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Abstract The utilization of industrial by-products in concrete production has gained significant attention due to its potential environmental and economic benefits. The increasing demand for sustainable construction materials has prompted researchers to explore alternative options that mitigate environmental concerns while maintaining desirable mechanical properties of concrete. This research paper investigates, the feasibility of utilizing copper slag as a partial replacement for fine aggregate in concrete through a systematic experimental study using response surface methodology (RSM). The study encompasses the optimization of concrete mix proportions by considering the varying levels of copper slag content (20%, 30%, and 40%), water-cement ratio (0.35, 0.40, and 0.45), and curing days (7, 14 and 28 days). Through a series of comprehensive laboratory experiments (RSM designed) and statistical analyses, this paper presents developed mathematical models, response surface plots, and contour plots and optimization of dosage of input variables for maximum compressive strength of the concrete. Results revels that curing days having strong influence on performance of compressive strength. The optimization study shows the optimal dosage for maximum performance of compressive strength was copper slag 35.90%, water-cement 0.38 and curing days 27.55 (approx. 28) days, the corresponding maximum compressive strength was 59.29 MPa. The utilization of copper slag as a replacement for fine aggregate in concrete not only addresses the issue of waste disposal but also contributes to resource conservation and reduces the carbon footprint associated with traditional construction practices.

The growing consumption of natural resources to meet the needs of road construction has become a significant challenge to environmental sustainability. Additionally, the increase in industrial by-products has raised global concerns due to their environmental impacts. The utilization of industrial by-products in asphalt mixtures offers an effective solution for promoting sustainable practices. The objective of this article is to conduct a bibliometric analysis and citation-based review to characterize and analyze the scientific literature on the use of steel slag aggregates, copper slag, phosphorus slag, bottom ash, fly ash, red mud, silica fume, and foundry sand in asphalt mixtures. Another aim is to identify research gaps and propose recommendations for future studies. The bibliometric analysis was conducted using VOSviewer software version 1.6.18, focusing on authors, co-authorship, bibliographic coupling, and countries. A total of 909 articles were selected for the bibliometric analysis. The findings indicate that more effort is needed to expand the application of industrial by-products in asphalt mixtures. Furthermore, these by-products should be utilized in different types of asphalt mixtures. The incorporation of industrial by-products into asphalt mixes also requires field validation and further laboratory investigations, particularly concerning aging and moisture resistance. In addition, the effects of chemical reactions involving industrial by-products on the long-term performance of asphalt layers should be evaluated. Finally, this article encourages engineers and researchers to intensify their efforts in utilizing industrial by-products for environmental sustainability. [ABSTRACT FROM AUTHOR]

Rice husk ash (RHA), an agricultural waste byproduct, has already been tested as a component in geopolymeric binders, typically as part of the precursor solid mix, alongside materials like fly ash (FA), slag, and cement. This study presents a novel approach where RHA is employed to create a solid activator, aimed at entirely replacing commercial sodium silicates. The synthesis process involves mixing RHA, NaOH (NH), and water by applying a SiO2/Na2O molar ratio equal to 1, followed by mild thermal treatment at 150 °C for 1 h, resulting in the production of a solid powder characterized by high Na2SiO3 content (60–76%). Additionally, microwave treatment (SiO2/Na2O = 1, 460 W for 5 min) increases the environmental and economical sustainability of alkali silicates production from RHA since this processing is 12 times faster than conventional thermal treatment reducing at the same time the final product's embodied energy. The efficacy of this new material as a sole solid activator for the geopolymerization of Greek FA is investigated through various techniques (XRD, FTIR, SEM). One-part geopolymers prepared with RHA-based solid activators demonstrated mechanical performance comparable to those prepared with commercial products (~62 MPa at 7 days). This research contributes to the advancement of sustainable construction practices emphasizing the importance of local materials and reduced environmental impact in achieving long-term sustainability goals. [ABSTRACT FROM AUTHOR]

The study explores the aftermath of a wastewater reservoir failure in a phosphate fertilizer industry, resulting in the release of acidic water containing phosphorus and sulfate compounds into the Ashalim stream's Nature Reserve in the Judean desert, which affected the soil surface biological crusts (biocrusts) layer. The study aims to examine contamination effects on biocrusts over 3 years at two research sites along the stream, compare effects between contaminated sites, assess rehabilitation treatments, and examine their impact on soil characteristics. Hypotheses suggest significant damage to biocrusts due to acidic water flow, requiring human intervention for accelerated restoration. The results indicate adverse effects on biocrust properties, risking its key role in the desert ecosystem. The biocrust layer covering the stream's ground surface suffered significant physical, chemical, and biological damage due to exposure to industrial process effluents. However, soil enrichment treatments, including biocrust components and organic material, show promising effects on biocrust recovery. [ABSTRACT FROM AUTHOR]

The objective of the REALight project is the development of a thermal process to produce lightweight aggregates in pilot scale and the implantation of a method to recover gypsum. Beside construction and demolition waste, various industrial by‐products are studied as raw materials. The raw materials have so far been unused or used in applications with lower quality requirements. To prove the performance of the lightweight aggregates, their technical properties are tested and their use in different applications is studied, e.g., for lightweight mortars as well as lightweight concretes. [ABSTRACT FROM AUTHOR]

