1、TS-2d M 323-1 AASHTO Standard Specification for Superpave Volumetric Mix Design AASHTO Designation: M 323-13 1. SCOPE 1.1. This specification for Superpave volumetric mix design uses aggregate and mixture properties to produce job-mix formulas for asphalt mixtures. 1.2. This standard specifies minim
2、um quality requirements for binder, aggregate, and asphalt mixtures for Superpave volumetric mix designs. 1.3. This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety concerns associated with its use. It is the responsibil
3、ity of the user of this procedure to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: M 320, Performance-Graded Asphalt Binder R 28, Accelerated Aging of Asphalt Binder Using a Pre
4、ssurized Aging Vessel (PAV) R 35, Superpave Volumetric Design for Hot Mix Asphalt (HMA) R 59, Recovery of Asphalt Binder from Solution by Abson Method T 11, Materials Finer Than 75-m (No. 200) Sieve in Mineral Aggregates by Washing T 27, Sieve Analysis of Fine and Coarse Aggregates T 164, Quantitati
5、ve Extraction of Asphalt Binder from Hot Mix Asphalt (HMA) T 176, Plastic Fines in Graded Aggregates and Soils by Use of the Sand Equivalent Test T 240, Effect of Heat and Air on a Moving Film of Asphalt Binder (Rolling Thin-Film Oven Test) T 283, Resistance of Compacted Hot Mix Asphalt (HMA) to Moi
6、sture-Induced Damage T 304, Uncompacted Void Content of Fine Aggregate T 308, Determining the Asphalt Binder Content of Hot Mix Asphalt (HMA) by the Ignition Method T 312, Preparing and Determining the Density of Hot Mix Asphalt (HMA) Specimens by Means of the Superpave Gyratory Compactor T 313, Det
7、ermining the Flexural Creep Stiffness of Asphalt Binder Using the Bending Beam Rheometer (BBR) T 315, Determining the Rheological Properties of Asphalt Binder Using a Dynamic Shear Rheometer (DSR) T 319, Quantitative Extraction and Recovery of Asphalt Binder from Asphalt Mixtures T 335, Determining
8、the Percentage of Fracture in Coarse Aggregate 2013 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2d M 323-2 AASHTO 2.2. ASTM Standards: D 4791, Standard Test Method for Flat Particles, Elongated Particl
9、es, or Flat and Elongated Particles in Coarse Aggregate D 5821, Standard Test Method for Determining the Percentage of Fractured Particles in Coarse Aggregate 2.3. Asphalt Institute Publication: MS-2, Mix Design Methods for Asphalt Concrete and Other Hot-Mix Types 2.4. National Asphalt Pavement Asso
10、ciation Publication: IS 128, HMA Pavement Mix Type Selection Guide 2.5. Other References: LTPP Seasonal Asphalt Concrete Pavement Temperature Models. LTPPBind 3.1, http:/ltpp- NCHRP Report 452: Recommended Use of Reclaimed Asphalt Pavement in the Superpave Mix Design Method: Technicians Manual. Nati
11、onal Cooperative Highway Research Program Project D9-12, Transportation Research Board, Washington, DC, 2001. 3. TERMINOLOGY 3.1. design ESALsdesign equivalent (80 kN) single-axle loads. 3.1.1. DiscussionDesign ESALs are the anticipated project traffic level expected on the design lane over a 20-yea
12、r period. For pavements designed for more or less than 20 years, determine the design ESALs for 20 years when using this standard. 3.2. air voids (Va)the total volume of the small pockets of air between the coated aggregate particles throughout a compacted paving mixture, expressed as a percent of t
13、he bulk volume of the compacted paving mixture (Note 1). Note 1Term defined in Asphalt Institute Manual MS-2, Mix Design Methods for Asphalt Concrete and Other Hot-Mix Types. 3.3. voids in the mineral aggregate (VMA)the volume of the intergranular void space between the aggregate particles of a comp
14、acted paving mixture that includes the air voids and the effective binder content, expressed as a percent of the total volume of the specimen (Note 1). 3.4. voids filled with asphalt (VFA)the percentage of the VMA filled with binder (the effective binder volume divided by the VMA). 3.5. dust-to-bind
15、er ratio (P0.075/Pbe)by mass, the ratio between the percent of aggregate passing the 75-m (No. 200) sieve (P0.075) and the effective binder content (Pbe). 3.6. nominal maximum aggregate sizeone size larger than the first sieve that retains more than 10 percent aggregate (Note 2). 3.7. maximum aggreg
16、ate sizeone size larger than the nominal maximum aggregate size (Note 2). Note 2The definitions given in Sections 3.7 and 3.8 apply to Superpave mixes only and differ from the definitions published in other AASHTO standards. 3.8. reclaimed asphalt pavement (RAP)removed and/or processed pavement mate
17、rials containing asphalt binder and aggregate. 2013 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2d M 323-3 AASHTO 3.9. primary control sieve (PCS)the sieve defining the break point between fine- and co
