Mechanical Properties and durability of clayey subgrade stabilized with iron ore mine tailing and hydrated lime

An appropriate solution for dealing with low-resistance and problematic soils is stabilization of the soil. Also, exploitation and use of mineral resources generates a lot of mine tailings. Increasing the production of these tailings has created a significant concern for the mining authorities, regarding to achieve more depot space and environmental issues caused by waste deposits. The purpose of this research is to stabilize red clay with hydrated lime and iron ore mine tailings. For this purpose, samples with 0, 2, 4 and 6% lime and 0, 10, 20 and 30% of iron ore tailings dense and prepared in three percent moisture content (optimum, wet side and dry side). In order to perform unconfined compression strength (UCS), the specimens were treated for 7, 28 and 56 days. Unconfined compressive strength test showed that by increasing lime content up to a specific value, the UCS increases, and increasing the amount of lime content to more than it will reduce the UCS of samples when the content of iron ore mine tailing remains constant. In addition, the UCS and elastic modules decrease with increasing moisture content and vice versa. The UCS of the 7-day, 28-day and 56-day samples increses 84 to 259%, 97 to 290% and 110 to 342%, respectively, in terms of lime percentage, Iron ore mine tailing percentage and moisture content. Also, the freezing and thawing test showed that by increasing the iron ore mine tailing up to a specific value (2 to 4%), reduces the weight and volume loss of samples, and after that the weight and volume loss increase. Results of this study confirms that the optimum percentage of hydrated lime is 2 and 4%, regrading to 20 and 10 percentage of tailing, respectively by considering both UCS and freezing and thawing criteria.