دانلود رایگان مقاله انگلیسی ویژگی سیمان کوره بلند بر اساس کلینکر سیمان پرتلند، سرباره انفجار و کوره سیمان - الزویر 2018

ABSTRACT

 This study has examined the effectiveness of characteristically different cement kiln dusts (CKDs) as a partial replacement for the ground granulated blastfurnace slag (GGBFS) in the development and production of three types of blastfurnace cements (CEM III/A, B, C) according to the standard EN 197-1. 27 CEM III cement blends, 9 blends per type of cement, i.e., CEM III/A, CEM III/B and CEM III/C, were prepared in the laboratory mill from industrial starting materials (Portland cement clinker, gypsum, GGBFS, CKDs). The addition of gypsum as the setting regulator was fixed at 4 mass % in all blends studied. The content of both CKDs (cement clinker dust and cement filter dust) as slag replacements was 4 mass % in all CKD blends studied. The ordinary Portland cement (OPC) type CEM I 42.5N was used as the control cement. The results have shown that the chemical composition and chemical and physical properties of prepared CEM III/A, B, C cement blends meet the EN 197-1 requirements. Strength development in these cement blends is obviously related to the  Portland cement clinker-to-GGBFS ratio. When compared to OPC, the blastfurnace cement  developed lower compressive strength at early ages, but equal or higher at later ages in more  cases, i.e., all 9 CEM III/A and 7 CEM III/B cement blends meet, while no CEM III/C cement  blend meets the EN 197-1 requirements for standard compressive strength Class 42.5N. From  the perspective of strength, the presence of the cement clinker dust is more effective than that of the cement filter dust due to their different chemical and mineralogical compositions.

4 Conclusions

The obtained results for chemical and physical as well as mechanical properties of all three types of blastfurnace cements (CEM III/A, B, C), which have been presented in this study, provide evidence that the CKDs (cement clinker dust or cement filter dust), collected from different sources during the production of Portland cement, can be directly and effectively used as a replacement for GGBFS. With the appropriate mix composition, i.e., the clinker-to GGBFS ratio, the addition of CKDs can provide satisfactory overall performance regarding  chemical requirements, setting time, volume stability, and mechanical properties. Although the addition of GGBFS results in lower strength at early ages, the replacement of Portland cement clinker by GGBFS up to 72 mass %, does not have any negative effect on the compressive strength of concrete after 28 days.