The structural performance of road pavements made with modified bituminous conglomerate

CONI, MAURO;PORTAS, SILVIA;Annunziata F.

2000-01-01

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Abstract

The characteristics of traffic loads are changing . In particular, they are increasing in quantity and magnitude. Therefore the mechanical characteristics of materials used for building road superstructures, as bituminous conglomerate and bonding agent, need to be improved. The more recent researches are aimed to improve the stress-strain behaviour by increasing the modulus of elasticity of bituminous conglomerate. In fact, the behaviour of the pavement improves significantly using “modified bituminous”. For modified bituminous the higher the modulus of elasticity the higher the flexural rigidity and the dynamic resistance are. Also, the higher the modulus of elasticity the less the thermal susceptibility and plastic deformation are. Overall, the main benefit is a longer service life of the pavement. Two different models of pavement were analysed using the finite element method. The two models were designed with same geometry (equal number of layers and same thickness) and bearing capacity of the agger, whereas either pavements were made with modified bituminous. The behaviour of the materials was simulated assuming an elastoplastic model. The load was applied in both static and dynamic conditions. The magnitude of both stress and strain was measured in correspondence of the interface between the base and the subbase of the pavements. The magnitude was resulted lower for the pavement made with modified bituminous. That becomes more evident long the wheeler-paths for superstructures made with low stiffness and bearing heavy loads. It was observed also that the structural characteristics of the pavement improves using modified conglomerate. The research will be carry on about the effect of dynamic loads on the durability of the pavement.