Assessment of Strength Development in Stabilized Soil with CBR Plus and Silica Sand

This paper investigates the potential use of a nano polymer stabilizer, namely CBR PLUS for stabilization of soft clay and formulation of an optimal mix design of stabilized soil with CBR PLUS and silica sand. The highway settlements induced by the soft clay are problematic due to serious damages in the form of cracks and deformation. With respect to this, soil compaction and stabilization is regarded as a viable method to treat shallow soft clayey ground for supporting highway embankment. The suitability of stabilized soil was examined on the basis of standard Proctor compaction, California Bearing Ratio (CBR), unconfined compression, direct shear and permeability falling head tests. Furthermore, the chemical compositions of the materials were determined using X-Ray Fluorescence (XRF) test. The objectives of this paper are (i) to stabilize the compacted soil with CBR PLUS and silica sand in the laboratory; and (ii) to evaluate the strength and CBR of the untreated and stabilized soil specimens. It was found that the optimal mix design of the stabilized soil is 90% clay, 1% CBR PLUS, 9% silica sand. It is further revealed that, stabilization increases the CBR and unconfined compressive strength of the combinations by almost 6-fold and 1.8-fold respectively. In summary, a notable discovery is that the optimum mix design can be sustainably applied to stabilize the shallow clay without failure.