Warm mix asphalt, made with technologies that let mix coat, haul and compact at lower temperatures than conventional hot mix, roughly 30 to 100 F cooler. Plants get there by foaming the binder with water injection, by adding chemical surfactants or by blending organic waxes. Lower temperatures cut fuel use and fumes, slow binder aging and widen the compaction window, and many contractors run WMA additives mainly as a compaction aid on long hauls or cold days.
Haul's an hour and ten, run the WMA additive so the last trucks still roll out before the mix stiffens up.
Also heard as
- warm mix
- warm-mix asphalt
Related terms
HMA
Hot mix asphalt: aggregate and binder mixed hot at a plant, hauled hot and compacted before it cools.
Drum plant
A continuous asphalt plant that dries the aggregate and mixes it with binder in one rotating drum.
Density
How tightly a compacted asphalt layer is packed, reported as a percentage of its maximum theoretical density.
Blue smoke
Bluish haze rising off the mix that signals overheated binder and premature hardening.