless otherwise shown on the plans. Perform any necessary tests to ensure RAP is appropriate for use.

The coarse RAP stockpile will contain only material retained by processing over a 3/8-in. or 1/2-in. screen unless otherwise approved. The fine RAP stockpile will contain only material passing the 3/8-in. or 1/2-in.

screen unless otherwise approved. The Engineer may allow the Contractor to use an alternate to the 3/8-in.

or 1/2-in. screen to fractionate the RAP. The maximum percentages of fractionated RAP may be comprised of coarse or fine fractionated RAP or the combination of both coarse and fine fractionated RAP.

Do not use RAP contaminated with dirt or other objectionable materials. Do not use RAP if the decantation value exceeds 5% and the plasticity index is greater than 8. Test the stockpiled RAP for decantation in accordance with Tex-406-A, Part I. Determine the plasticity index in accordance with Tex-106-E if the decantation value exceeds 5%. The decantation and plasticity index requirements do not apply to RAP samples with asphalt removed by extraction or ignition.

Table 4

Maximum Allowable Amounts of RAP1 Maximum Allowable

Fractionated RAP (%) Surface Intermediate Base

15.0 25.0 30.0

1. Must also meet the recycled binder to total binder ratio shown in Table 5.

2.8. Substitute Binders. Unless otherwise shown on the plans, the Contractor may use a substitute PG binder listed in Table 5 instead of the PG binder originally specified, if using recycled materials, and if the substitute PG binder and mixture made with the substitute PG binder meet the following:

the substitute binder meets the specification requirements for the substitute binder grade in accordance with Section 300.2.10., “Performance-Graded Binders;” and http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit236.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/400-A_series/pdfs/cnn406.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/100-E_series/pdfs/soi106.pdf

5 1/8/20 the mixture has less than 10.0 mm of rutting on the Hamburg Wheel test (Tex-242-F) after the number of passes required for the originally specified binder. Use of substitute PG binders may only be allowed at the discretion of the Engineer if the Hamburg Wheel test results are between 10.0 mm and 12.5 mm.

Table 5

Allowable Substitute PG Binders and Maximum Recycled Binder Ratios Originally Specified PG Binder

Allowable Substitute PG Binder for Surface Mixes

Allowable Substitute PG Binder for

Intermediate and Base Mixes

Maximum Ratio of Recycled Binder to Total Binder (%)

Surface Intermediate Base

76-223,4 70-22 70-22 10.0 20.0 25.0

70-221,4 N/A 64-22 10.0 20.0 25.0

64-221,2 N/A N/A 10.0 20.0 25.0

76-283,4 70-28 70-28 10.0 20.0 25.0

70-281,4 N/A 64-28 10.0 20.0 25.0

64-281,2 N/A N/A 10.0 20.0 25.0

1. Binder substitution is not allowed for surface mixtures.

2. Binder substitution is not allowed for intermediate and base mixtures.

3. Use no more than 10.0% recycled binder in surface mixtures when using this originally specified PG binder.

4. Use no more than 20.0% recycled binder when using this originally specified PG binder for intermediate mixtures. Use no more than 25.0% recycled binder when using this originally specified PG binder for base mixtures.

3. EQUIPMENT

Provide machinery, tools, and equipment necessary for proper execution of the work.

4. QUALITY CONTROL/QUALITY ASSURANCE

Produce the specified paving mixture. In addition to tests required by the specification, Contractors may perform other QC tests as deemed necessary.

4.1. Certification. Personnel certified by the Department-approved hot-mix asphalt certification program must conduct all mixture designs, sampling, and testing in accordance with Table 6. Supply the Engineer with a list of certified personnel and copies of their current certificates before beginning production and when personnel changes are made. Provide a mixture design developed and signed by a Level 2 certified specialist. Provide level 1A certified specialists at the plant during production operations. Provide Level AGG101 certified specialists for aggregate testing.

http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit242.pdf

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Table 6 Test Methods, Test Responsibility, and Minimum Certification Levels

Test Description Test Method Contractor Engineer Level1

1. Aggregate and Recycled Material Testing

Sampling Tex-221-F 1A/AGG101 Dry sieve Tex-200-F, Part I 1A/AGG101 Washed sieve Tex-200-F, Part II 1A/AGG101 Deleterious material Tex-217-F, Parts I & III AGG101 Decantation Tex-217-F, Part II AGG101 Los Angeles abrasion Tex-410-A TxDOT Magnesium sulfate soundness Tex-411-A TxDOT Micro-Deval abrasion Tex-461-A AGG101 Crushed face count Tex-460-A AGG101 Flat and elongated particles Tex-280-F AGG101 Linear shrinkage Tex-107-E AGG101 Sand equivalent Tex-203-F AGG101 Organic impurities Tex-408-A AGG101

