13th International Conference on Fracture June 16–21, 2013, Beijing, China -3- each binder have been presented in Table 2. Using the Marshall Mix design method, the optimum percentages of binders were determined as presented in Table 3. Table 1. Asphalt mixture aggregate gradation NO.4 NO.5 NO.6 Gradation number NMAS: 12.5mm NMAS: 9 mm NMAS: 4.75 mm Sieve size Passing percent 19 100 100 100 12.5 95 100 100 9 80 85 100 4.75 59 70 90 2.36 43 49.5 82.5 1.18 30 33 60 0.5 18 22 45 0.3 13 15 23.5 0.15 8 10 11.5 0.075 6 6 10 Table 2. Specifications of binders. Binder type 85-100 60-70 Unit Standard test Test 1.01 1.03 gr/cm3 ASTM D70 Specific Gravity (25 °C) 294 308 °C ASTM D92 Flash Point (Cleveland) 94 62 °C ASTM D5 Penetration (25 °C) 105 100 cm ASTM D113 Ductility (25 °C) 42 49 °C ASTM D36 Softening point 512 810 mm2/s ASTM D2170 Kinematic Viscosity @ 120 °C 221 420 mm2/s ASTM D2170 Kinematic Viscosity @ 135 °C 120 232 mm2/s ASTM D2170 Kinematic Viscosity @ 150 °C -1.98 – –1.12 – Penetration index (PI)a a PI = [1952 – 500 log (Pen 25) – 20SP] / [50 log (Pen25) – SP – 120] Table 3. Optimum percentages of binders for asphalt mixture samples Binder type Penetration grade 60-70 Penetration grade 85-100 NMAS (mm) 12.5 9 4.75 12.5 9 4.75 Lime stone aggregates 4.8 5.1 5.7 4.6 - - Siliceous aggregates 5.2 - - - - - 3. Specimen manufacturing and testing After mixing the aggregates (i.e. limestone and siliceous of different sizes) with binders (i.e. 60/70 and 85/100 bitumen) at 155oC, cylindrical specimens with diameter of 150 mm and height of 130
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