Correlation of Cement Performance Property Measurements with C3S/C2S Ratio Determined by Solid State 29Si NMR Measurements

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• 作者：Christopher L. Edwards ; Rickey Morgan ; Lewis Norman ; Gary P. Funkhouser ; Andrew R. Barron
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2008
• 出版时间：August 6, 2008
• 年：2008
• 卷：47
• 期：15
• 页码：5456-5463
• 全文大小：191K
• 年卷期：v.47,no.15(August 6, 2008)
• ISSN：1520-5045

文摘

The physicochemical and engineering performance properties of several API class G and H ordinary Portland cements (OPCs) from various foreign and domestic sources have been investigated in comparison with the tricalcium silicate/dicalcium silicate ratio (C₃S/C₂S) as determined by magic angle spinning (MAS) p>29p>Si nuclear magnetic resonance (NMR) experiments. XRF-derived oxide analysis appears to provide a lower C₃S/C₂S ratio than determined by NMR analysis. Furthermore, oxide analysis suggests that all the cements have a C₃S/C₂S ratio of 2−5, while our NMR method suggests the actual range is significantly broader. Determination of C₃S/C₂S ratios by NMR provides an effective method of analysis for cements, owing to NMR’s direct measurement of the minerals in question. NMR C₃S/C₂S ratios demonstrate predictive ability for the determination of engineering performance properties. This is especially the case for prediction of strength development; in keeping with generally accepted understanding of cement hydration behavior, the strength development correlates with increasing C₃S/C₂S ratio, i.e., C₃S content. The observed correlation between NMR-derived silicate ratio and strength development holds for cements in the presence of either a retarder (lignosulfonate) or a fluid loss additive (N,N-dimethylformamide/2-acrylamido-2-methylpropanesulfonic acid copolymer). No significant correlation is observed between C₃S/C₂S ratio and the 72 h crush strength. The lack of dependency of either thickening time or Young’s modulus to the C₃S/C₂S ratio as determined by MAS p>29p>Si NMR measurements suggests that these physical properties are independent of the relative silicate composition. No correlations are observed between any physical property and the silicate ratio derived from XRF data.