| 1. |
- Cwirzen, Andrzej, et al.
(författare)
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CHH Cement Composite
- 2009
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Ingår i: Nanotechnology in Construction 3. - Berlin : Encyclopedia of Global Archaeology/Springer Verlag. - 9783642009792 - 9783642009808 ; , s. 181-185
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Konferensbidrag (refereegranskat)abstract
- The compressive strength and electrical resistivity for hardened pastes produced from nanomodified Portland SR cement (CHH- Carbon Hedge Hog cement) were studied. The nanomodification included growing of carbon nanotubes (CNTs) and carbon nanofibers (CNFs) on the cement particles. Pastes having water to binder ratio of 0.5 were produced. The obtained hardened material was characterized by increased compressive strength in comparison with the reference specimens made from pristine SR cement, which was attributed to reinforcing action of the CNTs and CNFs. The electrical resistivity of CHH composite was lower by one order of magnitude in comparison with reference Portland cement paste
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| 2. |
- Mudimela, Prasantha R., et al.
(författare)
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Synthesis of carbon nanotubes and nanofibers on silica and cement matrix materials
- 2009
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Ingår i: Journal of Nanomaterials. - : Hindawi Limited. - 1687-4110 .- 1687-4129. ; 2009
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Tidskriftsartikel (refereegranskat)abstract
- In order to create strong composite materials, a good dispersion of carbon nanotubes (CNTs) and nanofibers (CNFs) in a matrix material must be obtained. We proposed a simple method of growing the desirable carbon nanomaterial directly on the surface of matrix particles. CNTs and CNFs were synthesised on the surface of model object, silica fume particles impregnated by iron salt, and directly on pristine cement particles, naturally containing iron oxide. Acetylene was successfully utilised as a carbon source in the temperature range from 550 to 750 °C. 5-10 walled CNTs with diameters of 10-15nm at 600 °C and 12-20nm at 750 °C were synthesised on silica particles. In case of cement particles, mainly CNFs with a diameter of around 30nm were grown. It was shown that high temperatures caused chemical and physical transformation of cement particles. © 2009 Prasantha R. Mudimela et al.
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| 3. |
- Nasibulin, Albert G., et al.
(författare)
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A novel cement-based hybrid material
- 2009
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Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Carbon nanotubes (CNTs) and carbon nanofibers (CNFs) are known to possess exceptional tensile strength, elastic modulus and electrical and thermal conductivity. They are promising candidates for the next-generation high-performance structural and multi-functional composite materials. However, one of the largest obstacles to creating strong, electrically or thermally conductive CNT/CNF composites is the difficulty of getting a good dispersion of the carbon nanomaterials in a matrix. Typically, time-consuming steps of purification and fimctionalization of the carbon nanomaterial are required. We propose a new approach to grow CNTs/CNFs directly on the surface of matrix particles. As the matrix we selected cement, the most important construction material. We synthesized in a simple one-step process a novel cement hybrid material (CHM), wherein CNTs and CNFs are attached to the cement particles. The CHM has been proven to increase 2 times the compressive strength and 40 times the electrical conductivity of the hardened paste, i.e. concrete without sand. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.
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| 4. |
- Nasibulina, Larisa I., et al.
(författare)
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Direct synthesis of carbon nanofibers on cement particles
- 2010
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Ingår i: Transportation Research Record. - : SAGE Publications. - 0361-1981 .- 2169-4052. ; :2142, s. 96-101
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Tidskriftsartikel (refereegranskat)abstract
- Carbon nanotubes (CNTs) and nanofibers (CNFs) are promising candidates for the next generation of high-performance structural and multifunctional composite materials. One of the largest obstacles to creating strong, electrically or thermally conductive CNT-CNF composites is the difficulty of getting a good dispersion of the carbon nanomaterials in a matrix. Typically, time-consuming steps are required in purifying and functionalizing the carbon nanomaterial. A new approach under which CNTs-CNFs are grown directly on the surface of matrix and matrix precursor particles is proposed. Cement was selected as the precursor matrix, since it is the most important construction material. A novel cement hybrid material (CHM) was synthesized in which CNTs and CNFs are attached to the cement particles by two different methods: screw feeder and fluidized bed reactors. CHM has been proved to increase the compressive strength by two times and the electrical conductivity of the hardened paste by 40 times.
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