The present research assists in resolving the issues allied with the disposal of industrial solid wastes/industrial by-products (IBPs) by developing sustainable IBPs based cement mortars. The applicability of IBPs as a feasible alternative to river sand in cement mortar has been evaluated by investigating the synergy among the ingredients, resulting engineering properties and microstructural developments at early and late curing ages. The study could effectively substitute 30% volume of river sand with bottom ash and 50% in the case of slag sand mortars. The experimental outcomes disclose that the practice of IBPs as fine aggregate enhances the engineering properties of mortar and the optimum replacement level lies at 10% and 40% usage of bottom ash and slag sand, respectively. The advanced characterization studies and particle packing density illustrate the refinement of pores by void filing action and accumulation of additional hydration products through secondary hydration reactions. The consumption of portlandite followed by increased hydration products formation observed through thermogravimetric analysis, X-ray diffraction analysis and energy dispersive X-ray spectroscopy that confirmed the contribution of finer fractions of IBPs to secondary hydration reactions. This constructive development was also observed from the lowering of wavenumber corresponding to Si–O–Si/Al vibration bands in Fourier transform infrared spectroscopy spectra. The improved microstructure resulted in enhancing the compressive strength by 9.01% and 18.18% in optimized bottom ash and slag sand mortars, respectively at the curing age of 120 days. Similarly, the water absorption reduced by 1.03% and 1.24% in bottom ash and slag sand mortars, respectively. [ABSTRACT FROM AUTHOR]

Abstract Industrial by-products; have received a lot of attention as a possible precursor for cement and/or concrete production for a more environmentally and economically sound use of raw materials and energy sources. Geopolymer is a potentially useful porous material for OPC binder applications. The use of industrial wastes to produce a greener geopolymer is one area of fascinating research. In this work, geopolymer pastes were developed using alkali liquid as an activator and metakaolin (MK), alumina powder (AP), silica fume (SF), and cement kin dust (CKD) as industrial by-products. Several geopolymer samples have been developed. Research has been carried out on its processing and related physical and mechanical properties through deep microstructure investigation. The samples were cured in water by immersion with relative humidity (95 ± 5%), and at room temperature (~ 19–23 °C) prior to being tested for its workability and durability. The effect of the different composition of precursors on water absorption, density, porosity, and the compressive strength of the prepared geopolymers have been investigated. The results showed that the compressive strength of geopolymers at 28 days of curing is directly proportional to the ratio of the alkali liquid. Ultimately, the best geopolymer paste mixture (GPD1 and GPD2), was confirmed to contain (15% of CKD + 85% MK and Alumina solution (55 wt%)) and (25% of CKD + 75% MK + Alumina solution (55 wt%)) respectively, with 73% desirability for maximum water absorption (~ 44%) and compressive strength (4.9 MPa).

With the development of industrial activities and the agricultural and mining industries, farmland soils are facing serious problems related to heavy metal contamination, especially cadmium (Cd) and arsenic (As) contamination. In this study, two industrial by-products, phosphogypsum (PG) and red mud (RM), were modified by lanthanum (La) impregnation to form a new composite (L-PR) to investigate the adsorption performance of Cd(II)/As(V) in both single and binary systems. The adsorption mechanisms of Cd(II)/As(V) on L-PR were analyzed using SEM, XRD, FTIR, and XPS. The passivation effect of L-PR on the Cd-As composite contaminated soil was confirmed through a soil cultivation experiment. The adsorption experiments revealed that L-PR showed superior adsorption capabilities for Cd(II) and As(V) compared to PG and RM. Additionally, L-PR was found to be less affected by changes in pH. The kinetic studies indicated that Cd(II) and As(V) adsorption by L-PR followed the second-order kinetic model most accurately. Isothermal adsorption experiments revealed that the adsorption of Cd(II) by L-PR was more in accordance with the Freundlich model, while As(V) was more in accordance with the Langmuir model. The mechanisms of Cd(II) and As(V) adsorption on L-PR involved electrostatic attraction, ion exchange, complexation, and precipitation. The adsorption of Cd(II) is dominated by complexation and precipitation, and the adsorption of As(V) is dominated by ion exchange and complexation. Soil cultivation experiments showed that L-PR significantly reduced the available Cd and As concentrations in soil by 86.01% and 27.80%, respectively, and it could induce the transformation of non-stable Cd(II)/As(V) to the more stable residual. In summary, L-PR exhibits facile preparation, excellent adsorption performance, and is capable of simultaneously removing Cd(II) and As(V) from aqueous solutions while immobilizing these contaminants in soil. These remarkable attributes made it a highly promising alternative for the simultaneous treatment of various toxic metal contaminants. [ABSTRACT FROM AUTHOR]

