USING THE ACMT TO DETERMINE THE CHLORIDE MIGRATION COEFFICIENT OF ITZ IN MORTAR

Author(s): Yang C.C. and Weng S.H.
Paper category: Proceedings
Book title: Proceedings of CONSEC13 Seventh International Conference on Concrete under Severe Conditions - Environment and Loading Volume I
Editor(s): Z.J. Li, W. Sun, C.W. Miao, K.Sakai, O.E. Gjørv, N.Banthia
ISBN: 978-2-35158-124-7
e-ISBN: 978-2-35158-134-6
Publisher: RILEM Publications SARL
Publication year: 2013
Pages: 553-563
Total Pages: 961
Language : English

Abstract: In this study, the electrochemical technique is applied to accelerate chloride ion migration in mortar to estimate its transport properties. The steady state chloride migration coefficient of mortar was determined experimentally as a function of the aggregate volume fraction to investigate the effect of aggregate content. In mortar, interfacial transition zone (ITZ) is the weaker zone of quality arround the fine aggregate than cement paste, so it was crucial to determine the properties of cementitious composites. In this study, specimens (w/b = 0.45) with various volume fractions of fine aggregate (Vf = 0, 0.1, 0.2, 0.3 and 0.4) were cast and tested. In order to determine the realitionship of the chloride migration coefficient of composite meterials which are cement paste, aggregate and interfacial transition zone (ITZ) by accelerate chloride migration test (ACMT), the two stages to calculate the migration coefficient of mortar. The first stage, mortar is considered as a two-phase composite material (cement paste and aggregate), and the migration coefficient of mortar is calculated by the equivalent inclusion method. The second stage, the ITZ phase is considered to be the three- phase and added in the three-phase model. The experimental results are fitted with the three- phase model. Based on the experimental and regression analytical results, the approximate chloride migration coefficient of ITZ is 6.23, 3.43, 4.87, and 1.35 times of the cement paste matrix migration coefficient for the ITZ thickness of 15 μm, 20 μm, 25 μm, and 30 μm, respectively.

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