Energies

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11 pages, 1266 KiB

Open AccessArticle

Lime Hemp Concrete with Unfired Binders vs. Conventional Building Materials: A Comparative Assessment of Energy Requirements and CO₂ Emissions

by Rotem Haik, Isaac A. Meir and Alva Peled

Energies 2023, 16(2), 708; https://doi.org/10.3390/en16020708 - 7 Jan 2023

Cited by 7 | Viewed by 2143

Abstract

This work assesses the energy requirements and CO₂ emissions of a building made of Lime Hemp Concrete (LHC) with alternative unfired binders as lime replacement, compared to buildings made of standard LHC, and several conventional building materials. The assessment is based on [...] Read more.

This work assesses the energy requirements and CO₂ emissions of a building made of Lime Hemp Concrete (LHC) with alternative unfired binders as lime replacement, compared to buildings made of standard LHC, and several conventional building materials. The assessment is based on ISO 14040, which deals with Life Cycle Assessment (LCA), and examines two aspects: energy, including pre-use phase Embodied Energy (EE), and use phase Operational Energy (OE); and CO₂ emissions, including pre-use phase Embodied Carbon (EC), and use phase Operational Carbon (OC). The EE and EC calculations are based on published databases, while OE and OC were obtained with EnergyPlus simulations. The assessment refers to a specific case study in an arid region, with extreme diurnal and seasonal fluctuations of temperature and relative humidity. Using LHC with 100% unfired binder as lime replacement was shown to save up to 90% of the total energy consumption and CO₂ emissions, as compared to conventional building materials. The findings of this research clearly demonstrate the high potential of LHC with unfired binders as lime replacement, which possesses the lowest energy requirements and CO₂ emissions, illustrating the potential for a building with significantly low environmental impact over its life cycle, i.e., when calculating both EE and EC, and OE and OC. Full article

(This article belongs to the Special Issue Low Energy and Carbon Footprint Building Materials - Waste Management and Recycling)

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16 pages, 4974 KiB

Open AccessArticle

Combined Effect of Coal Fly Ash (CFA) and Nanosilica (nS) on the Strength Parameters and Microstructural Properties of Eco-Friendly Concrete

by Grzegorz Ludwik Golewski

Energies 2023, 16(1), 452; https://doi.org/10.3390/en16010452 - 31 Dec 2022

Cited by 82 | Viewed by 2406

Abstract

Disposal of the coal fly ash (CFA) generated from thermal power plants in huge quantities is one of the major concerns for the industry, as well as the natural environment. On the other hand, CFA can be used within a certain percentage range [...] Read more.

Disposal of the coal fly ash (CFA) generated from thermal power plants in huge quantities is one of the major concerns for the industry, as well as the natural environment. On the other hand, CFA can be used within a certain percentage range in the cement concrete mix as a replacement for cement. Nanomaterials can also be used to improve the properties of concrete. Therefore, this study investigated the effects of nanosilica (nS) on the mechanical parameters and microstructure of CFA cement concretes. This study utilized an nS content of 5%, along with three CFA contents, i.e., of 0, 15, and 25% by volume. Mechanical property tests and a thorough overview of changes in the structure of modified concrete were carried out to study the effect of the CFA content on the analyzed parameters of concrete containing nS. This study had the goal of elucidating the reinforcing mechanisms of CFA concrete by nS and providing design guidance for the practical engineering applications of CFA-nS composites. Based on the conducted studies, it was found that the combined usage of nS and CFA has synergistic and positive effects on improving mechanical parameters and microstructure in such concretes. The combined strengthening of a cement matrix by nS and CFA can fill the pores and microcracks in concrete composites and effectively improve the mechanical properties and microstructure of such materials. In this study, the optimal improvement was achieved when the concentration of additions was 5% nS and 15% CFA. The 28-day compressive strength and splitting tensile strength were increased by 37.68 and 36.21%, respectively, in comparison to control concrete. Tailored blended cements composed of nS and CFA content (up to 30% replacement level) can significantly improve the parameters of concrete composites, as well as reduce the carbon footprint of cement-based materials—constituting a step toward the production of eco-friendly concretes. Full article

(This article belongs to the Special Issue Low Energy and Carbon Footprint Building Materials - Waste Management and Recycling)

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13 pages, 1585 KiB

Open AccessArticle

Design of Cement–Slag Concrete Composition for 3D Printing

by Leonid Dvorkin, Vitaliy Marchuk, Izabela Hager and Marcin Maroszek

Energies 2022, 15(13), 4610; https://doi.org/10.3390/en15134610 - 23 Jun 2022

Cited by 6 | Viewed by 1655

Abstract

The article presents a set of experimental-static models of the properties of fine-grained concretes on a cement–slag binder and quartz sand with the addition of a hardening accelerator made on a 3D printer. The influence of the factors of the composition of the [...] Read more.

