کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4913063 | 1428757 | 2017 | 10 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Characterization of the superficial weathering of bricks on the City Wall of Xi'an, China
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
سایر رشته های مهندسی
مهندسی عمران و سازه
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
This study characterized the influence of salts on bricks in correlation with the efflorescence, exfoliation and pelletizing occurring in the ancient brick wall at Xi'an, China. After 640 years of atmospheric exposure, many bricks have suffered from efflorescence, exfoliation and pelletizing. Different scientific instruments, such as optical microscopy (OM), X-ray fluorescence analysis (XRF), X-ray diffraction (XRD), thermal analysis (TGA/DTG) and X-ray photoelectron spectroscopy (XPS), have been applied to investigate the chemical and mineralogical components of the salty crusts and evaluate their species and accumulative quantities. The results show that the detected salts are chiefly aggressive deterioration problems that are causing serious damage to the brickwork. Calcium-containing salts with a dominant amount of calcite (CaCO3) and â¼2.3 at.% of gypsum (CaSO4·2H2O) were detected as the main components in the efflorescence sample, demonstrating the significantly large amount of efflorescence that occurs on shining days after rainy days. This results from the almost insoluble CaCO3 that occurs via a neutralization reaction of calcium hydroxide [Ca(OH)2] that migrates from the puddled clay core and carbon acids on the surface of the bricks. The flaking and powdering of bricks demonstrate different weathered morphologies that have similar material compositions that are classed as exfoliation and pelletizing and are responsible for the presence of some salty ions, such as C, S and N, due to halite (NaCl), thenardite (Na2SO4) and metal nitrates [M(NO3)n] at a total of 10 at.%. With a comprehensive cognitive objective, this research contributes to a new understanding of weathered phenomena that occur on the surface of bricks in brick-clay structures without neglecting the effective removal of salty ions that regularly accumulate on the surface of porous fictile structures.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Construction and Building Materials - Volume 149, 15 September 2017, Pages 139-148
Journal: Construction and Building Materials - Volume 149, 15 September 2017, Pages 139-148
نویسندگان
Pu-jun Jin, Yue Zhang, Su Wang, Xiao-gang Yang, Maolin Zhang,