Author(s): Sinta Rahmadani and Ahmad Prasetyo

Abstract: This study investigates the mechanical and durability performance of sustainable concrete incorporating recycled aggregates (RA) and industrial byproducts as supplementary cementitious materials (SCMs), including fly ash, silica fume, and ground-granulated blast-furnace slag (GGBS). The experimental program evaluated four concrete mixes with varying proportions of recycled aggregates (0-75%) and SCM replacements (0-40%) to assess compressive strength, tensile strength, modulus of elasticity, water absorption, sorptivity, and rapid chloride penetration. Results demonstrated that increasing RA content generally reduced compressive strength and durability due to higher porosity and weaker interfacial transition zones, while the inclusion of SCMs substantially mitigated these effects by densifying the matrix and refining pore structure. The 90-day strength gain confirmed the long-term pozzolanic activity of SCMs, and chloride permeability decreased notably at 20-30% SCM replacement, even in mixtures containing moderate levels of recycled aggregates. Statistical analysis using ANOVA confirmed that the influence of combined RA-SCM replacement levels on strength and permeability was significant (p < 0. 05). Microstructural analysis further revealed that SCM-blended concretes exhibited a compact interfacial transition zone and reduced microcracking, supporting enhanced durability. The study concludes that concrete containing up to 50% recycled aggregates with 20-30% SCM replacement can achieve a balance between sustainability and structural performance, making it suitable for general-purpose structural and non-structural applications. Practical recommendations include pre-treatment of recycled aggregates, optimized curing regimes, and adherence to performance-based mix design approaches to ensure consistent field performance. These findings contribute to advancing sustainable construction practices and reducing the environmental impact of concrete production through the effective reuse of waste and industrial byproducts.

Pages: 32-36 | Views: 8 | Downloads: 3

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