کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
6711219 1428719 2018 13 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Microstructure of four-graded roller compacted concrete
ترجمه فارسی عنوان
ریز ساختار چهار غلتکی بتنی فشرده
موضوعات مرتبط
مهندسی و علوم پایه سایر رشته های مهندسی مهندسی عمران و سازه
چکیده انگلیسی
This paper presents an experimental study on microstructure of four-graded RCC. Two temperatures of 20 °C and 40 °C were picked to represent interior and surface layers of four-graded RCC. The most used fly ash contents of 50% and 70% were selected, and two ages of 28 days and 56 days were tested. Three levels of paste, mortar and concrete were used to simulate different microstructural regions in four-graded RCC. 3D digital microscope experiment, micro-hardness test and back-scattered electron image analysis were carried out sequentially. It was found that four-graded RCC microstructure can be divided into three characteristic parts: bulk paste, interface transition zone around fine aggregate (ITZ-f) and interface transition zone around coarse aggregate (ITZ-c). By comparing the average wear width and depth, the strength and bonding ability of bulk paste was the highest, followed by ITZ-f and ITZ-c. Compared to the surface layer, the micro-mechanical strength of bulk paste and ITZ-f was higher in the interior layer, but that of ITZ-c was opposite. At early age, 50% fly ash content was more conducive to microstructure than 70%. The micro-hardness value of ITZ-c presented a decreasing trend with age and that of ITZ-f did not grow. In terms of product structure, Ca(OH)2 content in ITZ-c gradually decreased from aggregate surface to paste part, and Ca(OH)2 in ITZ-f had been partially converted to C-S-H gel. The proportions of hydration product and porosity were highest in ITZ-c, followed by ITZ-f, with bulk paste having the lowest. Microstructure of four-graded RCC was significantly affected by the combination of aggregate size and free water content on aggregate surface.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Construction and Building Materials - Volume 187, 30 October 2018, Pages 25-37
نویسندگان
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