18、arse-graded mixtures for each nominal maximum aggregate size. 3.10. reagent-grade solventa solvent meeting the level of chemical purity as to conform to the specifications for “reagent grade” as established by the Committee on Analytical Reagents of the American Chemical Society and used to extract
19、the asphalt binder from the mixture. 4. SIGNIFICANCE AND USE 4.1. This standard may be used to select and evaluate materials for Superpave volumetric mix designs. 5. BINDER REQUIREMENTS 5.1. The binder shall be a performance-graded (PG) binder, meeting the requirements of M 320, which is appropriate
20、 for the climate and traffic-loading conditions at the site of the paving project or as specified by the contract documents. 5.1.1. Determine the mean and the standard deviation of the yearly, 7-day-average, maximum pavement temperature, measured 20 mm below the pavement surface, and the mean and th
21、e standard deviation of the yearly, 1-day-minimum pavement temperature, measured at the pavement surface, at the site of the paving project. These temperatures can be determined by use of the LTPPBind 3.1 software or can be supplied by the specifying agency. If the LTPPBind software is used, the LTP
22、P high- and low-temperature models should be selected in the software when determining the binder grade. Often, actual site data are not available, and representative data from the nearest weather station will have to be used. 5.1.2. Select the design reliability for the high- and low-temperature pe
23、rformance desired. The design reliability required is established by agency policy. Note 3The selection of design reliability may be influenced by the initial cost of the materials and the subsequent maintenance costs. 5.1.3. Using the pavement temperature data determined, select the minimum require
24、d PG binder that satisfies the required design reliability. 5.2. If traffic speed or the design ESALs warrant, increase the high-temperature grade by the number of grade equivalents indicated in Table 1 to account for the anticipated traffic conditions at the project site. 2013 by the American Assoc
25、iation of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2d M 323-4 AASHTO Table 1Binder Selection on the Basis of Traffic Speed and Traffic Level Design ESALsb (Million) Adjustment to the High-Temperature Grade of the BinderaTraffic L
26、oad Rate StandardcSlowdStandinge25 5.3.2. Percent binder replacementIf the agency elects to use the percent binder replacement method, percent binder replacement is determined by the ratio of reclaimed binder to the total binder in the mixture. Geographical or project-by-project evaluations need to
27、be completed to determine the maximum RAP amounts allowed or the minimum percentage of virgin binder. Note 6If recycled binder properties are not available, efforts should be undertaken to characterize typical stockpiled materials. RAP samples should be taken from typical stockpiles in various geogr
28、aphical locations within the state and periodically evaluated to determine the effect 2013 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2d M 323-5 AASHTO of various percentages of RAP binder on typical
29、virgin PG binders. Details on the RAP evaluation process are contained in Appendix X2. 6. COMBINED AGGREGATE REQUIREMENTS 6.1. Size Requirements: 6.1.1. Nominal Maximum SizeThe combined aggregate shall have a nominal maximum aggregate size of 4.75 to 19.0 mm for HMA surface courses and no larger tha
30、n 37.5 mm for HMA subsurface courses. Note 7Additional guidance on selection of the appropriate nominal maximum size mixture can be found in the National Asphalt Pavement Associations IS 128. 6.1.2. Gradation Control PointsThe combined aggregate shall conform to the gradation requirements specified
31、in Table 3 when tested according to T 11 and T 27. Table 3Aggregate Gradation Control Points Nominal Maximum Aggregate SizeControl Points (Percent Passing) Sieve Size, mm 37.5 mm 25.0 mm 19.0 mm 12.5 mm 9.5 mm 4.75 mm Min Max Min Max Min Max Min Max Min Max Min Max 50.0 100 37.5 90 100 100 25.0 90 9
32、0 100 100 19.0 90 90 100 100 12.5 90 90 100 100 100 9.5 90 90 100 95 100 4.75 90 90 100 2.36 15 41 19 45 23 49 28 58 32 67 1.18 30 55 0.075 0 6 1 7 2 8 2 10 2 10 6 13 6.1.3. Gradation ClassificationThe combined aggregate gradation shall be classified as coarse-graded when it passes below the Primary
33、 Control Sieve (PCS) control point as defined in Table 4 (also see Figure 1). All other gradations shall be classified as fine-graded. Table 4Gradation Classification PCS Control Point for Mixture Nominal Maximum Aggregate Size (Percent Passing) Nominal maximum aggregate size 37.5 mm 25.0 mm 19.0 mm
