Utilization Of Waste Materials Research Articles

Using of microsilica for improvement of physical and mechanical properties of epoxide-based composite material

Utilization of industrial waste and secondary raw materials, in particular, in the production of metallic silicon and silicon-containing alloys, which include silica vapors (microsilica), is the main task of implementing environmental policy and solves the problem of their storage and negative impact on the environment, in order to reuse them in polymer composites. The use of microsilica as a filler in composite materials based on epoxy resins contributes to a positive effect on the basic properties of the resin, and also makes it possible to use the composite material as coatings and parts in the repair of machinery and equipment. The aim of the work was to establish the positive effect of microsilica as a filler in composite materials based on ED-20 epoxy resin on improving the physical and mechanical properties of composite materials. Within the framework of this work, studies were conducted to test composite materials based on ED-20 epoxy resin, differing in different filler content of 2, 5, 10, 15 wt. % on impact strength, tensile strength and modulus of elasticity, adhesion and impact strength of the coating. The analysis of the obtained results showed a positive effect of microsilica as a filler in composite materials based on ED-20 epoxy resin on the physical and mechanical properties of the composite material. The optimal filler content was determined, which is 2 % of the mass of the ED-20 epoxy resin, while an increase in adhesion, toughness of the composite material by 45 %, tensile strength and modulus of elasticity by 21 % and 5 %, respectively, and the strength of the coating on impact by 32 %, compared with the addition of microsilica in ED-20, which shows the prospects of using microsilica as a filler in composite materials

Fully waste-based solar evaporator in interfacial solar-driven seawater desalination

The scarcity of freshwater resources and the increasing demand for sustainable water treatment technologies have prompted the development of interfacial solar-driven seawater desalination (ISSD). However, designing stable solar evaporators to alleviate freshwater scarcity and reduce environmental stress remains a significant challenge. This study presents a solar evaporator from waste materials to address these challenges. The device comprises a photothermal membrane (CLPM) made from cattail leaf-based fibers (CLF) and cattail leaf-based carbon (CLC) with a simple crosslinking method using sodium alginate and CaCl2, a waste humidifier filter (WHF), and discarded packaging foam. The CLPM exhibits approximately 96 % solar absorption, achieving an evaporation rate of 1.38 kg m–2 h–1 when treating groundwater and 1.22 kg m–2 h–1 when desalinating a 3.5 wt % NaCl solution. The desalination performance of CLPM can be stable for 6 h due to the sufficient water provided by the WHF with vertical water conductivity channels. The desalination performance of CLPM can be restored by washing off the accumulated salts in a 3.5 wt % NaCl solution or by self-cleaning overnight, as verified by indoor and outdoor cycling experiments. 1 m2 of CLPM can produce approximately 5.3 kg of freshwater during the daytime, sufficient to meet two adults' daily water consumption needs. This waste-derived solar evaporator promotes the efficient utilization of waste materials and offers a sustainable solution to address freshwater scarcity while reducing environmental impact.

The performance and microstructure of alkali-activated artificial aggregates prepared from municipal solid waste incineration bottom ash

In order to reduce the negative environmental impact of municipal domestic waste incineration bottom ash (MSWIBA), it is converted into lightweight aggregates by cold bonding technology. To enhance the utilization of waste materials, minimize cement consumption, and fabricate artificial aggregates with superior comprehensive performance, we designed and synthesized alkali-activated aggregates (AAAs) in this study. This study used MSWIBA and ground granulated blast furnace slag (GGBFS) as precursors for alkali-activated aggregates (AAAs), activated by a mixture of sodium hydroxide solutions and sodium silicate. The physical and mechanical properties of AAAs, including water absorption, apparent density, crushing strength and carbon-resistance, were investigated at different NaOH concentrations. In addition, the microstructure, mineral composition, aggregation, porosity and heavy metal leaching behavior of AAAs were analyzed by SEM, XRD, FTIR, TGA, MIP and ICP techniques. All AAAs exhibited a consistent particle size distribution, characterized by apparent densities spanning the range of 1633–1940 kg/m3. The leaching levels of heavy metals align with the standards established by Chinese regulations. Among the different activator concentrations tested, aggregate (M4) displayed superior single-particle crushing strength (3.90 MPa) and better carbonization resistance. It also used a lower concentration of NaOH, which enabled more cost-effective and eco-friendly production. Overall, the findings suggest that MSWIBA can be a viable precursor for producing sustainable lightweight concrete, with 4 M NaOH being the optimal activator concentration for achieving the best performance.