The growing consumption of natural resources to meet the needs of road construction has become a significant challenge to environmental sustainability. Additionally, the increase in industrial by-products has raised global concerns due to their environmental impacts. The utilization of industrial by-products in asphalt mixtures offers an effective solution for promoting sustainable practices. The objective of this article is to conduct a bibliometric analysis and citation-based review to characterize and analyze the scientific literature on the use of steel slag aggregates, copper slag, phosphorus slag, bottom ash, fly ash, red mud, silica fume, and foundry sand in asphalt mixtures. Another aim is to identify research gaps and propose recommendations for future studies. The bibliometric analysis was conducted using VOSviewer software version 1.6.18, focusing on authors, co-authorship, bibliographic coupling, and countries. A total of 909 articles were selected for the bibliometric analysis. The findings indicate that more effort is needed to expand the application of industrial by-products in asphalt mixtures. Furthermore, these by-products should be utilized in different types of asphalt mixtures. The incorporation of industrial by-products into asphalt mixes also requires field validation and further laboratory investigations, particularly concerning aging and moisture resistance. In addition, the effects of chemical reactions involving industrial by-products on the long-term performance of asphalt layers should be evaluated. Finally, this article encourages engineers and researchers to intensify their efforts in utilizing industrial by-products for environmental sustainability.

Radiation Shielding Concrete plays a critical role in safeguarding against ionizing radiation, in nuclear power plants, medical facilities, and other radiation-sensitive environments. This review paper presents a comprehensive examination of radiation shielding concrete development, highlighting a novel approach that incorporates a diverse range of natural and industrial materials. Traditional radiation shielding concrete formulations rely heavily on virgin materials, contributing to environmental degradation and resource depletion. In contrast, this paper explores the innovative use of natural materials, industrial by-products, and waste materials, emphasizing the environmental sustainability and resource efficiency of such approaches. By harnessing these alternative materials, the paper outlines how radiation shielding concrete production can significantly reduce its ecological footprint while maintaining or even enhancing its radiation shielding capabilities. The paper delves into the functional aspects, composition variations, and performance characteristics of radiation shielding concrete, providing a holistic perspective on the diverse materials employed. Additionally, it thoroughly examines the factors influencing the effectiveness of radiation shielding concrete in nuclear power plants. Furthermore, this review discusses recent developments and advancements in radiation shielding concrete, offering insights into the cutting-edge research and innovations that are shaping the future of radiation shielding. The integration of natural and industrial materials presents promising avenues for enhancing the versatility, cost-effectiveness, and sustainability of radiation shielding concrete.

Under the dual-carbon target, CO2 mineralization through solid wastes presents a mutually beneficial approach for permanent carbon emission reduction at a low material cost, while also enabling the resource utilization of these wastes. However, despite its potential, a comprehensive understanding about the effect of industrial solid waste properties and operating parameters on the carbonation process, and the mechanism of direct aqueous carbonation is still lacking. A series of experiments were conducted to compare the carbonation performance of fly ash, steel slag, and carbide slag. Subsequently, CO2 mineralization by carbide slag was systematically studied under various operating parameters due to its high CO2 sequestration capacity. Results showed the reactivity of CaO and Ca(OH)2 was higher than that of CaO·SiO2 and 2CaO·SiO2. Carbide slag demonstrated a sequestration capacity of 610.8 g CO2/kg and carbonation efficiency ζCa of 62.04% under the conditions of 65 °C, 1.5 MPa initial CO2 pressure, 15 mL/g liquid-to-solid ratio, and 200 r/min stirring speed. Moreover, the formation of carbonates was confirmed through XRD, SEM-EDS, TG, and FTIR. A mechanism analysis revealed that initially, the rate of the carbonation process was primarily controlled by the mass transfer of CO2 in the gas–liquid interface. However, the rate-determining step gradually shifted to the mass transfer of Ca2+ in the solid–liquid interface as the reaction time increased. This study lays the foundation for the large-scale implementation of CO2 sequestration through carbide slag carbonation. [ABSTRACT FROM AUTHOR]

The utilization of industrial by-products (IBPs) in cement (OPC)-solidified sludge has been extensively studied as an approach to enhance the mechanical performance, but the presence of salt in groundwater and wetting–drying action would compromise the mass and mechanical behavior of such solidified sludge. Unfortunately, there is a paucity of research on the single or coupled impacts of these two phenomena on IBP–OPC-solidified sludge. This paper aims to address the research gap by exploring the durability of IBP–OPC-solidified sludge in distilled water, sulfate solution and chloride solution through the full immersion tests (IT) and cyclic wetting–drying (WD) tests. Samples were prepared where collected sludge was mixed with OPC and various types of IBPs (including fly ash, slag, calcium carbide residue and silica fume). The resulting unconfined compressive strength, mass loss, and visual changes of samples were evaluated after IT and WD tests. Furthermore, scanning electron microscopy, physisorption experiments, and X-ray diffraction tests were conducted to examine the microstructure, pore evolution and mineralogical characteristics, respectively. Grey correlation model analysis was used to quantify the relationship between components inside IBPs and strength. The results indicate that the use of IBPs is effective in minimizing the mass loss and strength degradation of OPC-solidified samples, with the exception of calcium carbide residue in a sulfate environment. The use of IBPs can promote the formation of C-(A)-S-H gels and increase the amount of hydrated products through pozzolanic reactions and reactions between salt and aluminosilicate phases. Furthermore, the pore volume of solidified samples tends to be reduced, creating a denser matrix with more smaller pores that contribute to excellent mechanical properties and durability. Overall, the findings suggest that IBP–OPC has the potential for promising applications in the high performance of solidified sludge in severe conditions, such as coastal and offshore engineering. [ABSTRACT FROM AUTHOR]