34、 12.5 mm 9.5 mm Primary control sieve 9.5 mm 4.75 mm 4.75 mm 2.36 mm 2.36 mm PCS control point, % passing 47 40 47 39 47 2013 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2d M 323-6 AASHTO Figure 1Super
35、pave Gradation Control Points for a 12.5-mm Nominal Maximum Size Aggregate Gradation 6.2. Coarse Aggregate Angularity RequirementsThe aggregate shall meet the percentage of fractured faces requirements, specified in Table 5, measured according to T 335. 6.3. Fine Aggregate Angularity RequirementsThe
36、 aggregate shall meet the uncompacted void content of fine aggregate requirements, specified in Table 5, measured according to T 304, Method A. 6.4. Sand Equivalent RequirementsThe aggregate shall meet the sand equivalent (clay content) requirements, specified in Table 5, measured according to T 176
37、. 6.5. Flat-and-Elongated RequirementsThe aggregate shall meet the flat-and-elongated requirements, specified in Table 5, measured according to D 4791, with the exception that the material passing the 9.5-mm sieve and retained on the 4.75-mm sieve shall be included. The aggregate shall be measured u
38、sing the ratio of 5:1, comparing the length (longest dimension) to the thickness (smallest dimension) of the aggregate particles. 6.6. When RAP is used in the mixture, the RAP aggregate shall be extracted from the RAP using a solvent extraction (T 164) or ignition oven (T 308) as specified by the ag
39、ency. The RAP aggregate shall be included in determinations of gradation, coarse aggregate angularity, fine aggregate angularity, and flat-and-elongated requirements. The sand equivalent requirements shall be waived for the RAP aggregate but shall apply to the remainder of the aggregate blend. 2013
40、by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2d M 323-7 AASHTO Table 5Superpave Aggregate Consensus Property Requirements Design ESALsa (Million) Fractured Faces, Coarse Aggregate,cPercent Minimum Uncom
41、pacted Void Content of Fine Aggregate, Percent Minimum Sand Equivalent, Percent Minimum Flat and Elongated,cPercent Maximum Depth from Surface Depth from Surface 100 mm 100 mm 100 mm 100 mm 0.3 million ESALs, and for 4.75-mm nominal maximum size mixtures, the specified VFA range shall be 66 to 77 pe
42、rcent. g For design traffic levels 3 million ESALs, and for 9.5-mm nominal maximum size mixtures, the specified VFA range shall be 73 to 76 percent. Note 9If the aggregate gradation passes beneath the PCS Control Point specified in Table 4, the dust-to-binder ratio range may be increased from 0.61.2
43、 to 0.81.6 at the agencys discretion. 2013 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2d M 323-8 AASHTO Note 10Mixtures with VMA exceeding the minimum value by more than 2 percent may be prone to flus
44、hing and rutting. Unless satisfactory experience with high VMA mixtures is available, mixtures with VMA greater than 2 percent above the minimum should be avoided. 7.3. The HMA design, when compacted according to T 312 at 7.0 0.5 percent air voids and tested in accordance with T 283, shall have a mi
45、nimum tensile strength ratio of 0.80. APPENDIX (Nonmandatory Information) X1. PROCEDURES FOR DEVELOPING A BLENDING CHART X1.1. Blending of RAP binders can be accomplished by knowing the desired final grade (critical temperature) of the blended binder, the physical properties (and critical temperatur
46、es) of the recovered RAP binder, and either the physical properties (and critical temperatures) of the virgin asphalt binder or the desired percentage of RAP in the mixture. X1.2. Determine the physical properties and critical temperatures of the RAP binder: X1.2.1. Recover the RAP binder using T 31
47、9 (Note X1) with an appropriate solvent. At least 50 g of recovered RAP binder are needed for testing. Perform binder classification testing using the tests in M 320. Rotational viscosity, flash point, and mass loss tests are not required. Note X1While T 319 is the preferred method, at the discretio
48、n of the agency, R 59 may be used. Research conducted under NCHRP 9-12 indicated that R 59 might affect recovered binder properties. X1.2.2. Perform original dynamic shear rheometer (DSR) testing on the recovered RAP binder to determine the critical high temperature, Tc(High), based on original DSR
49、values where G*/sin = 1.00 kPa. Calculate the critical high temperature as follows: X1.2.2.1. Determine the slope of the Stiffness-Temperature curve as follows: a = log(G*/sin )/T (X1.1) X1.2.2.2. Determine Tc(High) to the nearest 0.1C using the following equation: 11(1.00) ( )()cLog Log GTHigh Ta=+(X1