Characterization of recycled dredged Sediments: Toward circular economy in road construction

Granular solid materials are essential for civil engineering projects, but their limited availability and environmental impacts have resulted in exploring alternatives aligned with sustainable development. Utilizing waste materials as dredged sediments offer promising solutions for more sustainable construction practices, especially in road construction. However, end-of-life management of these materials remains a challenge, requiring a circular approach to ensure their sustainable use. This research aims to evaluate the viability of revalorization of recycled sediments (RSD) from a demolished road after its failure for their second use in road structures compared to the first valorization of raw sediments (SD). The usability and environmental acceptability were evaluated through physical, mechanical, durability, and environmental testing. The physical properties of RSD show lower particle density (2.55 g/cm3) than SD (2.59 g/cm3), and have less organic matter content and a non-plastic behavior. The immediate California bearing ratio (I-CBR) after solidification/stabilization treatment was around 165% higher for RSD than SD. The mechanical and durability performances of RSD were also better than SD in terms of water sensitivity and frost resistance, as well as at different curing ages 7, 28, 60, and 90 days. Additionally, the environmental leaching behavior of the trace elements in RSD matrix before and after treatment differed from SD, indicating varying road uses’ applicability. The findings highlight the potential of utilizing various wastes in constructions, thus promoting a closed-loop circular approach and reducing the need for virgin resources.

Utilization of titanium slag in cement grout for gamma radiation shielding: hydration, microstructure, mechanical properties and gamma-ray attenuation performance

The utilization of industrial waste materials for civil engineering structures has received massive attention in recent decades. In this work, the feasibility of using titanium slag to enhance the radiation attenuation properties of cementitious grout at the ages of 3 days and 2 years was studied. Titanium slag (TS) was incorporated as cement grout replacement at 0%, 10% 20% and 30%. Hardened blocks in dimension of 146×146×30mm were fabricated. The porosity of titanium slag was characterized while the phases in the raw materials as well as the fabricated grout were identified. The influence of the titanium slag addition on the grout hydration kinetics, density, compressive strength and porosity of hardened grouts was evaluated. The results show a decrease in density with the increase of titanium slag content as well as a decrease in compressive strength at curing ages of 3, 7 and 28 days. The slag also refined the microstructure, leading to a reduction in average pore diameter. Furthermore, the hardened blocks were subject to gamma-ray sources such as 137Cs (0.662 MeV) and 60Co (1.173 and 1.332 MeV) and the Linear Attenuation Coefficient (LAC) and Half Value Layer (HVL) were evaluated. The results show that increasing curing age improves the shielding performance of the composite. At 30% replacement, the LAC improvement of the samples exposed to Co sources (1.173 and 1.332 MeV) at 3 days was 11.7% and 12.8% respectively while at 2 years, 9.9% and 9.8% improvement was obtained. Reduced HVL is obtained for an increase in replacement percentage and increased curing age. Therefore, this gives an indication of the possibility of developing low-density radiation shielding cement-based materials.

Influence of reclaimed asphalt pavement aggregate on the performance of metakaolin-based geopolymer concrete at ambient and elevated temperatures

Considering the environmental concerns surrounding conventional cement concrete production and the increasing demand for more sustainable and green materials, recent research considered utilization of recycled waste materials (e.g., aggregates from concrete construction and demolition, and reclaimed asphalt pavement) as full or partial substitutes for natural aggregates. Another direction of the research considered the production of more sustainable binders as an alternative to conventional cement (e.g., geopolymer or alkali-activated materials).To serve the objective of utilizing waste materials and reducing negative environmental impact associated with the use of cement concrete, the present study investigated the potential of producing metakaolin-based geopolymer concrete incorporating reclaimed asphalt pavement (RAP) aggregate. This research comprised experimental testing of five concrete mixes with 0%, 25%, 50% and 100% coarse RAP aggregate replacing the natural aggregate. Tests included compressive stress–strain behavior at ambient conditions (i.e., compressive strength, elastic modulus, strain at peak strength and toughness), and flexural strength. The performance after heat exposure to elevated temperatures of 300 °C and 600 °C was also tested. Proposed models for predicting the elastic modulus, strain at peak strength, flexural strength, and compressive stress–strain relationship matched the experimental results well. Results indicated that natural aggregate replacement by 25 % RAP aggregate caused a reduction in the compressive and flexural strengths by 42.8% and 26.2%, respectively. The increase in the RAP aggregate content enhanced the strain at peak strength e.g., the strain at peak strength was 42.9% higher than the control mix when 100% RAP aggregate was utilized.

