alternating current (ac): Electric current that reverses direction periodically, normally 60 times per second.
anode: The collector of electrons in an electrical circuit. Anodes have positive polarity with respect the cathodes.
awwa: The American Water Works Association.
cathodic protection: Protection of metals that are immersed in water or in soil imparted by minute electrical currents of negative polarity.
ASTM International: Previously known as the American Society for Testing Materials.
chlorides: Chloride ions usually associated with sodium, calcium, potassium and magnesium that are common to road salt. Road salt causes stell pipes to corrode in soil.
See Corrosion FAQ
direct current: Electrical current that flows in one direction only.
fiberglass reinforced plastic (frp): Plastic material blended with glass fibers the function of which is to make the plastic stronger than it otherwise would be.
electrolyte: A water solution that conducts electricity.
fill canister (backfill): Material which surrounds impressed current (permanent) anodes, the function of which is to evenly distribute the electrons around the anode.
grounding systems: Conductors, usually copper rods, that are embedded in the ground, the function of which is to dissipate stray currents from electric or electronic appliances.
half cell: A nonpolarizable electrode that generates reproducible potentials against which variable potentials are evaluated. In the context of testing for corrosion, this is a copper rod that is immersed in an electrolyte (copper sulfate solution of water) in a plastic tube that has a porous seal at its tip.
heat treatment of metals: Heating and cooling of any metal to impart strength or toughness.
hot spots: Spots in a structure where corrosion of metal is greater than the average for the structure.
impressed current (permanent) anodes: an inert material that is a receptor for electrons.
mtbe: Methyl Tertiary Butyl Ether, an additive to gasoline that is very soluble in water.
nace international: Formerly "The National Association of Corrosion Engineers"
petrography: A branch of material science and geology that deals with description and systematic classification of rocks, minerals and composition of concrete by means of microscopic examination.
rebar (reinforcing bar): Steel rod that is embedded in concrete to make it stronger than it otherwise would be.
reference electrode: An electrode that has a constant electrical potential measured in volts when compared with itself or with a hydrogen electrode.
sacrificial anodes: A metal that when connected to a cathode, collects the electrons and in the process, dissolves.
shrinkage (concrete): Natural tendency of concrete mix to shrink after placement.
stripping column: Removing components of gasoline from water by blowing air through a cascading water stream in a tower. The same objective can be achieved by pumping water through a bed of activated carbon.
tailings: The refuse of material resulting from processing ground ore.
terrazzo: Mosaic flooring surface made by embedding chips of stone such as marble in mortar that is allowed to harden. The surface is usually polished to enhance the beauty of the marble chips.
wire ropes: Rope made of strands of wire.