Stone Matrix Asphalt (SMA) STONE MATRIX ASPHALT (SMA)
Part 1 — General
1.1 Section Includes
A.A surface course of one or more layers of fiber stabilized SMA comprised of aggregate, asphalt binder, hydrated lime, and other additives.
1.2 Related Sections
A.Section 02701 : Pavement Smoothness
B.Section 02742S: Project Specific Surfacing Requirements
C.Section 02745: Asphalt Material
D.Section 02746: Hydrated Lime
E.Section 02748: Prime Coat/Tack Coat
1.3 References
A.AASHTO M 325: Stone Matrix Asphalt (SMA)
B.AASHTO R 46 : Designing Stone Matrix Asphalt (SMA)
C.AASHTO R 67: Sampling Asphalt Mixtures after Compaction (Obtaining Cores)
D.AASHTO T 11: Materials Finer Than 75 μm (No. 200) Sieve in Mineral Aggregates by Washing
E.AASHTO T 19: Bulk Density (“ Unit Weight ”) and Voids in Aggregate
F.AASHTO T 27: Sieve Analysis of Fine and Coarse Aggregates
G.AASTHO T 85: Specific Gravity and Absorption of Coarse Aggregate
H.AASHTO T 89: Determining the Liquid Limit of Soils
I.AASHTO T 90: Determining the Plastic Limit and Plasticity Index of Soils Stone Matrix Asphalt (SMA)
J.AASHTO T 96: Resistance to Degradation of Small -Size Coarse Aggregate by Abrasion and Impact of the Los Angeles Machine
K.AASHTO T 104: Soundness of Aggregate by Use of Sodium Sulfate or Magnesium Sulfate
L.AASHTO T 112: Clay Lumps and Friable Particles in Aggregate
M.AASHTO T 166: Bulk Specific Gravity (Gmb) of Compacted Asphalt Mixtures Using Saturated- Surface Dry Specimens
N.AASHTO T 176: Plastic Fines in Graded Aggregates and Soils by Use of the Sand Equivalent Test
O.AASHTO T 195: Determining Degree of Particle Coating of Asphalt Mixtures
P.AASHTO T 209: Theoretical Maximum Specific Gravity (Gmm) and Density of Asphalt Mixtures
Q.AASHTO T 255: Total Evaporable Moisture Content of Aggregate by Drying
R.AASHTO T 278: Surface Frictional Properties Using the British Pendulum Tester
S.AAHTO T 279: Accelerated Polishing of Aggregates Using the British Wheel
T.AASHTO T 304: Uncompacted Void Content of Fine Aggregate
U.AASHTO T 305: Determination of Draindown Characteristics in Uncompacted Asphalt Mixtures
V.AASHTO T 335: Determining the Percentage of Fracture in Coarse Aggregate
W.ASTM C 612: Standard Specification for Mineral Fiber Block and Board Thermal Insulation
X.UDOT Materials Manual of Instruction.
Y.UDOT Minimum Sampling and Testing Requirements
Z.UDOT Quality Management Plans Stone Matrix Asphalt (SMA)
1.4 Definitions
A.Lot – The number of tons of S MA placed in a Production Day.
B.Minor Target Change – A change from the verified mix design gradation target on a maximum of two sieves with the following limitations.
1.The maximum change in the target gradation on the No. 8 or any coarser sieve is limited to 3 percent passing per sieve.
2.The maximum change in the target gradation on the No. 50 sieves is 2 percent passing per sieve.
3.The maximum change in the target gradation on the No. 200 sieve is 0.5 percent passing.
4.No target change may violate the mix design requirements in this Section.
C.Production Day – A 24 hour period in which S MA is being placed.
1.5 Submittals
A.Mix design for approval at least 10 working days before paving according to the UDOT Materials Manual of Instruction 962 .
B.Changes in job mix design
1.Submit a written request for a proposed change in the job- mix gradation.
a.Allow at least 12 hours for approval before incorporating a minor target change into production.
b.Allow at least six working days for verification and approval of any other change.
2.Include documentation supporting correlation between suggested target changes and mix design volumetric requirements.
a.Department acceptance test results or Contractor QC test data or both are acceptable.