Utilization of Ceramic Waste Material as Cement Substitution in Concrete

Researchers and engineers have been exploring alternative materials to partially substitute for cement in concrete to decrease carbon emissions and promote sustainability. Industrial pozzolanic waste is one such material that has gained attention as a potential substitute for cement. This research paper investigates the use of industrial pozzolanic waste materials, ceramic fine dust from the cyclones installed onto spray dryers in the process of manufacturing ceramic tiles, as a partial replacement for cement in concrete. Chemical analysis showed that ceramic dust could be used as pozzolana as ASTM C 618:2019. The study aims to evaluate the properties of fresh and hardened concrete; compressive strength; tensile splitting; and flexural strength of concrete mixtures. Additionally, specimens were subjected to durability performance: an acidic environment and water absorption tests. The cement was replaced in the concrete mix in proportions of 0, 5, 7, 10, 15, 20, and 30% by weight with a water-to-binder ratio of 0.45 at different curing periods. The results showed an increase in compressive strength of up to 10% replacement over time; fortunately, even with up to 30% replacement, it is still within the characteristic value of 30 MPa. The workability of the concrete decreases with replacement. The flexural tensile strength improved by 8% and the splitting strength by 5% with a replacement of 7% set against the control sample. The water absorption of concrete decreased by up to 10% replacement level, which was 15% less than that of the control mix. Concrete subjected to a 2% sulfuric acid solution (acid attack) revealed a loss in compressive strength when set against those not subjected to acid attacks. Based on the present research, ceramic dust as pozzolanic waste material can be used as a partial substitute for cement in the manufacture of good quality concrete under standard conditions.

Effective Utilization of Industrial and Constructional Solid Waste Materials in Foundry Mould Making to Prevent Environment Pollution and Conserve Natural Silica Sand

<p>Green sand moulding uses silica sand for metal casting. Silica sand mining and delivery to foundries destroy the ecosystem, making metal casting unsustainable. Due to increased sand-casting output and massive civil buildings in India, the silica sand supply is declining. The depletion and shortage of silica sand necessitate the search for viable replacements. Industrial solid waste from large-scale industrialization pollutes land, air, and water. In order to use industrial waste in large amounts, an attempt is made to use it as a replacement for natural resources. The main objective of this research is to reduce the consumption of silica sand in the foundry mould-making process. Silica sand is replaced with industrial solid waste, cupola slag, and construction solid waste sources like spent fire bricks and quarry dust, up to a considerable amount, to save the natural resources. Utilization of solid waste material in the mould-making process will reduce production costs and environmental pollution, like dumping solid waste materials on land. Sand tests like permeability, green compression strength, dry compression strength, and compactability were conducted to assess the moulding properties of these alternative moulding materials. The process parameters considered for this investigation were the percentage of bentonite binder and the percentage addition of alternative mould materials with silica sand. The various sand tests showed that 40%, 30%, and 20% of quarry dust, spent fire bricks, and cupola slag, respectively, will adequately replace silica sand for mould making. A bentonite binder of 8% is suitable for quarry dust mould, and a 10% bentonite binder is required for spent fire brick particles and cupola slag to yield better results. Aluminium castings were produced at the optimal mixture of these solid waste particles and silica sand. The results of mechanical tests such as hardness, tensile, and impact tests are comparable to those of silica sand castings.</p>

Wood plastic composites (WPC) waste based triboelectric nanogenerator for mechanical energy harvesting and self-powered applications

