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A platform for research: civil engineering, architecture and urbanism
Study on the hydration characteristics of steel slag cement
Abstract The direct use of stainless steel slag in cement presents potential weaknesses in terms of strength and the risk of cracking, which limits its large-scale utilization. Therefore, it was crucial to explore the use of stainless steel slag in clinker cement. In this study, the hydration characteristics of stainless steel slag cement (SS) and ordinary Portland cement (OPC) were compared and analyzed using isothermal calorimetry, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG-DTG), scanning electron microscopy (SEM), and heavy metal leaching tests. The study investigated the hydration heat, compressive strength at curing ages of 1d, 3d, 5d, 7d, and 28d, hydration products, and safety aspects of SS and OPC. Results showed that the optimum calcination temperature of stainless steel slag cement (SC) and Portland cement (PC) are 1350℃ and the holding time is 2 h. The clinker composition of the two is similar. The main minerals are dicalcium silicate (C2S), tricalcium silicate (C3S), tricalcium aluminate (C3A) and aluminum ferrite tetracalcium (C4AF). Compared with OPC, SS shows a delayed heat release peak during hydration. SS exhibited a delayed exothermic peak in the heat release during hydration compared to OPC. Furthermore, during the stable hydration period, SS produced more calcium aluminate-type solid solution, tightly encapsulating the crystal surface, and exhibited lower heat release. With an increase in curing age, the contents of acicular ettringite (AFt), C-S-H gel, and hexagonal calcium hydroxide (CH) gradually increased in both SS and OPC. Due to higher contents of C4AF, C3S, and C2S in SS, it produced more AFt and C-S-H than OPC. The compressive strength of both SS and OPC increased with curing age, reaching 55.4 MPa and 42.4 MPa at 28 days, meeting the requirements of the national standard (GB/T 21372-2008) in terms of initial and final setting times and f-CaO content. Additionally, heavy metal leaching and soluble Cr6+ tests indicated that their use is safe.
Highlights The hydration mechanism of cement was investigated by comparison and multi-means experiment. Stainless steel slag cement has low heat release and reduces the risk of cracking. The hydration products of stainless steel slag cement have more flocculent C-S-H, acicular AFt, and hexagonal Ca (OH) 2. Using 15% stainless steel slag instead of limestone calcined cement is feasible, 13 MPa higher than Portland cement, and is conducive to carbon reduction.
Study on the hydration characteristics of steel slag cement
Abstract The direct use of stainless steel slag in cement presents potential weaknesses in terms of strength and the risk of cracking, which limits its large-scale utilization. Therefore, it was crucial to explore the use of stainless steel slag in clinker cement. In this study, the hydration characteristics of stainless steel slag cement (SS) and ordinary Portland cement (OPC) were compared and analyzed using isothermal calorimetry, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG-DTG), scanning electron microscopy (SEM), and heavy metal leaching tests. The study investigated the hydration heat, compressive strength at curing ages of 1d, 3d, 5d, 7d, and 28d, hydration products, and safety aspects of SS and OPC. Results showed that the optimum calcination temperature of stainless steel slag cement (SC) and Portland cement (PC) are 1350℃ and the holding time is 2 h. The clinker composition of the two is similar. The main minerals are dicalcium silicate (C2S), tricalcium silicate (C3S), tricalcium aluminate (C3A) and aluminum ferrite tetracalcium (C4AF). Compared with OPC, SS shows a delayed heat release peak during hydration. SS exhibited a delayed exothermic peak in the heat release during hydration compared to OPC. Furthermore, during the stable hydration period, SS produced more calcium aluminate-type solid solution, tightly encapsulating the crystal surface, and exhibited lower heat release. With an increase in curing age, the contents of acicular ettringite (AFt), C-S-H gel, and hexagonal calcium hydroxide (CH) gradually increased in both SS and OPC. Due to higher contents of C4AF, C3S, and C2S in SS, it produced more AFt and C-S-H than OPC. The compressive strength of both SS and OPC increased with curing age, reaching 55.4 MPa and 42.4 MPa at 28 days, meeting the requirements of the national standard (GB/T 21372-2008) in terms of initial and final setting times and f-CaO content. Additionally, heavy metal leaching and soluble Cr6+ tests indicated that their use is safe.
Highlights The hydration mechanism of cement was investigated by comparison and multi-means experiment. Stainless steel slag cement has low heat release and reduces the risk of cracking. The hydration products of stainless steel slag cement have more flocculent C-S-H, acicular AFt, and hexagonal Ca (OH) 2. Using 15% stainless steel slag instead of limestone calcined cement is feasible, 13 MPa higher than Portland cement, and is conducive to carbon reduction.
Study on the hydration characteristics of steel slag cement
Ju, Jiantao (author) / Zhang, Qiming (author) / Luo, Ning (author) / Guo, Wenke (author) / Cao, Haibo (author) / Wang, Yonggang (author)
2024-02-24
Article (Journal)
Electronic Resource
English
Hydration characteristics of slag-blended cement at different temperatures
| Taylor & Francis Verlag | 2015
Early stage hydration of slag-cement
| Elsevier | 1983
Early stage hydration of slag-cement
| Elsevier | 1983