The article presents a set of experimental-static models of the properties of fine-grained concretes on a cement–slag binder and quartz sand with the addition of a hardening accelerator made on a 3D printer. The influence of the factors of the composition of the mixture and the effects of their interaction on the studied properties of concrete was established. By analyzing the models, the influence of the factors of mixture composition on the studied properties was ranked. The nature and degree of interrelation of individual properties of concrete are shown. A method for calculating the optimal compositions of concrete for a 3D printer, providing the specified properties at a minimum cost, is proposed. Full article

(This article belongs to the Special Issue Low Energy and Carbon Footprint Building Materials - Waste Management and Recycling)

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15 pages, 1930 KiB

Open AccessArticle

Foamed Eco-Geopolymer Modified by Perlite and Cellulose as a Construction Material for Energy-Efficient Buildings

by Izabela Kurek, Emilia Florek, Weronika Gozdur, Celina Ziejewska, Joanna Marczyk, Michał Łach, Kinga Korniejenko, Patrycja Duży, Marta Choińska, Magdalena Szechyńska-Hebda and Marek Hebda

Energies 2022, 15(12), 4297; https://doi.org/10.3390/en15124297 - 11 Jun 2022

Cited by 6 | Viewed by 2321

Abstract

Irreversible climate change, including atmosphere temperature extremes, is one of the most important issues of the present time. In this context, the construction industry requires solutions for increasing the energy efficiency of buildings through feedback between temperature adjustment inside buildings and better isolation [...] Read more.

Irreversible climate change, including atmosphere temperature extremes, is one of the most important issues of the present time. In this context, the construction industry requires solutions for increasing the energy efficiency of buildings through feedback between temperature adjustment inside buildings and better isolation of the external parts of buildings. Newly developed thermal insulation materials play an important role in this strategy. This paper presents the foamed geopolymer based on metakaolin that can be used as a modern facade material. In order to further improve its thermal insulation properties, the composition of geopolymer was modified with organic substances, i.e., perlite and cellulose fibers (30% and 50% of the volume). The thermal conductivity and insulation properties, density, mineral phases, absorbability, and compressive strength were improved for composite materials. It has been shown that the final properties of the foamed geopolymer can be controlled to a great extent by modifications, and the final properties determine its applicability. Full article

(This article belongs to the Special Issue Low Energy and Carbon Footprint Building Materials - Waste Management and Recycling)

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10 pages, 2190 KiB

Open AccessArticle

Adhesive Strength of Modified Cement–Ash Mortars

by Leonid Dvorkin, Patrycja Duży, Karolina Brudny, Marta Choińska and Kinga Korniejenko

Energies 2022, 15(12), 4229; https://doi.org/10.3390/en15124229 - 8 Jun 2022

Cited by 3 | Viewed by 1402

Abstract

The main aim of this article, carried out in relation to ash–cement mortars, is to determine the effect of complex additives of polyfunctional modifiers, including, in addition to superplasticizers, air-entraining and water-retaining additives, at different values of water–cement ratios. With the use of [...] Read more.

The main aim of this article, carried out in relation to ash–cement mortars, is to determine the effect of complex additives of polyfunctional modifiers, including, in addition to superplasticizers, air-entraining and water-retaining additives, at different values of water–cement ratios. With the use of experimental–statistical models, the complex effect on the adhesive strength of cement–ash mortars of water–cement and ash–cement ratios, as well as complex additives of polyfunctional modifiers, including air-entraining and water-retaining additives, is considered. The extreme nature of the water–cement and ash–cement ratios on the adhesive strength of ash–cement mortars are established. Their optimal values are in the ranges of 0.7–0.75 and 0.35–0.4, respectively. The addition of a naphthalene-formaldehyde superplasticizer makes it possible to increase the adhesive strength of mortars by up to 40%. A positive effect is achieved along with the addition of a superplasticizer by introducing optimal amounts of air-entraining and water-retaining additives into the mortar mixtures. Quantitative parameters of mortar compositions that positively affect adhesive strength are established. The influence on the adhesive strength of the fly ash was also investigated, as well as on the binder–sand ratio. In addition, a positive effect on the adhesive strength of modified cement–ash mortars was experimentally shown by increasing the specific surface area of fly ash by regrinding it and increasing the cement–sand ratio. Full article

(This article belongs to the Special Issue Low Energy and Carbon Footprint Building Materials - Waste Management and Recycling)

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17 pages, 12946 KiB

Open AccessArticle

Mechanical Response of Geopolymer Foams to Heating—Managing Coal Gangue in Fire-Resistant Materials Technology

by Mateusz Sitarz, Beata Figiela, Michał Łach, Kinga Korniejenko, Katarzyna Mróz, João Castro-Gomes and Izabela Hager

Energies 2022, 15(9), 3363; https://doi.org/10.3390/en15093363 - 5 May 2022

Cited by 17 | Viewed by 2138

Abstract

Two geopolymer foams were prepared from a thermally activated coal gangue containing kaolinite. As the foaming agent, aluminium powder and 36% hydrogen peroxide were used to obtain two levels of porosity. The materials’ high temperature performances were investigated: tensile and compressive strength evolution [...] Read more.

