A thesis submitted in partial fulfilment of the requirements for the degree of Master of Engineering, School of Engineering and Technology

Thesis (M. Eng.) - Asian Institute of Technology, 1981

Significant developments in the field of flexible pavement design and evaluation, and the role of the Benkelmen beam in the evaluation of flexible pavements over the last four decades, are reviewed and presented. The research background and the information required to make and interpret deflection measurements are presented along with discussion of the observations obtained for one highway site in Thailand. An idealised representation of the pavement system is described in order to define the aims of the evaluation process and the factors to be considered in achieving these aims. Pavement evaluation by deflection measurements at a site in Central Thailand produced a considerable amount of technical information on the use of the Benkelman beam for pavement design over soft soils. It was found that a seasonal deflect ion effect occurred on t he soft deltaic soils of the central plain of Thailand, and that an early life deflection of 0.5 mm of the 50-mm thick asphalt concrete surfacing (overlying a crushed rock base) indicated a life of 500,000 standard axles in this environment. Finally, a set of objectives for further developments of the deflection approach to design is proposed.