Effects of curing conditions on the evolution of coarse capillary pores in cement pastes

Title: Effects of curing conditions on the evolution of coarse capillary pores in cement pastes
Author(s): Shin-ichi Igarashi, Akio Watanabe
Paper category : conference
Book title: International RILEM Symposium on Concrete Science and Engineering: A Tribute to Arnon Bentur
Editor(s): J. Weiss, K. Kovler, J. Marchand, and S. Mindess
Print-ISBN: None
e-ISBN: 2912143926
Publisher: RILEM Publications SARL
Publication year: 2004
Nb references: 16
Language: English

Abstract: Effects of additional water supply and curing temperatures on the porosity and characteristics of the coarse capillary pore structure were investigated by quantitative SEM-BSE image analysis. The Powers model for hydration of cement was applied to the interpretation of the results of image analysis. The image analysis revealed that water curing from 24 hours after casting was not so effective for changing the coarse capillary porosity at an extremely low water/binder ratio. The gap-graded pore structure formed at early ages prevents water from penetrating into hardened cement pastes with a low water/cement ratio. Coarsening of the large capillary pore structure due to a high curing temperature was observed only for a specific water/cement ratio. High temperature curing increased the volume fraction and the threshold diameter of coarse capillary pores in the cement paste with that water/cement ratio. The effect of curing temperature on coarse capillary pore structure can be explained by the process of deposition of outer hydration products during the hydration of cement. The initial packing of cement particles may be crucial to the subsequent evolution of the coarse capillary pore structures.

Online publication: 2004-03-25
Publication type : full_text
Public price (Euros): 0.00
doi: 10.1617/2912143926.109