Applications of Expanded Clay in Underground Construction

Expanded clay is considered an affordable and efficient insulating material widely used to improve the thermal insulation of foundations, underground structures, and building components. For example, to insulate a basement, the surrounding soil can be excavated and replaced with coarse expanded clay gravel. Additionally, placing a layer of expanded clay beneath the foundation slab before pouring concrete significantly reduces heat loss through the foundation.
When installing underground utility lines, expanded clay is used to minimize the risk of freezing in pipes or cables that are placed above the local frost line. It also reduces heat loss where heating pipelines are in contact with soil. Due to the distinct reddish-brown color of certain grades of expanded clay, it can also be used as a signal layer (instead of red bricks or warning tapes) to indicate the presence of pipelines or other underground systems.
Recently, expanded clay has been increasingly applied in road construction and repair projects. When used as a lightweight fill, it reduces pressure and settlement on underlying soil. This is particularly beneficial in marshy or water-saturated soils, where traditional road-building techniques involve installing grillage foundations with limited strength and durability. Such roads are prone to intense settlement, leading to rapid surface degradation. Expanded clay fill helps roads better withstand heavy truck loads, and its drainage properties extend the service life of the pavement.
Expanded clay is also often used as a component in lightweight concrete mixtures for building wells and tunnels. It reduces the overall weight of the structure without compromising strength.

Expanded clay is widely used in various construction processes today. It possesses numerous beneficial characteristics that make it highly suitable for underground construction applications.
One of its key advantages is its durability. Expanded clay is resistant to biological degradation and can retain its properties for a long time, even in conditions of constant exposure to moisture and various types of soil. It is chemically inert and does not react with mineral fertilizers, organic substances, or other soil components.
Its lightweight nature, achieved through the foaming and firing of clay, results in porous granules that significantly reduce the load on the soil and lower construction costs. This makes it ideal for foundation work and underground installations.
Thanks to its porous structure, expanded clay also provides excellent thermal insulation. It is often used to insulate plumbing, electrical, and heating lines, helping prevent freezing and minimizing heat loss.
Environmentally, expanded clay is safe and sustainable. It contains no harmful additives and does not contaminate soil or groundwater, making it suitable for eco-friendly building practices.

Use of Expanded Clay in Underground Construction