CHAPTER 5 CONCRETE PAVEMENTS - TU Delft

5.3.3 Stresses due to temperature variations:
Temperature variations lead to stresses in the concrete top layer. These stresses can
be distinguished into (figure 5.8):
1. stresses due to a temperature change ∆T which is constant over the thickness
of the concrete layer
2. stresses due to a temperature gradient ∆t which is constant over the thickness
of the concrete layer
3. stresses due to an irregular temperature over the thickness of the concrete
layer.
Figure 5.8: Temperature in the concrete toplayer in case of heating at the surface.
A regular temperature increase or decrease ∆T leads to compressive and tensile
stresses respectively in the concrete toplayer due to friction over the underlying layer.
However, for plain concrete pavements (that generally consist of slabs with both a
length and a width smaller than 5 m (roads) or 7.5 m (airports) these stresses are
such small that they can be neglected.
The irregular temperature results in internal concrete stresses, which are only
relevant for very thick concrete slabs. For normal concrete slab thicknesses they also
can be neglected.
On the contrary, the temperature gradients ∆t cause flexural stresses in the concrete
slab, which are for plain concrete pavements in the same order of magnitude as
those caused by the traffic loadings, and thus cannot be neglected at all.
The temperature gradient ∆t is defined as (figure 5.8):
T Tb
∆ t =
(5.2)
h
t −
where: Tt = temperature (°C) at the top of the concrete layer
Tb = temperature (°C) at the bottom of the concrete layer
h = thickness (mm) of the concrete layer
For the structural design of plain concrete pavements in The Netherlands only the
positive temperature gradients are relevant because:
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