Abstract:
Infrastructure facilities are delivered for economic growth of countries' progress. Road transport
is the dominant mode of transport in developing countries like Ethiopia. Major types of distresses
observed on major sections of the trunk roads is permanent deformation in the form of rutting. As
the roads have experienced deterioration, which has given rise to the need for periodic
maintenance and rehabilitation. Pavement deformation or rutting is one of the key distresses that
affect the pavement performance. Performance of roads with regards to ride-ability and
roughness is known to have a significant cost implication to the road users in terms of
operational cost, in addition to affecting their safety and comfort. Aggregates are one of the key
building materials used in the construction industry and the largest portion of an asphalt
pavement. The general objective of this research is Investigating a modelling tool for rutting
prediction of Flexible pavement considering effects of aggregate gradation and quality of sub grade material.
Hence, in this study, a three-dimensional finite element model was developed, using ABAQUS
software, to predict rutting on flexible pavement considering effect of Sub-grade material quality
and gradation of aggregate. Flexible pavement modelling was performed using finite element
method; a 3-D dimensional finite element model using ABAQUAS (ver.6.14-1) computer
program was developed. The material in this model was assumed to be homogenous isotropic
linear elastic materials. Natural subgrade materials were modeled in terms of the elastic
modulus and Poisson’s ratios. The fine finite element mesh used in this study gives the values of
stresses and strain in each point. The results of rutting prediction of existing flexible pavement
and series of model created are discussed. According, to the modelling results the permanent
deformation (rutting) severity are increase as the resilient modulus of the pavement materials is
decrease. This thesis presented the static loading response of flexible pavement layers in terms of
strain, stress and deflection. Besides, investigate the effects of different aggregate gradation and
sub-grade material qualities. It was found that in the elastic domain, considering linearity of the
material and stress dependency can significantly affect the critical responses of the pavement
layers.
