The difficulty of achieving optimum moisture content for the compaction of soils in arid areas is outlined, and past experience in soil compaction at low moisture contents is reviewed. The construction of a trial road embankment of a black silty clay in Sudan is described. The plasticity index of the fill material was 26-36 and it was compacted at its field moisture content, 20 per cent less than the Proctor optimum moisture content. Two types of rollers were used and densities ranging from 94 to 105 per cent of Proctor maximum dry density were achieved. In spite of the low moisture content at which it was compacted, this embankment has performed satisfactorily for a year and a half and the road it carries has suffered no ill effects. The implications are examined of using dry compaction for road construction on expansive clays in arid areas.
ELLIS, C I (1980). Soil compaction at low moisture content - field trials in Sudan. 7th Regional Conference for Africa on Soil Mechanics and Foundation Engineering, Accra, Ghana, 1- 7 June 1980. TRL