Effects of Propylene Fiber and Nanosilica on Failure Mechanisms of Cement‐Stabilized Clay Subjected to Freeze–Thaw Cycles

ABSTRACT Construction of civil engineering structures on clay soils in cold areas can cause structural fracture/damage due to settlements from freeze–thaw (F–T) cycles. This study investigates the effects of propylene fiber and nanosilica on the mechanical and microstructural properties of cement‐stabilized clay in F–T conditions. Various tests measured unconfined compressive strength (UCS), stress–strain behavior, energy absorption capacity ( E u ) representing the energy to fracture, secant modulus ( E 50 ), and volume change (Δ V ) of the samples. Ductility/toughness was assessed using E u , whereas Δ V was used to evaluate cracking potential. The findings show that optimal amounts of fiber (0.2%) and nanosilica (2%) improve strength, but adding more reduces it. As evidenced by E u , fiber addition boosts energy absorption due to increased strain. Physicochemical analysis indicates that fibers improve mechanical interlocking. Furthermore, nanoparticles enhance cement efficiency by boosting chemical reactions due to their large surface area and filling voids with cementitious gels.