FLEXURAL PERFORMANCE UNDER WET-DRY CYCLES OF CEMENT-EUCALYPTUS ASH CRUSHED ROCK REINFORCED WITH POLYPROPYLENE FIBERS

Abstract

Cement-treated base incorporating eucalyptus ash (CTB-EA) is a promising pavement material due to its high strength and potential sustainability benefits. However, CTB-EA generally exhibits brittle behavior under flexural loading, resulting in limited post-cracking load-carrying capacity and energy absorption. Therefore, this study investigated the effect of polypropylene fiber reinforcement on the flexural performance of CTB-EA. Flexural tests were conducted in accordance with ASTM C1609 using fiber contents ranging from 0 to 1.25% by volume. In addition, the durability of the material was evaluated under 0, 1, 3, 6, 9, and 12 wetting–drying cycles. The results showed that the incorporation of polypropylene fibers significantly improved the residual flexural strength and toughness of CTB-EA. When the fiber content exceeded 0.50% by volume, the material behavior changed from deflection-softening to deflection-hardening, indicating a transition from brittle to ductile behavior with enhanced post-cracking performance. Among the investigated mixtures, a fiber content of 0.75% provided a favorable balance between flexural strength, residual strength, and toughness. Wetting–drying cycles progressively deteriorated the flexural performance of all mixtures due to the development of microcracks and degradation of internal bonding. Nevertheless, fiber-reinforced specimens maintained considerably higher toughness and post-cracking load-carrying capacity than the unreinforced mixture, even after 12 wetting–drying cycles. The findings demonstrate that polypropylene fibers effectively enhance the flexural performance, toughness, and durability of CTB-EA under wetting–drying conditions, thereby improving its suitability for pavement base applications.