Two geopolymer foams were prepared from a thermally activated coal gangue containing kaolinite. As the foaming agent, aluminium powder and 36% hydrogen peroxide were used to obtain two levels of porosity. The materials’ high temperature performances were investigated: tensile and compressive strength evolution with temperature. This study shows that the mechanical performances of developed geopolymer foams are similar to foam concrete of the same apparent density. The geopolymer foams from coal gangue present stable mechanical performances up to 600 °C. When the glass transition temperature is achieved, sintering occurs and mechanical performance increases. SEM observations confirm the glass transition and densification of the matrix at temperatures above 800 °C. Moreover, the XRD measurements revealed a high amount of mullite that forms at 1000 °C that explained the observed strength increase. The synthesis of good-quality geopolymer foams from coal gangue and its application as a thermal barrier is feasible. The constant level of porosity and its stable character in the range of temperatures 20–1000 °C ensures stable thermal insulation parameters with increasing temperature, which is extremely important for fire protection. Full article

(This article belongs to the Special Issue Low Energy and Carbon Footprint Building Materials - Waste Management and Recycling)

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Review

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22 pages, 7734 KiB

Open AccessReview

Low-Energy Clay–Cement Slurries Find Application as Waterproofing Membranes for Limiting the Migration of Contaminants—Case Studies in Poland

by Agata Stempkowska, Łukasz Wójcik, Krzysztof Adam Ostrowski and Tomasz Gawenda

Energies 2023, 16(1), 230; https://doi.org/10.3390/en16010230 - 25 Dec 2022

Cited by 4 | Viewed by 1383

Abstract

The purpose of this review was to present clay–cement suspensions that are mainly used in the construction and renovation of hydrotechnical facilities and flood protection. We present the characteristics of clay–cement slurries that are used in waterproofing barriers. One of their significant components [...] Read more.

The purpose of this review was to present clay–cement suspensions that are mainly used in the construction and renovation of hydrotechnical facilities and flood protection. We present the characteristics of clay–cement slurries that are used in waterproofing barriers. One of their significant components are clays of different types and origins. Examples of kaolin-type and smectite-type clays, which are associated minerals, as balanced components of suspensions are presented. As mentioned, before the hydration process, barriers are suspended, and the main test methods are rheometric measurements. Their rheological parameters, extremely important from the point of view of injection mechanics, are shown. The higher the flow limit and faster the reconstruction of thixotropic structures, the higher the energy input of the injection processes. After the hydration process, it is important to form agglomerates and seal the barrier; therefore, we present a summary of the strength results, filtration coefficients and microscopic images of the resulting structures. Additional properties of such barriers in terms of limiting contaminant migration are indicated. One of the aspects affecting the use of liquid slurries is their application methods; thus, a summary of low-energy slurry injection methods is also presented. Full article

(This article belongs to the Special Issue Low Energy and Carbon Footprint Building Materials - Waste Management and Recycling)

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26 pages, 2389 KiB

Open AccessReview

CO₂ Mineralization Methods in Cement and Concrete Industry

by Maciej Zajac, Jan Skocek, Mohsen Ben Haha and Jan Deja

Energies 2022, 15(10), 3597; https://doi.org/10.3390/en15103597 - 14 May 2022

Cited by 27 | Viewed by 9561

Abstract

Production of Portland clinker is inherently associated with CO₂ emissions originating from limestone decomposition, the irreplaceable large-scale source of calcium oxide needed. Besides carbon capture and storage, CO₂ mineralization is the only lever left to reduce these process emissions. CO₂ [...] Read more.

Production of Portland clinker is inherently associated with CO₂ emissions originating from limestone decomposition, the irreplaceable large-scale source of calcium oxide needed. Besides carbon capture and storage, CO₂ mineralization is the only lever left to reduce these process emissions. CO₂ mineralization is a reversal reaction to clinker production—CO₂ is bound into stable carbonates in an exothermic process. It can be applied in several environmentally and economically favorable ways at different stages of clinker, cement and concrete life cycle. These possibilities are assessed and discussed in this contribution. The results demonstrate that when combined with concrete recycling, the complete circularity of all its constituents, including the process CO₂ emissions from the clinker, can be achieved and the overall related CO₂ intensity significantly reduced. Full article

(This article belongs to the Special Issue Low Energy and Carbon Footprint Building Materials - Waste Management and Recycling)

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