Preventing frost heave

Frost-susceptible soils typically have a significant silt/fine sand content which allows the capillary rise of water. This water can turn to ice lenses in winter and further water is drawn up from the water table to balance the capillary forces. This cycle ultimately leads to heave at the surface which causes pavement cracking and uplifting.

This is further complicated as the upper ice thaws in winter. The volume of water held as ice is many times greater than water held by the soil under saturated conditions. The water cannot drain down through the soil as it is still frozen. The result is a further weakening of the highway as the subgrade’s ground-bearing capacity is diminished.

TERRAM FSB is a net-based geocomposite which provides the capillary break that the soil lacks and thus prevents the upward movement of water. Its installed cost is insignificant when compared with annual maintenance costs associated with such highway pavements.

Independent testing and field trials have confirmed the ability of TERRAM FSB to prevent the upward passage of water by capillary action.

• Babtie Engineering Laboratories, Geotextile materials to suppress frost heave in soils TERRAM 230gm geotextile with hydrophobic enhancement, 07/05/02. 

• US Army Corps of Engineers, Laboratory Investigation of the Use of Geotextiles to Mitigate Frost Heave, CRREL Report 90-6, 
August 1990.

TERRAM FSB is similarly effective in preventing the capillary rise of salt water that would otherwise contaminate sweet soil layers capable of sustaining vegetation.

This geocomposite can be used instead of the tradition 300mm thick stone layer which would have been used in the past. A much more environmental-friendly alternative, particular if stone is not locally available.

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