3.Submit samples according to the UDOT Materials Manual of Instruction 96 2 for a volumetric mix design verification for anything other than approved minor target change.
a.This includes changes in the aggregate source, asphalt binder source, or asphalt binder grade.
C.Corrective action plan according to this Section, Article 3 .3.
D.Refer to this Section, Article 1.7 for laboratory correlation submittals.
E.Mat j oint layout plan to the Engineer for review at least 10 calendar days before placement. Stone Matrix Asphalt (SMA)
1.6 Acceptance
A.Acceptance sampling and testing of material is according to UDOT Minimum Sampling and Testing Requirements.
B.Gradation and asphalt binder content
1.The Engineer evaluates a lot on the test results of four samples with the following exceptions:
a.Compute incentive/disincentive using the test results from three samples if only three samples can be taken for the production day .
b.Combine test results with the next day of production i f at least three r andom samples cannot be taken. Take one sample for each 500 tons, or portion thereof, from the following day’s production.
c.Add the lot to the previous day’s production for the final day’s production if three random samples cannot be taken.
d.The lot may be increased to include up to three production days when agreed upon in advance by both the Contractor and the Engineer when less than 900 tons are an ticipated per production day .
2.Evaluate the lot using the number of tests “ n” in Table 3.
3.The Engineer informs the Contractor of the time and place of sampling not more than 15 minutes before sampling.
4.Increase sample sizes to accommodate paired- T testing as required.
C.Density and Thickness
1.Obtain cores within two contract days after the pavement is placed. Refer to AASHTO R 67 .
a.The Engineer marks coring location for i n-place density.
b.Move transversely to a point 1 ft from the edge of the pavement for in-place density if the random location for coring falls within 1 ft of the edge of the overall pavement section (outer part of shoulders).
c.Fill core holes with S MA mix and compact.
d.The Department witnesses the coring operation, takes possession of the cores immediately, and begins testing the cores within 24 hours for density acceptance.
2.Density Requirements
a.The target for in- place density is 94.0 percent of Theoretical Maximum Specific Gravity
b.Use the average of the Theoretical Maximum Specific Gravity tests for each lot. Stone Matrix Asphalt (SMA)
3.Thickness Requirements
a.The Department accepts a lot for thickness when: 1) The average thickness is not more than ½ inch greater or ¼ inch less than the total design thickness specified. 2) No individual sublot shows a deficient thickness of more than ⅜ inch.
b.Excess Thickness – The Engineer may allow excess thickness to remain in place or may order its removal. 1) The Department pays for 50 percent of the mix for material in excess of the +½ inch tolerance when excess thickness is allowed to remain in place. 2) Remove and replace the entire depth of the course if it is necessary to remove portions of the course.
c.Deficient Thickness – Place additional material where lots or sublots are deficient in thickness. 1) The Department pays for material necessary to reach specified thickness. 2) The Department pays for 50 percent of the mix for additional material over specified thickness necessary to achieve minimum lift thickness. 3) Minimum compacted lift is 3 times the nominal maximum aggregate size.
d.Thickness tolerances established above do not apply to leveling courses. 1) Check final surfaces in stage construction.
e.Thickness acceptance for thin overlay pavement consists of checking thickness regularly with a depth probe during placement and taking corrective action as necessary.
D.The Department applies incentive/disincentive for Gradation/Asphalt Content, and In-Place Density. The Engineer computes Incentive/Disincentive for each lot.
1.Compute incentive/disincentive for Gradation/Asphalt Binder and In-place Density according to Table 1.
2.Base the incentive/disincentive on Percent within Limit (PT) computation using Tables 2, 3, and 4.
3.Use lowest single value combined for gradation (each of the sieves) and asphalt binder content for calculating the gradation/asphalt binder content incentive/disincentive.
4.Use Tables 2, 3, and 4 to determine PT for in- place density.
5.Meet PT of 88 or greater for in- place density or the D epartment does not pay incentives on gradation/asphalt binder content. Stone Matrix Asphalt (SMA)
6.Meet control requirements of Table 2 for VMA and VCA.
a.VCA MIX is less than VCA DRC or the Department does not pay incentive for gradation/asphalt binder content .
