Introduction
Materials and methods
Materials
Mix ID | Mix type | Optimum binder content (%) | Mixing/compaction temperatures (°C) | NMAS (mm) | Binder type | Foamed binder | Absorbed binder (%) | RAP content (%) |
---|---|---|---|---|---|---|---|---|
HMA S3 | HMA | 4.5 | 163/149 | 19 | PG 64-22 | No | 0.42 | 25 |
WMA S3 | WMA | 4.5 | 135/127 | 19 | PG 64-22 | Yes | 0.42 | 25 |
HMA S4 | HMA | 4.9 | 163/149 | 12 | PG 64-22 | No | 0.46 | 5 |
WMA S4 | WMA | 4.9 | 135/127 | 12 | PG 64-22 | Yes | 0.46 | 5 |
Sample preparation
Laboratory tests
Dynamic modulus (DM) test
Hamburg wheel tracking (HWT) test
Flow number (FN) test
Indirect tensile strength ratio (TSR) test
Moisture conditioning of compacted samples
AASHTO T 283 method
Moisture induced sensitivity test (MIST) conditioning
Results and discussion
Rutting performance
Dynamic modulus test
Hamburg wheel tracking (HWT) test
MIX ID | Average % air voids | Post compaction (mm) | Creep slope (mm/passes) | Inverse creep slope (passes/mm) | Stripping inflection point (passes) | Stripping slope (mm/passes) | Inverse stripping slope (passes/mm) |
---|---|---|---|---|---|---|---|
Conventional method | |||||||
HMA S3 | 6.8 | 1.1 | 0.000100 | 10,000 | N/A | N/A | N/A |
WMA S3 | 6.8 | 2.0 | 0.000150 | 6667 | 17,100 | 0.000417 | 2400 |
HMA S4 | 6.9 | 1.7 | 0.000067 | 15,000 | N/A | N/A | N/A |
WMA S4 | 7.0 | 1.8 | 0.000339 | 2946 | 12,000 | 0.000756 | 1324 |
MIX ID | Average % air voids | \(\Delta {\varepsilon }_{\mathrm{10,000}}^{vp}\) | LCSN | LCST |
---|---|---|---|---|
Method outlined by Yin et al. [25] | ||||
HMA S3 | 6.8 | 1.08E–06 | > 20,000 | – |
WMA S3 | 6.8 | 1.74E–06 | > 20,000 | – |
HMA S4 | 6.9 | 0.59E–06 | > 20,000 | – |
WMA S4 | 7.0 | 3.33E–06 | 4647 | 22,011 |
Flow number (FN) test
Ranking of asphalt mixes based on rutting performance
Mix ID | Dynamic modulus | HWT indices | Average FN | ||
---|---|---|---|---|---|
Rut depth at 10,000 wheel passes (mm) | Inverse creep slope (passes/mm) | \(\Delta {\varepsilon }_{\mathrm{10,000}}^{vp}\) | |||
HMA S3 | 1 | 1 | 2 | 2 | 1 |
WMA S3 | 3 | 3 | 3 | 3 | 3 |
HMA S4 | 2 | 2 | 1 | 1 | 2 |
WMA S4 | 4 | 4 | 4 | 4 | 4 |
Moisture-induced damage
Stripping infection point (SIP)
AASHTO T 283 method
MIST conditioning
Ranking of asphalt mixes based on moisture susceptibility
Mix ID | HWT test | ITS test | |||
---|---|---|---|---|---|
SIP | LCSN | LCST | TSRF–T | TSRMIST | |
HMA S3 | 1 | 1 | 1 | 1 | 1 |
WMA S3 | 3 | 1 | 1 | 3 | 3 |
HMA S4 | 1 | 1 | 1 | 2 | 2 |
WMA S4 | 4 | 4 | 4 | 4 | 4 |