Akademik Veri Yönetim Sistemi
NEW CONCEPTS AND ADVANCED STUDIES IN ENGINEERING, Asst. Prof. Dr. Umut ÖZKAYA, Editör, All Science Academy, Konya, ss.230-244, 2025
Geopolymer concrete (GPC) has emerged as a next-generation sustainable construction material that can significantly reduce the environmental impact associated with Ordinary Portland Cement (OPC). This chapter presents a comprehensive review and design-based evaluation of geopolymer concrete systems, highlighting the functional role of each component and optimizing key parameters for enhanced performance. Aluminosilicate sources (e.g., metakaolin, fly ash, volcanic tuff) react with alkali activators such as NaOH and Na₂SiO₃ through dissolution and polycondensation, forming N-A-S-H and C-A-S-H gels that constitute a dense, durable binder matrix. The integration of nano-silica, graphene oxide, and fibers (steel, basalt) further enhances microstructural compactness, ductility, and resistance to cracking. Polycarboxylate ethers improve workability under high alkalinity, while polyethylene glycol ensures moisture stability during curing. Optimal design parameters such as Si/Al (2-4), SiO₂/Na⁺ (2.0-2.5), solid/activator (2.0-2.5), and W/B (0.3-0.35) are identified to balance workability, polymerization efficiency, and mechanical strength. Thermal curing at 60 ± 2 °C for 24-48 h accelerates gel transformation and yields >90% of final strength. Experimental findings and literature data indicate that GPC exhibits superior resistance to sulfate and acid attack, chloride ion penetration, high temperatures (≤ 800 °C), and freeze–thaw cycles, with minimal strength loss compared to OPC. Furthermore, boron-modified formulations demonstrate potential as radiation and heavy metal barriers. Although the initial material cost of GPC is higher, its lower lifetime maintenance and replacement frequency render it economically advantageous. Overall, multi-component geopolymer concretes represent a technically and environmentally sustainable alternative for long-lasting infrastructure, marine, and high-temperature applications.