7.The following work is not eligible for incentive :
a.Items such as u tility work, traffic signals, detours, lane leveling, and driveways.
b.Small proj ects with plan quantities of Asphalt Mix less than 500 tons.
E.The Department applies incentive/disincentive for smoothness according to Section 02701 .
1.Refer to Section 02701 for smoothness requirements.
F.The Department rejects lot s:
1.If the PT for any individual gradation measurement listed in Table 3 is less than 60 percent .
2.If the PT for asphalt binder content or density is less than 52 percent.
3.The Engineer may accept a reject lot . Refer to Section 01456.
a.A price reduction of 3 5 percent of the pay item or $30 per ton, whichever is greater, will be assessed .
b.The lot will not be eligible for any incentive.
G.The Engineer may elect to accept material on visual inspection for work such as utility work, traffic signals, detours, lane leveling, and driveways , other hand work, or small projects with plan quantities less than 500 tons.
1.Lots accepted on visual inspection are not eligible for Incentive/Disincentive.
2.The Engineer reserves the option of conducting acceptance tests necessary to determine the material and workmanship meets the project requirements.
3.Acceptance for density may be based on establishing and maintaining a roller pattern to obtain maximum density without over-stressing the pavement. Stone Matrix Asphalt (SMA) Table 1 Incentive/Disincentive for Asphalt Binder Content, and Density PT Based on Min. Four Samples Incentive/Disincentive (Dollars/Ton) >99 96-99 92-95 88-91 84-87 80-83 76-79 72-75 68-71 64-67 60-63 <60 2.50 2.00 1.25 0.00 -0.26 -0.60 -0.93 -1.27 -1.60 -1.93 -2.27 Reject Incentive/Disincentive for Gradation PT Based on Min. Four Samples Incentive/Disincentive (Dollars/Ton) >99 96-99 92-95 88-91 84-87 80-83 76-79 72-75 68-71 64-67 60-63 56-59 52-55 <52 2.50 2.00 1.25 0.00 -0.26 -0.60 -0.93 -1.27 -1.60 -1.93 -2.27 -5.00 -10.00 Reject Table 2 Production Control for VMA and VCA MIX VMA Average Value, x, (%) Minimum of three Samples VCA MIX Job-Mix Design Action X ≥ 16.5 and X ≤18.5 VCA MIX < VCA DRC Continue Paving X < 16.5 or X >18.5 0 < VCA MIX - VCA DRC ≤ 0.5 % Stop Production until a corrective action plan is approved X < 15.5 or X >19.5 0.5 < VCA MIX - VCA DRC Stop Production and resubmit Mix Design Stone Matrix Asphalt (SMA) Table 3 Upper and Lower Limit Determination Parameter UL and LL 3/8” sieve for ½” SMA Target Value ± 5.0% #4 sieve Target Value ± 4.0% # 8 sieve Target Value ± 3.0% # 50 sieve Target Value ± 3.0% # 200 sieve Target Value ± 2.0% Asphalt Binder Content Target Value ± 0.35% Density Lower Limit: Target Value - 2.0% Upper Limit: Target Value + 3. 