Méthodologie de réhabilitation des chaussées au point de vue technique, économique et environnemental pour l'Afrique Subsharienne

Abstract

Rehabilitation is an integrated management process with a goal to maintain adequate road conditions structurally, reinforce their structures as needed and extend their service lives. Given that any road network is subject to the adverse effects of normal ageing combined to heavy traffic and weathering, commonly noted worldwide is the deterioration of the world highway system in general. This deterioration has important implications not only on user satisfaction but also on vehicle operating costs, on agency costs, and consequently on the economy in general. This has also equally important implications on the environmental footprint of our road infrastructure. This thesis aims at integrating technical and economical requirements and environmental constraints related to pavement rehabilitation, on a systems decision platform which would enable to place all considerations under the same multidimensional referential. This is justified in order to maximize the return on the investment, so that: benefits may be used to invest in other profitable projects, to help engineers identify the most appropriate intervention and to reduce greenhouse gas effects and energy use per vehicle, which would enable to fight efficiently against climate change. A validation study is carried out to compare many rehabilitation options on a stretch of almost 120 km of the RN2 road in the north of Senegal, according to this triple bottom line approach which involves a technical analysis based on the cause of deterioration and an economic and environmental analysis based on HDM-4 of the Permanent International Association of Road Congresses (PIARC) for the choice of the optimal economic and sustainable solution. The validation process demonstrated the applicability of the technical portion of the methodology and its usefulness by highlighting why the pavement had failed, a determining factor that was overlooked by the consulting engineer hired to design the solution and prepare the bidding documents. The results of the validation also highlighted the importance to use concrete roads in sub-Saharan Africa as they provide: • a better ride (IRI of 1 to 2,1mm/m over 20 years) than an asphalt pavement over time which is higher than that obtained with an asphalt pavement; • a savings of a USD 266 667 USD/km over the do-nothing strategy; • an energy saving of about 30% over the do-nothing strategy; • and CO2 emission reduction of about 32% over the do nothing strategy. All of these represent a considerable gain in technical and economic terms and in the joint fight against climate change.

Date	8 Aug 2016
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Gabriel J. Assaf (Supervisor)