Cover Image

Not for Sale



View/Hide Left Panel
Click for next page ( 23


The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement



Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.

OCR for page 22
22 A Manual for Design of Hot Mix Asphalt with Commentary Figure 3-7. Sketch of BBR test. to determine the low-temperature performance grade for the given binder. The main advantage of the direct tension test and associated analysis compared to BBR grading is that many polymer- modified binders have enhanced fracture properties that will result in a lower grading temperature using the direct tension test compared to that produced by BBR grading. Performance Grading--Specification Table 3-1 lists the various requirements for performance-graded asphalt binders, as described in AASHTO M 320 Table 1. In AASHTO M 320 Table 1, the low-temperature grade of the binder is based on creep stiffness and the m-value of the binder from the BBR. If the binder has a creep stiffness between 300 and 600 MPa, the direct tension failure strain requirement can be used in lieu of the creep stiffness requirement. There is also a Table 2 in AASHTO M 320 which uses the critical low cracking temperature from the direct tension test to determine the low- temperature grade of the binder. AASHTO M 320 Table 1 is the most commonly used specifica- tion for PG binders. (a) (b) Figure 3-8. Photographs of the direct tension test: (a) specimen and mold and (b) test device.

OCR for page 22
Asphalt Binders 23 Table 3-1. Specification for performance-graded asphalt binders. PG 46 PG 52 PG 58 Binder Performance Grade: -34 -40 -46 -10 -16 -22 -28 -34 -40 -46 -16 -22 -28 -34 -40 Design high pavement temperature, C: <46 <52 <58 Design low pavement temperature, C: 34 40 46 10 16 22 28 34 40 46 16 22 28 34 40 Test on Original Binder Flash Point Temperature (T 48), Min., C 230 Viscosity (T 316) Maximum value of 3 Pa-s at 135 test temperature, C Dynamic Shear (T 315) G*/sin , minimum value 1.00 kPa, at 46 52 58 10 rad/s and Test Temperature, C Tests on Residue from Rolling Thin Film Oven (T 240) Mass Loss, Maximum, % 1.00 Dynamic Shear (T315) G*/sin , minimum value 2.20 kPa, at 46 52 58 10 rad/s and Test Temperature, C Tests on Residue from Pressure Aging Vessel (R 28) PAV Aging Temperature, C 90 90 100 Dynamic Shear (T 315) G* sin , maximum value 5,000 kPa, at 10 7 4 25 22 19 16 13 10 7 25 22 19 16 13 10 rad/s and Test Temperature, C Creep Stiffness (T 313) Stiffness, maximum value 300 Mpa -24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30 m-value, minimum value 0.30, at 60 sec and Test Temperature,C Direct Tension (T 314) Failure strain, minimum value 1.0%, at -24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30 1.0 mm/min and Test Temperature, C PG 64 PG 70 Binder Performance Grade: -10 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -40 Design high pavement temperature, C: <64 <70 Design low pavement temperature, C: 10 16 22 28 34 40 10 16 22 28 34 40 Tests on Original Binder Flash Point Temperature (T 48), Min., C 230 Viscosity (T 316) Maximum value of 3 Pa-s at 135 test temperature, C Dynamic Shear (T 315) G*/sin , minimum value 1.00 kPa, at 64 70 10 rad/s and Test Temperature, C Tests on Residue from Rolling Thin Film Oven (T 240) Mass Loss, Maximum, % 1.00 Dynamic Shear (T 315) G*/sin , minimum value 2.20 kPa, at 64 70 10 rad/s and Test Temperature, C Tests on Residue from Pressure Aging Vessel (R 28) PAV Aging Temperature, C 100 100 (110) Dynamic Shear (T 315) G* sin , maximum value 5,000 kPa, at 31 28 25 22 19 16 34 31 28 25 22 19 10 rad/s and Test Temperature, C Creep Stiffness (T 313) Stiffness, maximum value 300 Mpa 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 m-value, minimum value 0.30, at 60 sec and Test Temperature,C Direct Tension (T 314) Failure strain, minimum value 1.0%, at 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 1.0 mm/min and Test Temperature, C (continued on next page)