Optimization of Low-Carbon Footprint Quaternary and Quinary (37% Fly Ash) Cementitious Nanocomposites with Polycarboxylate or Aqueous Nanosilica Particles
The dispersion medium of nano-SiO2 (nS) particles can have a significant effect on the properties of nanoparticles themselves and consequently on the cement binders it will be added to. In this paper, nS particles dispersed in (a) polycarboxylate or (b) water were added to a low-carbon footprint ref...
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Wiley
2019-01-01
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| Series: | Advances in Materials Science and Engineering |
| Online Access: | http://dx.doi.org/10.1155/2019/5931306 |
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| author | Styliani Papatzani Kevin Paine |
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| description | The dispersion medium of nano-SiO2 (nS) particles can have a significant effect on the properties of nanoparticles themselves and consequently on the cement binders it will be added to. In this paper, nS particles dispersed in (a) polycarboxylate or (b) water were added to a low-carbon footprint reference binder containing 43% Portland cement (PC), 20% limestone powder (LS), and 37% fly ash (FA) by mass of binder. Eight quaternary binders containing nS, PC, LS, and FA and eight quinary binders comprising nS, PC, LS, FA, and silica fume (μS) were investigated. nS was added at 0.1%, 0.2%, 0.5%, or 1.0% by mass of binder as a replacement of LS for the quaternary binders and at 0.5% or 1.0% for the quinary binders. The nanoparticles were examined via transmission and X-ray scanning electron microscopy (TEM/SEM/EDX). For the pastes, compressive strength tests and thermal gravimetric analyses (TGAs) were performed at days 1, 7, 28, and 56, all testified to additional pozzolanic activity and additional C–S–H production. X-ray diffraction analyses and backscattered scanning electron imaging carried out on specific formulations also confirmed this finding at days 1, 28, and 56. Notwithstanding the additional pozzolanic reactivity, nS particles could not mitigate the delayed hydration of the reference paste in the early ages. In such complex formulations, the hydration products seem to create a wrapping around the FA particles delaying their activation at early ages. At later ages, the 0.5% nS addition provided strength, microstructural, and hydration improvements. The polycarboxylate/nS particles provided more pronounced strength improvements at 0.5% addition, possibly due to their superplasticizing effect. Lastly, a tabulated literature review on the thermal decomposition ranges of the hydration products of cementitious nanocomposites is also presented. |
| format | Article |
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| institution | Kabale University |
| issn | 1687-8434 1687-8442 |
| language | English |
| publishDate | 2019-01-01 |
| publisher | Wiley |
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| series | Advances in Materials Science and Engineering |
| spelling | doaj-art-7f0557b6eee1498fbcd53c613780d9862025-02-03T01:30:04ZengWileyAdvances in Materials Science and Engineering1687-84341687-84422019-01-01201910.1155/2019/59313065931306Optimization of Low-Carbon Footprint Quaternary and Quinary (37% Fly Ash) Cementitious Nanocomposites with Polycarboxylate or Aqueous Nanosilica ParticlesStyliani Papatzani0Kevin Paine1BRE Centre for Innovative Construction Materials, University of Bath, BA2 7AY Bath, UKBRE Centre for Innovative Construction Materials, University of Bath, BA2 7AY Bath, UKThe dispersion medium of nano-SiO2 (nS) particles can have a significant effect on the properties of nanoparticles themselves and consequently on the cement binders it will be added to. In this paper, nS particles dispersed in (a) polycarboxylate or (b) water were added to a low-carbon footprint reference binder containing 43% Portland cement (PC), 20% limestone powder (LS), and 37% fly ash (FA) by mass of binder. Eight quaternary binders containing nS, PC, LS, and FA and eight quinary binders comprising nS, PC, LS, FA, and silica fume (μS) were investigated. nS was added at 0.1%, 0.2%, 0.5%, or 1.0% by mass of binder as a replacement of LS for the quaternary binders and at 0.5% or 1.0% for the quinary binders. The nanoparticles were examined via transmission and X-ray scanning electron microscopy (TEM/SEM/EDX). For the pastes, compressive strength tests and thermal gravimetric analyses (TGAs) were performed at days 1, 7, 28, and 56, all testified to additional pozzolanic activity and additional C–S–H production. X-ray diffraction analyses and backscattered scanning electron imaging carried out on specific formulations also confirmed this finding at days 1, 28, and 56. Notwithstanding the additional pozzolanic reactivity, nS particles could not mitigate the delayed hydration of the reference paste in the early ages. In such complex formulations, the hydration products seem to create a wrapping around the FA particles delaying their activation at early ages. At later ages, the 0.5% nS addition provided strength, microstructural, and hydration improvements. The polycarboxylate/nS particles provided more pronounced strength improvements at 0.5% addition, possibly due to their superplasticizing effect. Lastly, a tabulated literature review on the thermal decomposition ranges of the hydration products of cementitious nanocomposites is also presented.http://dx.doi.org/10.1155/2019/5931306 |
| spellingShingle | Styliani Papatzani Kevin Paine Optimization of Low-Carbon Footprint Quaternary and Quinary (37% Fly Ash) Cementitious Nanocomposites with Polycarboxylate or Aqueous Nanosilica Particles Advances in Materials Science and Engineering |
| title | Optimization of Low-Carbon Footprint Quaternary and Quinary (37% Fly Ash) Cementitious Nanocomposites with Polycarboxylate or Aqueous Nanosilica Particles |
| title_full | Optimization of Low-Carbon Footprint Quaternary and Quinary (37% Fly Ash) Cementitious Nanocomposites with Polycarboxylate or Aqueous Nanosilica Particles |
| title_fullStr | Optimization of Low-Carbon Footprint Quaternary and Quinary (37% Fly Ash) Cementitious Nanocomposites with Polycarboxylate or Aqueous Nanosilica Particles |
| title_full_unstemmed | Optimization of Low-Carbon Footprint Quaternary and Quinary (37% Fly Ash) Cementitious Nanocomposites with Polycarboxylate or Aqueous Nanosilica Particles |
| title_short | Optimization of Low-Carbon Footprint Quaternary and Quinary (37% Fly Ash) Cementitious Nanocomposites with Polycarboxylate or Aqueous Nanosilica Particles |
| title_sort | optimization of low carbon footprint quaternary and quinary 37 fly ash cementitious nanocomposites with polycarboxylate or aqueous nanosilica particles |
| url | http://dx.doi.org/10.1155/2019/5931306 |
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