Flexible pavement differ from rigid pavement in terms of load distribution. In flexible pavements load distribution is primarily based on layered system. While, in case of rigid pavements most of the load carries by slab itself and slight load goes to the underlying strata.
Structural capacity of flexible pavement depends on the characteristics of every single layer. While, the structural capacity of rigid pavements is only dependent on the characteristics of concrete slab. This is so, because of low bearing soil capacity of underlying soil.
In flexible pavements, load intensity decreases with the increase in depth. Because of the spreading of loading in each single layer. While, in case of rigid pavement maximum intensity of load carries by concrete slab itself, because of the weak underlying layer.
In flexible pavement deflection basin is very deep, because of its dependency on the underlying layers. While in case of rigid pavement, deflection basin is shallow, this is because of independency of rigid pavement on the underlying layers.
Flexible pavement has very low modulus of elasticity (less strength). Modulus of elasticity of rigid pavement is very high, because of high strength concrete and more load bearing capacity of the pavement itself. Than compared to flexible pavements.
In flexible pavements, underlying layers play very important role. Therefore, more role are playing only underlying layers. In case of rigid pavements, slight function of underlying layers. Maximum role is playing by the top layer (that is slab) by itself. Therefore, minute part is taking by sub layers.