Donor and government investments remain insufficient to ensure the development and preservation of roads in Sub-Saharan Africa countries (SSA). Management tools that could help the decision-making process regarding the sustainable construction and preservation of roads are lacking. The direct effects of these shortcomings are the low density of paved roads and the increase of the deterioration rate of existing roads.
In SSA, social and environmental aspects are rarely included in pavement management decision-making process.
The objective of this thesis is to develop an approach for the prioritization of road construction and preservation projects by integrating technical, economic, social and environmental aspects at the network level, and then at the project level.
This approach is based on the Road Funding Priority Index (RFPI) for the appropriate prioritization and selection of road projects at the network level, and two integrated rational methods for the respective choices of the best road upgrading alternative and the best road periodic maintenance alternatives at the project level.
In the first part, a RFPI is proposed to rank the two types of road projects (construction and preservation projects) in order of priority. This index is based on principal components analysis of road data to include technical, economic, social and environmental indicators. Subsequently, ten high-priority road projects, totaling 330 km including four construction projects (upgrading of unpaved roads) and six preservation projects are selected according to their eligibility to the donor road funding program and their RPFIs. These high-priority roads projects are candidate sections to upgrading and periodic maintenance alternatives requiring in-depth investigations and analysis at the project level, hence the importance of establishing integrated rational methods.
In the second part of this thesis, an integrated rational method is proposed to choose the best upgrading alternative for unpaved road sections (high-priority road construction projects). This method is based on mechanistic-empirical pavement structural design and the integration of environmental and social aspects into the classic economic analysis via a multi-criteria analysis. The asphalt concrete (AC) upgrading alternative selected using this method, maximize net present value and social benefits, and reduce the risk of accidents and air pollution.
In the third part of this thesis, a second integrated rational method is suggested to choose the best road preventive maintenance alternatives (best periodic maintenance activity) according to the reduction of energy consumption, the savings of pollutant emissions costs (CCVEE) and total transport costs (CTCV), and budget constraints over a period of 20 years during the pavement operation phase. The best preventive alternatives selected based on this method are periodic maintenance activities that reduce approximately 23% of the total vehicle consumption energy (EGLOB) and save approximately 23% of the CCVEEs and 30% of the CTCVs.
This thesis highlights the importance and demonstrates the possibility of using the concept of sustainable roads with the quantitative and qualitative integration of technical, economic, social and environmental indicators and criteria for the sustainable management of roads in SSA at the network and project levels.
| Date | 7 Apr 2020 |
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| Original language | French |
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| Awarding Institution | - École de technologie supérieure
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| Supervisor | Gabriel J. Assaf (Supervisor) |
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Kaba, E. K. (Author),
Assaf (Supervisor),
7 Apr 2020Student thesis: Doctoral thesis › Doctorate in Engineering: Engineering