Effects of calcium nitrate and sodium thiocyanate as antifreeze additives on the performance of alkali-activated slag concrete exposed to low temperatures in the fresh state
Cold Regions Science and Technology, cilt.251, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 251
- Basım Tarihi: 2026
- Doi Numarası: 10.1016/j.coldregions.2026.105040
- Dergi Adı: Cold Regions Science and Technology
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Artic & Antarctic Regions, Compendex, Geobase, INSPEC, Academic Search Ultimate (EBSCO), Engineering Source (EBSCO)
- Anahtar Kelimeler: Alkali-activated slag, Ca(NO3)2, Cold weather concrete, Low temperatures, NaSCN, Sustainability
- Atatürk Üniversitesi Adresli: Evet
Özet
In this study, the effects of antifreeze additives on the mechanical performance and microstructural characteristics of slag-based concrete exposed to cold weather in the fresh state were investigated. For this purpose, concretes were produced without additives and with antifreeze agents, namely calcium nitrate (Ca(NO3)2) and sodium thiocyanate (NaSCN), using blast furnace slag, activated by NaOH and Na2SiO3. Four curing regimes were applied: laboratory curing, heat curing at 90 °C for 72 h, and exposure to −5 °C and − 10 °C for 12 h. All samples were then stored in the laboratory until testing days, and the compressive and flexural strengths, ultrasonic pulse velocities (UPV), mineralogical compositions through X-ray diffraction (XRD), and microstructure via Scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) were evaluated. As a result, the compressive strengths of mixtures containing sodium thiocyanate and calcium nitrate increased by 64% and 61%, respectively, compared to 32% in the control group at −5 °C, while at −10 °C the gains reached 112% and up to 300%, respectively; the control group exhibited a 39% increase. The mixture containing both sodium thiocyanate and calcium nitrate (SCN) exhibited a 236% strength increase at −10 °C and achieved the highest 28-day compressive strengths, reaching 33 MPa at −5 °C and 29 MPa at −10 °C. Overall, sodium thiocyanate was more effective than calcium nitrate, while their combined use produced a synergistic effect that effectively mitigated the adverse effects of cold weather on both fresh and hardened alkali-activated slag-based concretes.