2. Asphalt Binder Sampling Asphalt binder sampling Tex-500-C, Part II 1A/1B

3. Mix Design & Verification Design and JMF changes Tex-204-F 2 Mixing Tex-205-F 2 Molding (TGC) Tex-206-F 1A Molding (SGC) Tex-241-F 1A Laboratory-molded density Tex-207-F, Parts I & VI 1A Rice gravity Tex-227-F, Part II 1A Ignition oven correction factors2 Tex-236-F, Part II 2 Indirect tensile strength Tex-226-F 1A Hamburg Wheel test Tex-242-F 1A Boil test Tex-530-C 1A

4. Production Testing Mixture sampling Tex-222-F 1A/1B Molding (TGC) Tex-206-F 1A Molding (SGC) Tex-241-F 1A Laboratory-molded density Tex-207-F, Parts I & VI 1A Rice gravity Tex-227-F, Part II 1A Gradation & asphalt binder content2 Tex-236-F, Part I 1A Moisture content Tex-212-F, Part II 1A/AGG101 Hamburg Wheel test Tex-242-F 1A Boil test Tex-530-C 1A

1. Level 1A, 1B, AGG101, and 2 are certification levels provided by the Hot Mix Asphalt Center certification program.

2. Refer to Section “Production Testing,” for exceptions to using an ignition oven.

4.2. Reporting, Testing, and Responsibilities. Use Department-provided templates to record and calculate all test data pertaining to the mixture design. The Engineer will use Department templates for any production and placement testing. Obtain the current version of the templates at http://www.txdot.gov/inside-txdot/forms-publications/consultants-contractors/forms/site-manager.html or from the Engineer.

The maximum allowable time for the Engineer to exchange test data with the Contractor is as given in Table 7 unless otherwise approved. The Engineer will immediately report to the Contractor any test result that requires suspension of production or placement or that fails to meet the specification requirements.

http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit221.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit200.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit200.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit217.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit217.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/400-A_series/pdfs/cnn410.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/400-A_series/pdfs/cnn411.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/400-A_series/pdfs/cnn461.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/400-A_series/pdfs/cnn460.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit280.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/100-E_series/pdfs/soi107.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit203.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/400-A_series/pdfs/cnn408.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/500-C_series/pdfs/aph500.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit204.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit205.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit206.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit241.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit207.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit227.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit236.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit226.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit242.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/500-C_series/pdfs/aph530.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit222.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit206.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit241.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit207.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit227.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit236.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit212.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit242.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/500-C_series/pdfs/aph530.pdf http://www.txdot.gov/inside-txdot/forms-publications/consultants-contractors/forms/site-manager.html http://www.txdot.gov/inside-txdot/forms-publications/consultants-contractors/forms/site-manager.html

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Table 7 Reporting Schedule

Description Reported By Reported To To Be Reported Within Production Testing

Gradation

Engineer Contractor 1 working day of completion of the test

Asphalt binder content Laboratory-molded density Hamburg Wheel test Moisture content Boil test Binder tests

4.3. Mixture Design.

4.3.1. Design Requirements. The Contractor will design the mixture using a Superpave Gyratory Compactor (SGC). A Texas Gyratory Compactor (TGC) may be used when shown on the plans. Use the dense-graded design procedure provided in Tex-204-F. Design the mixture to meet the requirements listed in Tables 1, 2, 3, 4, 5, 8, 9, and 10.

4.3.1.1. Design Number of Gyrations (Ndesign) When the SGC Is Used. Design the mixture at 50 gyrations (Ndesign). Use a target laboratory-molded density of 96.0% to design the mixture; however, adjustments can be made to the Ndesign value as noted in Table 9. The Ndesign level may be reduced to at least 35 gyrations at the Contractor’s discretion.

Use an approved laboratory from the Department’s MPL to perform the Hamburg Wheel test in accordance with Tex-242-F, and provide results with the mixture design, or provide the laboratory mixture and request that the Department perform the Hamburg Wheel test. The Engineer will be allowed 10 working days to provide the Contractor with Hamburg Wheel test results on the laboratory mixture design.

The Engineer will provide the mixture design when shown on the plans. The Contractor may submit a new mixture design at any time during the contract. The Engineer will verify and approve all mixture designs (JMF1) before the Contractor can begin production.