5% Enter table in the appropriate sample size column and round down to the nearest value. Stone Matrix Asphalt (SMA) Table 4 Quality Index Values (QU or QL) for Estimating Percent Within Limits PU or PL n=3 n=4 n=5 n=6 n=7 n=8 n=10 n=12 n=15 n=20 100 1.16 1.50 1.75 1.91 2.06 2.15 2.29 2.35 2.47 2.56 99 1.16 1.47 1.68 1.79 1.89 1.95 2.04 2.09 2.14 2.19 98 1.15 1.44 1.61 1.70 1.77 1.80 1.86 1.89 1.93 1.97 97 1.15 1.41 1.55 1.62 1.67 1.69 1.74 1.77 1.80 1.82 96 1.15 1.38 1.49 1.55 1.59 1.61 1.64 1.66 1.69 1.70 95 1.14 1.35 1.45 1.49 1.52 1.54 1.56 1.57 1.59 1.61 94 1.13 1.32 1.40 1.44 1.46 1.47 1.49 1.50 1.51 1.53 93 1.12 1.29 1.36 1.38 1.40 1.41 1.43 1.43 1.44 1.46 92 1.11 1.26 1.31 1.33 1.35 1.36 1.37 1.37 1.38 1.39 91 1.10 1.23 1.27 1.29 1.30 1.31 1.32 1.32 1.32 1.33 90 1.09 1.20 1.23 1.24 1.25 1.25 1.26 1.26 1.27 1.27 89 1.08 1.17 1.20 1.21 1.21 1.21 1.21 1.21 1.22 1.22 88 1.07 1.14 1.16 1.17 1.17 1.17 1.17 1.17 1.17 1.17 87 1.06 1.11 1.12. 1.12 1.12 1.13 1.13 1.13 1.13 1.13 86 1.05 1.08 1.08 1.08 1.08 1.08 1.08 1.08 1.08 1.08 85 1.03 1.05 1.05 1.05 1.05 1.04 1.04 1.04 1.04 1.04 84 1.02 1.02 1.02 1.01 1.01 1.01 1.00 1.00 1.00 1.00 83 1.00 0.99 0.98 0.97 0.97 0.96 0.96 0.96 0.96 0.96 82 0.98 0.96 0.95 0.94 0.94 0.93 0.93 0.92 0.92 0.92 81 0.96 0.93 0.92 0.91 0.90 0.90 0.89 0.89 0.89 0.88 80 0.94 0.90 0.88 0.87 0.86 0.86 0.85 0.85 0.85 0.85 79 0.92 0.87 0.85 0.84 0.83 0.83 0.82 0.82 0.82 0.81 78 0.89 0.84 0.82 0.81 0.80 0.79 0.79 0.78 0.78 0.78 77 0.87 0.81 0.79 .0.78 0.77 0.76 0.76 0.75 0.75 0.75 76 0.84 0.78 0.76 0.75 0.74 0.73 0.72 0.72 0.72 0.72 75 0.82 0.75 0.73 0.72 0.71 0.70 0.69 0.69 0.69 0.68 74 0.79 0.72 0.70 0.68 0.67 0.67 0.66 0.66 0.66 0.65 73 0.77 0.69 0.67 0.65 0.64 0.64 0.62 0.62 0.62 0.62 72 0.74 0.66 0.64 0.62 0.61 0.61 0.60 0.59 0.59 0.59 71 0.71 0.63 0.60 0.59 0.58 0.58 0.57 0.56 0.56 0.56 70 0.68 0.60 0.58 0.56 0.55 0.55 0.54 0.54 0.54 0.53 69 0.65 0.57 0.55 0.54 0.53 0.52 0.51 0.51 0.51 0.50 68 0.62 0.54 0.52 0.51 0.50 0.50 0.48 0.48 0.48 0.48 67 0.59 0.51 0.49 0.48 0.47 0.47 0.46 0.45 0.45 0.45 66 0.56 0.48 0.46 0.45 0.44 0.44 0.43 0.42 0.42 0.42 65 0.53 0.45 0.43 0.42 0.41 0.41 0.40 0.40 0.40 0.39 64 0.49 0.42 0.40 0.39 0.38 0.38 0.37 0.37 0.37 0.37 63 0.46 0.39 0.37 0.36 0.35 0.35 0.35 0.34 0.34 0.34 62 0.43 0.36 0.34 0.33 0.33 0.33 0.32 0.31 0.31 0.31 61 0.39 0.33 0.31 0.30 0.30 0.30 0.29 0.29 0.29 0.28 60 0.36 0.30 0.28 0.27 0.26 0.26 0.25 0.25 0.25 0.25 59 0.32 0.27 0.25 0.25 0.24 0.24 0.24 0.23 0.23 0.23 Stone Matrix Asphalt (SMA) Table 4 Continued PU/PL n=3 n=4 n=5 n=6 n=7 n=8 n=10 n=12 n=15 n=20 58 0.29 0.24 0.23 0.22 0.21 0.21 0.21 0.21 0.21 0.20 57 0.25 0.21 0.20 0.19 0.19 0.19 0.18 0.18 0.18 0.18 56 0.22 0.18 0.17 0.16 0.16 0.16 0.16 0.16 0.15 0.15 55 0.18 0.15 0.14 0.14 0.13 0.13 0.13 0.13 0.13 0.13 54 0.14 0.12 0.11 0.11 0.11 0.11 0.10 0.10 0.10 0.10 53 0.11 0.09 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 52 0.07 0.06 0.06 0.05 0.05 0.05 0.05 0.05 0.05 0.05 51 0.04 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 50 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Stone Matrix Asphalt (SMA) Table 5 Definitions, Abbreviations, and Formulas for Acceptance Term Explanation Target Value (TV) The target values for gradation and asphalt binder content are given in the CONTRACTOR’s mix design. The target value for density is 94.0 percent of maximum (Rice) density. Average (AVE) The sum of the lot’s test