کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10640060 | 995868 | 2005 | 6 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Effects of aluminates on the formation of geopolymers
دانلود مقاله + سفارش ترجمه
دانلود مقاله ISI انگلیسی
رایگان برای ایرانیان
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی مواد
مواد الکترونیکی، نوری و مغناطیسی
پیش نمایش صفحه اول مقاله

چکیده انگلیسی
The mechanisms of Al speciation and hydrolysis in geopolymer systems are investigated based on the partial charge model together with preliminary experimental validation. Calculation of the partial charges of species discloses that the positive partial charge of the Al atom is always higher than that of Si atom under conditions of similar pH values, suggesting greater tendency of [Al(OH)4]â tetrahedra to attract negatively charged groups from other species. Given Al atom with four hydroxyl groups under alkaline conditions and the potential to expand its coordination number with greater ease, condensation reactions involving aluminate species appear to occur much more readily. Thus, the model essentially predicts that aluminate species promote condensations reaction owing to factors such as their partial charge and the number of hydroxyl groups, implying that the solubility of aluminate sources (i.e. metakaolin) and the distribution of [Al(OH)4]â ions have an important influence on the mechanical properties of inorganic polymers. Corresponding experimental data on aluminate dissolution obtained from progressive milling of metakaolin particles demonstrated that varying particle sizes and different degrees of aggregation of metakaolin can have an important influence on inorganic polymer properties such as setting time, microstructure and compressive strength. The results indicate that milled metakaolin powders with high specific surface area have faster setting characteristics, higher compressive strength, and possess a more homogeneous microstructure, attributable to Al availability as predicted by the partial charge model.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Materials Science and Engineering: B - Volume 117, Issue 2, 15 March 2005, Pages 163-168
Journal: Materials Science and Engineering: B - Volume 117, Issue 2, 15 March 2005, Pages 163-168
نویسندگان
Luqian Weng, Kwesi Sagoe-Crentsil, Trevor Brown, Shenhua Song,