This work aims to evaluate the effect of the extrusion temperature of poly(lactic acid) (PLA) with different grape pomace (GP) content for the development of active biocomposite films. Two different GP concentrations (10 and 15 wt.%) were used to obtain GP/PLA composites through extrusion at three different temperature profiles. The biocomposites were characterized through optical, thermal, structural, and mechanical tests. In addition, the antimicrobial and antioxidant capacity of materials were evaluated. Results showed GP antioxidant components are stable up to 180°C. The incorporation of GP in PLA resulted in red‐color films with a high color difference (ΔE > 30). The glass transition, cold crystallization, and melting temperatures as well as the tensile strength of PLA decreased by increasing GP concentration in the films; however, elastic modulus and elongation at break increased. The biocomposite with lowest GP content had better antimicrobial activity against Escherichia coli and Listeria innocua. Contrary, 15% GP/PLA composite showed the highest antioxidant activity. Nevertheless, high extrusion temperature profile reduced the bioactivity of materials due to the GP degradation. These results showed the feasibility and best extrusion temperature profile to develop active materials using wine by‐products, which could be applied as active food packaging. [ABSTRACT FROM AUTHOR]

The stabilisation of soft soils using the traditional binders cement and quicklime are known to emit large amounts of carbon dioxide. To reduce this carbon footprint, substitutes such as industrial by-products have been thoroughly tested as viable alternatives for soil stabilisation. However, recent research has also shown that biochar from biomass pyrolysis can in some instances have a positive stabilisation effect and even result in a carbon-negative footprint. This paper presents a laboratory study to investigate the stabilisation effect of five industrial by-products and four types of biochar on three natural Norwegian soils: two clays with low and high water contents and one peat with a very high water content. The soils and binders were characterised by their mineralogical and chemical compositions. The biochars had varying stabilisation effects on the clays when combined with cement, with some negative stabilisation effects, whilst the effect was very beneficial in the peat, with a strength increase of up to 80%. The industrial by-products showed opposite results, with beneficial effects in the clays and a strength increase of up to 150%, but negative stabilisation effects in the peat. Correlating the mineralogical and chemical compositions to stabilisation effects was found to be challenging. [ABSTRACT FROM AUTHOR]

This paper investigates the mechanical properties under laboratory and field conditions of a concretelike blend made of fluorogypsum (FG), fly ash, and portland cement for artificial-reef construction, which is referred to as a FG-based blend. The 28-day compressive strength and relative volumetric expansion of the FG-based blend were statistically characterized. After 1 year of immersion in brackish water under field conditions, the compressive strength of the FG-based blend experienced a moderate reduction when compared with material under laboratory conditions but did not degrade below its 28-day value. Visual examination of the immersed specimens indicated that aquatic organisms are attracted to the proposed material. Field investigation of a small artificial-reef structure made of a FG-based blend indicated that sea floor settlement due to the weight of the structure was small. A preliminary cost analysis comparing the cost of artificial reefs constructed with different materials suggests that the proposed FG-based blend is a promising environment-friendly economic material for artificial-reef construction.

Mushroom production is a growing sector as the demand for this product is increasing. The quantity of waste and by-products generated along the supply chain is however considerable (about 20% of the fresh weight is disposed). Although the recovery of chitosan from mushrooms has been extensively studied, little has been done to optimize the recovery of proteins, which make up to 20% of dry weight. In the present work, six different by-products were studied for their crude composition and their protein fraction was characterized in detail. Then, a comparative study was conducted on three different extraction techniques (environmentally friendly aqueous extraction, ultrasound-assisted extraction, and enzyme-assisted extraction). Enzyme-assisted extraction has proven to be the most efficient technique in terms of protein extraction yield, even though the protein fraction is extracted in the form of peptides and not whole proteins. The lowest degree of hydrolysis is instead given by the ultrasound-assisted extraction, which however shows a rather high degree of racemization which decreases the quality of the proteins. The aqueous extraction, despite the low extraction yield, gave the purest protein extracts. [ABSTRACT FROM AUTHOR]

Astaxanthin is a natural carotenoid with strong antioxidant activity. In this paper, the effects of carbon source, corn steep liquor, distiller grains, and initial pH on the growth and astaxanthin production of Phaffia rhodozyma D3 were evaluated. The optimal medium composition was 32 g/L glucose, 12 g/L corn steep liquor as nitrogen source, and the initial pH was 6.7. Phaffia rhodozyma D3 was cultured in a shake flask under these optimized conditions, the biomass was 6.47 g/L, the astaxanthin/OD475 was 15.16, and the astaxanthin content was 1.41 mg/g. The astaxanthin content was further increased to 4.70 mg/g by the combination of TiO2 stimulation and the expanding cultivation of P. rhodozyma D3 in a 5 L fermenter, which was 2.81 times that of the control group. Expanding fermentation implies the possibility of large-scale production in the astaxanthin industry. Corn steep liquor was used as an alternative nitrogen source to culture P. rhodozyma D3, which could both reduce the production cost of astaxanthin and increased the by-products utilization rate. [ABSTRACT FROM AUTHOR]