results for a measured characteristic divided by the number of test results , the arithmetic mean. Standard Deviation (s) The square root of the value formed by summing the squared difference between the individual test results of a measured characteristic and AVE, divided by the number of test results minus one. This statement does not limit the methods of calculations of s; other methods that obtain the same value may be used. Upper Limit (UL) The value above the TV of each measured characteristic that defines the upper limit of acceptable production. (Table 3) Lower Limit (LL) The value below the TV of each measured characteristic that defines the lower limit of acceptable production. (Table 3) Upper Quality Index (QU) QU = (UL - AVE)/s Lower Quality Index (QL) QL = (AVE - LL)/s Percentage of Lot Within UL (PU) Determined by entering Table 4 with QU. Percentage of Lot Within LL (PL) Determined by entering Table 4 with QL. Total Percentage of Lot (PL) Within UL and LL (PT) PT = (PU + PL) - 100 Incentive/Disincentive Determined by entering Table 1 with PT or PL. Values for AVE, s, QU, and QL will be calculated to a minimum two decimal place accuracy that will be carried through all further calculations. Rounding to lower accuracy is not allowed.
1.7 Laboratory Correlation
A.Perform the following to be eligible for dispute resolution:
1.Perform split -sample, paired t-testing with the Department based on project quality control testing using UDOT LQP qualified lab.
a.Perform split -sample, paired- t analysis on all mix acceptance tests related to volumetric properties and the following background testing: Stone Matrix Asphalt (SMA) 1) Maximum Theoretical Specific Gravity of Mix (Gmm), AASHTO T 209 2) Bulk Specific Gravity of Mix (Gmb), AASHTO T 166 3) Bulk Specific Gravity of Coarse Aggregates (Gsb), AASHTO T 85
b.Continue until attaining successful paired t-test results, meeting α = 0.05, for a minimum of two consecutive production days (UDOT Materials Manual of Instruction, Part 8, Appendix C).
c.The engineer may require that all QC testing data be received before disclosure of the QA testing results. This applies to paired t-test and all subsequent QA/QC testing data.
B.Submit a detailed report showing tabular summaries of daily test data, paired t-testing calculations and any corrections made to account for failed comparisons.
C.Submit summary before submitting engineering analysis for dispute resolution.
1.8 Dispute Resolution
A.Refer to Section 01456 when disputing the validity of the Department’s acceptance tests.
Part 2 — Products
2.1 Asphalt Binder
A.Project Specific Surfacing Requirements – Refer to Section 02742S .
B.Asphalt Material – Refer to Section 02745 and Quality Management Plan 509: Asphalt Binder C Use the minimum asphalt binder content specified in Table 10 unless called out differently in 02742S for the project.
2.2 Aggregate
A.Use c rusher processed virgin aggregate material consisting of crushed stone, gravel, or slag.
B.Refer to Table 6, to determine the suitability of the aggregate.
