Conductive and earthing concrete

Ordinary concrete is an insulator – its resistivity lies in the range of 10⁶ to 10⁹ Ω·m. Conductive concrete is produced by adding a carbon filler that forms a continuous conductive network within the cement matrix. Once the so-called percolation threshold is reached, the resistivity drops by several orders of magnitude – to units or tens of Ω·m. The structural material becomes a conductor.

For this purpose we supply graphite, calcined petroleum coke, calcined anthracite and carbon black – loose, as a pre-blended mix with cement, or as a bag of cement with a pre-weighed sachet of graphite inside.

Earthing concrete and earth electrode backfills

The most common application. In rocky, sandy and dry soils with high resistivity it is difficult to achieve the required earth resistance with a conventional earth electrode. Conductive concrete or a conductive backfill around the electrode increases its effective surface area and reduces the contact resistance to the surrounding soil – the earthing (grounding) system reaches the required value with fewer electrodes and independently of seasonal moisture.

• foundation and driven earth electrodes for buildings, substations and HV transmission towers
• earthing of solar farms and telecommunication masts
• lightning protection
• earth electrodes in rocky ground, on bedrock and in high-resistivity backfills

Other applications of conductive concrete

• Antistatic and ESD floors – dissipation of static charge in facilities handling electronics, explosives or flammables.
• Self-heating concrete – conductive concrete connected to a low voltage works as a heating element. Snow and ice melting on bridges, ramps, access roads and platforms without heating mats.
• Electromagnetic shielding – carbon fillers increase the shielding effectiveness of cementitious composites. Shielded rooms, server rooms, measurement laboratories.
• Self-sensing concrete – conductive concrete changes its resistance with strain. Monitoring of overload, cracking and fatigue in a structure.
• Anodes and grouts for cathodic protection – see the Cathodic protection page.
• Architectural concrete – fine graphite gives a dark grey to anthracite shade with a metallic sheen, without organic pigments.

Forms of supply

• Loose material – graphite, graphitised petroleum coke, calcined anthracite, calcined petroleum coke
• Pre-blended dry mix – graphite and cement, optionally with sand, fillers or fibres, ready to use
• Cement with a dosing sachet – a bag of cement with a pre-weighed dose of graphite inside; one bag = one batch, nothing to weigh on site
• Grain size: micronised powder, 0–1 mm, 1–4 mm, 3–12 mm or to specification
• Packaging: 20 and 25 kg bags, 1 t big bags, bulk

Please contact us and we will propose a solution.