کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1456115 1509752 2015 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Identification of the hydrate gel phases present in phosphate-modified calcium aluminate binders
ترجمه فارسی عنوان
شناسایی فازهای ژل هیدرات موجود در گیرنده های آلومینیوم کلسیم اصلاح شده فسفات
موضوعات مرتبط
مهندسی و علوم پایه سایر رشته های مهندسی مهندسی صنعتی و تولید
چکیده انگلیسی

The conversion of hexagonal calcium aluminate hydrates to cubic phases in hydrated calcium aluminate cements (CAC) can involve undesirable porosity changes and loss of strength. Modification of CAC by phosphate addition avoids conversion, by altering the nature of the reaction products, yielding a stable amorphous gel instead of the usual crystalline hydrate products. Here, details of the environments of aluminium and phosphorus in this gel were elucidated using solid-state NMR and complementary techniques. Aluminium is identified in both octahedral and tetrahedral coordination states, and phosphorus is present in hydrous environments with varying, but mostly low, degrees of crosslinking. A 31P/27Al rotational echo adiabatic passage double resonance (REAPDOR) experiment showed the existence of aluminium–phosphorus interactions, confirming the formation of a hydrated calcium aluminophosphate gel as a key component of the binding phase. This resolves previous disagreements in the literature regarding the nature of the disordered products forming in this system.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Cement and Concrete Research - Volume 70, April 2015, Pages 21–28
نویسندگان
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