Experimental Investigation of Fiber-Reinforced Cement-Stabilized Fly Ash for Pavement Structural Layers

The increasing generation of fly ash from thermal power plants has created significant challenges related to its disposal and environmental management. At the same time, the construction of pavement infrastructure requires large quantities of suitable materials for subgrade, sub-base, and base layers. The utilization of fly ash as a pavement construction material provides an opportunity to address both problems through sustainable engineering practices. However, the relatively low strength, high compressibility, and sensitivity of untreated fly ash restrict its direct application in structural pavement layers. The present study investigates the improvement of fly ash through stabilization with cement and reinforcement with fibers. Cement was incorporated to promote bonding and pozzolanic reactions, while discrete fibers were introduced to improve tensile resistance, crack control, ductility, and load-transfer characteristics. The engineering behavior of the stabilized and fiber-reinforced fly ash was evaluated using compaction, unconfined compressive strength (UCS), and California Bearing Ratio (CBR) tests. The experimental results indicate that cement stabilization significantly improves the strength characteristics of fly ash. Increasing cement content results in an increase in water demand because of cement hydration and particle interaction. The maximum dry density initially shows minor variation and subsequently increases with cement addition. The addition of fibers further enhances the mechanical performance by providing reinforcement and restricting crack propagation. The combined use of cement and fibers therefore offers considerable potential for converting fly ash into a value-added material for pavement structural layers. The study demonstrates that fiber-reinforced cement-stabilized fly ash can contribute to sustainable pavement construction while reducing dependence on conventional natural aggregates and providing an environmentally beneficial method for fly ash utilization.