The utilization of waste materials for energy production and storage is gaining significant attention due to its numerous advantages, including waste material reuse and the reduction of environmental pollution. A promising technology in this field is triboelectric nanogenerators (TENG), which have proven to be a simple and cost-effective method for harnessing ambient mechanical energy using waste materials. This report focused on applying waste wood-plastic composite (WPC) collected from the house construction sites to fabricate TENG for energy harvesting. The fabricated TENG device exhibited an output voltage and current of approximately 31 V and 30 µA, respectively, with a power density of 107.5 mW/m2. Moreover, the device successfully powered around 80 LEDs and portable electronic devices. By repurposing waste materials like WPC and utilizing TENG technology, this approach showcases the potential for efficient and sustainable energy generation.

Marine Clay Soil Treated with Demolished Tile Waste: A Systematic Literature Review

This systematic literature review investigates the stabilization of marine clay soil using demolished tile waste. The study adopts the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) method to comprehensively analyze existing research in this area.The utilization of waste materials for soil stabilization has gained significant attention due to environmental concerns and sustainability objectives. In this review, we explore the effectiveness of using demolished tile waste as a stabilizer for marine clay soil. The analysis reveals that different types of waste materials exhibit varying degrees of improvement in the soil's properties. The results demonstrate a consistent increase in shear strength after stabilization, indicating the suitability of demolished tile waste as a stabilizing agent for soft clay soils. Interestingly, the highest strength is not obtained at the largest additive quantities. Instead, most research papers report a peak in strength at specific additive proportions and curing time, followed by a decline. This phenomenon occurs when the hydration process is complete, and large lumps form between the clay particles. Furthermore, the size of the additive also plays a crucial role in enhancing the strength of problematic soils. Optimal additive size leads to better distribution and interaction with the clay particles, contributing to improved stabilization results. This review provides valuable insights into the potential of utilizing demolished tile waste for enhancing the engineering properties of marine clay soil. The findings highlight the importance of carefully selecting the type and quantity of additives to achieve the desired stabilization outcomes.

Evaluation of Asphalt Binder and Mixture Properties by Incorporation of Waste Plastics

The improper disposal of waste materials, such as plastics, presents a severe environmental problem. However, an innovative approach to address this issue involves incorporating these waste products into asphalt. This not only improves the characteristics of the asphalt binder but also offers an efficient and responsible method for disposing of these materials. The purpose of this study is to investigate the effects of adding different amounts of polyethylene terephthalate and low-density polyethylene to a 60/70 penetration grade bitumen. Several tests were performed to determine the performance of modified asphalt binder. Binder adhesion and moisture resistance were evaluated using rolling bottle test and pneumatic adhesion tensile test. Comprehensive laboratory test results showed that the binder modified with low-density polyethylene and the control binder both had lower adhesion and moisture resistance compared to the binder containing 12 percent polyethylene terephthalate. This finding suggests that incorporating polyethylene terephthalate into asphalt binder enhances its adhesive properties and makes it more resilient against moisture. Not only does this innovative approach address the environmental issue of improper waste disposal, but it also improves the overall performance of asphalt. By effectively utilizing waste materials, such as polyethylene terephthalate, in the production of asphalt, contribute to a more sustainable and eco-friendly infrastructure.

An impressive pristine biochar from food waste digestate for arsenic(V) removal from water: Performance, optimization, and mechanism

Anaerobic digestion has become a global practice for valorizing food waste, but the recycling of the digestate (FWD) remains challenging. This study aimed to address this issue by utilizing FWD as a low-cost feedstock for Ca-rich biochar production. The results demonstrated that biochar pyrolyzed at 900 °C exhibited impressive As(V) adsorption performance without any modifications. Kinetic analysis suggested As(V) was chemisorbed onto CDBC9, while isotherm data conformed well to Langmuir model, indicating monolayer adsorption with a maximum capacity of 76.764 mg/g. Further analysis using response surface methodology revealed that pH value and adsorbent dosage were significant influencing factors, and density functional theory (DFT) calculation visualized the formation of ionic bonds between HAsO42− and CaO(110) and Ca(OH)2(101) surfaces. This work demonstrated the potential of using FWD for producing Ca-rich biochar, providing an effective solution for As(V) removal and highlighting the importance of waste material utilization in sustainable environmental remediation.

