Influence of carbon nanofiber clustering on the chemo-mechanical behavior of cement pastes

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• 作者：Lesa Brown ; Florence Sanchez ; ^{florence.sanchez@vanderbilt.edu" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Carbon nanofibers ; Durability ; Decalcification ; Cement-based materials ; Agglomeration
• 刊名：Cement and Concrete Composites
• 出版年：2016
• 出版时间：January 2016
• 年：2016
• 卷：65
• 期：Complete
• 页码：101-109
• 全文大小：4433 K

文摘

The influence of carbon nanofiber (CNF) clustering on the chemo-mechanical behavior of cement pastes subjected to a decalcifying environment was studied. Portland cement pastes with and without CNFs were exposed to a concentrated solution of ammonium nitrate to accelerate decalcification. Microstructural changes and evolution of the porosity were examined as a function of exposure duration. Changes in the flexural response of the cement paste with CNFs were studied and reviewed in relation to CNF clustering and microstructural evolution. Results showed a strong coupling between decalcification, CNF clustering, microstructural evolution, and the flexural properties of the cement paste. After 7 days of decalcification by NH₄NO₃, the CNF clusters acted as weak zones that reduced the flexural strength retention of the cement paste. However, after 125 days of decalcification by NH₄NO₃, a dissolution-filling mechanism within the clusters created a better bond with the surrounding cement paste, slowing down the loss of flexural strength and providing added ductility to the cement paste.