کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1457464 | 989262 | 2009 | 8 صفحه PDF | دانلود رایگان |
The pozzolanic reaction between portlandite and different types of nearly pure natural zeolites was studied. Analcime, phillipsite, chabazite, erionite, mordenite and clinoptilolite-rich tuffs were mixed with portlandite and water (1:1:2 by weight), and the progress of the pozzolanic reaction was quantitatively determined by thermogravimetrical analyses from 3 to 180 days.A thorough characterization of the raw materials was performed by quantitative XRD, XRF, SEM-EDX, BET specific surface area measurements, grain-size analyses, FTIR and Cation Exchange Capacity measurements. The difference in reactivity of the samples containing zeolites with varying Si/Al ratios, as well as between clinoptilolite-rich samples exchanged with different cations or ground to different grain sizes was assessed.The results indicate that the external surface area only influences the short-term reactivity, whereas the cation content has an effect on both the long- and short-term reactivity. The early reactivity of the unexchanged samples can be explained by these two parameters, but their long-term reactivity is mainly related to the Si/Al ratio of the zeolites. Samples with zeolites rich in Si react faster then their Al-rich counterparts.
Journal: Cement and Concrete Research - Volume 39, Issue 3, March 2009, Pages 233–240