Application of Nano Silica in Concrete for Enhanced Resistance against Sulfate Attack

Moslemi, Amir; Khosravi, Arash; Izadinia, Mohsen; Heydari, Mohaddeseh

doi:10.4028/www.scientific.net/amr.829.874

Cited by 17 publications

(19 citation statements)

References 8 publications

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“…As a result of the NS grains' capacity to act as an inner filler inside the cementitious mix, the NS may be utilized to lower the permeability of the concrete by refining the pore structure. Arel and Thomas [165] studied the efficacy of NS and micro-silica as a partial substitute for cement in the presence of sulphate assaults. Their mortar mixes had a w/c of 0.5 and were subjected to a 7% sodium sulphate solution for 23 weeks.…”

Section: Sulphate Resistancementioning

confidence: 99%

Nano-Silica-Modified Concrete: A Bibliographic Analysis and Comprehensive Review of Material Properties

et al. 2022

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Several review studies have been performed on nano-silica-modified concrete, but this study adopted a new method based on scientometric analysis for the keywords’ assessment in the current research area. A scientometric analysis can deal with vast bibliometric data using a software tool to evaluate the diverse features of the literature. Typical review studies are limited in their ability to comprehensively and accurately link divergent areas of the literature. Based on the analysis of keywords, this study highlighted and described the most significant segments in the research of nano-silica-modified concrete. The challenges associated with using nano-silica were identified, and future research is directed. Moreover, prediction models were developed using data from the literature for the strength estimation of nano-silica-modified concrete. It was noted that the application of nano-silica in cement-based composites is beneficial when used up to an optimal dosage of 2–3% due to high pozzolanic reactivity and a filler effect, whereas a higher dosage of nano-silica has a detrimental influence due to the increased porosity and microcracking caused by the agglomeration of nano-silica particles. The mechanical strength might enhance by 20–25% when NS is incorporated in the optimal amount. The prediction models developed for predicting the strength of nano-silica-modified concrete exhibited good agreement with experimental data due to lower error values. This type of analysis may be used to estimate the essential properties of a material, therefore saving time and money on experimental tests. It is recommended to investigate cost-effective methods for the dispersion of nano-silica in higher concentrations in cement mixes; further in-depth studies are required to develop more accurate prediction models to predict nano-silica-modified concrete properties.

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Section: Sulphate Resistancementioning

confidence: 99%

Nano-Silica-Modified Concrete: A Bibliographic Analysis and Comprehensive Review of Material Properties

et al. 2022

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“…Another study on self-compacting concrete confirmed this trend, where the water absorp-tion, capillary absorption and chloride ions penetration are reduced with the addition of nano-SiO 2 (Jalal et al 2012). The resistance against sulfate attack increases and the water permeability decreases, with the addition of nano-SiO 2 (Du et al 2014;Ji 2005;Moslemi et al 2014). The nano-Al 2 O 3 also contribute to a better durability performance, since a study conducted by Kiachehr and Niloofar (2013) concluded that concrete containing nano-Al 2 O 3 improved the freeze-thaw resistance.…”

Section: Introductionmentioning

confidence: 88%

Influence of Nano-SiO2, Nano-Al2O3, and Nano-ZnO Additions on Cementitious Matrixes with Different Powder and Steel Fibers Content

Carmo

Costa

Soldado

et al. 2021

ACT

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In the study herein presented three types of nanoparticles, with different dosages, were used, namely nano-SiO 2 , nano-Al 2 O 3 and nano-ZnO, which were combined with different concrete formulations. The main goal is to improve the eco-efficiency of concrete, using simultaneously a partial replacement of Portland cement by industrial by-products and reduced amounts of nanoparticles, aiming to avoid the reduction, or even enhance, both mechanical and durability properties of the final mixtures. The interaction between the steel fibers added to the matrixes and the nanoparticles is also addressed. To analyze the effects of nanoparticles additions in the properties of both mortar and concrete mixtures, several tests were performed in fresh and hardened states. Durability indicators were also evaluated, namely, capillary absorption, immersion water absorption and carbonation depth. It was concluded that an increase of both flexural and compressive strengths can be obtained with nanoparticles additions, but that effect depends on the powder dosages used in the binder matrixes and on the type and dosages of nanoparticles. Regarding the matrixes with steel fibers, no additional gains were obtained combining simultaneously nanoparticles with those fibers. It was also concluded that the nano-ZnO addition significantly delay the concrete hardening and show a negative effect when combined with the steel fibers.

