Unsaturated soil mechanics in the design and performance of pavements

Pavements are designed using assumed moduli of the layers and permanent deformation properties of the base course in order to account for the effects of traffic and the weather on the long term performance of the pavement. Performance includes the rate of development of roughness, rutting, and various forms of cracking. However, when the pavement is constructed, acceptance of the project rarely includes verifying that the as-built pavement has the properties that were assumed when it was designed. This paper shows how the use of the principles of unsaturated soil mechanics brings us closer to being able to both design and verify the design assumptions as part of the construction quality control and quality assurance process. The Soil Water Characteristic Curve (SWCC) and a new characteristic, the Soil Dielectric Characteristic Curve (SDCC) are of central importance to these processes and can be easily constructed using simple laboratory equipment that is robust enough to take into the field and on to a construction site. The importance of suction in controlling the important performance related properties of pavement layers is illustrated with several examples relating to different forms of pavement distress in which suction plays an important role. 2013 Taylor & Francis Group, London.

Unsaturated soil mechanics in the design and performance of pavements Conference Paper