STABILISATION OF NIGER DELTA FAT CLAY WITH BLEND OF BINDERS FOR SUBGRADE APPLICATION - PART 1
Construction of roads on fine-grained soils without any form of stabilisation is a major problem all over the world. In this study, a fat clay having poor subgrade rating (A-7-6) was mixed with blends of sand, drill cuttings ash (DCA), lateralite, and Portland Cement (PC) to improve its plasticity, California Bearing Ratio (CBR), and swell. The sand effected better particle grading of the clay and addition of PC increased its strength. Blends of DCA-PC and lateralite-PC effected friability, improved workability, and also increased the strength of the soil. Blends ratio: sand-PC (4:1); DCA-PC (1:1); and lateralite-PC (2:1) gave the best stabilising effect on the fat clay. The improvements noted were: plasticity index < 30, soaked CBRvalues > 20% after 24 hours and >10% after 96 hours, low swell (0.002 â€“ 0.008%). Thus, this study revealed that the fat clay could be optimised for subgrade application using these stabilising additives.