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Carbon fibers' percolation in smart cementitious materials considering sand characteristics
https://orcid.org/http://orcid.org/0000-0003-2339-3962
Self-sensing concrete, is created by including electrically conductive fibers in cement-based materials. These fibers may help reduce electrical resistivity and develop a piezo resistive behavior. Smart Concrete is therefore able to serve as a structural and a sensing material simultaneously, which eliminates the need for external instrumentation in structural health monitoring. The presence of sand has been found to influence resistivity in the case of fibrous mortar. This phenomenon is referred to as “double percolation”. However, little attention has been paid to how the size of sand grains impacts the electrical percolation. The originality of this paper is to study the effect of sand, its particle size distribution and volume fraction within fibrous mortars, for different carbon fibers percolation status. Two types of sand were compared: a standard sand (0–2 mm) and a fine sand (0–0.5 mm). Four volume fractions of sand were compared, each one presenting a different connectivity status of sand structure. The percolation threshold of carbon fibers was estimated analytically. The analytical results were validated experimentally, using AC impedance measurements between 4 Hz and 1 MHz. The “double percolation” phenomenon was confirmed. The novelty was to illustrate the effect of sand particle size distribution on the impedance of fibrous mortar: for a sand volume fraction up to 40%, standard sand had a beneficial effect on the electrical impedance at a fiber volume fraction below 0.3%, and a very slight detrimental effect when that fraction exceeds 0.3%. For fine sand, no beneficial effect of sand aggregates on the impedance was observed. For both sands, the impedance of mortars with a 50% sand volume fraction was considerably higher than for cement paste, confirming the relevance of the double percolation theory. The usage of standard sand below maximum packing density is recommended.
Carbon fibers' percolation in smart cementitious materials considering sand characteristics
https://orcid.org/http://orcid.org/0000-0003-2339-3962
Self-sensing concrete, is created by including electrically conductive fibers in cement-based materials. These fibers may help reduce electrical resistivity and develop a piezo resistive behavior. Smart Concrete is therefore able to serve as a structural and a sensing material simultaneously, which eliminates the need for external instrumentation in structural health monitoring. The presence of sand has been found to influence resistivity in the case of fibrous mortar. This phenomenon is referred to as “double percolation”. However, little attention has been paid to how the size of sand grains impacts the electrical percolation. The originality of this paper is to study the effect of sand, its particle size distribution and volume fraction within fibrous mortars, for different carbon fibers percolation status. Two types of sand were compared: a standard sand (0–2 mm) and a fine sand (0–0.5 mm). Four volume fractions of sand were compared, each one presenting a different connectivity status of sand structure. The percolation threshold of carbon fibers was estimated analytically. The analytical results were validated experimentally, using AC impedance measurements between 4 Hz and 1 MHz. The “double percolation” phenomenon was confirmed. The novelty was to illustrate the effect of sand particle size distribution on the impedance of fibrous mortar: for a sand volume fraction up to 40%, standard sand had a beneficial effect on the electrical impedance at a fiber volume fraction below 0.3%, and a very slight detrimental effect when that fraction exceeds 0.3%. For fine sand, no beneficial effect of sand aggregates on the impedance was observed. For both sands, the impedance of mortars with a 50% sand volume fraction was considerably higher than for cement paste, confirming the relevance of the double percolation theory. The usage of standard sand below maximum packing density is recommended.
Carbon fibers' percolation in smart cementitious materials considering sand characteristics
https://orcid.org/http://orcid.org/0000-0003-2339-3962
Self-sensing concrete, is created by including electrically conductive fibers in cement-based materials. These fibers may help reduce electrical resistivity and develop a piezo resistive behavior. Smart Concrete is therefore able to serve as a structural and a sensing material simultaneously, which eliminates the need for external instrumentation in structural health monitoring. The presence of sand has been found to influence resistivity in the case of fibrous mortar. This phenomenon is referred to as “double percolation”. However, little attention has been paid to how the size of sand grains impacts the electrical percolation. The originality of this paper is to study the effect of sand, its particle size distribution and volume fraction within fibrous mortars, for different carbon fibers percolation status. Two types of sand were compared: a standard sand (0–2 mm) and a fine sand (0–0.5 mm). Four volume fractions of sand were compared, each one presenting a different connectivity status of sand structure. The percolation threshold of carbon fibers was estimated analytically. The analytical results were validated experimentally, using AC impedance measurements between 4 Hz and 1 MHz. The “double percolation” phenomenon was confirmed. The novelty was to illustrate the effect of sand particle size distribution on the impedance of fibrous mortar: for a sand volume fraction up to 40%, standard sand had a beneficial effect on the electrical impedance at a fiber volume fraction below 0.3%, and a very slight detrimental effect when that fraction exceeds 0.3%. For fine sand, no beneficial effect of sand aggregates on the impedance was observed. For both sands, the impedance of mortars with a 50% sand volume fraction was considerably higher than for cement paste, confirming the relevance of the double percolation theory. The usage of standard sand below maximum packing density is recommended.
Carbon fibers' percolation in smart cementitious materials considering sand characteristics
Mater Struct
Allam, Hamza (author) / Duplan, François (author) / Amziane, Sofiane (author) / Burtschell, Yves (author)
2023-06-01
Article (Journal)
Electronic Resource
English
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