This paper describes the importance of the moisture-suction condition on the behaviour of expansive soils and its significance to road engineering in an arid climate. The Transport Research Laboratory has developed instrumentation and techniques to measure both the moisture and the suction beneath roads.
An example is given of some early results where the moisture and suction have been measured below a new road in an arid area. The results indicate that transient moisture-suction conditions as well as the equilibrium
conditions may be important to the road design engineer. The techniques can be easily used to evaluate the moisture and suction conditions beneath roads.
First International Symposium on Engineering Characteristics of Arid Soils, City University, London, 5-8 July 1993. TRL - Crowthorne, UK. pp. 18