The aim of this study was to analyse specific greenhouse gas emissions savings for a variety of agricultural residues, industrial by-products, and municipal biowaste. One of the most viable alternatives to fossil fuels is bioenergy, particularly biogas produced by the anaerobic digestion of renewable feedstocks. The revised Renewable Energy Directive (D 2018/2001) recognizes that biogas production from agricultural residues, livestock production, and industrial by-products is an acknowledged greenhouse gas mitigation technology in cases where their use results in a certain level of specific greenhouse gas savings. This study delivered values for the maximum transport distance of agricultural residues and industrial by-products to achieve the greenhouse gas (GHG) emissions-saving requirement defined by Directive 2018/2001. It analysed the greenhouse gas emissions reduction for numerous feedstocks for which Directive 2018/2001 has not defined the default and typical values but which could be used as sustainable substitutes for currently dominantly used maize silage in biogas production. The results obtained in this work define the maximum transport and distribution distance for which biogas produced from considered feedstocks achieved required specific greenhouse gas emissions savings (80%), compared with fossil fuel comparator. The obtained results can be used as the constraints in the optimisation of the biomass supply chains for the feedstocks considered in this work. [ABSTRACT FROM AUTHOR]

With the development of industrial activities and the agricultural and mining industries, farmland soils are facing serious problems related to heavy metal contamination, especially cadmium (Cd) and arsenic (As) contamination. In this study, two industrial by-products, phosphogypsum (PG) and red mud (RM), were modified by lanthanum (La) impregnation to form a new composite (L-PR) to investigate the adsorption performance of Cd(II)/As(V) in both single and binary systems. The adsorption mechanisms of Cd(II)/As(V) on L-PR were analyzed using SEM, XRD, FTIR, and XPS. The passivation effect of L-PR on the Cd-As composite contaminated soil was confirmed through a soil cultivation experiment. The adsorption experiments revealed that L-PR showed superior adsorption capabilities for Cd(II) and As(V) compared to PG and RM. Additionally, L-PR was found to be less affected by changes in pH. The kinetic studies indicated that Cd(II) and As(V) adsorption by L-PR followed the second-order kinetic model most accurately. Isothermal adsorption experiments revealed that the adsorption of Cd(II) by L-PR was more in accordance with the Freundlich model, while As(V) was more in accordance with the Langmuir model. The mechanisms of Cd(II) and As(V) adsorption on L-PR involved electrostatic attraction, ion exchange, complexation, and precipitation. The adsorption of Cd(II) is dominated by complexation and precipitation, and the adsorption of As(V) is dominated by ion exchange and complexation. Soil cultivation experiments showed that L-PR significantly reduced the available Cd and As concentrations in soil by 86.01% and 27.80%, respectively, and it could induce the transformation of non-stable Cd(II)/As(V) to the more stable residual. In summary, L-PR exhibits facile preparation, excellent adsorption performance, and is capable of simultaneously removing Cd(II) and As(V) from aqueous solutions while immobilizing these contaminants in soil. These remarkable attributes made it a highly promising alternative for the simultaneous treatment of various toxic metal contaminants.

