307.01 242 SECTION 307 – BITUMINOUS PLANT MIX BASE (HOT MIX)
307.01 Description ................................ ................................ ................... 242
307.02 Materials ................................ ................................ ...................... 242
307.03 Composition of Mixtures ................................ ............................. 243
307.04 Equipment ................................ ................................ .................... 249
307.05 General ................................ ................................ ......................... 249
307.06 Preparing the Subgrade, Sub -base, or Surface ............................. 249
307.07 Thickness and Surface Requirement ................................ ............ 250
307.08 Method of Measurement ................................ .............................. 250
307.09 Basis of Payment ................................ ................................ .......... 250
DESCRIPTION
307.01 Description
This work consists of constructing one or more base course layers of aggregate and asphalt, prepared in a hot bituminous mixing plant and spread and compacted on a prepared subgrade, granular sub -base, or base. MATERIALS
307.02 Materials
Provide materials as specified in: Aggregate for Mixture, Grading A, ACRL, AS, B, BM, BM2, C, CS, or CW ..... 903.06 Asphalt Cement, Grade PG 64-22, 70-22, 76-22, 82-22 ........ 904.01 Bituminous Additives ................................ ........................ 921.06.B The specific grading of aggregate to be used will be specified in the Contract or shown on the Plans. The Engineer will accept mineral ag gregate, bituminous material, and the plant mix in accordance with 407.02. 307.03 243 307.03 Composition of Mixtures
A.General The bituminous base and/or leveling course shall be composed of aggregate and bituminous materials. The hot plant mixes shall comply with the applicable requirements of 407.03. Combine the specified mineral aggregate and asphalt cement in proportions that will meet the design composition limits specified in Table 307.03 -1. Table 307.03-1: Mixture Composition Mixtures Proportions of Total Mixture, Perc ent by Weight Combined Mineral Aggregate, % Asphalt Cement, % (1) Grading AS and ACRL 96.3 - 97.7 2.3 - 3.7 Grading A 95.8 - 96.7 3.3 - 4.2 Grading B, BM , and BM2 93.8 - 95.8 4.2 - 6.2 Grading C and CW 93.8 - 95.8 4.2 - 6.2 Grading CS 92.3 - 94.7 5.3 - 7.7
1.If the effective combined specific gravity of the aggregate exceeds 2.80, the Engineer may adjust the proportions specified. In addition, combine the materials with the required amount of bitumen to meet the design properties specified in Table 307.03-2, except that on low volume roads (ADT 1,000 or below), the minimum stability shall be 1,500 pound -feet and the VMA and dust -asphalt ratio will be waived for 307-B, 307-BM, 307-BM2 and 307 -C mixes. 307.03 244 Table 307.03-2: Mixture Design Properties Mix (1) Stability (minimum) lbf (2) Design Void Content % (2) Production Void Content, %
2.VMA (minimum) % (2) Dust- Asphalt Ratio (3) 307-B 2,000 4.0±0.2 3-5.5 11.5 0.6-1.5 307-BM 2,000 4.0±0.2 3-5.5 13.5 0.6-1.5 307-BM2 2,000 4.0±0.2 3-5.5 13.5 0.6-1.5 307-C 2,000 4.0±0.2 3-5.5 13.0 0.6-1.5 307-CS 2,000 3.0±0.5 1-5 --- --- 307-CW 1,500 4.0±0.2 3-5 13.0 0.6-1.5
1.To identify critical mixes and make appropriate adjustments, the mix design shall meet these design properties for the bitumen content range of Optimum Asphalt Cement ±0.25%.
2.Tested according to AASHTO T 245 with 75 blows with the hammer on each end of the test specimen, using a Marshall Mechanical Compactor.
