What information does the shape of the deflection bowl give?
The shape of the deflection bowl allows detailed structural analysis of the pavement. Basically, the outer deflections define the stiffness of the subgrade while the bowl shape close to the loading plate allows analysis of the stiffness of the near surface layers. A broad bowl with little curvature, indicates that the upper layers of the pavement are stiff in relation to the subgrade. A bowl with the same maximum deflection but high curvature around the loading plate, indicates that the upper layers are weak in relation to the subgrade. With the critical layer identified in this manner, existing or potential distress mechanisms can be identified and therefore the most fitting treatment may be designed.
