Below-ground pipework

The use of Laterlite Expanded Clay or its hydrophobic variant Laterlite Plus as fill for below-ground pipework or incorporated into engineered structures (bridges, tunnels, etc.) offers the following technical and practical advantages:

• easy and safe to lay. The granularity and lightness of these products make them easy to lay, requiring little or no compaction. The clay granules close the voids around the pipework by simple gravity, minimising the risk of damaging it, as can typically occur when backfilling or compacting with traditional aggregates.
• reduced risk and simplified maintenance. When re-excavation is required at a later date, the expanded clay makes it easy to locate the position of the pipework, reducing the risk of accidental breakage. Because the expanded clay is lightweight and loose it is easy to remove and simplifies the inspection process.
• thermal insulation. The layer of expanded clay insulates the pipework, reducing thermal dispersion and minimising the risk of freezing if water pipes have been buried close to the surface or have been laid to fall with a very shallow angle of slope.
• protection from vibration and settlement. Additional loading on buried pipelines caused by ground settlement, vibration, seismic movement, or landslip is not transferred to the pipework itself. This is a particularly significant advantage if the pipework carries flammable or toxic liquids or gases and is under pressure.
• By preventing water from stagnating close to pipework, the draining capacity of expanded clay safeguards its long-term durability. The Laterlite Plus hydrophobic variant ensures that the level of humidity in the immediate vicinity of the pipework will be extremely low.

For these applications the expanded clay is usually laid loose, although to meet specific strength or cohesion requirements it can be bound with cement to create a pervious draining concrete (Latermix Cem Classic and Maxi).