Chemical fixation of CO2 and its utilization as C1 building block into fine chemicals are among key areas of research to mitigate greenhouse gas effect. The catalysts requirement to form cyclic organic carbonates by coupling reaction between CO2 and epoxides is a well‐stablished strategy for CO2 fixation. In this work, this coupling reaction has been investigated using a catalytic system comprised by a selected industrial mining raw material, with potential valorization interest, and a commercial cocatalyst. Herein, industrial mining raw materials are explored as a renewable, recyclable, nontoxic, cheap, and ready‐available catalysts for the transformation of CO2 into highly valuable products such as cyclic carbonates. Initial experiments with the mining materials and alternative by‐products of industrial valorization interest were carried out using propylene oxide (OP) as an initial selected oxirane. The most active raw materials were fully characterized to study their morphology, composition, and surface hydroxyl groups to determine active basic sites as novel heterogeneous base catalysts. The achieved yield of cyclic carbonate in these preliminary experiments was observed in the range of 37–85% for the different tested catalysts. In the case of the most active by‐product used as catalyst (Sulfamag), propylene carbonate reached the yield of 85% as a higher result obtained under mild conditions. Sulfamag was selected to optimize reaction conditions, including the study of different cocatalysts. Moreover, coupling reactions between CO2 and other aliphatic and aromatic epoxides were also performed efficiently for Sulfamag, showing yields between 71 and 91% and selectivity of 99% under mild conditions, demonstrating their potential as a renewable raw material solid‐based heterogeneous catalyst in the synthesis of different cyclic carbonates from CO2 and epoxides. Furthermore, Sulfamag showed high recycling efficiency in a test of four cycles and the deactivation of catalyst was compared with commercially available MgO. © 2022 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The protection of the environment must be a priority in our society, and the construction sector can contribute significantly to this goal. Construction, being one of the industrial sectors that is more demanding in terms of raw materials, must reinforce its effort to implement, in a more profound and systematic way, the paradigm of the circular economy. In this sense, in recent years several studies have been trying to contribute solutions aimed at reintroducing industrial by-products or residues in new products for the construction industry. It should be noted that nowadays it is increasingly important to introduce a higher percentage of recycled materials in concrete. In this context, the present work addresses the appropriateness of a design procedure proposed to maximize the content of electric arc furnace slag (EAFS) and include recycled tire steel fibers (RTSF) in the production of more sustainable structural concretes. For this, the properties of various concrete mixtures at the fresh and hardened state, obtained by the substantial substitution of coarse and fine natural aggregates by EAFS and fly ash (FA), were investigated. The design of EAFS mixtures was based on two conventional reference mixtures (REF1 and REF2), and by using the modified Andreasen and Andersen particle packing model, these were optimized to achieve maximum packing density. Compressive strength, modulus of elasticity behavior, and fresh and physical properties were assessed in order to define the best mix proportions with respect to the predefined requirements of ordinary mixtures. Untreated recycled tire steel fibers (RTSF) were included in the developed sustainable concrete to perform a comparison of the physical properties with unreinforced concretes developed with natural aggregates (REF2) and with EAFS aggregates (EAFS8D1). This incorporation was intended to improve the physical behavior of unreinforced concretes with EAFS aggregates. Mixtures with high percentages of waste aggregates up to 70% (in weight), and 10% (in weight) of FA were obtained, showing competitive mechanical behavior compared to REF1 and REF2. These concrete compositions showed minimum and maximum compressive strengths between 9 MPa and 37 MPa, respectively. This study coverd the two major classes of concrete used as structural material, namely structural concrete and fiber reinforced concrete. [ABSTRACT FROM AUTHOR]

By-products from different industries could represent an available source of carbon and nitrogen which could be used for bioethanol production using conventional Saccharomyces cerevisiae yeast. Spent cherry brine and whey are acid food by-products which have a high organic matter content and toxic compounds, and their discharges represent significant environmental and economic challenges. In this study, different combinations of urea, yeast concentrations, and whey as a nutrient source were tested for bioethanol production scale-up using 96-well microplates as well as 7.5 L to 100 L bioreactors. For bioethanol production in vials, the addition of urea allowed increasing the bioethanol yield by about 10%. Bioethanol production in the 7.5 L and 100 L bioreactors was 73.2 g·L−1 and 103.5 g·L−1 with a sugar consumption of 81.5% and 94.8%, respectively, using spent cherry brine diluted into whey (200 g·L−1 of total sugars) supplemented with 0.5 g·L−1 urea and 0.5 g·L−1 yeast at 30 °C and a pH of 5.0 after 96 h of fermentation for both systems. The results allow these by-products to be considered low-economic-value alternatives for fuel- or food-grade bioethanol production. [ABSTRACT FROM AUTHOR]

The studies on Lightweight Geopolymer concrete (LGC) are leading-edge in the development of sustainable and eco-friendly concrete. Attempts were being made to develop LGC by various methods of production. This paper reviews about previously published research work on lightweight geopolymer concrete and the observations to the material binders - an alternate to the Ordinary Portland Cement (OPC) by the utilization of industrial by-products, alkaline activator solution, foaming agents, chemical expansive agents, lightweight aggregate, production methods, and their physical and mechanical properties. The main focus is to investigate pore size formation, density, compressive strength and curing conditions. From the review it is found that the stabilization of foam and the control of efflorescence are the two challenging problems faced by the industry for the mass production of lightweight geopolymer foam concrete. Furthermore, topics for future work in this field were suggested. [ABSTRACT FROM AUTHOR]

The study focuses on the development of electrically conductive asphalt mixtures (ECA) using industrial by-products such as recycled carbon fibers (CF), graphite powder (GP), and steel slag (SS) – all of which possess electrical conductivity, rendering them conductive additives. Percolation theory was applied to determine precise quantities of these additives, along with the appropriate modification of the granular skeleton to incorporate them without altering the bitumen content. The goal was to develop conductive materials which achieve volumetric properties comparable to conventional asphalt mixes and ensure adequate mechanical properties. The research evaluates the impact of the conductive additives on electrical resistivity, mechanical, and heat generation properties of the asphalt mixtures. In this study, ECA was successfully developed, achieving electrical resistivity values of 0.016 Ωm for electrically conductive asphalt mastics (ECAM) (4.4 % CF by volume of bitumen) and 2.51 Ωm (5.0 % CF and 4.9 % GP by volume of bitumen) for electrically conductive asphalt concretes (ECAC). Furthermore, a clear correlation was identified between the mixture components, the type of applied current, the heat generated in the ECA, and the electrical resistivity of the samples, as well as the impact of the conductive additives on the mechanical properties. • Electrically conductive asphalt mixtures were made using recycled carbon fibers, graphite powder, and steel slag. • ECA mixtures were developed with mechanical properties comparable to conventional asphalt mixtures. • In this study, ECA was successfully developed, achieving electrical resistivity values of 2,51 Ω·m. [ABSTRACT FROM AUTHOR]

