Coke breeze backfill

Coke breeze backfill: overview

The performance of cathodic protection anodes largely depends on the backfill, which provides low soil resistivity at minimal cost. The key characteristics of a good backfill are bulk density, resistivity, porosity, flow and purity.

This coke breeze offers low bulk density, low resistivity, high porosity, good flow and high purity (low sulphur content minimising corrosion risk). It is supplied in crates of 40 bags of 25 kg, i.e. 1 tonne, with ample stock for fast delivery.

What the backfill does

An impressed current anode buried directly in soil faces that soil's resistance and is consumed unevenly. Carbonaceous backfill surrounds it with a conductive medium: it increases the effective exchange area, lowers the groundbed resistance and shifts part of the consumption onto the carbon instead of the anode.

The criteria that matter

Low resistivity reduces the voltage the rectifier must supply. Porosity lets the gases produced at the anode escape, which would otherwise end up insulating it. Purity, and in particular a low sulphide content, avoids introducing corrosive compounds around the groundbed. Grain size and good flow make for even filling with no air pockets, especially in boreholes.

Coke breeze backfill: technical specifications

Coke breeze backfill: documentation