Frost Depth in concrete

[SteveHen]

How do I calculate the frost depth in a concrete slab?

I am working in an area where typical frost depth is around 6 feet. But as concrete is a worse insulator than typical soils, is the frost depth greater? how do i calculate this?

We have a 2m thick reinforced concrete base slab for a highway tunnel. Initial ideas were to put surface water drainage pipes within the slab but these would then be above the frost depth.

Should the drainage pipe therefore be placed below the concrete slab? And would we need to provide a layer of insulation board?

We don't want the drainage pipes to freeze, block up and the area to flood!

 

[rookierick]

This is an iteresting question, and you have probably solved it by now. I live in an area where frost depth is about 3 feet. We routinely place drain lines withing this zone. The assumption is that if there is water flowing fast enough in the cold, then it will not turn to ice. But if the water velocity/energy decreases, it freezes. There must be some way to create a temperature/velocity curve in which anything on one side would be ice, and the other side would be liquid water. Then you could just calculate your in-pipe velocities and check the curve to see if it would be frozen or liquid for the given temperature.

I have no idea about calculating frost depth through concrete, though...sorry.