Provide the Engineer with a mixture design report using the Department-provided template. Include the following items in the report:

the combined aggregate gradation, source, specific gravity, and percent of each material used;

asphalt binder content and aggregate gradation of RAP stockpiles;

the target laboratory-molded density (or Ndesign level when using the SGC);

results of all applicable tests;

the mixing and molding temperatures;

the signature of the Level 2 person or persons that performed the design;

the date the mixture design was performed; and a unique identification number for the mixture design.

http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit204.pdf

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Table 8 Master Gradation Limits (% Passing by Weight or Volume) and VMA Requirements

Sieve Size

B Fine Base

C Coarse Surface

D Fine

Surface

F Fine

Mixture 2″ – – – –

1-1/2″ 100.01 – – – 1″ 98.0–100.0 100.01 – –

3/4″ 84.0–98.0 95.0–100.0 100.01 – 1/2″ – – 98.0–100.0 100.01 3/8″ 60.0–80.0 70.0–85.0 85.0–100.0 98.0–100.0 #4 40.0–60.0 43.0–63.0 50.0–70.0 70.0–90.0 #8 29.0–43.0 32.0–44.0 35.0–46.0 38.0–48.0

#30 13.0–28.0 14.0–28.0 15.0–29.0 12.0–27.0 #50 6.0–20.0 7.0–21.0 7.0–20.0 6.0–19.0 #200 2.0–7.0 2.0–7.0 2.0–7.0 2.0–7.0

Design VMA, % Minimum

– 13.0 14.0 15.0 16.0

Production (Plant-Produced) VMA, % Minimum

– 12.5 13.5 14.5 15.5

1. Defined as maximum sieve size. No tolerance allowed.

Table 9 Laboratory Mixture Design Properties

Mixture Property Test Method Requirement

Target laboratory-molded density, % (SGC) Tex-207-F 96.0 Design gyrations (Ndesign for SGC) Tex-241-F 501 Indirect tensile strength (dry), psi Tex-226-F 85–2002 Boil test3 Tex-530-C –

1. Adjust within a range of 35–100 gyrations when shown on the plans or specification or when mutually agreed between the Engineer and Contractor.

2. The Engineer may allow the IDT strength to exceed 200 psi if the corresponding Hamburg

Wheel rut depth is greater than 3.0 mm and less than 12.5 mm.

3. Used to establish baseline for comparison to production results. May be waived when approved.

Table 10 Hamburg Wheel Test Requirements

High-Temperature Binder Grade Test Method Minimum # of Passes

@ 12.5 mm1 Rut Depth, Tested @ 50°C

PG 64 or lower Tex-242-F

10,0002

PG 70 15,0003

PG 76 or higher 20,000

1. When the rut depth at the required minimum number of passes is less than 3 mm, the

Engineer may require the Contractor to increase the target laboratory-molded density (TGC) by 0.5% to no more than 97.5% or lower the Ndesign level (SGC) to at least 35 gyrations.

2. May be decreased to at least 5,000 passes when shown on the plans.

3. May be decreased to at least 10,000 passes when shown on the plans.

4.3.1.2. Target Laboratory-Molded Density When The TGC Is Used. Design the mixture at a 96.5% target laboratory-molded density. Increase the target laboratory-molded density to 97.0% or 97.5% at the Contractor’s discretion or when shown on the plans or specification.

4.3.2. Job-Mix Formula Approval. The job-mix formula (JMF) is the combined aggregate gradation, target laboratory-molded density (or Ndesign level), and target asphalt percentage used to establish target values for hot-mix production. JMF1 is the original laboratory mixture design used to produce the trial batch.

Furnish a mix design report (JMF1) with representative samples of all component materials and request http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit207.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit241.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit226.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/500-C_series/pdfs/aph530.pdf

9 1/8/20 approval to produce the trial batch. Provide approximately 10,000 g of the design mixture and request that the Department perform the Hamburg Wheel test if opting to have the Department perform the test. The Engineer will verify JMF1 based on plant-produced mixture from the trial batch unless otherwise determined.

The Engineer may accept an existing mixture design previously used on a Department project and may waive the trial batch to verify JMF1. Provide split samples of the mixtures and blank samples used to determine the ignition oven correction factors. The Engineer will determine the aggregate and asphalt correction factors from the ignition oven used for production testing in accordance with Tex-236-F.

The Engineer will use a TGC calibrated in accordance with Tex-914-K in molding production samples samples if the TGC is used to design the mix.

