Composites Based on Alternative Raw Materials at High Temperature Conditions

Melichar, Tomáš; Bydžovský, Jiří; Dufka, Ámos

doi:10.3311/ppci.9820

Cited by 3 publications

(6 citation statements)

References 14 publications

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“…Secondary raw materials are an important part of the raw material base for most types of industry. Thanks to the use of secondary raw materials, it is possible to reduce the consumption of primary raw materials, which are in most cases non-renewable 22 . Secondary raw materials equally replace and at the same time facilitate technological processes in the production of various materials, thus reducing the energy and material demand of products 23 .…”

Section: Introductionmentioning

confidence: 99%

Electrically conductive composite materials with incorporated waste and secondary raw materials

Baránek

Černý

Drochytka

et al. 2023

Sci Rep

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Silicate composites have very low conductivity in general. It is possible to achieve an electrical resistivity decrease by adding an electro-conductive filler. The conductive mixture consists of cementitious binder, various types of silica sand, and graphite-based conductive fillers. One of the research focusses is partial substitution of ordinary raw materials by alternative components (waste materials by-products and secondary raw materials) and its influence on composite properties. The alternative components studied were fly ash as a partial binder replacement, waste graphite from two different sources and steel shavings as a substitute for conductive filler. Resistivity of cured conductive silicate-based specimens was analysed in relation to changes in physico-mechanical properties in context of microstructural changes in the hardened cementitious matrix (by optical and scanning electron microscopy with energy disperse analysis). Partial substitution of cement by fly ash was found to reduce the electrical resistivity of the composite. Some of the waste graphite fillers significantly reduce the resistivity of the cement composite and increase the compressive strength. It was proven, that is possible to replace primary conductive fillers by secondary raw materials.

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Section: Introductionmentioning

confidence: 99%

Electrically conductive composite materials with incorporated waste and secondary raw materials

Baránek

Černý

Drochytka

et al. 2023

Sci Rep

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“…The cement composite material may be generally characterized as a material of the structure that contains a bonding agent on the basis of cement, a specific type of filler, water, and other components and admixtures [1,2]. The mutual synergic effect of all these components determines the resulting properties of the composite.…”

Section: Introductionmentioning

confidence: 99%

“…Generally, it could be said that cement composites show slight electron movements due to the presence of n-type conductivity [2]. Among other influences, the volume of the aggregate in the concrete has a reducing effect on the electrical conductivity of concrete.…”

Section: Introductionmentioning

confidence: 99%

“…The distribution of the electric current within the sample is affected by a number of external parameters [2]. Otten focuses on monitoring the effects of humidity on electric conductivity, comparing samples treated with hydrophobic impregnations with those untreated and coming to the conclusion that, with increasing material moisture content, the electrical resistivity decreases, while also the temperature of the samples has an effect on electrical resistivity (he monitored 4, 20 and 36 • C) in contrast to what has been reported for cement-CNF composites by Gawel et al, which behave in the opposite way (with decreasing material moisture, the resistivity decreases) [34,35].…”

Section: Introductionmentioning

confidence: 99%

“…[35,40,41]. During the design of the composites, the electronic trans-port, Seebeck effect, Thompson effect, electron contributions, percolation and molecular dynamics must also be considered [2].…”

Section: Introductionmentioning

confidence: 99%

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Impact of Carbon Particle Character on the Cement-Based Composite Electrical Resistivity

et al. 2021

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Electroconductive cement-based composites are modern materials that are commonly used in many industries such as the construction industry, among others. For example, these materials can be used as sensors for monitoring changes in construction, grounding suspension, and resistance heating materials, etc. The aim of the research presented in this article is to monitor the impact of carbon particle character on cement-based electroconductive composites. Four types of graphite were analyzed. Natural and synthetic types of graphite, with different particle sizes and one with improved electrically conductive properties, were tested. For the analysis of the electrical conductivity of powder raw materials, a new methodology was developed based on the experience of working with these materials. Various types of graphite were tested in pure cement paste (80% cement, 20% graphite) as well as in a composite matrix, which consisted of cement (16.8%), a mixture of silica sand 0–4 mm (56.4%), graphite filler (20.0%) ground limestone (6.7%) and super plasticizers (0.1%). The resistivity and physical-mechanical properties of the composite material were determined. Furthermore, the resistivity of the test samples was measured with a gradual decrease in saturation. It may be concluded that graphite fillers featuring very fine particles and high specific surface are most suitable and most effective for creating electrically conductive silicate composites. The amount, shape and, in particular, the fineness of the graphite filler particles thus creates suitable conditions for the creation of an integrated internal electricity-conductive network. In the case of the use of a coarse type of graphite or purely non-conductive fillers, the presence of an electrolyte, for example, in the form of water, is necessary to achieve a low resistivity. Samples with fine types of graphite fillers achieved stable resistivity values when the sample humidity changed. The addition of graphite fillers caused a large decrease in the strength of the samples.

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Examination of Microstructure of Cement Composite Material for Renovation of Horizontal Structures

Mészárosová

Černý

Drochytka

et al. 2019

KEM

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Development of new material is focused on modification of properties of materials with silicate binder so that these could be used for renovation of horizontal structures of high-temperature devices and at the same time contribute to reduction of heat transportation of constructions with higher surface temperature (in this case 200 and 500 °C). Main requirements for this material is low volume weight and low coefficient of thermal conductivity. This paper assesses influence of exposition to higher temperatures on microstructure.

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Composites Based on Alternative Raw Materials at High Temperature Conditions

Abstract: This paper presents newly developed polymer-cement composites. The primary binder (cement) was partially substituted by

Cited by 3 publications

References 14 publications

Electrically conductive composite materials with incorporated waste and secondary raw materials

Electrically conductive composite materials with incorporated waste and secondary raw materials

Impact of Carbon Particle Character on the Cement-Based Composite Electrical Resistivity

Examination of Microstructure of Cement Composite Material for Renovation of Horizontal Structures

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