Energy Savings Associated with the Use of Fly Ash and Nanoadditives in the Cement Composition

Golewski, Grzegorz Ludwik

doi:10.3390/en13092184

Cited by 74 publications

(35 citation statements)

References 103 publications

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“…As a result of hydration, hydration products (calcium hydroxide, calcium silicate hydrate) are precipitated within the free spaces between the cement particles. This precipitation most likely contributes to increased separation between the CNFs in a twofold manner: (1) The distances between the CNFs may increase as a result of cement particle volume increase, associated with water binding and the precipitation of hydration products (amorphous calcium silicate hydrate and crystalline calcium hydroxide [35]) on their surface. (2) On the other hand, the nonconductive hydration products may precipitate in the spaces between fibers, leading to the loss of electric contact between them.…”

Section: Effect Of W/c Ratio and Pore Water Content On Bulk Resistivimentioning

confidence: 99%

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Effects of Water Content and Temperature on Bulk Resistivity of Hybrid Cement/Carbon Nanofiber Composites

et al. 2020

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Cement nanocomposites with carbon nanofibers (CNFs) are electrically conductive and sensitive to mechanical loads. These features make them useful for sensing applications. The conductive and load sensing properties are well known to be dependent on carbon nanofiber content; however, much less is known about how the conductivity of hybrid cement–CNF depend on other parameters (e.g., water to cement ratio (w/c), water saturation of pore spaces and temperatures above ambient temperature). In this paper we fill-in these knowledge gaps by: (1) determining a relationship between the cement–CNF bulk resistivity and w/c ratio; (2) determining the effect of water present in the pores on bulk resistivity; (3) describing the resistivity changes upon temperature changes up to 180 °C. Our results show that the increase in the water to cement ratio results in increased bulk resistivity. The decrease in nanocomposite resistivity upon a stepwise temperature increase up to 180 °C was found to be related to free water release from cement pores and the dry materials were relatively insensitive to temperature changes. The re-saturation of pores with water was not reversible with respect to electrical resistivity. The results also suggest that the change in the type of electrical connection can lead to two orders of magnitude different bulk resistivity results for the same material. It is expected that the findings from this paper will contribute to application of cement–CNF-based sensors at temperatures higher than ambient temperature.

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Section: Effect Of W/c Ratio and Pore Water Content On Bulk Resistivimentioning

confidence: 99%

“…Cement nanocomposites have recently gained much attention. Nanoparticles are added not only to engineer the mechanical properties [1][2][3][4] of the composites but also to render cement electrically conductive and responsive to mechanical load [5,6].…”

Section: Introductionmentioning

confidence: 99%

Effects of Water Content and Temperature on Bulk Resistivity of Hybrid Cement/Carbon Nanofiber Composites

et al. 2020

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“…It was previously shown that adding blast furnace slag and fly ash could be useful in developing concrete resistance. However, the use of mineral admixtures is limited, and it is necessary to study improvement methods for general applications [2,3].…”

Section: Introductionmentioning

confidence: 99%

“…The use of rubber crumbs in the concrete asphalt mixture increases the plasticity of the whole mixture and protects the cured concrete from cracking and shrinkage under thermal expansion and contraction. In recent years, extensive researchers have performed studies on the use and application of rubber crumbs in concrete [3]. Studies on the rubber size effect on concrete strength properties have shown that, although the strength of the concrete containing rubber crumbs decreases compared to the mixtures made of aggregates, the plastic capacity of the concrete increases considerably.…”

Section: Introductionmentioning

confidence: 99%

Nano Silica and Metakaolin Effects on the Behavior of Concrete Containing Rubber Crumbs

2020

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The excessive production of worn tires remaining from the transportation system and the lack of proper procedures to recycle or reuse these materials have caused critical environmental issues. Due to the rubber’s toughness, this material could be implemented to increase concrete toughness, and by crushing the tires concrete aggregates can be replaced proportionally with rubber crumbs and large quantities of scrapped rubber. However, this substitution decreases the concrete strength. In this study, crushed rubber with sizes from 1 to 3 mm and 3 to 6 mm were replaced by 5%, 10%, and 15% sand; the combination of two additives of nano silica and metakaolin additives with optimum values was used to compensate the degradation of the strength and improve the workability of the concrete. Moreover, the compressive strength, tensile behavior, and modulus of elasticity were measured and compared. The results indicate that the optimum use of nano silica and metakaolin additives could compensate the negative effects of the rubber material implementation in the concrete mixture while improving the overall workability and flowability of the concrete mixture.

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“…Additionally, FA-based geopolymer binders display a reliable resilience to heat curing. Nevertheless, the main drawbacks associated with the application of FA are its poor strength when cured in ambient temperature, the high required molarity (UP 10 M) of sodium hydroxide, and high demand for an alkaline solution [22]. Accordingly, there is no benefit of using FA separately to achieve a satisfactory alkali-activated binder.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Mechanical and Environmental Properties of Engineered Alkali-Activated Green Mortar

2020

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Currently, alkali-activated binders using industrial wastes are considered an environmentally friendly alternative to ordinary Portland cement (OPC), which contributes to addressing the high levels of carbon dioxide (CO2) emissions and enlarging embodied energy (EE). Concretes produced from industrial wastes have shown promising environmentally-friendly features with appropriate strength and durability. From this perspective, the compressive strength (CS), CO2 emissions, and EE of four industrial powder waste materials, including fly ash (FA), palm oil fly ash (POFA), waste ceramic powder (WCP), and granulated blast-furnace slag (GBFS), were investigated as replacements for OPC. Forty-two engineered alkali-activated mix (AAM) designs with different percentages of the above-mentioned waste materials were experimentally investigated to evaluate the effect of each binder mass percentage on 28-day CS. Additionally, the effects of each industrial powder waste material on SiO2, CaO, and Al2O3 contents were investigated. The results confirm that adding FA to the samples caused a reduction of less than 26% in CS, whereas the replacement of GBFS by different levels of POFA significantly affected the compressive strength of specimens. The results also show that the AAM designs with a high volume FA provided the lowest EE and CO2 emission levels compared to other mix designs. Empirical equations were also proposed to estimate the CS, CO2 emissions, and EE of AAM designs according to their binder mass compositions.

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Energy Savings Associated with the Use of Fly Ash and Nanoadditives in the Cement Composition

Cited by 74 publications

References 103 publications

Effects of Water Content and Temperature on Bulk Resistivity of Hybrid Cement/Carbon Nanofiber Composites

Effects of Water Content and Temperature on Bulk Resistivity of Hybrid Cement/Carbon Nanofiber Composites

Nano Silica and Metakaolin Effects on the Behavior of Concrete Containing Rubber Crumbs

Evaluation of Mechanical and Environmental Properties of Engineered Alkali-Activated Green Mortar

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