Quaternary Cement-Free Blend Development for Construction Applications
7th fib Congress on Structural Concrete 2050: Towards Carbon Neutrality, AI Design, and Robotic Construction, 2026, Lisbon, Portekiz, 15 - 19 Haziran 2026, ss.2968-2977, (Tam Metin Bildiri)
- Yayın Türü: Bildiri / Tam Metin Bildiri
- Basıldığı Şehir: Lisbon
- Basıldığı Ülke: Portekiz
- Sayfa Sayıları: ss.2968-2977
- Anahtar Kelimeler: anhydrite, calcium hydroxide, Fly Ash, Ground granulated blast-furnace slag, Mechanical performance, Microstructural characterisation, Quaternary Cement-Free Blend
- Orta Doğu Teknik Üniversitesi Adresli: Evet
Özet
Portland cement, as one of the primary binders used in construction, is responsible for an important portion of CO2 emissions to the atmosphere. One way to reduce the high carbon footprint of the construction industry is by reducing cement consumption and turning to alternative binders. Industrial by-products such as ground granulated blast furnace slag (BFS), and fly ash (FA) are among the most common raw materials used in alternative binders; however, they often yield weak mechanical performance when used without other additives. One way to improve the mechanical performance is through strong lab-grade chemical additives, which, although effective, can be costly and difficult to handle. This study focuses on the development of a cheap quaternary cement-free blend using BFS, FA, anhydrite (AN) and calcium hydroxide (CH) without the addition of any other chemical admixture or thermal treatment. The binary blend of BFS and FA resulted in poor mechanical strength, indicating its limited use for construction. However, the incorporation of AN and CH resulted in a significant increase in compressive strength, improved water resistance and a reduction in setting time. The paste blends containing BFS, FA, AN, and CH developed compressive strength, reaching 24 to 29.3 MPa at 28 days and 25 to 40 MPa at 90 days. C-A-S-H/C-S-H and ettringite were identified as the main hydration products by SEM and XRD analysis. Thermal exposure of 28-day-old specimens showed a reduction in strength due to decomposition of primary hydration products.