Frost resistance and micro pore structure change of mortar exposed to different climate conditions

Author(s): Yukio Hama, Yoshihiko Kishimoto, M. Zakaria
Paper category: Conference
Book title: 2nd International conference on Microstructural-related Durability of Cementitious Composites
Editor(s): Guang Ye, K. Van Breugel, Wei Sun, Changwen Miao
Print ISBN: 978-2-35158-129-2
e-ISBN: 978-2-35158-123-0
Publisher: RILEM Publications SARL
Pages: 630-638
Total Pages: 8
Language: English

Abstract: 
Micro pore structure is an important factor affecting the properties of mortar and concrete, such as strength and durability. For example, the frost resistance, which is quite needed for better durability performance of concrete members, is affected by the volume of micro pore with 40-2000 nm diameter. It was pointed out recently that the nanostructure of C-S-H and the micro pore structure of concrete are remarkably changed by drying or drying-wetting cycles, and thus the frost resistance can be consecutively degraded by those changes. However, the clarification of the environmental action on frost damage and microporosity has not been fully understood. The aim of this study is to investigate the influence of environmental conditions (drying temperature, relative humidity, drying period and dryingwetting
cycles) on the frost resistance and micro pore structure distribution. Micro pore structure of mortar specimens subjected to drying conditions in the laboratory, as one test set, and exposed to different climate conditions at three outdoor locations, as another test set, was quantified using Mercury Intrusion Porosimetry (MIP) method. RILEM CIF test was also carried out to evaluate the frost resistance of tested mortar specimens. The results of both the outdoor exposure test and the laboratory test revealed that not only the volume of 40-2000 nm diameter pore but also the unconnected pore volume can be increased by high temperature drying. Furthermore, it was clarified that the drying temperature is more critical to the coarsening of micro pore structure and the degradation of frost resistance than humidity.

Online publication: 2013
Publication Type: full_text
Public price (Euros): 0.00