3.The dust-asphalt ratio is the percent of the total aggregate sample that passes the No. 200 sieve , as determined by AASHTO T 11 , divided by the percent asphalt in the total mix. If the material s proposed for use do not meet the design criteria specified in Table 307.03 -2, find other suitable sources of materials. If the material at the asphalt plant will not combine within the tolerances of the Job Mix F ormula (JMF), provide a new design.
B.Recycled Asphalt Pavement and Recycled Asphalt Shingles
1.Recycled Asphalt Pavement (RAP). The Contractor may use asphaltic concrete removed from a Department project or other State Highway Agency project by an approved method and stored in a Department approved stockpile. RAP combined with the appropriate aggregate, asphalt cement, and anti -strip additive when required shall produce a mixture that meet s 903.06 and 307. The Contractor may incorporate RAP in the mixes specified in Table
307.03 3.
307.03 245 Table 307.03-3: Mixtures Using RAP Mix Type % RAP (Non- processed) (1) Maximum % RAP (Processed) (2) Maximum % RAP Processed & Fractionated (3) Maximum Particle Size (inches) 307-ACRL 0 00 - - 307-AS 0 10 10 - 307-A 15 20 35 1-1/2 307-B 15 30 35 1-1/2 307-BM 15 30 35 3/4 307-BM2 15 30 35 3/4 307-C 15 30 35 3/8 307-CW 15 30 35 1/2 307-CS 0 15 25 5/16
1.“Non-processed” refers to RAP that has not been crushed and screened or otherwise sized prior to its use.
2.“Processed” refers to RAP that has been crushed and screened or otherwise sized such that the maximum recycled material particle size is less th an that listed in Table 307.03 -3 prior to entering the dryer drum.
3.“Fractionated” refers to RAP that has been processed over more than one screen, producing sources of various maximum particle sizes (e.g., 3/4 to 1/2 inch, 1/2 inch to #4, etc.). The Contractor may use the larger percentages of fractionated RAP specified only if individual fractions of two different maximum particle size are introduced into the plant as separate material sources for increased control. All mixes shall contain at least 65% virgin asphalt. The Contractor shall o btain a representative sample from the recycled material stockpile and shall establish a gradation and asphalt cement content. The Contractor shall determine the gradation and asphalt content of the recycled material at the beginning of a project and every 2,000 tons thereafter. The stockpile asphalt cement content for all recycled material shall not vary by more than 0.8%. The stockpile gradation tolerance for all recycled material on each sieve is specified in Table 307.03 -4. 307.03 246 Table 307.03-4: Stockpile Gradation Tolerance Sieve Size Tolerance 3/8 inch and larger ± 10% No. 4 ± 8% No. 8 ± 6% No. 30 ± 5% No. 200 ± 4% The Engineer will accept the mixture for aggregate gradation and asphalt content in accordance with 407.20.B. Provide a special mix design with asphalt content in the range of 5 to 7% where 307 -C Mix is used as a surface on the shoulder. Perform sampling and testing of the planings as well as new materials for bid purposes, and for the submission of the Job Mix Formula (JMF) as specified in 407.03. Submit all additives to the Engineer for approval at the same time other materials are submitted for design verification. After mixing, verify t he moisture content of the total mix is no more than 0.1% as determined by oven drying. Provisions for lowering the temperature because of boiling or foaming shall not apply.
