The fine end of the particle size distribution, below roughly 0.1 mm, down to micron-sized reactive alumina and microsilica. Fines fill the voids between coarse aggregate, carry most of the bond and set water demand and flow. They are also the first part of the lining slag attacks, because the matrix holds the impurities and porosity. Losing fines through segregation, rebound or careless mixing weakens the installed lining.
All the fines are sitting on top of that pour, somebody over-vibrated it and it segregated.
Also heard as
- matrix fines
- micro-fines
- matrix
Related terms
Grog
Pre-fired clay or crushed brick added as aggregate to cut shrinkage and cracking in refractory bodies.
Low-cement castable
Dense castable with 1 to 2.5 percent lime from cement, using micro-fines and dispersants for strength and low porosity.
Rebound
Material that bounces off the wall during gunning instead of sticking, wasted and often harmful.
Stinger
Shop name for the immersion vibrator head pushed into fresh castable to consolidate it.
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.
Paper Optics & TestingFiber fragments and small particles that pass a fine screen and have an outsized effect on sheet optics.
Asphalt PavingThe dust-sized part of the aggregate passing the No. 200 sieve, which stiffens the binder into a mastic.