Impact of lime kiln dust on the mechanical properties and freeze-thaw durability of nanoclay-stabilized kaolin soil

Stabilization of clayey soils using traditional stabilizers such as lime and cement raises significant environmental concerns. Recent studies have shown that despite the strength limitations of nanoclay (NC) and the slow rate of pozzolanic reactions associated with lime kiln dust (LKD) in soil stabilization, these materials exhibit promising performance as environmentally friendly stabilizers. This study investigates the combined effects of NC and LKD with the aim of overcoming these limitations and improving the mechanical behavior and durability of kaolin soil. Laboratory testing included mechanical and durability tests supported by microstructural analyses. The results indicate that the addition of LKD to NC-treated soil resulted in an approximately tenfold increase in both unconfined compressive strength and indirect tensile strength. These improvements are attributed to pore filling by NC and the occurrence of pozzolanic reactions induced by LKD, leading to the formation of C–S–H and C–A–H gels. Mechanical strength increased with curing time due to the gradual completion of pozzolanic and hydration reactions. Furthermore, the stabilizers improved durability and CBR values, reduced the required pavement thickness by 65.7%, and resulted in significant cost savings in highway construction. In addition, compared with cement and lime, the use of these additives reduced CO₂ emissions by approximately threefold and decreased energy consumption by more than tenfold. • Kaolin soil stabilized using nanoclay (NC) and Lime Kiln Dust (LKD). • NC and LKD increased strength by pozzolanic reaction and viscous gel formation. • NC and LKD improved UCS, ITS, CBR and durability under freeze–thaw cycles. • NC and LKD reduced asphalt thickness, notably lowering pavement construction costs. • LKD and NC, serves as an eco-friendly solution for kaolin stabilization.