Unconfined compressive strength and freeze-thaw resistance of fine-grained soil stabilised with bottom ash, lime and superplasticiser

Non-traditional soil stabilisers for stabilising marginal soils could be a viable and alternative solution to traditional stabilisers in terms of cost prohibitive as well as enhancement of engineering characteristics. In this preliminary attempt of the study, an applicability of the superplasticiser, which is quite common in concrete production but not so in soil stabilisation, has been investigated for stabilisation of a fine-grained soil (low-plasticity clay) compared with the combinations of traditional stabilisers of bottom ash and lime, as an alternative non-traditional soil stabiliser. An extensive experimental programme including unconfined compressive strength (UCS) tests has been conducted for this aim. Based on the testing results, the engineering characteristics (i) the stress-strain curves, (ii) failure modes of specimens, (iii) UCS, (iv) elasticity modulus (Es) and (v) energy absorption capacity (Ed) [Consoli, N. C., Montardo, J. P., Prietto, P. D. M., & Pasa, G. S. (2002). Engineering behavior of a sand reinforced with plastic waste. Journal of Geotechnical and Geoenvironmental Engineering, 128(6), 462-472] of stabilised clay with superplasticiser, bottom ash and lime have been figured out for pre- and post-freezing and thawing conditions, with the discussion in detail. The results indicate that the superplasticisers separately or in combination with bottom ash and lime produce satisfactory engineering characteristics for stabilisation of clay for pre- and post-freezing and thawing conditions. The influences in the stabiliser combinations are statistically significant for the entire results of UCS (p-value < .05), which is moderately correlated with the Es and Ed. On the basis of the UCS values due to the requirements of the standard guide, the compositions including superplasticiser, lime, lime+superplasticiser, lime+bottom ash for non-freeze-thaw, lime+superplasticiser for freeze-thaw are found to effectively improve the native clay. The understanding from the findings with the discussions through the study is relatively promising for the use of superplasticiser in the soil stabilisation.