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Capillary absorption and chloride penetration into neat and water repellent shcc under imposed strain



Title: Capillary absorption and chloride penetration into neat and water repellent shcc under imposed strain
Author(s): F.H. Wittmann, P. Wang, P. Zhang, T.J. Zhao and F. Beltzung
Paper category : conference
Book title: 2nd International RILEM Conference on Strain Hardening Cementitious Composites (SHCC2-Rio)
Editor(s): R.D. Toledo Filho, F.A. Silva, E.A.B. Koenders and E.M.R. Fairbairn
ISBN: 978-2-35158-120-9
e-ISBN: 978-2-35158-121-6
Publisher: RILEM Publications SARL
Publication year: 2011
Pages: 165 - 172
Total Pages: 8
Nb references: 7
Language: English


Abstract: Ductility of SHCC is due to multi-crack formation. Cracks are preferential pathways for ingress of water and salt solutions into the composite material. Direct tensile tests have been run on dumbbell specimens made of SHCC. The material has been characterized by the strain hardening relation. With the aim to prevent penetration of water into cracks part of the test specimens were made with integral water repellent SHCC (IWR SHCC) by adding silane emulsion to the fresh mortar. The surface of another group of specimens has been impregnated with silane gel (SI SHCC). It could be shown that capillary absorption of neat SHCC increases significantly with progressing strain hardening as more and wider cracks are being formed. The liquid transgresses the entire thickness of the specimen (30 mm) in a short time. If chloride solution enters the cracks a typical chloride profile is established close to the surface in contact with the salt water. Later chloride accumulates near the opposite surface too. Results have been confirmed by direct observation of moisture migration by means of neutron radiography. According to the results obtained, the tolerable strain has to be limited to values well below 0.5 % if the material is to protect reinforced concrete structures in aggressive environment.


Online publication: 2012-01-25
Publication type : full_text
Public price (Euros): 0.00