Abstract Background Eimeria spp. are widespread apicomplexan parasites known to cause coccidiosis in livestock, resulting in reduced animal welfare and productivity, particularly in sheep. The treatment options are limited, and there is an emerging development of resistance against registered pharmaceuticals. Spruce bark is rich in plant secondary metabolites (PSM), such as condensed tannins, which are bioactive compounds previously shown to have antiparasitic activity. Here, we examined the anticoccidial properties of bark extract of Norway spruce (Picea abies) against a field isolate of ovine Eimeria spp. by treating Eimeria-infected pre-ruminant lambs with water-extracted bark daily for 12 days. We hypothesised that the bark extract would reduce the faecal oocyst excretion and, consequently, the severity of diarrhoea. Results Oral administration of spruce bark extract significantly reduced the excretion of Eimeria oocysts in milk-fed lambs post treatment till the end of the trial 22 days post infection. This difference in oocyst excretion between the treated and the untreated infected animals increased with time. Compared to the untreated and the sham-infected control group, the group treated with bark extract had softer faeces and reduced milk intake during the treatment period. After discontinuing the treatment, the treated animals got a more solid and formed faeces compared to that of the untreated control group, and the milk intake increased to the level of the sham-infected, untreated control group. The bark extract treated animals had a lower body weight and a lower mean daily body weight gain throughout the whole duration of the experiment. Conclusions Bark extract from Norway spruce showed marked anticoccidial properties by reducing the faecal oocyst count and associated diarrhoea in young lambs. Simultaneously we experienced detrimental effects of the treatment, displayed as reduced feed intake and daily body weight gain. Therefore, we suggest conducting similar studies with lower bark extract dosage to explore the possibilities of a better trade-off to reduce the negative impact while maintaining the antiparasitic effect.

Slags and rubber from end-of-life tires represent a liability to the steel and tire industry, causing economic and environmental problems that are difficult to manage. Transport infrastructures can use these industrial by-products instead of extracting natural raw materials, but the adequate mechanical performance of the materials needs to be assured. This paper addresses the mechanical behaviour of slag–rubber mixtures in the laboratory with CBR, monotonic and cyclic triaxial tests. In addition, light falling weight deflectometer tests were also performed in a physical model. The results were analysed to meet technical specifications from Brazil, Portugal and Australia using railway sub-ballast layers, capping layers or road pavement layers as the base and sub-base to identify the applicability range of slag–rubber mixtures for transport infrastructures. Concerning the analysed parameters, it was demonstrated that slag–rubber mixtures can show resilient behaviour and strength adequate for the support layers of transport infrastructures provided that the rubber content is below 5% in weight and that the slag is milled to comply with the grain size distribution ranges available in the technical specifications of the cited countries. [ABSTRACT FROM AUTHOR]

Macauba palm fruits (Acrocomia aculeata and Acrocomia totai) are emerging as sources of high-quality oils from their pulp and kernels. The protein-rich macauba kernel meal (MKM) left after oil extraction remains undervalued, mainly due to the lack of suitable deoiling parameters and integrated protein recovery methods. Therefore, the present study aimed to produce protein concentrates from MKM using sieve fractionation. The deoiling parameters, comprising pressing, milling, and solvent extraction, were improved in terms of MKM functionality. The combination of hydraulic pressing, milling to 1 mm, and the hexane extraction of A. aculeata kernels resulted in MKM with the highest protein solubility (77.1%), emulsifying activity index (181 m2/g protein), and emulsion stability (149 min). After sieve fractionation (cut size of 62 µm), this meal yielded a protein concentrate with a protein content of 65.6%, representing a 74.1% protein enrichment compared to the initial MKM. This protein concentrate showed a reduced gelling concentration from 8 to 6%, and an increased emulsion stability from 149 to 345 min, in comparison to the MKM before sieving. Therefore, sieve fractionation after improved deoiling allows for the simple, cheap, and environmentally friendly recovery of MKM proteins, highlighting the potential of macauba kernels as a new source of protein. [ABSTRACT FROM AUTHOR]

Growing in the field of construction, 3D printing allows to build non-standard shapes and to optimise the use of resources. The development of printable materials requires good control of the fresh state of the material—between mixing and printing, a printable material has to evolve from fluid matter to be pumpable (extrudability) up to a matter supporting its own weight and those of superior layers (buildability). Our researches are focused on printable materials used in large printers, i.e., printers able to build structural pieces for buildings. As many pumps and printers can be used to achieve a wide range of parts, this paper presents a simple method to provide valuable guidance to users when a decision needs to be made about printable materials. In this context, our researches both try to maximise the use of industrial by-products to reduce the environmental cost of printed material and to propose tests easy to carry out in the field. Consequently, on the one hand, some printable materials that mainly include quarry washing fines have been developed and, on the other hand, Fall cone and Vicat tests have been used to determine the printability limit. By not focusing on a single formula, the novelty of this paper is to present to readers some parametric models, i.e., a methodology that can be used according to their own devices and applications. Based on a design of experiments, 20 formulas have been tested. Parameters that influence the quality of printing are highlighted. Mechanical tests results at hardened state and shrinkage measurements are also shown to demonstrate the ability of some formulas to be structural materials: compressive strengths at 28 days between 7.50 MPa and 18.40 MPa. [ABSTRACT FROM AUTHOR]

