Piezoresistive behaviours of cement-based sensor with carbon black subjected to various temperature and water content

Dong, Wenkui; Li, Wengui; Lü, Na; Qu, Fulin; Vessalas, K; Sheng, Daichao

doi:10.1016/j.compositesb.2019.107488

Cited by 147 publications

(42 citation statements)

References 49 publications

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“…Moreover, even if the cementitious substrate is wet or contains ions (for example deriving from de-icing salts), sensors electrical response is not influenced by environmental conditions. On the contrary, when CNTs are directly immersed in the bulk cementitious matrix, the surrounding environment directly influences sensing ability [26][27][28][29].…”

Section: Fe-sem Micrographsmentioning

confidence: 99%

“…However, even if the electrical conductivity of cementitious materials is significantly increased while maintaining or even improving their mechanical properties, their implementation is limited due to several environmental factors (such as humidity and temperature) affecting the measurement [26][27][28][29][30]. Moreover, the huge amount of fillers to be used in the bulk matrix as well as, the potential toxicity of functionalized CNTs when mixed on-site [31], discourages their diffusion.…”

Section: Introductionmentioning

confidence: 99%

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Preparation and Characterization of Polypropylene/Carbon Nanotubes (PP/CNTs) Nanocomposites as Potential Strain Gauges for Structural Health Monitoring

et al. 2020

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Polypropylene/carbon nanotubes (PP/CNTs) nanocomposites with different CNTs concentrations (i.e., 1, 2, 3, 5 and 7 wt%) were prepared and tested as strain gauges for structures monitoring. Such sensors were embedded in cementitious mortar prisms and tested in 3-point bending mode recording impedance variation at increasing load. First, thermal (differential scanning calorimetry (DSC), thermo-gravimetric analysis (TGA)), mechanical (tensile tests) and morphological (FE-SEM) properties of nanocomposites blends were assessed. Then, strain-sensing tests were carried out on PP/CNTs strips embedded in cementitious mortars. PP/CNTs nanocomposites blends with CNTs content of 1, 2 and 3 wt% did not show significant results because these concentrations are below the electrical percolation threshold (EPT). On the contrary, PP/CNTs nanocomposites with 5 and 7 wt% of CNTs showed interesting sensing properties. In particular, the best result was highlighted for the PP/CNT nanocomposite with 5 wt% CNTs for which an average gauge factor (GF) of approx. 1400 was measured. Moreover, load-unload cycles reported a good recovery of the initial impedance. Finally, a comparison with some literature results, in terms of GF, was done demonstrating the benefits deriving from the use of PP/CNTs strips as strain-gauges instead of using conductive fillers in the bulk matrix.

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Section: Fe-sem Micrographsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Preparation and Characterization of Polypropylene/Carbon Nanotubes (PP/CNTs) Nanocomposites as Potential Strain Gauges for Structural Health Monitoring

et al. 2020

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“…In terms of the effect of water content, it could be deduced that the initial conductive passages disappeared due to the decreased pore solutions after drying treatment. Different from the cementitious composites filled with conductive nanoparticles, whose electrical conductivity probably improved with the drying process due to the decreasing surrounded water content to reduce the contact resistance between nanoparticles (Dong et al, 2019c), the water loss content and disappeared conductive passages connecting nearby rubber crumbs caused the worse conductivity for the rubberized cement mortar. It can demonstrate that the enhanced conductivity of cementitious composites was not only simply due to the connected rubber crumbs but also with the assistance of conductive pore solutions.…”

Section: Resultsmentioning

confidence: 99%

“…Generally, one of the functionalities of the conductive cementitious composites is for structural health monitoring (SHM), due to their given piezoresistivity. Some investigators (Chung, 2002; Cui et al, 2017; Danoglidis et al, 2016; Ding et al, 2019; Dong et al, 2019c; Han et al, 2007, 2011, 2015b; Konsta-Gdoutos and Aza, 2014; Liu et al, 2018; Ou and Han, 2009; Wang and Chung, 1998; Xiao et al, 2010, 2011; Yoo et al, 2019) have studied the piezoresistivity of conductive cementitious composites with different conductors, such as carbon fibres, carbon nanotubes and carbon black, and concluded the improved sensing capacity for the composites reinforced by nanomaterials, especially for those possessing longer aspect ratios (Baeza et al, 2013; Chen et al, 2004; Park et al, 2010). Dong et al (2019e) and Han et al (2015a) summarized various factors, ranging from raw materials, manufacturing procedures, loading regimes, resistivity measurements to environmental factors, which influence the piezoresistivity of cementitious composites, and they compared results from different investigations with clarifications.…”

