Applications of Expanded Clay

How Strength Is Measured

Strength of Expanded Clay

Lightweight, durable, environmentally safe, and cost-effective, expanded clay is used across a wide range of industries.

• In construction, it is valued for its thermal insulation properties. It is commonly used to insulate floors, roofs, and basements, and is also filled into trenches and greenhouses for the same purpose.
• Expanded clay is a key component in lightweight concrete products such as blocks, monolithic structures, and wall panels.
• Small-fraction granules made from fired clay serve as effective filtering media for water treatment processes.
• In road and dam construction, expanded clay is used to reinforce embankments and slopes.
• It is also utilized in landscaping — both in its natural form and in colored variants — to decorate paths, plazas, and other outdoor features.
• In agriculture, it is mixed into soil as a medium for hydroponics, improving aeration and moisture retention.

The strength of expanded clay is determined under laboratory conditions. The granules are placed in a cylinder and subjected to compressive force using a press. The strength rating is defined by the load the granules can withstand. Based on this resistance, the material is assigned a specific strength grade.
The measurement process involves the following steps:

1. A steel cylinder with a removable bottom is partially filled with sand.
2. An expanded clay granule is placed on top of the sand.
3. The granule is covered with another layer of sand.
4. A plunger is inserted into the cylinder.
5. A hydraulic press is used to gradually apply pressure until the granule breaks, indicated by a characteristic cracking sound.
6. At the point of breakage, the pressure gauge needle will move in the opposite direction.
7. This procedure is repeated 5–6 times, and the average value is calculated to determine the material’s strength level.

Expanded clay is produced by firing natural clay, resulting in an eco-friendly material widely used in construction and agriculture. It appears as a loose collection of lightweight clay pellets that function as a structural filler. Despite their lightness and porous nature, expanded clay granules possess a high degree of strength. Knowing the strength grade is essential for assessing the reliability and durability of blocks made from this material.