Effect of adding nano-calcined clay and nano-lime on the geotechnical properties of expansive clayey soil

Abstract

The objective of this paper is to investigate the effect of nano-calcined clay (NCC) and nano-lime (NL) on some engineering properties of the expansive clayey soil. Three soil samples quarried from three different sites in the south of Syria have been investigated. They were thermally treated up to three different levels (450, 650 and 850°C) for 3 hours. Then, they were ground to have a particle size of less than 100 nano-meter. Three replacement levels of NCC were used, i.e. 0%, 1% and 2%. XRD technique has been employed to detect the phases occurring in the clayey samples before and after the thermal treatment. Pozzolanic activity of the calcined clayey soil has been studied using the modified Chapelle test. Atterberg limits, compaction, free swell, swelling pressure, linear shrinkage, shear strength and CBR have particularly been investigated. Test results revealed the positive effect of NCC. Plasticity index (PI) was reduced by more than 50% when 2% NCC was added to the natural soil. In addition, 0.6% NL was added to further investigate the combined effect of NL and NCC on the properties of the clayey soil. All investigated properties were significantly improved when NCC and NL were added together, i.e. swelling pressure and linear shrinkage values were reduced to less than 15% when compared with those of the natural soil.

Effect of Nano-Silica on Consolidation and Permeability Properties of Lateritic Soil

“…The increase in pre-consolidation pressure could be as result of changes in mechanical behaviour of the treated soil due to nano-silica particles within the soil matrix which has high specific surface and hence increased reactivity leading to formation of strength enhancing compounds such as hydrated calcium silicates and aluminate (Salwa et al 2015;Nabanita et al, 2016;Eswaramoorthi et al, 2017;Al-Swaidani et al, 2019). Effect of nano-silica on compression Index: The variation of compression index, Cc, with increased percentages of the nano-silica and different curing periods is shown in Figure 3.…”

“…In geotechnical engineering, the technology is applied by introducing nanoparticles to the soil with a view of enhancing the overall engineering performance of the targeted soil. Some researchers (Ghazi et al, 2011;Alireza et al, 2013;Pham and Nguyen, 2014;Ramesh and Chandrika, 2017;Eswaramoorthi et al, 2017;Ran et al, 2018;Al-Swaidani et al, 2019) have used nanoparticles to enhance engineering behaviour of marginal soils. The introduction of nano particles into the soil alters the chemical as well as the physical behaviour of the soil owing largely to increased specific surface of particles at nano level, morphological changes as well as increased surface charges (Salwa et al, 2015).…”