RESUMEN
Hydrochloric acid is prevalent in numerous industries; leakage of this acid may cause persistent problems in the soil. The study aims to prevent any adverse impact of acid on the strength characteristics of silty clay soil by modifying the soil's acid resistance. In this study, unconfined compression tests are performed to investigate the strength of contaminated silty clay soil with concentrations of 4%, 8%, and 12% of HCl solution and the strength of treated soil with 0.4%, 0.5%, 0.6%, and 0.8% of nano-magnesium oxide. In addition, the strength of the soil enhanced with nano-MgO contaminated with different concentrations of hydrochloric acid was investigated to assess the effect of nano-MgO on modifying the acid resistance of clay soil. Moreover, the FE-SEM test was performed to analyze the microstructure of the soil under different circumstances. Based on the results, the strength of clay soil decreased due to contamination with the hydrochloric acid solutions; the reduction in strength was more noticeable when the acid solution became more acidic. Adding 0.6% of nano-magnesium oxide enhances the strength by about 114%. Findings show that adding 0.6% nano-MgO to the soil before exposing it to hydrochloric acid can enhance its acid resistance; the strength of the treated soil with nano-MgO was better at resisting the acid than the untreated soil.
RESUMEN
Some Clayey soils are generally categorized as weak soils, and structures lying on such soils have been exposed to severe damage. Therefore, the central thesis of this paper is the impact of a waste material known as a silica fume as nano and micro material on soil's behaviour. To evaluate the effects of those additives on Atterberg limits, compaction characteristics and unconfined compressive strength, clayey soil samples have been transformed using micro and nano silica fume (by-product materials). In the current investigation, silica fume is used at four different percentages: 0, 2, 4, and 7%. The results show that the plasticity index of soil decreases with the addition of micro silica and increases with the addition of nano-silica. Increasing nano silica percentage improves the dry density of the compacted soil and reduces the optimum moisture content. An opposite behavior is observed with adding micro silica to compacted soil. Finally, 4% of silica fume is found to be the optimum dosage to improve the unconfined compressive strength of the treated soil with both additives. As a result, treating the weak clay soil with micro and/or nano-silica fume has the potential to be impactful.