Behavioural studies on binary blended high strength self compacting geopolymer concrete exposed to standard fire temperature

The production of Ordinary Portland Cement Concrete (OPCC) results in high carbon emissions and energy demand, necessitating the search for eco-friendly alternatives. Geopolymers, which utilize waste materials, are identified as a suitable alternative. Industrial by-products such as Fly Ash (FA), Ground Granulated Blast Furnace Slag (GGBS), and Metakaolin (MK) are used as precursor materials for binary blended High Self-Compacting Geopolymer Concrete (HSGC) production. Two HSGC mixes and one normal strength self-compacting mix are developed for comparison. This study aims to look at the residual strength characteristics of NSGC and HSGC specimens. Binary blended NSGC, HSGC, and temperature exposure are the key factor examined in the present study. The current study aimed to evaluate the residual strength of NSGC and HSGC exposed to temperature exposure using the ISO 834 guidelines. HSGC specimens are divided into four groups based on curing and cooling type: ambient curing, oven curing, air cooling, and water cooling. Mechanical properties such as Compression Strength, Tensile Strength, and Flexural Strength before and after exposure to elevated temperature are evaluated. Microstructural investigations are conducted to examine the internal structure of the binary blended HSGC mixes. The experimental results are validated using Indian code (IS 456), American code (ACI 318), European code (EC2), and Australian code (AS 3600). Compressive strength of the HSGC specimens was severely reduced when subjected to 1029 ℃, resulting in the formation of wider cracks attributed to the degradation of the gel structure. The oven-cured specimens possess 72 to 80% loss in strength, whereas ambient-cured specimens possess 77 to 86% loss in strength. The findings reveal that the binary blended mix FA/MK = 1 exhibits higher strength loss (%) compared to FA/GGBS and FA. Ambient-cured HSGC specimens exhibit higher mass loss than oven-cured HSGC mixes, and water-cooled samples show higher strength loss and wider cracks compared to air-cooled specimens. The scientific value of this study lies in the the fire performance and residual mechanical properties of binary blended HSGC mixes developed under various curing and cooling methods. Also, the experimental results are validated with multiple international codes (American, Australian and Indian Standards). These findings contribute to the understanding on the behaviour of HSGC under elevated temperature conditions by providing valuable insights for the development of eco-friendly concrete alternatives with improved fire performance.

Mechanical and Physical Performance of Portland Cement Composites with Partial Replacements of Metakaolin and Ulexite

Fabricating green binding materials are gaining a great importance in the construction sector recently. This rising interest is based upon the need for more sustainable and environment-friendly alternatives to conventional cementitious materials by utilizing waste materials and mineral by-products in the binding matrices through partial or complete replacement with Portland cement. In this paper, an experimental investigation was conducted to examine the effect of using a boron waste, namely ulexite, along with metakaolin as partial replacements with Portland cement. By this means, flow table, setting time, compressive and flexural strengths, unit weight, water absorption, and porosity tests were carried out on twelve different specimens, including the amount of ulexite of 5% and 7%, metakaolin of 10% and 20%, and amount of superplasticizer additive of 1%. The main conclusions of this work showed that using ulexite and metakaolin up to certain percentages is beneficial in terms of mechanical and physical properties. A further increase in the addition can lead to a decrease in the performance of the matrix.

A Comprehensive Overview of the Utilization of Recycled Waste Materials and Technologies in Asphalt Pavements: Towards Environmental and Sustainable Low-Carbon Roads