1.Coarse aggregates: Stone Matrix Asphalt (SMA)
a.Retained on No. 4 sieve. AASHTO T 27
2.Fine aggregates:
a.Clean, hard grained, and angular.
b.Passing the No. 4 sieve. AASHTO T 27 Table 6 Test Method Test No. Specification One Fractured Face AASHTO T 335 100% min. Two Fractured Face AASHTO T 335 90% min. Fine Aggregate Angularity AASHTO T 304 45 min. Flakiness Index UDOT MOI (Based on 3/8 inch and above) 25% max. L.A. Wear AASHTO T 96 28% max. Sand Equivalent AASHTO T 176 (Pre -wet method) 60 min. Plasticity Index (Does not apply to Mineral Filler) AASHTO T 89 and T 90 0 max. Unit Weight AASHTO T 19 75 lb/cu. ft. min. Polishing* AASHTO T 278 and T 279 31 min. Soundness (sodium sulfate) AASHTO T 104 10% max. loss with five cycles Clay Lumps and Friable Particles AASHTO T 112 2% max Natural Fines N/A 0 max. * The Department has the right to waive this requirement if the aggregates have proven acceptable through successful past performance as determined by the Engineer. Stone Matrix Asphalt (SMA)
C.Meet the gradation requirements in Table 7. (AASHTO T 11, AASHTO T 27) Table 7 Control Sieve Size ½ inch 3/8 inch ¾ inch 100 100 ½ inch 90 - 100 100 3/8 inch 45 - 78 90 - 100 No. 4 20 - 28 26 - 50 No. 8 16 - 24 20 - 28 No. 16 13 - 21 13 - 21 No. 30 12 - 18 12 - 18 No. 50 12 - 15 12 - 15 No. 200 8 - 10 8 - 10
2.3 Additives / Stabilizers
A.Hydrated Lime: Meet the requirements of Section 02746.
B.Stabilizing additive : Made from virgin basalt, diabase, slag, or cellulose treated with a cationic sizing agent to enhance disbursement of the fiber as well as increase adhesion of the fiber surface with the asphalt binder and control drain- down. Meet AASHTO M 325.
1.Mineral Fiber
a.Dosage rate between 0.3 percent to 0.6 percent, by weight of the total mix.
b.Average fiber length 0.25 inches, maximum
c.Average Fiber thickness 0.0002 inches, maximum
d.Shot content (ASTM C 612) Passing No. 60 sieve 90 – 100 percent Passing No. 230 sieve 65 – 100 percent
2.Cellulose Fiber
a.Dosage rate for cellulose is 0. 2 percent to 0.4 percent by weight of total mix. Stone Matrix Asphalt (SMA)
b.Using Alpine sieve analysis, f iber length of 0.25 inches maximum passing the No. 100 sieve 70 percent (± 10 percent ).
c.Using a mesh screen analysis, fibers will pass No. 20 sieve 85 percent (± 10 percent ) No. 40 sieve 65 percent ( ±10 percent) No. 140 sieve 30 percent ± 0 percent )
d.Ash content will be 18 percent ( ± 5 percent)
e.PH will be 7.5 ( ± 1.0)
f.Oil absorption will be 5.0 ( ± 1.0 percent )
g.Moisture content will be <5 percent by weight of cellulose
C.Mineral Filler: Consists of finely divided mineral matter such as rock dust, slag dust, hydrated lime, hydraulic cement, fly ash, or other suitable mineral matter. Free flowing and free of lumps.
1.Meet the following requirements: Table 8 Sieve Size Percent Passing No. 30 100 No. 50 95 – 100 No. 200 55 – 100 No. 450 40 max.
2.No organic impurities
3.Plasticity Index less than 4 (not appropriate for h ydrated lime and hydraulic cement)
2.4 Job-Mix Design
A.Perform Stone Matrix Asphalt Mix Design according to UDOT Manual of Instruction 962.
1.Submit for verification at least 10 working days before beginning paving.
2.Do not begin paving until verification is complete.
B.Meet the following requirements : Table 9 Mix Design Compaction Parameters Design Gyrations % of G mm* 100 96.5 * G mm: Maximum theoretical specific gravity of mix. Stone Matrix Asphalt (SMA) Table 10 Minimum Asphalt Binder Content Combined Aggregate Bulk Specific Gravity Including Lime Gsb Minimum Asphalt Binder Content %*
2.375 - 2.424 6.8
2.425 - 2.474 6.7
2.475 - 2.524 6.6
2.525 - 2.574 6.5
2.575 - 2.624 6.3
2.625 - 2.674 6.2
2.675 - 2.724 6.1
> 2.724 6.0 * Percent of total mix. Table 11 Mix Design Requirements SMA design mixing and compaction temperatures Provided by the Engineer Voids in Mineral Aggregate (VMA) AASHTO R 46 , using G sb. Equation based on percent of total mix. 17.0% min. Voids In Course Aggregate (Stone Matrix Asphalt Mix Design) VCA MIX < VCA DRC Hamburg Wheel Tracker < 10.00 mm at 20,000 Cycles. Draindown ( AASHTO T 305) 0.30 max.
