Paper presented at the 31st Annual Southern African Transport Conference 9-12 July 2012 "Getting Southern Africa to Work", CSIR International Convention Centre, Pretoria, South Africa.
The moisture-density (MDD) graph can be replaced by the voids ratio-water ratio graph (ER graph) which is a more suitable indicator of soil strength. The voids ratio E, and the
water ratio R, are ratios of volume and are the true parameters of a soil’s strength, being
independent of mass. Mathematical equations for the E-R and MDD curves are developed enabling the peak condition of strength to be obtained from only one M/D test if the soil’s particle relative density is known. Compression strength (resistance to further densification) and CBR strength (resistance to particle dislocation) are related and the insitu and soaked CBR for a compacted soil layer can be assessed by graphical or mathematical means.
