Influence of fly ash and polypropylene fiber on raveling resistance, sound absorption, and environmental impact of porous concrete
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Department of Environmental Engineering, Hasanuddin University
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Bambang Bakri
Department of Environmental Engineering, Hasanuddin University
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ABSTRACT
This study investigates the influence of fly ash (FA) and polypropylene (PP) fiber on raveling resistance, sound absorption, and environmental impact of porous concrete. Four mixtures were prepared, including a reference mix (RM), a PP fiber-reinforced mix (M1), and two mixes incorporating FA at 15% (M2) and 30% (M3) substitution levels. Durability was assessed by the raveling resistance, sound absorption coefficient (SAC) by an impedance tube, and environmental performance by embodied energy (EE) and carbon footprint (CF), with efficiency indices calculated. Results indicate that PP fibers decreased the mass loss by 42% compared to RM and improved SAC values up to 0.92 at 630 Hz, reflecting enhanced raveling resistance and mid-frequency absorption. In contrast, FA substitution reduced EE from 2571.8 MJ/m³ (RM) to 2369.0 MJ/m³ (M3) and lowered CF from 452.9 to 363.9 kgCO₂-eq/m³, representing up to 19.6% environmental improvement, but increased mass loss and reduced SAC when combined with PP fibers. Overall, PP fibers primarily enhanced durability and acoustic efficiency, whereas FA provided clear environmental benefits, though trade-offs emerged when used together.