Article 2025 · 2 citations

Comprehensive evaluation of fresh, mechanical, durability, and thermal properties of one-part alkali-activated slag composites with hybrid fibers and activated carbon

Bekiroglu, Ridvan, Bayraktar, Oguzhan Yavuz, Benli, Ahmet, Yilmazoglu, Mehmet Ugur, Turkel, Ihsan, Kaplan, Gokhan

Abstract

The incorporation of activated carbon (AC) into construction materials offers a sustainable pathway for valorizing agricultural waste, enhancing certain performance aspects, and reducing the environmental footprint of cementitious systems. In this study, the effects of coconut-shell-derived AC and hybrid fiber reinforcement on the mechanical and durability properties of one-part alkali-activated slag composites (AACs) were evaluated. Sixteen mixtures were produced by replacing ground granulated blast-furnace slag (GBFS) with AC at 0 %, 7.5 %, and 15 % by mass, and adding 2 vol% total fibers as glass fiber (GF), polypropylene fiber (PPF), or hybrids. Increasing AC content consistently reduced flowability (up to -11.8 % at 15 % AC) and oven-dry density (from 2226 kg/m(3) in reference to 1985 kg/m(3) at 15 % AC + 2 % PPF) while increasing porosity (from 3.66 % to 13.09 %) and water absorption (from 2.59 % to 6.77 %). The reference mixture reached 28-day compressive and flexural strengths of 47.73 MPa and 2.49 MPa, respectively. The highest compressive strength (48.61 MPa) was obtained with 0 % AC + 2 % GF, while 15 % AC + 2 % PPF yielded the lowest (26.17 MPa). PPF-rich systems delivered the best flexural performance (up to 4.34 MPa at 0 % AC + 2 % PPF) and minimized drying shrinkage (601 mu epsilon vs. 1065 mu epsilon in unreinforced control). Sorptivity increased markedly with AC (1.19 -> 5.84 kg/m(2)), especially in GF-rich blends. After 300 degrees C exposure, several mixtures gained strength (+14.35 % for 0 % AC + 2 % PPF), but at 600 degrees C losses reached -45.36 % (15 % AC + 2 % PPF) and at 900 degrees C all mixes lost > 76 % of initial strength. After 90-day immersion, 10 % H2SO4 caused up to 53.6 % strength loss, whereas Na2SO4 attack resulted in minimal losses (as low as 3.44 % in 85 % GBFS + 15 % AC + 1 % GF + 1 % PPF). Optimal performance was achieved with <= 7.5 % AC and GF-dominant fiber blends, balancing sustainability with strength, toughness, and durability.

Keywords

Alkali-activated composites Activated carbon Hybrid fiber reinforcement Mechanical properties Durability performance High-temperature resistance FLY-ASH GEOPOLYMERS SHRINKAGE BEHAVIOR CEMENT WASTE

WoS Categories

Construction & Building Technology Engineering, Civil Materials Science, Multidisciplinary

Sustainable Development Goals

Responsible Consumption and Production

Citation

Journal: CONSTRUCTION AND BUILDING MATERIALS
Year: 2025
Volume: 501
ISSN: 0950-0618
eISSN: 1879-0526
DOI: 10.1016/j.conbuildmat.2025.144381
WoS UID: WOS:001616626900004

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