The Engineer may perform Tex-530-C and retain the tested sample for comparison purposes during production. The Engineer may waive the requirement for the boil test.

4.3.3. JMF Adjustments. If JMF adjustments are necessary to achieve the specified requirements, the adjusted JMF must:

be provided to the Engineer in writing before the start of a new lot;

be numbered in sequence to the previous JMF;

meet the mixture requirements in Table 4 and Table 5;

meet the master gradation limits shown in Table 8; and be within the operational tolerances of the current JMF listed in Table 11.

The Engineer may adjust the asphalt binder content to maintain desirable laboratory density near the optimum value while achieving other mix requirements.

Table 11 Operational Tolerances

Description Test Method Allowable Difference Between Trial Batch and JMF1 Target

Allowable Difference from Current JMF Target

Individual % retained for #8 sieve and larger Tex-200-F or Tex-236-F

Must be within master grading limits in Table 8

±5.01,2

Individual % retained for sieves smaller than #8 and larger than #200 ±3.01,2

% passing the #200 sieve ±2.01,2 Asphalt binder content, % Tex-236-F ±0.5 ±0.32 Laboratory-molded density, % Tex-207-F ±1.0 ±1.0 VMA, %, min Tex-204-F Note 3 Note 3

1. When within these tolerances, mixture production gradations may fall outside the master grading limits; however, the % passing the #200 will be considered out of tolerance when outside the master grading limits.

2. Only applies to mixture produced for Lot 1 and higher.

3. Mixture is required to meet Table 8 requirements.

4.4. Production Operations. Perform a new trial batch when the plant or plant location is changed. Take corrective action and receive approval to proceed after any production suspension for noncompliance to the specification. Submit a new mix design and perform a new trial batch when the asphalt binder content of any RAP stockpile used in the mix is more than 0.5% higher than the value shown on the mixture design report.

4.4.1. Storage and Heating of Materials. Do not heat the asphalt binder above the temperatures specified in Item 300, “Asphalts, Oils, and Emulsions,” or outside the manufacturer’s recommended values. Provide the Engineer with daily records of asphalt binder and hot-mix asphalt discharge temperatures (in legible and discernible increments) in accordance with Item 320, “Equipment for Asphalt Concrete Pavement,” unless otherwise directed. Do not store mixture for a period long enough to affect the quality of the mixture, nor in any case longer than 12 hr. unless otherwise approved.

4.4.2. Mixing and Discharge of Materials. Notify the Engineer of the target discharge temperature and produce the mixture within 25°F of the target. Monitor the temperature of the material in the truck before shipping to ensure that it does not exceed the maximum production temperatures listed in Table 12. The Department will not pay for any mixture produced above the maximum production temperatures listed in Table 12.

http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit236.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/900-K_series/pdfs/cal914.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/500-C_series/pdfs/aph530.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit200.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit236.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit236.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit207.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit204.pdf

10 1/8/20

Table 12 Maximum Production Temperature

High-

Temperature Binder Grade1

Maximum Production Temperature

PG 64 325˚F

PG 70 335˚F

PG 76 345˚F

1. The high-temperature binder grade refers to the high-temperature grade of the virgin asphalt binder used to produce the mixture.

Control the mixing time and temperature so that substantially all moisture is removed from the mixture before discharging from the plant. The Engineer may determine the moisture content by oven-drying in accordance with Tex-212-F, Part II, and verify that the mixture contains no more than 0.2% of moisture by weight. The Engineer will obtain the sample immediately after discharging the mixture into the truck, and will perform the test promptly.

4.5. Hauling Operations. Clean all truck beds before use to ensure that mixture is not contaminated. Use a release agent shown on the Department’s MPL to coat the inside bed of the truck when necessary.

4.6. Production Acceptance.

4.6.1. Production Lot. Each day of production is defined as a production lot. Lots will be sequentially numbered and correspond to each new day of production. Note that lots are not subdivided into sublots for this specification.

4.6.2. Production Sampling.

4.6.2.1. Mixture Sampling. The Engineer may obtain mixture samples in accordance with Tex-222-F at any time during production.

4.6.2.2. Asphalt Binder Sampling. The Engineer may obtain or require the Contractor to obtain 1 qt. samples of the asphalt binder at any time during production from a port located immediately upstream from the mixing drum or pug mill and upstream from the introduction of any additives in accordance with Tex-500-C, Part II. The Contractor will notify the Engineer when the sampling will occur. The Engineer may test any of the asphalt binder samples to verify compliance with Item 300, “Asphalts, Oils, and Emulsions.”

