Deflection hardening of sustainable fiber–cement composites

Abstract

In the present study sisal fiber–cement composites reinforced with 4% and 6% of short fibers were developed and their physical–mechanical behavior was characterized. To ensure the composite sustainability and durability, the ordinary Portland cement matrix was modified by adding fly ash and metakaolin, and the natural aggregate was substituted by 10% and 20% of recycled concrete aggregate. Flat sheets were cast in a self-compacted cement matrix and bending tests were performed to determine the first crack, postpeak strength and toughness of the composites. Cyclic flexural tests were carried out to determine the stiffness variation of composite due to cracking formation and propagation. It can be seen that the reinforcement provided by short sisal fibers for recycled cement matrices guaranteed a composite with multiple cracking and an increase of strength after the first crack. Reduction of stiffness and increase the damping capacity of composite are verified with progressive cracking.