Short organic fibers, usually polypropylene, added at around 0.1 percent by weight to dense castables. They melt at about 160 to 170 C, well before steam pressure peaks, and leave a network of fine channels that raises permeability so water vapor can escape. They are cheap insurance against explosive spalling in low-cement castables and thick sections.
Make sure the burnout fibers went in, that pour is 300 millimetres thick and it's low cement.
Also heard as
- organic fibers
- polypropylene fibers
- PP fibers
Related terms
Explosive spalling
Violent failure of a castable during first heat-up when trapped steam pressure blows the lining apart.
Dry-out
Controlled first heat-up of a new monolithic lining to drive off water without cracking or spalling.
Low-cement castable
Dense castable with 1 to 2.5 percent lime from cement, using micro-fines and dispersants for strength and low porosity.