Permeability
The ability of concrete to allow fluids or gases to pass through it. Lower permeability = better durability against chloride, sulfate, and freeze-thaw attack.
Permeability is controlled by w/c ratio, curing, and the use of mineral admixtures. Tested by RCPT, water permeability, or sorptivity.
A by-product of iron manufacturing, ground to cement fineness. Used as a supplementary cementitious material at 25-65% replacement of cement.
A by-product of coal-fired power plants, used as a pozzolanic addition to concrete. Reacts with calcium hydroxide to form additional C-S-H.
The ratio of the weight of water to the weight of cement in a concrete mix. The single most important factor controlling strength and durability.
A test measuring the resistance of concrete to chloride ion penetration, indicating durability in marine or de-icing environments. Result reported in coulombs.