2.Recycled Asphalt Shingles (RAS). RAS may be included to a maximum of 3% of the total weight of mixture. The percentage of RAS used will be considered part of the maximum allowable RAP percentage. The ratio of added new asphalt binder to total asphalt binder shall be 65% or greater for all 307 mixes . Either the mix producer or the RAS supplier shall obtain a representative sample from the recycled material stockpile and establish a gradation and asphalt cement content as required. Determine s hingle asphalt binder content according to AASHTO T 164 Method A, with a minimum sample size of 500 grams. Determine the gradation and asphalt content of the recycled material at the beginning of the Project and every 2,000 tons of recycled material used thereafter. The stockpile asphalt cement content for all recycled material shall not vary by more than 0.8%. All RAS material shall be processed 307.03 247 to a minimum 100 % passing the 3/8 inch sieve and a minimum 90 % passing the No. 4 sieve. To conduct the gradation testing, air dry a 500 to 700-gram sample of processed s hingle material, dry sieve over the 3/8 -inch and No. 4 sieves, and weigh . For mix design purposes, the Contractor may use the aggregate gradation specified in Table 307.03 -5 as a standard gradation instead of determining the shingle gradation according to AASHTO T 30. Table 307.03-5: Standard Gradation (for Mix Design Purposes) Sieve Size Total Percent Passing 3/8 inch 100 No. 4 97 No. 8 95 No. 16 80 No. 30 60 No. 50 50 No. 100 40 No. 200 30 An aggregate bulk specific gravity (G sb) of 2.650 may be used instead of determining the shingle aggregate G sb according to AASHTO T 84. In addition, the effective binder available for mixing with additional aggregates shall be considered as 75% of the total binder content as determined by AAS HTO T 164 and shall be the value listed as the RAS binder content on the JMF . Scrap asphalt shingle shall not contain extraneous waste materials. Extraneous materials including, but not limited to, asbestos, metals, glass, rubber, nails, soil, brick, tars , paper, wood, and plastics , shall not exceed 0. 5% by weight as determined on material retained on the No. 4 sieve. To conduct deleterious material testing, take a representative 500 to 700-gram sample of processed shingle material, place over the No. 4 sieve, and pick and weigh all extraneous waste material retained on the No. 4 sieve. Base the percent of extraneous material on the total sample weight. 307.03 248 RAS shall contain less than the maximum percentage of asbestos fibers based on testing procedures estab lished by the Department , or State or Federal environmental regulatory agencies. Analyze a minimum of one sample of processed asphalt roofing material for every 500 tons of material processed for the presence of asbestos . Before a JMF for a particular design is approved, submit the following, along with the materials and information specified in 407.03:
a.Certification by the processor of the shingle scrap describing the shingle scrap content and source.
b.A 1000-gram sample of the processed RAS material for inspection (new designs only) . Stockpile RAS separate from other salvage material. Do not blend RAS material in a stockpile with other salvage material. Do not blend Manufacture Waste Scrap Shingles (MWSS) a nd Tear-Off Scrap Shingles (TOSS). In addition, do not blend virgin sand material with the processed shingles, to minimize agglomeration of the shingle material. All RAS supplied to a Department project shall come from a certified shingle processor/suppl ier approved by the Division of Materials and Tests.
C.Anti-Strip Additive Check asphaltic concrete mixtures (Grading A, AS, ACRL, B, BM, BM2, C, CS , and CW) for stripping by the following methods:
1.The Ten Minute Boil test for dosage rate and the Root - Tunnecliff procedure (A STM D 4867) for moisture susceptibility. Do not use the Ro ot-Tunnecliff procedure (ASTM D 4867) with the following mixtures: Gr ading A, AS, ACRL , and B.
2.For mixtures not requiring design , the Ten Minute Boil test for dosage rate and moisture susceptibility. 307.04 249 Mix an approved antistrip agent with the asphalt cement at the dosage as specified in 921.06.B. EQUIPMENT
307.04 Equipment
Provide equipment as specified in 407.04 through 407.08. If using recycled mix, modify the asphalt plant as approved by the Engineer to accommodate the addition of asphalt planings. If using a batch plant to produce recycled mix, heat the aggregate to a temperature that will transfer sufficient heat to the cold planings to produce a mix of uniform temperature within the specified range. CONSTRUCTION REQUIREMENTS
307.05 General
Conform to the construction requirements specified in 407.09 and 407.11 through 407.17.
