Effect of nano-modified additives on properties of concrete mixtures during winter season

Svintsov, Alexander P.; Shchesnyak, Evgeny L.; Galishnikova, Vera V.; Федюк, Роман; Stashevskaya, Nadezhda A.

doi:10.1016/j.conbuildmat.2019.117527

Cited by 56 publications

(19 citation statements)

References 31 publications

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“…The presence of the amorphous silica fume altered the frost damage mechanism and acted as a strength accelerator due to the formation of a denser microstructure having a lower water penetration during freezing. Therefore, even without the presence of the air-entrainment a good frost durability is achieved (Figure 8) [89,[95][96][97]. Based on previous studies, using over 15% silica fume corresponds to a high-water requirement.…”

Section: Composite Portland Cement-based Concretesmentioning

confidence: 99%

A Review of the Mechanical Properties and Durability of Ecological Concretes in a Cold Climate in Comparison to Standard Ordinary Portland Cement-Based Concrete

et al. 2020

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Most of the currently used concretes are based on ordinary Portland cement (OPC) which results in a high carbon dioxide footprint and thus has a negative environmental impact. Replacing OPCs, partially or fully by ecological binders, i.e., supplementary cementitious materials (SCMs) or alternative binders, aims to decrease the carbon dioxide footprint. Both solutions introduced a number of technological problems, including their performance, when exposed to low, subfreezing temperatures during casting operations and the hardening stage. This review indicates that the present knowledge enables the production of OPC-based concretes at temperatures as low as −10 °C, without the need of any additional measures such as, e.g., heating. Conversely, composite cements containing SCMs or alkali-activated binders (AACs) showed mixed performances, ranging from inferior to superior in comparison with OPC. Most concretes based on composite cements require pre/post heat curing or only a short exposure to sub-zero temperatures. At the same time, certain alkali-activated systems performed very well even at −20 °C without the need for additional curing. Chemical admixtures developed for OPC do not always perform well in other binder systems. This review showed that there is only a limited knowledge on how chemical admixtures work in ecological concretes at low temperatures and how to accelerate the hydration rate of composite cements containing high amounts of SCMs or AACs, when these are cured at subfreezing temperatures.

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Section: Composite Portland Cement-based Concretesmentioning

confidence: 99%

A Review of the Mechanical Properties and Durability of Ecological Concretes in a Cold Climate in Comparison to Standard Ordinary Portland Cement-Based Concrete

et al. 2020

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“…-studies of the possibility of using nanopowders as catalyst supports. Using SiO 2 nanoparticles, which have a high and chemically active surface, one can purposefully influence [68][69][70][71][72][73][74][75][76][77][78][79]:…”

Section: Prospects For Research and Applications Of Hydrothermal Nanomentioning

confidence: 99%

“…-reducing content of Ca(OH) 2 up to 20% to 30% and, thus, increasing content of CSH gel in hardened concrete because of rapid kinetics of pozzolanic reaction of SiO 2 nanoparticles with Ca(OH) 2 [74,75]; hydrothermal SiO 2 nanoparticles with great specific surface area up to 500 m 2 /g and high chemical activity due the surface density of Si-OH groups up to 4.9 nm −2 , which significantly accelerates the kinetics of pozzolanic reaction [68,77,78]; -increase the volume fraction of C-S-H gel phases with greater elasticity and hardness, Ca/Si relation due to modification of nanostructure of hardened concrete, and, as a result, increase the compressive and bending strength of concrete, reduce pore volume, increase water resistance, frost resistance, chemical resistance, and, as a result, the durability of concrete.…”

Section: Prospects For Research and Applications Of Hydrothermal Nanomentioning

confidence: 99%

Hydrothermal SiO2 Nanopowders: Obtaining Them and Their Characteristics

2020

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The technological mode of obtaining amorphous SiO2 nanopowders based on hydrothermal solutions is proposed in this study. Polycondensation of orthosilicic acid as well as ultrafiltration membrane separation, and cryochemical vacuum sublimation were used. The characteristics of nanopowders were determined by tunneling electron microscopy, low-temperature nitrogen adsorption, X-ray diffraction, and small-angle X-ray scattering. The scheme allows to adjust density, particle diameters of nanopowders, specific surface area, as well as diameters, area and volume of the pore. Thus, the structure of nanopowders is regulated—the volume fraction of the packing of spherical particles in aggregates and agglomerates, the size of agglomerates, and the number of particles in agglomerates. The pour densities of the nanopowders depend on the SiO2 content in sols, which were 0.02 to 0.3 g/cm3. Nanoparticles specific surface area was brought to 500 m2/g by low temperature polycondensation. Nanoparticle aggregates specific pore volume (0.2–0.3 g/cm3) weakly depend on powders density. The volume fraction of the packing of SiO2 nanoparticles in aggregates was 0.6–0.7. Solid samples of compacted nanopowders had a compressive strength of up to 337 MPa. Possible applications of hydrothermal SiO2 nanopowders are considered.

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“…The main scope of the development of PC and PC-based concrete is the improvement of its mechanical properties. Previous studies have shown various approaches in this area [ 20 , 21 , 22 ]. However, the process of the PC production is very burdensome for the environment.…”

Section: Introductionmentioning

confidence: 99%

MOC Doped with Graphene Nanoplatelets: The Influence of the Mixture Preparation Technology on Its Properties

et al. 2021

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The ongoing tendency to create environmentally friendly building materials is nowadays connected with the use of reactive magnesia-based composites. The aim of the presented research was to develop an ecologically sustainable composite material based on MOC (magnesium oxychloride cement) with excellent mechanical, chemical, and physical properties. The effect of the preparation procedure of MOC pastes doped with graphene nanoplatelets on their fresh and hardened properties was researched. One-step and two-step homogenization techniques were proposed as prospective tools for the production of MOC-based composites of advanced parameters. The conducted experiments and analyses covered X-ray fluorescence, scanning electron microscopy, energy-dispersive spectroscopy, high-resolution transmission electron microscopy, sorption analysis, X-ray diffraction, and optical microscopy. The viscosity of the fresh mixtures was monitored using a rotational viscometer. For the hardened composites, macro- and micro-structural parameters were measured together with the mechanical parameters. These tests were performed after 7 days and 14 days. The use of a carbon-based nanoadditive led to a significant drop in porosity, thus densifying the MOC matrix. Accordingly, the mechanical resistance was greatly improved by graphene nanoplatelets. The two-step homogenization procedure positively affected all researched functional parameters of the developed composites (e.g., the compressive strength increase of approximately 54% after 7 days, and 37% after 14 days, respectively) and can be recommended for the preparation of advanced functional materials reinforced with graphene.

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Effect of nano-modified additives on properties of concrete mixtures during winter season

Cited by 56 publications

References 31 publications

A Review of the Mechanical Properties and Durability of Ecological Concretes in a Cold Climate in Comparison to Standard Ordinary Portland Cement-Based Concrete

A Review of the Mechanical Properties and Durability of Ecological Concretes in a Cold Climate in Comparison to Standard Ordinary Portland Cement-Based Concrete

Hydrothermal SiO2 Nanopowders: Obtaining Them and Their Characteristics

MOC Doped with Graphene Nanoplatelets: The Influence of the Mixture Preparation Technology on Its Properties

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