Accueil Stations Cryopedometer

Cryopedometer

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Description

Stations with automatic cryopedometer, placed at particularly sensitive points of the road network, can automatically monitor the temperature of the road and ground at varying depths, to accurately track the changes in the depth of frost in the roadway and to inform technical staff of the risks of thaw barriers.

In winter, it is necessary to protect some routes exposed to the adverse effects of frost.
The freeze-thaw cycle can cause deformation of the road if it is driven over (mechanical stresses due to the passage of vehicles) during the thaw period.

 Through daily tracking of changes in temperatures measured inside of the road, maintenance crews can make the decision to place a thaw barrier (French highways regulation).
Traffic is temporarily interrupted and deformation is attenuated

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Implantation

Civil engineering 

The cryopedometer is sealed vertically in the road after a simple coring.

Its cable runs into a channel.

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Solar station

The smart cryopedometer may be associated with a roadside cabinet in which a battery can power a GPRS MODEM and its antenna.
The power consumption of the station is low, the battery life can be calibrated to cover the electrical needs of a winter road maintenance season (6 months for example).
A solar panel can also be added to ensure continued power supply.

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Temperature probes 

The length of cryopedometer, the number of measuring points and their depth is determined by the needs of the customer.

The standard probe is 90 cm, which allows for 16 measurement points.

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Use of data

Unlike the manual cryopedometer, the automatic cryopedometer requires no travel to retrieve temperatures.
Connected to a measuring station, it communicates its data directly.
The temperature curve readings are then viewed on a local PC and/or online.

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Thaw barrier

What happens to the road when it freezes or thaws? 

When the temperature is below 0°, the ice enters the ground to a depth dependent on the intensity and duration of the cold spell. The frozen thickness can reach several dozens of centimetres and is measured in roads using the cryopedometer.

Highway network roads tend to swell under the effect of frost and moisture, but their integrity is not yet affected.

When thawing, the top surface of the road is the first to thaw while the foundation, still frozen, has not yet recovered its weight bearing ability.

  When the temperature becomes positive again, the frost thickness decreases from the surface and from the base of the frozen part.

In effect, calories from the atmosphere reduce the upper isotherm and those from the substratum increase the lower isotherm.

When these two isotherms converge, the thaw is complete.  

When the frost depth exceeds the thickness of the road, the risk of thaw barriers exists.

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The thaw barrier is a French road traffic regulation for thawing periods, usually in the form of a provisional tonnage limitation, in order to protect the foundations of the road. 

Realisations

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· Through daily tracking of changes in temperatures measured inside of the road, maintenance crews can make the decision to place a thaw barrier (French highways regulation).
Traffic is temporarily interrupted and deformation is attenuated