Mechanical Properties and Shrinkage of One-Part Sodium Metasilicate Activated Slag/Fly Ash-Based Mixes: Effects of Polypropylene and Steel Fibers Incorporation
7th fib Congress on Structural Concrete 2050: Towards Carbon Neutrality, AI Design, and Robotic Construction, 2026, Lisbon, Portekiz, 15 - 19 Haziran 2026, ss.3273-3282, (Tam Metin Bildiri)
- Yayın Türü: Bildiri / Tam Metin Bildiri
- Basıldığı Şehir: Lisbon
- Basıldığı Ülke: Portekiz
- Sayfa Sayıları: ss.3273-3282
- Anahtar Kelimeler: fly ash, mechanical properties, One-part alkali-activated materials, shrinkage, steel fiber
- Yıldız Teknik Üniversitesi Adresli: Evet
Özet
Cement production is responsible for approximately 8% of global CO2 emissions. To address these high emissions, alkali-activated materials have emerged as a more sustainable alternative to conventional cement-based systems by enabling the use of industrial by-products and waste materials as precursors. In this study, ground granulated blast furnace slag and fly ash were used as precursors, and sodium metasilicate was utilized as the alkali activator. Fly ash was substituted with slag at high levels (20% and 40% by weight), and polypropylene and steel fibers (12 mm in length) were incorporated at 1% by volume to improve mechanical properties and enhance shrinkage resistance. The flowability of mortar samples was assessed using the mini-slump test immediately after production. Compressive strength was evaluated at 3, 7, and 28 days, while flexural strength was determined at 28 days. Additionally, drying shrinkage was monitored over a 28-day period. The effects of different fly ash substitution ratios and the incorporation of different fibers on capillary and gel voids were evaluated using the Archimedes method. The study revealed that mixes with high volumes of fly ash can achieve acceptable mechanical properties. Steel fibers significantly reduced drying shrinkage, while polypropylene fibers caused increasing capillary pore volume.