C.Mortar must meet the following. Refer to UDOT Materials Manual of Instruction 962.
1.Unaged DSR G*/sin delta ≥ 5 kPa
2.RTFO aged DSR G*/sin delta ≥ 11 kPa
3.PAV aged BBR Stiffness ≤ 1500 Mpa
2.5 Contractor Initiated Changes In Stone Matrix Asphalt Mix
DESIGN
A.Submit requests in writing to the Engineer at least 12 hours before incorporating changes into production. Stone Matrix Asphalt (SMA)
B.Submit a field volumetric mix design for all target changes.
1.Include documentation supporting correlation between suggested target changes and mix design volumetric requirements. Department acceptance or Contractor QC testing data is acceptable.
2.Field volumetric mix design verification consists of three sets of two gyratory specimens run at the new target gradation, asphalt binder content , or both .
a.The Department’s previous acceptance tests are acceptable for field verification.
3.The Engineer, in consultation with the Region Materials Engineer, provides written concurrence of the verified field volumetric mix design if the field volumetric mix design meets the volumetric requirements .
4.Submit a new laboratory volumetric mix design from a laboratory qualified by UDOT Central Materials if the field volumetric mix verification does not meet the volumetric requirements .
a.Allow at least 7 working days for verification.
5.The Department may allow up to two minor target changes per project without penalty to the Contractor.
a.The Department charges $1 ,000 for each additional minor target change.
6.The Department performs up to two volumetric mix design verifications at no cost to the Contractor.
a.The Department charges $3 ,000 for each additional laboratory or field verification required including all laboratory or field volumetric mix design verifications required due to contractor initiated target changes.
C.Submit a new laboratory volumetric mix design if changes occur in the aggregate source, asphalt binder source, or grade.
D.Do not make changes to production mix until request is reviewed and verified by the R esident Engineer in consultation with the R egion Materials Engineer .
Part 3 — Execution
3.1 Sma
A.Dry aggregate to an average moisture content of not more than 0.2 percent by weight.
1.May be verified by AASHTO T 255 . Stone Matrix Asphalt (SMA)
2.Adjust burners to avoid damage or soot contamination of the aggregate.
B.Treat aggregate with hydrated lime. Refer to Section 02746.
1.Use m ethod A or B .
2.The Department applies a deduction for mix produced by a non-certified supplier to cover the costs of inspection.
3.The deduction is applied according to the UDOT Quality Management Plan 514 Hot -Mix Asphalt.
C.Coat with asphalt binder 100 percent of the particles passing and 98 percent of the particles retained on the No. 4 sieve.
1.May be verified by AASHTO T 195 .
2.Discontinue operation and make necessary corrections if material is not properly coated.
D.Maintain temperature of the SMA between identified compaction limits as defined on Volumetric Mix Design Verification Letter.
1.The Department rejects materials heated over the identified limits.
2.Remove all material rejected by the Department for overheating.
3.2 Sma Plant
A.Provide the following:
1.Positive means to determine the moisture content of aggregate on a daily basis .
2.Positive means to sample all material components.
3.Sensors to measure the temperature of the SMA at discharge.
4.The ability to maintain discharge temperature of the mix according to the mix design.
B.Asphalt Binder Storage Tanks:
1.Provide positive means of determining the quantity of material in the tank at any time.
2.Provide positive means of sampling the asphalt binder from the tanks.
C.Fiber Supply System:
1.Provide a separate proportioning device interlocked with the aggregate feed or weigh system to maintain correct proportions and uniform distribution for all rates of production and batch sizes.
2.Provide flow indicators or sensing devices interlocked with plant controls.
3.Uniformly distribute fibers in aggregate before injectin g the asphalt into the mixer. (8 to 12 seconds) Stone Matrix Asphalt (SMA)
4.Do not allow the fiber to become entrained in the exhaust system of the plant.