307.06 Preparing the Subgrade, Sub-base, or Surface
The Plans will indicate whether the plant -mixed base is to be constructed on a treated or untreated subgrade or sub -base, on a granular base, or on an existing surface. Ensure that the surface u pon which the plant mix base is to be constructed meets 205, 207, 302, 303, 304, or 309, whichever is applicable. If shown on the Plans, condition the surface as specified in
407.10 Condition existing mineral aggregate base as specified in 310.
Construct prime coa t or tack coat as specified in 402 or 403, respectively. Do not place AS/ACRL which cannot be covered by the next course of pavement within the same construction season. Only place bituminous pl ant-mix base mixture on a surface that is dry and free of loose particles and other undesirable materials. 307.07 250 307.07 Thickness and Surface Requirement Control thickness during the spreading operation by frequently measuring the freshly spread mixture to establish a relationship between the uncompacted mixture and the completed course. Thickness or spread rate in pounds per square yards shall be within r easonably close conformity with that shown on the Plans. Each course shall have a thickness after compaction of not more than 4 inches, unless otherwise approved by the Engineer. The surface of the base shall meet the requirements specified in 407.18, and when tested in accordance with 407.18, the deviation of the surfaces from the testing edge of the straightedge shall not exceed the amounts specified in Table 307.07 -1. Table 307.07-1: Maximum Surfac e Deviation Mixture Maximum Deviation (inches) Grading A, ACRL , and AS 1/2 Grading B, BM, BM2, C, CS , and CW 3/8 COMPENSATION
307.08 Method of Measurement
The Department will measure Mineral Aggregate, including Mineral Filler when required, and Asphalt Cement for Bituminous Plant Mix Base and other related items in accordance with 407.19.
307.09 Basis of Payment
The Department will pay for accepted quantities at the contract prices in accordance with 407.20. For bidding purposes, use the asphalt cement content specified in Table
307.09 1 for the designated mix.
307.09 251 Table 307.09-1: Asphalt Cement Content Mix Type Asphalt Content 307 A 4.0% 307 AS 3.5% 307 ACRL 3.5% 307 B 4.3% 307 BM 5.0% 307 BM2 5.0% 307 C 5.0% 307 CW 6.0% 307 CS 6.5% If the Engineer sets an asphalt content other than that specified in Table
307.09 1, the Department will calculate a price adjustment, based on the
asphalt content set by the Engineer and the Monthly Bituminous Index for the specific grade asphalt on the m ix design, in accordance with 407.20. 309.01 252 SECTION 309 – AGGREGATE -CEMENT BASE COURSE
309.01 Description ................................ ................................ ................... 252
309.02 Materials ................................ ................................ ...................... 252
309.03 Equipm ent ................................ ................................ .................... 253
309.04 Limitations ................................ ................................ ................... 254
309.05 Preparing the Existing Subgrade ................................ .................. 254
309.06 Cement Application, Mixing, and Spreading ............................... 254
309.07 Compaction ................................ ................................ .................. 255
309.08 Finishing ................................ ................................ ...................... 256
309.09 Construction Joints ................................ ................................ ....... 256
309.10 Thickness and Surface Tolerances ................................ ............... 256
309.11 Curing ................................ ................................ .......................... 256
309.12 Traffic and Maintenance ................................ .............................. 256
309.13 Method of Measurement ................................ .............................. 257
309.14 Basis of Payment ................................ ................................ .......... 257
DESCRIPTION
309.01 Description
This work consists of constructing a base of mineral aggregate and Portland cement on a prepared surface. MATERIALS
309.02 Materials
Provide materials as specified in: Water ................................ ................................ .................. 302.03.B Portland Cement, Type I ................................ ........................ 901.01 Portland-Pozzolan Cement, Type IP ................................ ...... 901.01 Crushed Stone or Sla g, Grading D ................................ ................................ .......... 903.05 Aggregate, Crushed or Uncrushed Gravel or Chert ............... 903.15
Source: Tennessee Standard Specifications for Road and Bridge Construction, 2021 Edition. Pages 251–260 of 1,072.