Given the prevailing concerns about greenhouse gas emissions, global warming, and the growing demand for renewable resources, the pavement industry, among others, is actively engaged in researching and exploring low-carbon materials and technologies. Despite the growing interest in low-carbon asphalt pavement, there is still a significant knowledge gap regarding the use of various waste materials and technologies to achieve this goal. This study aims to close this gap by conducting a systematic review and scientometric assessment of the existing studies on the use of waste materials and technologies for low-carbon asphalt pavement. The study spans the years 2008 to 2023, and the scientometric analysis was conducted using the VOS viewer application. The study identifies materials and technologies in this area by examining co-authored country studies, publication sources, and keyword co-occurrence. It should be noted that a limited number of waste materials that allow CO2 emissions reduction was analyzed in this study. However, other waste categories, such as bio-oils and polymers, which can provide positive either environmental or economic impacts on the production of paving materials, were not considered in the scope of the study. Based on the current review, it was found that integrating recycled waste materials like recycled asphalt pavement, biochar, or crumb rubber with alternative mixing technologies such as warm mix asphalt and cleaner energy can significantly reduce CO2 emissions. China and the United States were identified as key research contributors to the low-carbon pavement. Furthermore, biomass-based fuel and electric construction equipment lower carbon and greenhouse gas emissions by 36–90% and 67–95%, respectively. However, before various recycled waste materials and technologies can be widely used in the asphalt industry, various challenges need to be addressed, including cost concerns, performance and durability concerns, standardization and regulations, availability, integration with existing facilities, and insufficient field and long-term data. The review identified critical research gaps, such as the absence of a homogeneous and reliable standard method for low-carbon asphalt pavement, limited field performance data, and a life cycle assessment approach in analyzing the emission reduction effects. The reviews will aid in the paradigm shift to a more carbon-friendly pavement industry that uses recycled waste materials and technologies.

Critical review on the development of biomass waste as precursor for carbon material as electrocatalysts for metal-air batteries

The latest and state-of-art research on biomass waste-derived carbon materials synthesized for air electrodes used in metal-air batteries were succinctly and comprehensively reviewed in this report. This report also aims to provide greater understanding as well as to identify the strength and challenges of metal-air batteries (MAB), biomass wastes as precursor and the synthesis steps of carbon materials from biomass wastes as well as to propose several research routes for the shortcomings of carbon material synthesis from biomass wastes. MAB is a promising energy storage technology, but its commercialization was hindered due to the absence of a stable and active bifunctional electrocatalyst as well as costly air cathode material. The air cathode which is the key component of MAB is desired to have bifunctional catalytic properties and hierarchical porous structure. Carbon materials were known to be able to perform as an electrode material while acting as a catalyst towards the charge-discharge reactions. Due to its abundance and renewability, biomass wastes have great potential as low-cost and sustainable precursors to synthesize carbon materials as the air cathode while achieving waste reduction. The synthesis of carbon electrocatalyst from biomass waste usually include but not limited to pretreatments, carbonization, activation and doping. The synthesis method controls the structure and size, as well as the elemental content of carbon particles. Activation and doping of heteroatoms or metals were proven to enhance the efficiency and stability of the synthesized carbon material. However, each biomass waste have unique properties which requires tailored synthesis method to obtain carbon material with desired properties. Information on the synthesis methods as well as other crucial information were reviewed in this work which can help to spur more research to promote the utilization of biomass waste materials in energy storage application and to accelerate the commercialization of MAB.

Chemical and Bioactive Screening of Green Polyphenol-Rich Extracts from Chestnut By-Products: An Approach to Guide the Sustainable Production of High-Added Value Ingredients.