D.Mineral Filler Supply System :
1.Provide a separate proportioning device interlocked with the aggregate feed or weigh system to maintain correct proportions and uniform distribution for all rates of production and batch sizes.
2.Provide flow indicators or sensing devices interlocked with plant controls.
3.Uniformly distribute filler in aggregate before injectin g asphalt into the mixer.
4.Do not allow the filler to become entrained in the exhaust system of the plant.
3.3 Cease Production
A.Cease production when any two out of three consecutive lots meet one of the following criteria:
1.A net disincentive.
2.Air voids averaged for each lot are less than 2.5 or greater than 4.5 percent.
B.Refer to Table 2 of this section.
C.Submit a corrective action plan to the Engineer before production continues indicating the changes in production procedures that will be implemented to correct the deficiencies .
1.Address the specific issues contributing to the cease production directive.
2.The Engineer must approve the revised plan before production continues.
D.The Engineer may require a new mix design.
3.4 Surface Preparation
A.Locate, reference, and protect all utility covers, monuments, curb and gutter, and other components affected by the paving operations.
B.Remove all moisture, dirt, sand, leaves, and other objectionable material from the prepared surface before placing the mix.
C.Allow sufficient cure time for prime coat/tack coat before placing SMA. Refer to Section 02748. Stone Matrix Asphalt (SMA)
3.5 Surface Placement
A.Provide a 3:1 (horizontal to vertical) sloped edge adjacent to the next lane to be paved when full -width or echelon paving is impractical and more than one pass is required.
B.Construct the longitudinal joint to within 6 inches of the lane lines or at the center of the lane at the direction of the Engineer, but never in a wheel path.
1.Core and test all longitudinal joints for compaction according to the specification if the lift is 2 or more inches thick .
2.Verify all edges of the adjacent areas to through lanes have straight and uniform longitudinal lines and neat vertical edges.
3.Fill core holes with SMA mix and compact.
C.Adjust the production of the mixing plant and material delivery until a steady paver speed is maintained.
D.Do not allow construction vehicles, general traffic, or rollers to pass over the uncompacted end or edge of freshly placed mix until the mat temperature drops to a point where damage or differential compaction will not occur.
E.Taper the end of a course subjected to traffic at approximately 50:1 (horizontal to vertical).
1.Make a transverse joint by saw or wheel cutting and removing the portion of the pass that contains the tapered end.
2.Tack the contact surfaces before fresh mix is placed against the compacted mix.
F.Use a Material Transfer Vehicle (MTV) to apply all courses of SMA. Use an MTV that internally performs additional mixing of the SMA mix and then deposits material into the paver at a uniform temperature and consistency.
1.Use other approved means to deposit material into the paver when an MTV is impractical, placements such as utility work, traffic signals, detours, lane leveling, and driveways , side street tie -ins, other hand work, or small projects with plan quantities less than 500 tons.
3.6 Compaction
A.Use a small compactor or vibratory roller in addition to normal rolling at structures.
B.Operate in a transverse direction next to the back wall and approach slab. Stone Matrix Asphalt (SMA)
C.Use a 9 ton (minimum) roller.
D.Roll surf ace immediately after placement staying as close as possible to the lay -down machine and assuring proper mix design placement temperatures.
1.Minimize the use of vibratory rollers.
E.Do not use full Pneumatic tire rollers.
F.Discontinue vibration if aggregate breakdown occurs or if bleeding occurs.
3.7 Limitations
A.Do not place SMA on frozen base or subbase.
B.Use a release agent that does not dissolve asphalt and is satisfactory to the Engineer for all equipment and hand tools used to mix, haul, and place the SMA.
C.Do not place SMA during adverse climatic conditions such as precipitation or when roadway surface is icy or wet.
D.Place SMA from April 15, to October 15, and when the air temperature in the shade and the roadway surface temperature are above 50 degrees F.
1.The Department determines if it is feasible to place SMA outside these dates and temperature.
2.Obtain authorization from the Engineer before paving outside these limits .
Source: Utah Standard Specifications for Road and Bridge Construction, 2026 Edition. Pages 485–505 of 1,331.