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Pro058

Kinetics of ice growth in cement and concrete



Title: Kinetics of ice growth in cement and concrete
Author(s): Z. Sun, G.W. Scherer
Paper category : conference
Book title: International RILEM Symposium on Concrete Modelling - ConMod '08
Editor(s): E. Schlangen and G. De Schutter
Print-ISBN: 978-2-35158-060-8
e-ISBN: 978-2-35158-076-9
Publisher: RILEM Publications SARL
Publication year: 2008
Pages: 183 - 190
Total Pages: 8
Nb references: 18
Language: English


Abstract: Air voids protect concrete from frost damage, but the mechanism is still not clear. Our results confirm early experiments by Helmuth and Powers that showed that air-entrained concrete contracts upon freezing, while non-air-entrained concrete expands. Shrinkage results from ice in the voids that sucks water from the mesopores, creating negative pore pressure; the magnitude of the contraction is shown to be consistent with the pressure predicted using thermodynamics and poromechanics. However, air voids do not seem to promote nucleation, so it remains to be proved how the ice gets into the voids. One possibility is that freezing in larger pores pushes water into the voids where it freezes, and thereby initiates contraction. If this is correct, then some damage could result from the initial freezing, so it might be beneficial to introduce nucleating agents into air voids to improve frost protection.


Online publication: 2009-06-15
Publication type : full_text
Public price (Euros): 0.00