Comparative Evaluation of Pavement Performance A Case Study on Bus stop stations in Addis Ababa
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Date
2017-11
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Addis Ababa University
Abstract
A pavement surface should be durable material, laid down on an area intended to sustain vehicular traffic load without any significant fail in any palace in the road network. Distresses are manifestation of pavement failure. Different types of distress are visible on bus stops areas of Addis Ababa roads with different level of surface condition. The present road condition of Addis Ababa bus stops areas shows rapid deterioration. The severity of pavement distresses is even more critical on the major bus-depots were the traffic volume of busses is comparatively higher than other bus stops found on the road network. This study cover on making assessment of asphalt pavement condition on bus stops areas, identifying causes of pavement distress. Visual distress assessment were carried out on selected test sections in order to have better understanding of the pavement on bus stop areas. The visual survey analysis indicates that almost all bus stops found in test roads have very low PCI value which rated as poor pavement surface but the bus-depots PCI values indicate that the pavement is failed.
The study also covers the design of both a cement concrete and flexible pavement with and without geogrid material and computation of respective costs over a study period of 30 years for the sections, to inform whether it will be cheaper to introduce concrete pavement on the bus stop or retain the flexible pavement. In addition to cost the study shows the performance of concrete pavement relative to flexible pavement using Kenpave software analysis.
To design the pavements and to do LCCA both primary and secondary data were collected. The traffic count data was used to come up with the pavement design details which included respective pavement layers, materials used and ultimately used for computation of unit costs for each pavement which was used for Present Worth economic evaluation method for life cycle cost comparison. From the evaluation of the study, flexible pavement was cheaper in initial construction however, over the analysis period, a concrete pavement are found more economical. And also in Kenpave software analysis concrete pavement is better in performance than flexible pavement. Addition of geogrid material to the pavement layer increase both the cost and performance of the pavement. It is therefore recommended that in the bus stop sections of the road, it would be preferably cheaper to introduce concrete pavement and have also good performance.
Keywords: Flexible pavement, Cement concrete pavement, Geogrid, Pavement distress, Life cycle cost comparison between concrete pavement and flexible pavement, Pavement performance.
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Keywords
Bus stop stations in Addis Ababa, Pavement