The material finer than 75 microns, also called minus 200 or P200, coming from crushing, from natural sand and from baghouse dust returned to the mix. Fines combine with binder to form a mastic that stiffens the mix, but too many soak up binder, cut VMA and make a mix tender. Superpave controls them with the dust-to-binder ratio, the percent passing No. 200 divided by the effective binder content, usually held between 0.6 and 1.2.
Fines are up to 6.8 percent and the dust ratio's out, have the plant waste some baghouse dust before the mat starts checking.
Also heard as
- P200
- minus 200
- dust
Related terms
Baghouse
The fabric-filter dust collector that cleans the exhaust from an asphalt plant's dryer.
VMA
Voids in mineral aggregate: the space between aggregate particles available for binder and air.
Gradation
The distribution of particle sizes in an aggregate blend, reported as percent passing each sieve.
Tender mix
Mix that shoves and moves under the rollers instead of compacting, often within a certain temperature range.
Same word, different worlds
Powder particles smaller than the specified size range, which cause buildup, spitting and poor flow.
Powder CoatingThe smallest particles in a powder, roughly under 10 microns, which fluidize, charge and recycle poorly.
Refractories & Furnace LiningsSmallest particle fraction of a refractory mix, which fills the gaps between coarse grains and forms the bond.
Paper Optics & TestingFiber fragments and small particles that pass a fine screen and have an outsized effect on sheet optics.