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Backfill Materials

The type of backfill used in a groundbed depends on whether the cathodic protection system is sacrificial or impressed.

Particle size and shape are also important when specifying a backfill. Both parameters determine the contact area between anode and earth whilst influencing the porosity of the column which is important for gas ventilation. A general purpose coke breeze is for use in shallow horizontal and vertical groundbeds. It has a resistivity of 35 W cm. For deep well applications a special calcined petroleum coke breeze is available. It has a resistivity of 15 W cm and can be pumped.