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“…In the equilibration stage, the NVT ensemble was used for 700 ps to relax all the SO 2 configurations, whereas in the production stages, the simulations were performed in the NVE ensemble for 3000 ps, obtaining the MSD plots. It is worthy of mentioning that, for relaxation purposes, a less accurate NVT method is sufficient; however, to achieve more profound insight into the trajectories, the NVE ensemble gives more reliable and accurate results. ,, The equations of motion were integrated using the Verlet leapfrog algorithm with 1.0 fs time step. To investigate the loading effect, the simulations were performed with 4, 8, 16, and 32 molecules of SO 2 in each UC.…”

Section: Simulation Details and Methodsmentioning

confidence: 99%

Loading-Dependent Diffusion of SO₂ in 13X and 5A Using Molecular Dynamics: Effects of Extraframework Ions and Topology

Taghdisian¹,

Tasharrofi²,

Firoozjaie³

et al. 2019

J. Chem. Eng. Data

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In the present study, the effects of loading, topology, and extraframework ions on SO 2 diffusion in zeolites 13X and 5A were investigated using molecular dynamics simulation. The study was performed at different loadings, that is, 4, 8, 16, and 32 molecules per unit cell (UC) and various temperatures, that is, 300, 400, 500, and 600 K. The simulation results showed that in the same SO 2 loading and temperature, the self-diffusion coefficients in zeolite 13X are higher than those of 5A, which can be attributed to the smaller pore window size along with strong electrostatic forces of Ca cations in 5A. This result is in accordance with higher mean square displacements (MSDs) of SO 2 molecules in zeolite 13X, in which more hopping can be observed between cages. A closer inspection of the MSD plots in a short time interval (e.g., 200 ps) demonstrates a stepwise behavior which is an important aspect of topology effects, where the hopping between cages and relaxation within cages take place. In both types of zeolites, the self-diffusion coefficient of SO 2 molecules initially displays a slight increase at low loading and follows a slow decrease at high loading of SO 2 . Such a loading-dependent behavior can be attributed to various interactions between SO 2 −SO 2 and SO 2 −zeolites/cations. With increasing the loading from 4 to 16 molecules/UC, although the SO 2 −SO 2 interaction increases, interaction between SO 2 molecules and zeolites (or cations) decreases, which leads to less restriction on diffusing SO 2 molecules. However, increasing the loading from 16 to 32 molecules/UC eventually increases the collision frequency among gas molecules, which is unfavorable to the diffusion process, and therefore, self-diffusion decreases.

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Application of Nano Silica in Concrete for Enhanced Resistance against Sulfate Attack

Cited by 17 publications

References 8 publications

Nano-Silica-Modified Concrete: A Bibliographic Analysis and Comprehensive Review of Material Properties

Nano-Silica-Modified Concrete: A Bibliographic Analysis and Comprehensive Review of Material Properties

Influence of Nano-SiO<sub>2</sub>, Nano-Al<sub>2</sub>O<sub>3</sub>, and Nano-ZnO Additions on Cementitious Matrixes with Different Powder and Steel Fibers Content

Loading-Dependent Diffusion of SO₂ in 13X and 5A Using Molecular Dynamics: Effects of Extraframework Ions and Topology

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Application of Nano Silica in Concrete for Enhanced Resistance against Sulfate Attack

Cited by 17 publications

References 8 publications

Nano-Silica-Modified Concrete: A Bibliographic Analysis and Comprehensive Review of Material Properties

Nano-Silica-Modified Concrete: A Bibliographic Analysis and Comprehensive Review of Material Properties

Influence of Nano-SiO<sub>2</sub>, Nano-Al<sub>2</sub>O<sub>3</sub>, and Nano-ZnO Additions on Cementitious Matrixes with Different Powder and Steel Fibers Content

Loading-Dependent Diffusion of SO2 in 13X and 5A Using Molecular Dynamics: Effects of Extraframework Ions and Topology

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Loading-Dependent Diffusion of SO₂ in 13X and 5A Using Molecular Dynamics: Effects of Extraframework Ions and Topology