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Internal erosional behaviour of a lignosulfonate-treated
dispersive soil has been studied using apparatus designed
and built at University of Wollongong. The effectiveness
of lignosulfonate-treated dispersive clay on its erosion
resistance has been investigated and its advantages over
traditional admixtures (cement) have been presented.
Lignosulfonate is a non-toxic admixture that can stabilise
certain erodible and dispersive soils effectively, without
causing any adverse environmental impact on the
ground unlike some traditional stabilisers. Test results
show that the erosional parameters such as critical shear
stress and coefficient of soil erosion are improved with
the increase in the amount of lignosulfonate. Knowledge
about the clay particles and lignosulfonate interaction
mechanisms is pertinent for long-term environmental
sustainability of treated soils, a factor which is poorly
understood at microscopic level. Considering this, X-ray
diffraction, and Fourier transform infrared spectroscopy,
scanning electron microscopy and energy dispersive
X-ray spectroscopy were carried out on representative
samples to understand the stabilisation mechanism at
the particle scale level. The improvement of
performance exhibited by the lignosulfonate-treated soil
can be mainly attributed to the reduction of the doublelayer thickness by the neutralisation of surface charges of
the clay particles and the formation of more stable
particle clusters by polymer bridging.