This study compares granite, limestone, shale, and pumice fillers in asphalt mastic at 130-170°C and builds response-surface models of temperature, filler content, and rotational speed effects on viscosity to support asphalt mixing and compaction design.
Key findings
- Temperature and filler content dominated viscosity, while speed controlled non-Newtonian degree by filler. Transition occurred at 15-20%, near an effective packing threshold of 32-34%. Pumice reached shear-thickening n=1.22; granite showed n≈0.88-0.94. At 160°C, workability limits were about 30% for granite/limestone and 22% for pumice. Model R² values were 0.84-0.96.
Why this matters globally
Evidence-based matching of local fillers to production temperature could reduce energy use, compaction problems, and pavement variability, especially for porous alternative minerals.
Thai researcher contribution
The KMITL civil-engineering team combined filler characterization, rheology experiments, and process modeling to translate mineral properties into manufacturing guidance.
Limitations to consider
One binder and a bounded laboratory domain were studied; empirical RSM should not be extrapolated. Full-mixture aging, moisture, adhesion, fatigue, rutting, and field performance were not tested, and workability is not equivalent to pavement durability.