Pavement Performance Evaluation And Maintenance Decision-making In Rwanda

In the process of using the highway pavement,under the influence of various uncertain factors such as the environment and climate,the increasing of traffic load year by year,the maintenance and repair level of the maintenance management unit,the pavement service performance will show a trend of attenuation,with different degrees of damage,among which rutting and transverse cracks are the most common types of damage,which not only reduce the pavement performance serviceability,It will even cause fatal damage to the road surface,increase the traffic cost of vehicles,and shorten the service time of the road surface.Therefore,maintaining good pavement performance is the precondition for the road to provide safe,fast and comfortable driving,and pavement maintenance is the necessary condition for the road to maintain good performance,which can be divided into daily maintenance and regular maintenance?The American Association of State Highway and Transportation Officials(AASHTO)defines pavement management as the effective and efficient directing of the various activities involved in providing and sustaining pavements in a condition acceptable to the travelling public at the least life cycle cost.The General Directorate of Highways allocates millions of resources for lots of works such as the routine maintenance of pavement,traffic services,fighting against snow and ice,and the prettifying of roadsides every year,then,it is very essential that maintenance-repair works must be considered beforehand ?With the increasing maintenance cost,many road organizations cannot meet the needs of all road maintenance projects.Therefore,the maintenance work must be carried out scientific decision-making.Rwanda is one of the fastest growing countries in East Africa,and it invests a lot of money in infrastructure construction(housing,transportation,etc.)every year.However,with the increase of traffic load and pavement age of Rwanda's road network,the proportion of road pavement that needs to be maintained every year is also increasing.Under the condition of limited investment in pavement maintenance in Rwanda,due to the lack of scientific and systematic decision-making methods and decision-making aids,most of the organization staff in most regions make decision-making of pavement treatment based on their own experience and judgment.Rwanda's highway organizations urgently need a scientific pavement maintenance decision system(PMS)to provide basis for maintenance and repair decisions.Rwanda's maintenance department makes the decision of pavement maintenance as reconstruction after serious pavement damage,and rarely carries out the performance maintenance after scientific maintenance decision.At the same time,Rwanda's road management department does not pay attention to the collection and preservation of pavement use data.The type and quality of these data are not up to standard,which makes it impossible to analyze the cost-effectiveness of existing maintenance countermeasures.In order to make the data available for analysis and research,the research data must include: Road section name,road section stake number,management and maintenance unit,road condition survey date,pavement performance data,road section grade,performance report,road maintenance history.Timely collection of road condition data can effectively evaluate the performance of the pavement,provide the deterioration curves of the pavement,and make scientific maintenance decisions for the pavement.The purpose of this study is to recommend the maintenance decision system to Rwanda road network agency and other relevant organizations in charge of roads as a strategy to provide objective information and useful data to any road manager or customer for analysis,so as to make the maintenance decision more scientific,cost-effective and defensible decisions related to the maintenance of the road network.The result shows that precipitation and CBR found to be a significant predictor for both deflection and IRI on Rwandan flexible pavement performance and CBR is strongly correlated with precipitation.The analysis also shows that considered Predictors for the research are strongly related to the Deflection model more than to IRI model.Therefore,the climate input precipitation was found to be a more important factor for predicting different pavement performance in Rwanda,for further studies the temperature and Pavement Condition Index(PCI)need to be collected and analyzed,and then the results would be compared.Decision tree has been also suggested to support the greater effectiveness of decision making and program development in Rwanda pavement performance evaluation for Maintenance decisions and be able to select at right time the most appropriate preventive maintenance treatments for a particular pavement by improving the efficiency of decision-making involving in pavement management activities.Therefore this research will be a good manual to provide feedback on the consequences of future decisions by being able to predict the right time to apply a right treatment to achieve and sustain a desired level of service at the minimum practicable life-cycle and Facilitate communication,cooperation,and coordination of pavement management activities within an agency in Rwanda.