Fillings of Natural and Artificial Cavities

Expanded Clay Aggregate (ECA®) is light weight, high grain resistance, high drainage capacity, stiffness and eco-friendly, it can prevent concentration of strain that can conclude with the general collapse of the structure. The presence of a hole into the ground may concentrate traction and compressive strain that can conclude with the general collapse of the structure.

Over recent years much attention has been given to the influence of the interfacial zone  between Expanded Clay Aggregate (ECA®) and cement paste on the various properties of concrete to fill cavities created naturally or artificially.

For high strength Expanded Clay Aggregate (ECA®) with a dense outer layer the nature of the interfacial zone between aggregate and cement paste is similar to that for normal weight aggregate. For ECA® with a weaker and more porous outer layer and for aggregate without any outer layer, the interfacial zone is more dense and homogeneous. Also for such aggregates the bond appears to be better due to an improved mechanical interlocking between the aggregate and the cement paste. The nature of the interfacial zone appears to depend on the microstructural characteristics of the aggregate.

In scenarios where below Ground cavities are one above another or where not enough is known about the ground conditions, it woud be particularly risky to overload the surrounding ground. Ideal situation would be to fill the cavities with Lightweight Expanded Clay Aggregate (ECA®)

Many a times the ideal option to fill the non-used underground tanks is not found. Expanded Clay Aggregate (ECA®) is used for making disused underground tanks by filling them and leaving them in place. As compared to filling with a traditional aggregate, an ECA® fill will reduce additional load and lateral thrust avoiding the risk of settlement.


  • Positive load redistribution
  • Reduced additional loading and minimal alteration of tension state of ground below the filled cavity thus minimizing the lateral thrust.
  • Ease of execution
  • No alteration of water flows within the ground
  • Safe protection from fire