Description: It is especially important to use various building materials in road construction. For the long service life of traffic roads, the road surface and infrastructure must have the same load carrying capacity. The load-bearing layers are exposed to large temperature fluctuations and thus to frost. Evaluation of the building materials used according to their freezing properties can be carried out by the frost heave test according to the Swiss standard SN 670 321a (2001).

Before starting the test, the optimal water content of the soil sample is determined. The simple 5-day test includes a full freeze-thaw cycle with realistic temperature gradients. The sample cup is made of an insulating material so that the formation of a thermal bridge is prevented. The increase is determined continuously and with micrometer accuracy by means of a high precision LVDT indicator. In addition, temperatures are recorded on the ground and the surface of the soil sample.

The aim of the research is to determine:

• Maximum expansion during freezing
• lift coefficient
• Reduction in load bearing capacity after dissolution (CBR-Wert = “California Bearing Ratio”)