TY - JOUR
T1 - Electrically induced microstructural changes in portland cement pastes
AU - Sohn, Donggy
AU - Mason, Thomas O.
N1 - Funding Information:
This work was supported by the National Science Foundation through the Science and Technology Center for Advanced Cement-Based Materials under grant no. DMR-91-20002. The authors are grateful to Professors Lynn Johnson and Hamlin Jennings and to Jin-Ha Hwang, John Shane, and Steve Ford for helpful discussions.
Copyright:
Copyright 2018 Elsevier B.V., All rights reserved.
PY - 1998
Y1 - 1998
N2 - Portland cement pastes 1 day to 1 month old were each subjected to a single cycle of 1250 V/m electric field (15 s forward, 15 s off, 15 s reverse) and analyzed for microstructural/transport changes by impedance spectroscopy. All samples experienced an irreversible increase in resistance, as much as 20-25%, which decreased with increasing age of the paste. Subsequent applications of field produced no additional changes. The resistance increases were shown to be attributable to decreases in pore network connectivity rather than to changes in overall degree of hydration, capillary porosity, or pore fluid conductivity. It is proposed that electro-osmotic swelling of product near `bottleneck' pores results in the decreased connectivity. Ramifications for electrocuring, electromigration, electrochemical chloride treatment, and permeability studies of cement based products and structures are also discussed.
AB - Portland cement pastes 1 day to 1 month old were each subjected to a single cycle of 1250 V/m electric field (15 s forward, 15 s off, 15 s reverse) and analyzed for microstructural/transport changes by impedance spectroscopy. All samples experienced an irreversible increase in resistance, as much as 20-25%, which decreased with increasing age of the paste. Subsequent applications of field produced no additional changes. The resistance increases were shown to be attributable to decreases in pore network connectivity rather than to changes in overall degree of hydration, capillary porosity, or pore fluid conductivity. It is proposed that electro-osmotic swelling of product near `bottleneck' pores results in the decreased connectivity. Ramifications for electrocuring, electromigration, electrochemical chloride treatment, and permeability studies of cement based products and structures are also discussed.
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U2 - 10.1016/S1065-7355(97)00056-4
DO - 10.1016/S1065-7355(97)00056-4
M3 - Article
AN - SCOPUS:0032046942
VL - 7
SP - 81
EP - 88
JO - Cement and Concrete Research
JF - Cement and Concrete Research
SN - 0008-8846
IS - 3-4
ER -