Characterisation of the elastic properties of existing pavements : state of the art

Abstract

Various aspects of the determinations and use of elastic moduli of pavements materials are herein addressed. Included is an investigation into the sensitivity of pavement life to changes in elastic material parameters, an update of moduli derived from Multi-Depth Deflectometer test results, a brief investigation of different back calculation techniques and a literature survey concentrating on information considered applicable to South African conditions. Recommendations are made regarding techniques or approaches used to determine elastic moduli rather than giving ranges of values form materials. Emphasis is placed on the concept of "expert intervention" in the design and assessment of pavements due to complex interaction of various factors. These include environmental, loading, materials and construction considerations. A reliable, fully automated, computerised system taking all these factors into consideration is at present not feasilble. Areas where further work is required are noted and recent publications on some of the "new" techniques of material testing are included.