Premium
Galvanised constructional elements in contact with prestressing steel tendons
Author(s) -
Mietz J.,
Burkert A.,
Lehmann J.,
Burkert A.,
Eich G.
Publication year - 2008
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/maco.200804114
Subject(s) - galvanization , materials science , cracking , metallurgy , corrosion , stress corrosion cracking , hydrogen embrittlement , hydrogen , stress (linguistics) , composite material , chemistry , layer (electronics) , linguistics , philosophy , organic chemistry
In order to clarify under which practical conditions real risks for hydrogen‐induced stress corrosion cracking of prestressing steels exist laboratory investigations in aqueous solutions and concrete as well as tests with stressed prestressing steels were carried out. While different distances between steel and zinc (cathode and anode) showed only a negligible influence on the polarisation of the steel a significant dependence on the area ratio steel/zinc was observed. A critical area ratio of 10:1 can be defined above which polarisation of the steel to hydrogen evolution potentials is unlikely. The results obtained in the laboratory concerning the critical area ratio were confirmed by on‐site investigations in a precasting plant. Exposure tests with hydrogen loading did not lead to fractures during the testing time for approved prestressing steels. The characteristic mechanical values determined immediately after the hydrogen loading tests did not show significant changes. Thus, an indirect contact between prestressing steels and galvanised elements can be estimated as uncritical. But a direct contact has to be excluded by compliance with DIN 1045‐1, i.e minimal distance of 2 cm between prestressing steel and galvanised elements.