Macro-defect-free processing and low-frequency dielectric response of calcium aluminate cements

Sliva, Paul; Gururaja, T.R.; Scheetz, Barry E.

doi:10.1016/0167-577x(86)90108-4

Cited by 8 publications

(4 citation statements)

References 2 publications

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“…As mentioned in the Introduction section, the AC permittivity of a cement-based material after hydration may increase [11][12][13][14] or decrease 15 with increasing water/cement ratio. In contrast, this work shows that the DC polarization decreases with increasing water/cement ratio.…”

Section: F I G U R Ementioning

confidence: 95%

“…The permittivity decreases during the hydration of cement since the proportion of free water decreases as hydration takes place. [5][6][7][8][9] In a similar vein, the permittivity of the cement-based material after hydration increases with the humidity 10 and with increasing water/cement ratio, [11][12][13][14] though the opposite trend of the permittivity decreasing with increasing water/cement ratio has also been reported. 15 The permittivity is also affected by the admixtures, such as latex (styrene butadiene), methylcellulose, silica fume, graphite, and slag, which introduce interfaces and additional phases in the material.…”

Section: Introductionmentioning

confidence: 93%

“…As the water serves as a source of ions, this ratio is expected to affect the polarization. Indeed, the permittivity typically increases as the water/cement ratio increases 11–15 …”

Section: Introductionmentioning

confidence: 99%

“…Indeed, the permittivity typically increases as the water/cement ratio increases. [11][12][13][14][15] Self-sensing pertains to a nonstructural function in which a structure senses its condition (e.g., stress, strain, damage, and temperature) without the incorporation of sensors. This ability enables the structure to be multifunctional.…”

Section: Introductionmentioning

confidence: 99%

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DC electric polarization of cured cement paste being unexpectedly hindered by free water

Öztürk

Chung

2021

J Am Ceram Soc.

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Electric polarization is basic to the dielectric behavior, which is pertinent to the science and applications of cement‐based materials. This work reports the dynamics of the DC‐current‐induced electric polarization/depolarization of cured cement paste and their dependence on the water/cement ratio. This dependence has not been previously reported for any cement‐based material. The extent of the polarization is unexpectedly found in this work to decrease as the water/cement ratio increases, indicating that the free water hinders the polarization. This hindrance is due to (i) the dominance of ions behind the polarization (as supported by the previously reported increase in permittivity with increasing temperature), and (ii) the polar water molecules partly shielding the ions from the applied electric field. The fraction of ions in the pore solution that participates in the polarization increases with the polarization time and is 4.5 × 10‐14 for 570 s of polarization at a current of 1 μA for water/cement ratio 0.35. Upon increasing the water/cement ratio (0.3–0.4), the polarization rate decreases, the polarization extent at a given polarization time decreases, and the time to reach polarization saturation decreases. The polarization/depolarization rate decreases as the current application progresses because the polarization/depolarization hinders further polarization/depolarization. The degree of this hindrance increases with increasing water/cement ratio. Thus, a higher water/cement ratio is preferred if less polarization is desired as in resistance‐based self‐sensing, whereas a lower water/cement ratio is preferred if more polarization is desired as in capacitance‐based self‐sensing.

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Section: F I G U R Ementioning

confidence: 95%

Section: Introductionmentioning

confidence: 93%

“…As the water serves as a source of ions, this ratio is expected to affect the polarization. Indeed, the permittivity typically increases as the water/cement ratio increases 11–15 …”

Section: Introductionmentioning

confidence: 99%