Nanostructured Clay (NC) and the Stabilization of Lateritic Soil for Construction Purposes

Abstract

The use of Nanostructured Clay additive in lateritic soil stabilization and their effect at different percentages on the natural soil was investigated. The preliminary tests on the soil showed it was an A-2-7 soil, according to AASHTO classification. The soil sample was also observed to be silty clayey sand and the general rating as a sub-grade material was ‘GOOD’. The consistency limits result shows that the value of the LL for the natural soil is 47% and 25.15% was recorded for the plastic limit (PL) and finally the PI was 21.85% i.e. highly plastic soil. Further, the effect of the addition of NC in the proportions of 3%, 6%, 9%, 12% and 15% by weight of the stabilized Umuntu Olokoro lateritic soil was investigated. The consistency limits results showed that the addition of variable proportions of NC considerably improved the plasticity of the stabilized soil which gave 13.8%; a medium plastic material at 15% NC addition, compared to the preliminary result of 0% by weight additive which gave 21.85%; a highly plastic material. The strength properties’ test showed significant improvements with the addition of NC; CBR test result recorded 29% at 15% by weight proportion of NC which satisfies the material condition for use as sub-base material and the UCS test results similarly improved consistently and recorded a maximum UCS of 340.18kN/m² at 15% by weight proportion of NC addition which satisfies “very stiff” material consistency for use as sub-base material. With the foregoing, the addition of various proportions of NC to the stabilized lateritic soil has presented to be a Geotechnical solution to the varied environmental failures on the road pavements. Hence NC satisfies all the material conditions for use as a sub-base material for the stabilization and improvement of the strength characteristics of lateritic soils. Finally, we call on the relevant agencies to use NC as an additive in stabilizing weak lateritic soils for use as either sub-grade or sub-base materials to save both cost and the structural failures on the roads in south eastern Nigeria.

Keywords: Environmental Geotechnics; Pavement Geotechnics; Soil Stabilization; Weak Lateritic Soil; South Eastern Nigeria.