Sürdürülebilir Kalkınma Amaçları

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• MakaleAçık Erişim2026Scopus SJRQ1/r/munzur/1047
  Sustainable hybrid activation: Synergistic effects and optimization of one-part alkali-activated slag using sodium sulfate and sodium carbonate

  Orhan, Taha Yusuf; Balun, Bilal; Dener, Murat; Karataş, Mehmet

  The development of one-part alkali-activated materials (AAMs) using near-neutral and moderately alkaline salts offers a promising, low-carbon alternative to hazardous two-part systems. However, overcoming delayed reaction kinetics and setting anomalies remains a critical challenge. This study systematically investigates the fresh state, mechanical, and microstructural evolution of one-part slag mortars activated by sodium sulfate (Na2SO4), sodium carbonate (Na2CO3), and their hybrid combinations, adopting a hybrid binder approach through modification with calcium-rich additives (Portland cement, hydrated lime, and quicklime). Results demonstrate that while Portland cement ensures a controlled dissolution rate and balanced setting times across all environments, the incorporation of 7.5% quicklime in pure carbonate media triggers an instantaneous flash set. This extreme reactivity leads to a severe structural collapse, plunging the 90-day compressive strength to 16.11 MPa. Microstructural analyses (TGA and FTIR) suggest a link between this mechanical failure and a massive accumulation of unreacted portlandite (4.51% mass loss) rather than cohesive C-(A)-S-H gel formation, a degradation further corroborated by a drastic attenuation in ultrasonic pulse velocity (UPV). Conversely, the synergistic implementation of hybrid sulfate-carbonate activators effectively mitigates these anomalies. Sulfate ions buffer early-age kinetics to prevent flash setting-recovering the collapsed strength up to 29.16 MPa while carbonate ions facilitate sustained late-age matrix densification. Ultimately, tailoring specific calcium boosters within a hybrid activator framework presents a highly robust and potentially low-carbon framework for developing sustainable binders for practical on-site construction applications.

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  AtıfScopus3·WoS2·OpenAlex2

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• MakaleYalnız künye2025Scopus SJRQ1/r/munzur/848
  Dunite powder as a green precursor in one-part alkali-activated composites: Effects on mechanical and durability properties

  Benli, Ahmet; Bayraktar, Oğuzhan Yavuz; Karataş, Mehmet; Bodur, Burak; Yılmazoğlu, Mehmet Uğur; Kaplan, Gökhan

  Natural pozzolans are a sustainable alternative to Portland cement, offering abundant alumina and reactive silica for geopolymer production. Due to their simple extraction methods, they are cost-effective and environmentally friendly. This study explores the utilization of dunite powder (DP) as a sustainable precursor in one-part alkali-activated slag-based composites (AAC), aiming to evaluate its potential to partially replace granulated blast furnace slag (GBFS). The mechanical, fresh, and durability properties of the composites were investigated by varying DP replacement levels (0%, 15%, 30%, and 60%) under an activator dosage of sodium metasilicate, with the mixtures cured at 80 °C for 24 h and subsequently exposed to ambient conditions. The compressive and flexural strengths were evaluated at 7, 28, and 91 days, while the fresh properties (flowability and setting time), durability under sulfate attack, high-temperature resistance, freeze-thaw resistance, dry shrinkage, sorptivity and microstructural characteristics (SEM, XRD, and FT-IR) were also examined. The compressive strength decreased with higher DP content, with the 60% DP mixture showing a 43% strength reduction at 28 days compared to the reference mixture. However, the 30% DP mixture achieved a favorable balance between strength and sustainability, demonstrating a compressive strength decrease of only 11% at 91 days. The mixture containing 15% DP demonstrated the best performance under high-temperature conditions and freeze-thaw cycles. The 60% DP mixture exhibited the highest mass and strength loss when exposed to temperatures above 400 °C and a 15% compressive strength reduction after 120 days of immersion in a 10% MgSO4 solution.

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  AtıfScopus29·OpenAlex22

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• MakaleYalnız künye2024Scopus SJRQ1/r/munzur/1774
  Sustainable use of boron waste and volcanic scoria in slag-based self-compacting alkali-activated mortars: fresh, mechanical and durability properties

  Yön, Merve Şahin; Yön, Burak; Karataş, Mehmet; Benli, Ahmet

  Sustainable self-compacting alkali-activated concrete (SCAAC) manufacturing is an environmentally friendly concrete that has a reduced carbon footprint than ordinary concrete. Alkali-activated binders have been demonstrated in experiments to reduce concrete's energy consumption and carbon emissions by over 50%. This paper focuses on manufacturing boron waste (BW), volcanic scoria (VS) and ground blast furnace slag (GBFS) incorporated binary and ternary blends of self-compacting alkali-activated mortars (SCAAM). The main objective of this study is to investigate the fresh, mechanical, durability and microstructural properties of SCAAM based on binary and ternary mixtures of BW, VS, and GBFS. SCAAM samples were synthesized at 60 °C and 100 °C for 72 h then exposed to ambient cured at 3, 28 and 90 days. The compressive strength, flexural strength, physical, and sorptivity properties of the SCAAM mixtures, as well as flowability, were investigated. The performance of the produced blends at freeze-thaw exposure were also examined. SEM, and EDS was also used to examine the microstructures of the mixtures. The findings showed that 50% GBFS and 50%VS based SCAAM mixture heat cured at 100oC activated with NS/NH ratio of 3.0 produced a compressive strength of 40 MPa at 90 days. The findings indicated that inclusion of BW to the SCAAM mixtures decreased the compressive strength notably regardless of NS/NH ratio and curing temperature. Inclusion of BW also affected the durability performance negatively.

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  AtıfScopus38·WoS36·OpenAlex35

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