Laboratory Investigations of Frozen Strength

Following production of material for the truck arrester bed from the Randon source, two series of tests were conducted to investigate the frozen strength of the aggregate. As would be expected, there is a direct correlation between moisture content and strength; the more ice, the stronger the frozen material. For the material to work as intended in winter conditions, it is necessary that the moisture content be as low as possible. This in turn is related to the ability to drain water and the cleanliness of the aggregate.

Runaway Truck
In September 2003, a truck entered the bed and became stuck as designed. It appears that the trucker had not heeded the warnings at the approach to the bed and pulled to the left to overtake a slower truck and entered the bed for the upper end. The materials were not frozen. It is not thought that the brakes had failed. As found in earlier testing, the tractor wheels became deeply embedded but the trailer wheels showed relatively little embedment and travelled in the grooves made by the wheels in front.