Bituminous pavement rehabilitation design

Abstract

South Africa is a country fortunate in possessing a well developed network of paved roads that provides a basic and often overlooked facility for the social and economic welfare of the country. However, an accute shortage of funds available for pavement rehabilitation is endangering the integrity of this network, making continuous research for improved and more economical rehabilitation procedures necessary. I believe that this thesis, provides in a need for improved techniques, as a uniform approach is advocated, incorporating the best available procedures applicable throughout the country. In compiling the document, specific attention was given to current South African practice, ensuring that the recommended procedures are based on the use of readily available equipment and techniques familiar to engineers in this country. Guidelines to all the main stages of rehabilitation investigations are contained in a logical and systematic procedure of investigation, evaluation, analysis, rehabilitation design and finally. economic appraisal of applicable options. In the process full use is made of past pavement behaviour and pavement condition, thereby making possible an early assessment of additional information needed. Although evaluation and analysis procedures are suggested for use, no formal method in this regard is excluded, provided the method is relevant to the case and information obtainable will benefit the analysis in terms of the probable influence on the best rehabilitation strategy to follow. By assessment of the value of information obtainable, much emphasis is placed on the optimum utilization of available resources in designing the best applicable remedy to an existing problem. This procedure is demonstrated by the inclusion of a study that I undertook in co-ordination with the Transvaal Roads Department for the NITRR. This case study demonstrates the applicability of the various evaluation, analyses and rehabilitation design methods, and the use of decision trees in an economic analysis to select the best applicable rehabilitation option. In conclusion the consequences of implementation to date are investigated. Recommendations for further research and possible improvements for future revisions of the recommended procedure are finally looked at.