Integrated geotechnical and mineralogical evaluation of the subgrade of some failed pavements along Enugu-Onitsha expressway Southeastern Nigeria.

This research is focused on the constant pavement failure in parts of the Enugu-Onitsha expressway. The failed portions are constructed on the natural subgrade known to be the Shale of Enugu and Mamu formations southeastern Nigeria. Five samples each were obtained from the formations and were subjected to geotechnical test, mineralogical analysis, scanning electron microscopy (SEM) and, statistical analysis.