The productivity and biological activity of the entomopathogenic fungus Beauveria bassiana (F-145) strain during the liquid-phase cultivation on various substrates for developing a biopesticide in its native form was analyzed (the research was carried out in 2019). For submerged cultivation, by-products from dairy and beer production (milk whey and brewing spent grain liquor) were used as components of the nutrient medium with addition of diesel fuel (DF) and Tween-80 as inducers of biological activity. It has been established, that the productivity of the strain on industrial by-product substrates was 1.5-2 times higher than on the Czapek medium. A high yield of a mycelial biomass with a titer of 108 -1010 CFU/ml was shown in a 5-day suspension based on a mixture of milk whey and brewing spent grain liquor. The biological activity of the culture suspension of the strain was determined. It was shown that the nematicidal activity of Beauveria bassiana strain with regard to nematodes of the Rhabditis sp. was largely manifested in a suspension obtained on a mixed medium with the addition of inducers. Ninety per cent death at mobile nematode stages was registered within one or two days of test-organism incubation. A complex nutrient medium composition containing by-products and inducers contributed to the preservation of the biological activity of the strain. The strain nematicidal activity was established at the level of 67-80 per cent with a titer of 106 -107 CFU/ml when the suspension was stored for 67 days.

The need to transit to greener options in soil stabilisation has revamped research on the use of industrial and agricultural by-products in order to cut down on the current carbon footprint from the use of ordinary Portland cement (OPC) and lime related binders for the treatment of problematic soils. This study is a review on the use of geopolymers constituted by alkali activation of several industrial wastes such as pulverised fuel ash (PFA), ground granulated blast furnace slag (GGBS), metakaolin (MK), glass powder (GP), palm oil fuel ash (POFA), silica fume (SF), rice husk ash (RHA), volcanic ash (VA), and marble powder (MP) for the stabilisation of weak clays. The performance of stabilised clays as subgrade and subbase materials for road pavement construction was evaluated by comparing the 7 day UCS of the treated clays with the strength requirement for stabilised materials as outlined in BS EN 16907-4. The result of the study shows that geopolymers can be employed in improving the engineering properties of problematic clays to meet practical applications. Strength improvement was observed in the stabilised clays with increased precursor content, molarity of alkaline activator, and curing period.

The stabilisation of soft soils using the traditional binders cement and quicklime are known to emit large amounts of carbon dioxide. To reduce this carbon footprint, substitutes such as industrial by-products have been thoroughly tested as viable alternatives for soil stabilisation. However, recent research has also shown that biochar from biomass pyrolysis can in some instances have a positive stabilisation effect and even result in a carbon-negative footprint. This paper presents a laboratory study to investigate the stabilisation effect of five industrial by-products and four types of biochar on three natural Norwegian soils: two clays with low and high water contents and one peat with a very high water content. The soils and binders were characterised by their mineralogical and chemical compositions. The biochars had varying stabilisation effects on the clays when combined with cement, with some negative stabilisation effects, whilst the effect was very beneficial in the peat, with a strength increase of up to 80%. The industrial by-products showed opposite results, with beneficial effects in the clays and a strength increase of up to 150%, but negative stabilisation effects in the peat. Correlating the mineralogical and chemical compositions to stabilisation effects was found to be challenging.

This study is framed within the circular economy model through the valorisation of industrial by-products. This research shows the results of producing self-compacting mortars (SCMs) with electric arc furnace dust (EAFD) and other industrial by-products such as fly ash, conforming (FA) or not conforming (NcFA), from coal-fired power plants, or recovery filler (RF) from hot-mix asphalt plants. Three batches of SCMs, each with one industrial-by product (FA, NcFA, or RF), and three levels of EAFD ratio incorporation (0%, 10%, 20%), were tested. An extra batch with a greater amount of FA was manufactured. When the incorporation ratio of EAFD rose, the mechanical strength decreased, due to the presence of a calcium zinc hydroxide dihydrate phase; nevertheless, this decrease diminished over time. All SCM mixes, except the 40C 40FA 20 EAFD mix, were above 20 MPa at 28 days. All mixes named 70C and 40C reached 40 and 30 MPa, respectively, at 90 days. Mixes with EAFD showed less capillarity and no difference in water absorption by immersion with respect to mixes without EAFD after 91 days. The SCMs designed proved to be stable in terms of leaching of the heavy metals contained in EAFD, where all the hardened SCMs were classified as inert. [ABSTRACT FROM AUTHOR]