文章基本信息

标题：Unsaturated nanoporomechanics
本地全文：下载
作者：Hoang Nguyen ; Saeed Rahimi-Aghdam ; Zdeněk P. Bažant 等
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2020
卷号：117
期号：7
页码：3440-3445
DOI：10.1073/pnas.1919337117
出版社：The National Academy of Sciences of the United States of America
摘要：Although some important advances in the modeling of sorption and hygrothermal deformations of nanoporous materials such as hydrated cement paste, shale, coal, and some other rocks and soils have already been made, a comprehensive nanoporomechanics theory remains elusive. Here we strive to formulate it based on Gibb’s free energy of the solid–fluid system and on the recently derived Nguyen–Rahimi–Bažant (NRB) isotherm, which corrects the Brunauer–Emmett–Teller (BET) isotherm for the effect of hindered adsorbed water in filled nanopores and extends through the capillary range up to saturation. The challenge is to capture all of the basic types of relevant published experimental data, including 1) a complete sorption isotherm of hydrated cement paste (including the capillary range), 2) pore size distribution, 3) autogenous shrinkage, 4) drying shrinkage and swelling, 5) water loss or humidity change due to heating, 6) thermal expansion at various humidities, and 7) water loss of specimens caused by compression. The previous models can fit only a few data types. The present model fits all of them. It is ready for computer simulations needed to minimize the deleterious moisture effects on long-time deformations, cracking damage, and fracture in concrete infrastructure and thereby to reduce indirectly the enormous carbon footprint of concrete. Adaptations to shale, coal beds, etc., are possible.
关键词：unsaturated poromechanics ; hindered adsorbed water ; Biot coefficient ; shrinkage ; swelling