4.6.3. Production Testing. The Engineer will test at the frequency listed in the Department’s Guide Schedule of Sampling and Testing and this specification. The Engineer may suspend production if production tests do not meet specifications or are not within operational tolerances listed in Table 11. Take immediate corrective action if the Engineer’s laboratory-molded density on any sample is less than 95.0% or greater than 98.0%, to bring the mixture within these tolerances. The Engineer may suspend operations if the Contractor’s corrective actions do not produce acceptable results. The Engineer will allow production to resume when the proposed corrective action is likely to yield acceptable results.

The Engineer may use alternate methods for determining the asphalt binder content and aggregate gradation if the aggregate mineralogy is such that Tex-236-F does not yield reliable results. Use the applicable test procedure if an alternate test method is selected.

http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit212.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit222.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/500-C_series/pdfs/aph500.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit236.pdf

11 1/8/20

Table 13 Production Testing

Description Test Method Individual % retained for #8 sieve and larger Tex-200-F or Tex-236-F

Individual % retained for sieves smaller than #8 and larger than #200 % passing the #200 sieve Laboratory-molded density Tex-207-F Laboratory-molded bulk specific gravity VMA Tex-204-F Moisture content Tex-212-F, Part II Theoretical maximum specific (Rice) gravity Tex-227-F Asphalt binder content Tex-236-F Hamburg Wheel test Tex-242-F Asphalt binder sampling and testing Tex-500-C Boil test Tex-530-C

1. Testing performed by the Materials and Test Division or designated laboratory.

4.6.3.1. Voids in Mineral Aggregates (VMA). The Engineer may determine the VMA for any production lot. Take immediate corrective action if the VMA value for any lot is less than the minimum VMA requirement for production listed in Table 8. Suspend production and shipment of the mixture if the Engineer’s VMA result is more than 0.5% below the minimum VMA requirement for production listed in Table 8.

4.6.3.2. Hamburg Wheel Test. The Engineer may perform a Hamburg Wheel test at any time during production, including when the boil test indicates a change in quality from the materials submitted for JMF1. Suspend production until further Hamburg Wheel tests meet the specified values when the production samples fail the Hamburg Wheel test criteria in Table 10.

4.6.4. Individual Loads of Hot-Mix. The Engineer can reject individual truckloads of hot-mix. When a load of hot-mix is rejected for reasons other than temperature, contamination, or excessive uncoated particles, the Contractor may request that the rejected load be tested. Make this request within 4 hr. of rejection. The Engineer will sample and test the mixture. If test results are within the operational tolerances shown in Table 11, payment will be made for the load. If test results are not within operational tolerances, no payment will be made for the load.

5. MEASUREMENT

Hot mix will be measured by the ton of composite hot-mix, which includes asphalt, aggregate, and additives.

Measure the weight on scales in accordance with Item 520, “Weighing and Measuring Equipment.”

6. PAYMENT

The materials furnished in accordance with this Item and measured as provided under “Measurement,” will be paid for at the unit price bid for the types shown below.

6.1. Hot Mix (Site Delivery). Payment will be made for the mixture type, SAC, and binder specified. This price is full compensation for furnishing materials, assistance provided in sampling, loading, hauling, delivery of materials, furnishing scales and labor for weighing and measuring, and equipment, labor, tools, and incidentals. If bid codes in the estimate indicate location numbers, each location will be shown in the plans.

6.2. Hot Mix (Vehicle Pickup). Payment will be made for the mixture type, SAC, and binder specified. This price is full compensation for furnishing materials, assistance provided in sampling, loading, furnishing scales and labor for weighing and measuring, and equipment, labor, tools, and incidentals.

Trial batches will not be paid for unless approved by the Department.

http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit200.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit236.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit207.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit204.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit212.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit227.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit236.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/200-F_series/pdfs/bit242.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/500-C_series/pdfs/aph500.pdf http://ftp.dot.state.tx.us/pub/txdot-info/cst/TMS/500-C_series/pdfs/aph530.pdf

2.8. Substitute Binders. Unless otherwise shown on the plans, the Contractor may use a substitute PG binder listed in Table 5 instead of the PG binder originally specified, if using recycled materials, and if the substitute PG binder and mixture made ...

4.6.4. Individual Loads of Hot-Mix. The Engineer can reject individual truckloads of hot-mix. When a load of hot-mix is rejected for reasons other than temperature, contamination, or excessive uncoated particles, the Contractor may request that the re...