An experimental study of salt movement and accumulation within unsaturated granular road pavements

Concentration of salts within road pavements has been shown to cause damage to road surfacings and affect road pavement performance. The present study explores the mechanisms of road pavement salinisation with a focus on roads within areas at risk of environmental salinity. Soil columns of unsaturated compacted clay subgrade and road pavement material were established under laboratory conditions. A number of combinations of surfacing, pavement structure and saline bath solution were constructed. Volumetric water content and electrical conductivity was measured over a period of several months using on-sample instrumentation and destructive means. The experimental design and preliminary results from instrumented columns and destructive testing of one set of columns harvested after 6 weeks are discussed.