Abstract:
Road structure deformation is a critical issue for flexible pavement. Pavement distress such as
fatigue cracking and rutting deformation are the most serious for pavement sustainability. Due
to repetitive traffic loading during its service life and environmental factors causes pavement
distress, which affects the serviceability and durability of pavement structures.
Particularly, In Ethiopia several roads are failed before they gave full service. This study aims
to conduct future performance of a pavement structure, evaluate existing pavement structure
and mechanistic response. Therefore, to achieve the objective of the study, nonlinear finite
element and multi-layer leaner elastic methods are utilized for analyses of flexible pavement
structural response mechanism. In Situ Pavement structures and mechanical property of flexible
pavement evaluated by Dynamic Cone Penetrometer (DCP), and multi-layer elastic and finite
element used for analysis of pavement structural response by utilizing JULEA and ABAQUS
software respectively. Finally predicting on service performance of flexible pavement
comparatively based on JULEA and ABAQUs critical strain result by using asphalt institute
(AI) distress prediction model. From the study, the results of road section number one, two and
three are drawn as (a) pavement thickness and strength (CBR) of granular base course (200
mm, 71%), (200 mm, 79%) and (200 mm, 71%) respectively. (b)For sub-base course pavement
thickness and CBR values are (200 mm, 31%), (175 mm, 33%) and (275 mm, 21%)
respectively. (c)Subgrade soil had infinite thickness with CBR value of 10%, 20% and 6%
respectively. (d)Asphalt concrete had similar thickness 50 mm for all section. (e) the Resilient
modulus (elastic modulus) of base course 269 Mpa, 288 Mpa and 267Mpa, sub-base course
158 Mpa, 165 Mpa and 123 Mpa, and subgrade soil 77 Mpa, 120 Mpa and 55 Mpa
respectively. It was concluded that from JULEA multilayer elastic analysis, vertical
compressive strain predicted as 0.075 damage ratio and 13 year of minimum pavement
performance. However, from ABAQUS nonlinear finite element analysis of section one, vertical
compressive strain value at top of subgrade soil predicted as 0.060 damage ratio and 16 year
of minimum pavement performance. Therefore, it is concluded that so that, 13 years are taken
as governing predicted performance year for Jimma-Bonga flexible pavement road.
