Integrated Experimental and Microstructural Analysis of Basalt Fiber- Reinforced Cemented Soils: Multivariable Strength Prediction and Residual Behavior Assessment

This study investigates the mechanical performance and internal structure of cement-stabilized clay reinforced with basalt fibers, aiming at geotechnical applications. A total of 36 mix designs were tested, varying in cement content (4%, 8%, and 12%), fiber content (0%, 0.4%, 0.8%, and 1.2%), and curing periods (7, 14, and 28 days). Unconfined compressive strength (UCS) and residual strength were measured to assess both peak and post-peak behavior. The inclusion of basalt fibers notably enhanced strength and ductility, particularly at 0.8% and 1.2% fiber content. Strength development was also positively influenced by higher cement content and extended curing time, with significant improvement observed after 28 days. Scanning electron microscopy (SEM) revealed dense bonding zones between fibers and the cement matrix, supporting improved crack resistance and stress transfer. Statistical analyses, including multivariable regression and ANOVA, confirmed that cement, fiber dosage, and curing duration significantly influenced strength outcomes. The UCS model achieved strong predictive accuracy (R² = 0.82), while the residual strength model showed moderate correlation (R² = 0.48). These findings highlight the potential of basalt fiber-reinforced cemented soils for civil engineering applications that demand enhanced durability, ductility, and post-failure resilience, such as subgrades, embankments, and slope reinforcement.