Opportunities for the valorisation of agro-industrial residues of the chestnut (Castanea sativa Mill.) production chain have been fostered with the production of multifunctional polyphenol-rich extracts with the potential to be introduced as natural additives or active components in several products. Nonetheless, it is crucial to explore the feasibility of different extracts from the various by-products for these applications through the exhaustive study of their composition and bioactivities without losing sight of the sustainable character of the process. This work aimed at the screening of the phenolic compound composition and bioactivities of different green extracts of chestnut burs, shells and leaves, as the first step to establish their potential application as natural ingredients, primarily as food preservatives. To this end, maceration (MAC) as a conventional extraction method besides ultrasound and microwave-assisted extractions (UAE and MAE) was employed to obtain the extracts from chestnut by-products using water (W) and hydroethanolic solution (HE) as solvents. Phenolic compounds were analysed by HPLC-DAD-(ESI-)MS/MS; the antioxidant capacity was assessed by colourimetric assays, and the antimicrobial activity was evaluated against several strains of food-borne bacteria and fungi. The leaf extracts obtained by MAC-HE and UAE-HE presented the highest concentration of phenolic compounds (70.92 ± 2.72 and 53.97 ± 2.41 mg.g-1 extract dw, respectively), whereas, for burs and shells, the highest recovery of total phenolic compounds was achieved by using UAE-HE and UAE-W (36.87 ± 1.09 and 23.03 ± 0.26 mg.g-1 extract dw, respectively). Bis-HHDP-glucose isomers, chestanin and gallic acid were among the most abundant compounds. Bur extracts (MAC-HE and UAE-HE) generally presented the highest antioxidant capacity as measured by TBARS, while the best results in DPPH and reducing power assays were found for shell extracts (MAE-W and MAC-HE). Promising antibacterial activity was noticed for the aqueous extracts of burs, leaves and hydroethanolic extracts of shells, with emphasis on the MAE-W extract of burs that showed bactericidal activity against E. cloacae, P. aeruginosa and S. aureus (MBC 5 mg.mL-1). Overall, it can be concluded that chestnut by-products, including burs, shells and leaves, are sources of polyphenolic compounds with significant antioxidant and antimicrobial activities. The choice of extraction method and solvent greatly influenced the composition and bioactivity of the extracts. These findings highlight the potential of chestnut by-products for the development of natural additives, particularly for food preservation, while also emphasizing the importance of sustainable utilization of agricultural waste materials. Further research is warranted to optimize extraction techniques and explore additional applications for these valuable bioactive compounds.

Advancements in the synthesis and processing of alkali-activated materials: Activator and precursors

Alkali-activated materials (AAMs) have gained attention in recent years as a sustainable alternative to traditional portland cement-based materials. This is due to their lower carbon footprint and ability to utilize waste materials as raw materials. However, the high embodied carbon and limited local supply of the conventional activators and precursors hinder large-scale deployment and acceptance as a sustainable alternative to portland cement-based materials. Nonetheless, the synthesis and processing of AAMs have been actively researched in recent years, leading to various advancements in the field. This review paper aims to provide an overview of the current state-of-the-art materials utilized in synthesizing AAMs and identify the areas for future research. Hence, it summarizes advancements in synthesizing AAMs regarding alternative activators and precursors and discusses the impact of these advancements on the properties of AAMs, such as strength, durability, and sustainability. Furthermore, this review addresses current challenges associated with the synthesis of AAMs.

Utilization of Waste Material in Road Sub Grade for Stabilization of Soil

Abstract: Soil stabilization is a quite common process for nearly all the building projects. Broadly, all kinds of soil stabilization may be classified into two groups, i.e. mechanical stabilization and chemical stabilization. In mechanical stabilization, the grading of a soil is modified by mixing it with other sorts of soils of various grades. By doing so, a compacted soil mass may be achieved. On the opposite hand, chemical stabilization is related to the modification of soil properties by the addition of chemically active materials. In soil stabilization, it's important to grasp the material properties involved within the mixture and also the outcome after mixing.

Laboratory Study on Influence of Blending Conditions on Chemo-Thermal Characteristics of Lignin-Modified Bitumen

Environmental approaches in the asphalt industry have focused on utilizing waste materials as modifiers. Lignin is a high-potential bitumen modifier due to its characteristics; however, the blending process with bitumen is critical. This study investigates the chemo-thermal characteristics of lignin-modified bitumen under two different blending protocols, including a mechanical and high-shear mixer to evaluate its performance as a modifier. According to the protocols, 5, 10, and 20% of Kraft lignin was added to a PG 58S−28 bitumen. The samples were subjected to analysis using Brookfield Rotational Viscosity (BRV), Dynamic Shear Rheometer (DSR), Fourier-Transform Infrared Spectroscopy (FTIR), Environmental Scanning Electron Microscopy (ESEM), Thermogravimetric Analysis (TGA), and Differential Scanning Calorimetry (DSC) tests. The BRV and DSR test results indicate a remarkable alteration in the rheological properties of lignin-modified bitumen under blending conditions. The FTIR analysis indicated that Kraft lignin did not produce new functional groups. The fibril structures of the bitumens are affected by Kraft lignin content and blending conditions due to ESEM. The Kraft lignin and blending conditions influence the thermal behavior of bitumen. The findings highlight Kraft lignin’s potential as a bitumen modifier, and the fact that its characteristics are influenced by the blending protocol and Kraft lignin content.