Application of AC impedance technique in study of lightweight aggregate-paste interface

Kong, Lijuan; Hou, Lirong; Bao, Xin

doi:10.1016/j.conbuildmat.2015.02.079

Cited by 34 publications

(8 citation statements)

References 31 publications

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“…Based on this model, the effects of hydration time, silica fume replacement, and water-to-cement ratio on the high-frequency arc were determined [15]. In addition, the microstructure of the interfacial transition zone (ITZ) between the different aggregates and the cement paste was studied [16]. The relationships between the impedance characteristics and the pore solution concentration, porosity, and mean pore size have been established to reflect the degree of hydration and microstructural evolution of cement-based materials [17,18].…”

Section: Introductionmentioning

confidence: 99%

The Effects of Multi-Walled Carbon Nanotubes and Steel Fibers on the AC Impedance and Electromagnetic Shielding Effectiveness of High-Performance, Fiber-Reinforced Cementitious Composites

2019

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This study aimed to investigate the effect of multi-walled carbon nanotubes (MWCNTs) and steel fibers on the AC impedance and electromagnetic shielding effectiveness (SE) of a high-performance, fiber-reinforced cementitious composite (HPFRCC). The electrical conductivity of the 100 MPa HPFRCC with 0.30% MWCNT was 0.093 S/cm and that of the 180 MPa HPFRCC with 0.4% MWCNT and 2.0% steel fiber was 0.10 S/cm. At 2.0% steel fiber and 0.3% MWCNT contents, the electromagnetic SE values of the HPFRCC were 45.8 dB (horizontal) and 42.1 dB (vertical), which are slightly higher than that (37.9 dB (horizontal)) of 2.0% steel fiber content and that (39.2 dB (horizontal)) of 0.3% MWCNT content. The incorporation of steel fibers did not result in any electrical percolation path in the HPFRCC at the micro level; therefore, a high electrical conductivity could not be achieved. At the macro level, the proper dispersion of the steel fibers into the HPFRCC helped reflect and absorb the electromagnetic waves, increasing the electromagnetic SE. The incorporation of steel fibers helped improve the electromagnetic SE regardless of the formation of percolation paths, whereas the incorporation of MWCNTs helped improve the electromagnetic SE only when percolation paths were formed in the cement matrix.

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Section: Introductionmentioning

confidence: 99%

The Effects of Multi-Walled Carbon Nanotubes and Steel Fibers on the AC Impedance and Electromagnetic Shielding Effectiveness of High-Performance, Fiber-Reinforced Cementitious Composites

2019

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“…In order to build the relation between the compressive strength between the pore network, the possible pore network in cement system should be considered. As shown in Figure 8, the pore network can be classified into three categories: (1) Continuously connected conductive path (consists of a series of capillaries connected continuously through an aperture, referred to as CCP, whose resistivity is denoted as R ccp ), (2) Discontinuous connected conductive path (consisting of discontinuous micropores continuously blocked by a cement matrix, referred to as DCP, whose resistivity is expressed as R cp ), (3) Insulation path (the path of formation of dense continuous matrix formed by hydration products and unhydrated cement, referred to as ICP) (Song, 2000;Kong et al, 2015;Hu et al, 2019).…”

Section: Relation Between Eis Parameters and Compressive Strengthmentioning

confidence: 99%

“…Snyder et al believed that OH-was the main conductive ion in the pore solution of cementable materials. The reduction of hydroxyl group would lead to the increase of electromigration, making the ion transport through the pore easier and the value of R ccp lower (Kong et al, 2015). On the other hand, in alkaline solution (pH = 12), excessive OH − promotes the hydration process of cement, and the hydration products are generated too much and too fast, so that the products are not evenly distributed among each other, and more early hydration products wrap the unhydrated particles, which hinders the As shown in Figure 9, the trends of R cp is similar to that of R ccp .…”

Section: Relation Between Eis Parameters and Compressive Strengthmentioning

confidence: 99%

Monitoring the hydration behavior of hardened cement paste affected by different environmental pH regimes

Zhu

Liu²,

Zhang³

2022

Front. Mater.

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The purpose of this paper is to investigate the hydration behavior of hardened Portland cement paste cured in different environmental pH values by compressive strength, XRD, TG-DTG and EIS. Meanwhile, a newly proposed equivalent circuit model is built to establish the correlation between the electrochemical parameters and compressive strength of cement paste. The results show that the matrix strength, hydration products and pore structure of hardened cement paste are significantly affected by different pH values. According to the in-situ nondestructive monitoring of EIS, the evaluating for the matrix strength of cement-based materials can be achieved by calculating the resistivity of discontinuous connected pores (Rcp) in the recommended equivalent circuit model.

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“…As it can be seen, Rgb has a major influence on the electrical behaviour of the mortars. The structure of the interfacial tranzition zone (ITZ) between agregate and cement paste, has a major influence on the concrete or mortar properties [53]. This zone, often said to be 50 micrometer in thickness, determines the weakness of the composite materials [54].…”

Section: Figure 7 Equivalent Circuitmentioning

confidence: 99%

Self-sensing Piezoresistive Composites Based on Cement Incorporating Low Dosage of Carbon Black Used as Multifunctional Construction Materials

Pârvan¹,

Voicu²,

Bădănoiu³

et al. 2020

Rev. Chim.

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HIGHLIGHTS -Carbon black (CB) particles in nanometric domain can be successfully incorporated in cement matrices in order to obtain special concretes/mortars with self-sensing properties. -Piezorezistivity monitoring of mortars is a non-destructive method used to assess the structural characteristics of composite materials. -The presence of CB in studied mortars provides a specific electrical sensitivity which may change when curing time increases. The paper presents the manufacture and characterization of special mortars based on Portland cement (PC) and a nanopowder with electrical properties (carbon black - CB). These materials were characterized from the point of view of mechanical strengths as well as properties specific for self-sensing materials i.e. variation of electrical signal when applying a mechanical strain. The electrical signal and mechanical strength values are strongly dependent on the composition and microstructure of mortars.The values of electrical resistance are strongly correlated with the composition, morphology and curing time of the mortars. In this study significant changes of the electrical behaviour (piezoresistivity) of the mortars vs. curing time (90 or 180 days) were noticed, so this must be considered in practical applications. The best results were obtained for the mortars with 0.5-3 wt.% CB cured for 180 days.

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Application of AC impedance technique in study of lightweight aggregate-paste interface

Cited by 34 publications

References 31 publications

The Effects of Multi-Walled Carbon Nanotubes and Steel Fibers on the AC Impedance and Electromagnetic Shielding Effectiveness of High-Performance, Fiber-Reinforced Cementitious Composites

The Effects of Multi-Walled Carbon Nanotubes and Steel Fibers on the AC Impedance and Electromagnetic Shielding Effectiveness of High-Performance, Fiber-Reinforced Cementitious Composites

Monitoring the hydration behavior of hardened cement paste affected by different environmental pH regimes

Self-sensing Piezoresistive Composites Based on Cement Incorporating Low Dosage of Carbon Black Used as Multifunctional Construction Materials

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