The utilization of active recycled powder from various construction wastes in preparing ductile fiber-reinforced cementitious composites: A case study

This work studies the feasibility of using recycled powder (RP) from construction waste to prepare fiber-reinforced cementitious composites (FRCC). The activity index of recycled powder from various construction wastes is 73.5-82.6% when RP particle size is lower relative to cement, and RP can be used as alternative binder in cementitious composites. The micro structure of RP is irregular, and the added RP decreases the hydration products and matrix strength of its prepared cementitious composites. The flexural load and displacement of RP-prepared FRCC increase with increasing dosage of PVA fiber. The utilized RP decreases the ultimate flexural load of FRCC, while increasing the ultimate flexural displacement. A good strain-hardening behavior occurs when high-volume RP incorporates, and multiple cracks form and distribute on the surface of RP-prepared FRCC; moreover, the decreased RP particle size improves the strain-hardening characteristic of its newmade FRCC. Keeping the substitution rates of fly ash and RP are the same, the ultimate flexural displacement and load of FRCC including RP are lower and higher than those of FRCC including fly ash, respectively. The utilized RP reduces the compressive strength of prepared FRCC, but the flexural strength to compressive strength ratio increases with increasing RP replacement ratios in FRCC. The addition of RP increases the toughness index of FRCC by 4.2-14.1% relative to FRCC without RP.