India’s road network carries over 90% of passenger traffic and over 65% of its freight movement. Therefore, effective maintenance of road networks is to be accorded the highest importance. Assignin...

Prioritisation of pavement maintenance sections deploying functional characteristics of pavements

Les investissements des bailleurs de fonds et des gouvernements demeurent clairement insuffisants pour assurer le developpement et la preservation des reseaux routiers dans les pays d’Afrique subsaharienne (ASS). Les outils de gestion qui pourraient faciliter la prise de decisions economiquement viables et socialement acceptables pour la construction, la preservation et la rehabilitation durables des routes manquent. Les effets directs de ces lacunes sont la faible densite de routes revetues et la deterioration avancee des routes existantes.

Dans les pays d’Afrique subsaharienne, la prise en compte des aspects sociaux et environnementaux dans la prise de decision en gestion des chaussees est en effet tres limitee, voire inexistante.

C’est dans ce cadre, que cette these a pour objectif de proposer une approche qui permet de prioriser les projets de construction et de preservation de routes, en integrant les aspects techniques, economiques, sociaux et environnementaux, au niveau reseau puis au niveau projet.

Cette approche est basee sur l’indice de priorite de financement des routes (IPFR) pour la priorisation et la selection adequates des projets routiers au niveau reseau. Cet indice se base sur la saisie et l’analyse en composantes principales de donnees routieres pour en degager des indicateurs techniques, economiques, sociaux et environnementaux.

Dans la premiere partie de cette these, un IPFR est propose pour classer conjointement les deux types de projets routiers par priorite de financement. Par la suite, quatre projets de construction (bitumage de routes non-revetues) et six projets de preservation, totalisant 330 km de routes, ont ete selectionnes selon leur admissibilite au programme du bailleur de fonds et sur la base de leur IPFR. Ces projets prioritaires necessitent des investigations et des analyses approfondies au niveau projet, d’ou l’importance de developper des methodes rationnelles integrees.

Au niveau projet, deux methodes rationnelles integrees permettent de determiner respectivement les meilleures interventions de bitumage et d’entretien periodique.

Une premiere methode rationnelle integree est proposee dans la seconde partie de cette these afin de choisir les meilleures options de bitumage pour les routes non revetues. Cette methode est fondee sur le dimensionnement mecaniste-empirique et l’integration des aspects environnementaux et sociaux dans l’analyse economique conventionnelle via une analyse multicritere. L’option de bitumage en enrobe dense (ED), selectionnee grâce a cette methode, permet de maximiser la valeur actuelle nette et les avantages sociaux, d’ameliorer le confort au roulement et de reduire le risque d’accident ainsi que de reduire la pollution atmospherique.

Une deuxieme methode rationnelle est presentee dans la troisieme partie de cette these pour determiner les meilleures interventions d’entretien de routes candidates selon la reduction de consommation d’energie, la reduction des quantites et des couts des emissions polluantes (CCVEE), des couts totaux de transports (CTCV) et des contraintes budgetaires sur une periode de 20 ans. Les meilleures interventions choisies a l’aide de cette deuxieme methode sont des options d’entretien periodique permettant de reduire d’environ 23% la consommation d’energie, d’economiser environ 23 % des CCVEE et 30 % des CTCV.

En conclusion, cette these demontre l’importance et la possibilite d’utiliser le concept des routes durables par l’integration quantitative et qualitative des facteurs techniques, economiques, sociaux et environnementaux pour la gestion durable des routes en ASS aux niveaux reseau et projet.

Développement d’une approche pour la préservation et le développement d’un sous-réseau routier en Afrique subsaharienne

The combined influence of traffic and environment causes every pavement to deteriorate over time. Maintenance actions help to delay the rate of pavement deterioration. Pavement maintenance demand large amount of fund, resources and time. Prioritization of maintenance work enables to allocate fund and resources in an effective way based on the performance evaluation of the pavement section(s). There are different maintenance prioritization mechanisms exist to evaluate a pavement. From the review of past literature, it is observed that fuzzy logic has not been used to evaluate interlocking concrete block pavements (ICBP). This research is an attempt to implement fuzzy logic for the purpose of maintenance prioritization on ICBP. The distresses of ICBP considered in this study are rutting, depression and damaged paver blocks. The distress density is given as inputs in the fuzzy prioritization model. The outputs are the pavement condition index (PCI) and the maintenance strategy to be adopted. An experts’ survey was conducted to define the boundaries of the membership functions of the input (distresses) and output (PCI and maintenance strategies) parameters. The triangular membership function is used in this study. The maintenance strategies suggested are routine and preventive maintenance, major and minor rehabilitation and reconstruction. The fuzzy model developed in this work has been demonstrated with a case study.

Maintenance prioritization of interlocking concrete block pavement using fuzzy logic

A method was developed to recommend improvements for unsealed earth and gravel roads that are not up to the standard expected for their functional class. As part of a pilot asset management program carried out by the Wyoming Technology Transfer Center, roads were rated for several distresses, including corrugations-washboards, rutting, potholes, loose aggregate, drainage, dust, and overall condition by using a visual survey method. These ratings were used to calculate a surfacing serviceability index (SSI) for each road section. This SSI was compared with the minimum acceptable SSI for the section's functional class. When the section's SSI was below this threshold value, improvement tasks were selected from a decision matrix, and the most expensive task was recommended to address the section's inadequate surface condition. This process allows an agency to present its elected officials with a list of roads in their network that need improvement, along with an estimate of the cost of these improvements. The...

Improvement Recommendations for Unsealed Gravel Roads

The objective of this paper was to develop fuzzy models for asphalt pavement performance. The fuzzy logic can convert linguistic or qualitative variables into quantitative values. This feature makes it possible to gather experts’ experience about the knowledge they have on factors that affect the pavement performance and its state condition. Forms developed in an organized way were applied for acquiring the knowledge from experts on pavement construction and maintenance. The variables pavement age, traffic, International Roughness Index (IRI) and Flexible Pavement Condition Index (FPCI) were associated with numerical scales and linguistic concepts such as new, old, light, heavy, good, fair, and poor. From the information obtained through the application of forms, variables were modeled with the aid of software InFuzzy and fuzzy models were developed for IRI and FPCI. For validating the model, a straight line adjustment was used to relate the predicted to the observed data. Also, the corresponding correlation coefficient (r) was calculated and residuals were analyzed. The developed models fitted to observed data and correlation coefficient r = 0.71 and 0.70, respectively.

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Development of fuzzy models for asphalt pavement performance

A pavement management system formulated according to the specific needs and resources of a highway agency should ensure satisfactory pavement performance with minimal maintenance cost. The success of a pavement management system depends on the pavement condition data, accuracy of the prediction of pavement performance, and project-and network-level rehabilitation planning. Of these, the most labor-intensive, time-consuming, and costly component is the collection of pavement condition data. The inventory data include roughness, skid resistance, and surface distresses. Although mechanical instruments are available for rapid collection of roughness and skid resistance data, the collection of distress data for low-volume rural roads is still manual and hence labor-intensive and time-consuming. Subjective rating techniques prove to be a solution to this problem, but their reliability is poor due to the subjectivity associated with them. Therefore, there is a need for a rapid and cost-effective yet reliable met...

Kuncheria P Isaac

Papers

Prioritization of Low-Volume Pavement Sections for Maintenance by Using Fuzzy Logic