Section: Introductionmentioning

confidence: 99%

Mechanical strength and self-sensing capacity of smart cementitious composite containing conductive rubber crumbs

Dong

Wang

et al. 2020

Journal of Intelligent Material Systems and Structures

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The effects of conductive rubber crumbs on the mechanical properties and self-sensing capacities of cementitious composites are investigated in this study. The rubberized cementitious composites with five different contents of conductive rubber crumbs are incorporated, ranging from 0%, 10%, 20%, 30% and 40% by mass of fine aggregate. Under the uniaxial cyclic compression, all the conductive rubber crumbs–filled cement composites exhibit excellent repeatability of piezoresistivity. The mortar with 20% conductive rubber crumbs at a water-to-binder ratio of 0.42 displayed the best piezoresistive sensitivity. Based on the relative positions of conductive rubber crumbs in the rubberized cement mortar, three conductive mechanisms were proposed for the conductive rubber crumbs, including complete isolation state, neighbouring state and the contact state. The isolation state plays a dominant role when the content of the conductive rubber crumbs is low, in which the piezoresistive behaviour is mainly controlled by the resistivity changes in cement matrix. In the neighbouring state, pores or voids in the gaps between nearby conductive rubber crumbs make the conductive rubber crumbs easier to connect, thus decreasing the resistivity under uniaxial compression. As for the contact state, the decreased contact resistance and the absence of sand between conductive rubber crumbs lead to higher resistivity changes under cyclic compression. The related results indicate that conductive rubber crumbs in cement mortar have application potentials for structural health monitoring.

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“…These possibilities will be elucidated in future studies. Last but not least, similar concepts of multifunctional aggregates can also be adopted in the research and development of emerging materials, such as alkali-activated cement, magnesium [55][56][57][58][59] phosphate cement, and smart materials and systems.…”

Section: Research Papermentioning

confidence: 99%

Multifunctional Lightweight Aggregate Containing Phase Change Material and Water for Damage Mitigation of Concrete

Liao¹,

Kumar²,

Khayat³

2019

ES Mater.Manuf.

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This paper presents an innovative concept of multifunctional lightweight aggregate, which is produced by loading phase change material (PCM) into the interior of lightweight sand (LWS) and sealing the surface pores using water. The PCM loaded in the LWS functionalizes it as a temperature management agent in concrete, and the water in surface pores enables internal curing. It has been found that the particle shape and pore structure of crushed expanded shale LWS makes it an ideal carrier for PCM, loading sufficient PCM and maintaining better (compared to natural sand) mechanical interlocking. When coupled with the internal curing effect, the LWS yields an interpenetrated interfacial transition zone with the cement paste, leading to a compressive strength comparable to natural sand mortar. The hydration products penetrated into the surface pores also helps stabilizing PCM in the LWS. However, any PCM residuum non-stabilized in LWS tends to compromise the strength. Under an optimized scenario, the LWS-PCM composite aggregate is produced by grading, PCM impregnation, rinsing, and water saturation. A mortar proportioned with this aggregate yields comparable 28-day strength to the reference mortar and a 63% lower autogenous o shrinkage (because of internal curing). Furthermore, it shows a 7 C lower semi-adiabatic temperature rise, delayed appearance of peak temperature and gentled cooling curve. These results indicate that the functional aggregate can effectively mitigate the risk of thermal cracking in early-age mass concrete. In addition, PCM remained in aged concrete has a potential to improve its adaptivity to temperature fluctuations in the service environment.

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Piezoresistive behaviours of cement-based sensor with carbon black subjected to various temperature and water content

Cited by 147 publications

References 49 publications

Preparation and Characterization of Polypropylene/Carbon Nanotubes (PP/CNTs) Nanocomposites as Potential Strain Gauges for Structural Health Monitoring

Preparation and Characterization of Polypropylene/Carbon Nanotubes (PP/CNTs) Nanocomposites as Potential Strain Gauges for Structural Health Monitoring

Mechanical strength and self-sensing capacity of smart cementitious composite containing conductive rubber crumbs

Multifunctional Lightweight Aggregate Containing Phase Change Material and Water for Damage Mitigation of Concrete

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