Neutron radiography, a powerful method for investigating water penetration into concrete

Title: Neutron radiography, a powerful method for investigating water penetration into concrete
Author(s): F.H. Wittmann, P. Zhang, T-J. Zhao, E. Lehmann, P. Vontobel
Paper category : conference
Book title: The 50-year Teaching and Research Anniversary of Prof. Sun Wei on Advances in Civil Engineering Materials
Editor(s): C. Miao, G. Ye and H. Chen
Print-ISBN: 978-2-35158-098-1
e-ISBN: 978-2-35158-099-8
Publisher: RILEM Publications SARL
Publication year: 2010
Pages: 61 - 70
Total Pages: 10
Nb references: 12
Language: English

Abstract: Service life of reinforced concrete structures depends on the quality of concrete, the cover thickness, and the aggressiveness of the environment. Water and harmful compounds dissolved in water are taken up into the porous structure of concrete by capillary action and diffusion or a combination thereof. The combined process is very complex and cannot be described by simple models. Therefore prediction of service life of reinforced concrete structures in aggressive environment remains unreliable. In this contribution it will be shown that neutron radiography is a very powerful method to study moisture uptake and movement in porous materials such as concrete. Results will provide us with a solid basis for reliable predictive models.

First fundamentals of the test method will be briefly described. It will be shown how this method can be applied to follow the time dependent process of capillary suction quantitatively. In addition uptake of water in the vicinity of cracks has been studied in some detail. It is of particular interest that movement of water into the interface between steel reinforcement and concrete and into the fracture process zone ahead of a crack tip can be visualized and determined quantitatively by means of neutron radiography. It is the first time that these decisive processes with respect to durability can be studied in detail. The obtained results will be discussed and the potential of the test method for future investigations will be outlined. Results presented in this contribution will help us to understand better deteriorating processes in reinforced concrete structures and to find ways to improve durability.

Online publication: 2010-04-22
Publication type : full_text
Public price (Euros): 0.00