Materials Waste Research Articles

Performance Investigation of Diatomite Modified Asphalt Mixtures for Different Diatomite Ratios and Grinding Sizes

Modification of asphalt mixtures has become almost mandatory today due to increased stresses in pavements, shortening of load cycle times, and decreases in binder quality. For this reason, many additives can be added to bitumen or asphalt mixture. Industrial material wastes can also be among these additives. When diatomite material is used as a performance enhancer in asphalt mixtures, it significantly improves the main performance indicators of the asphalt mixture. However, low temperature cracking of diatomite-modified asphalt mixtures is still controversial in the literature. This study evaluated the asphalt mixture in terms of low-temperature cracking, water damage, and rutting, depending on the diatomite grinding size (gradation) and addition ratio. Three different sizes of diatomite additives (106, 212 and 300-micron maximum diameter) were used at three addition ratios (5, 10 and 15% by weight of bitumen). According to the test results, it was seen that the mechanical properties of asphalt mixtures were significantly affected by the addition ratios and diatomite sizes, and the use of 300-micron maximum diameter diatomite at the rate of 10% and 15% was more effective. However, according to the BBR test results, the use of diatomite additives with a maximum size of 106 µm at 5% slightly increased the low temperature cracking resistance.

Seaweed waste in eco-friendly construction materials: Valorization of Sargassum ash as a mineral addition in fiber cements

Many coastal regions have recently faced significant challenges due to the excessive accumulation of sargassum. This genus of brown marine algae generates greenhouse gases such as methane and carbon dioxide during decomposition, as well as toxic gases such as hydrogen sulfide and ammonia. The substantial influx of these algae on shores brings far-reaching impacts on the environment, climate, health, and the economy. One way to mitigate these impacts is by using this biomass for energy production and applying the resulting ash as an alternative material in the construction industry. As such, this study aims to analyze the feasibility of sargassum ash as a replacement for limestone in fiber cement. This not only offers an environmentally responsible solution for its disposal, but also adds economic value to a material commonly seen as a waste. Several analyses were conducted on the physical and mechanical properties of fiber cement with varying percentages of limestone replaced by sargassum ash (0, 25, 50, 75, and 100 %), as well as its durability and Life Cycle Assessment (LCA). The fiber cement with 100 % sargassum ash exhibited a 74 % increase in specific energy compared to the fiber cement without the ash after accelerated aging. This mix design also presented better environmental performance in 15 of the 18 impact categories. The results demonstrate that ash holds potential as an alternative material in fiber cement manufacturing.

A Review of the Utilization of Recycled Powder from Concrete Waste as a Cement Partial Replacement in Cement-Based Materials: Fundamental Properties and Activation Methods

Recycled powder (RP) is the primary by-product generated during the reclamation process of construction and demolition waste (CDW). There is existing literature on the use of RP as supplemental cementitious materials (SCMs) in cement-based materials, but a comprehensive evaluation on the characteristics of RP generated from concrete waste has been missing until now. This paper critically reviews the use of RP from concrete waste in cement-based materials, as concrete waste makes up a significant amount of CDW and other components have designated recycling methods. In this sense, this study conducted a critical analysis on the use of RP as an SCM, using detailed literature research. The technology used for producing RP is detailed along with its chemical, mineralogy, and microstructural characteristics. Fresh-state properties in cementitious matrices with RP are introduced with the view of mechanical grinding, thermal activation, carbonation, chemical treatment, biomineralization, mineral addition, nano activation, and carbonation. The review highlights the significant potential of utilizing RP in cement-based materials. Specifically, RP can be advantageously utilized in the production of value-added construction materials.

Experimental study on the utilization of Fly ash solid waste in tunnel shotcrete materials

AbstractFly ash has emerged as a prominent solid waste in China, leading to various environmental concerns and posing a threat to the health of living organisms, including humans. To enhance the industrial applicability of this waste material, a novel approach has been proposed wherein sand is replaced with fly ash as the primary raw material for wall grouting of coal mine roadways. To address the issue of low compressive strength and to improve the properties of fly ash shotcrete materials, a method employing an alkali activator to stimulate the chemical activity of fly ash has been put forward. The long‐term effectiveness of the shotcrete material has been evaluated using compressive strength testing and scanning electron microscopy testing methods. The impact of replacing sand with fly ash on the compressive strength of shotcrete and the activation effect of sodium sulfate (Na2SO4), NaOH, and Na2SiO3 on fly ash shotcrete have been studied. The results indicate that the compressive strength of fly ash shotcrete shows optimal improvement when the content of Na2SO4 is 3%. The ideal ratio of cement to fly ash is 1:3. Therefore, incorporating an appropriate amount of alkaline activator could effectively address the compressive strength issues of fly ash shotcrete materials.

Potential Utilization of Rice Waste in the Construction Sector: A Multi-Criteria Decision Analysis Approach

Effective management of agricultural waste is an important contribution to environmental sustainability and economic development, especially considering the significant volume of agricultural residues produced worldwide. Rice is a widely cultivated crop in Colombia, and its high production results in a high amount of wastes, which is often underutilized due to a lack of knowledge regarding its potential value-added applications. On the other hand, the construction industry has become increasingly aware of the necessity to develop materials with reduced environmental impact. Therefore, this study explores the application of the Analytic Hierarchy Process (AHP) to evaluate various alternatives for utilizing rice waste in construction materials; the alternatives were evaluated based on criteria tailored to the needs of local agricultural communities in the Tolima region of Colombia. The findings highlight the potential of rice husk ash (RHA) as an environmentally responsible alternative in the construction sector, offering a viable solution for waste management while contributing to the economic development of small-scale farmers.

Predictive models for properties of hybrid blended modified sustainable concrete incorporating nano-silica, basalt fibers, and recycled aggregates: Application of advanced artificial intelligence techniques

The main objective of this work is to improve the compressive strength of concrete, specially in sustainable construction is to develop more precise predictive modeling techniques. The compressive strength prediction of basalt fiber reinforced concrete filled with nano-silica and recycled aggregates can be done using a hybrid deep learning model suggesting the use of the combination of Convolutional Neural Networks and Long Short-Term Memory networks. The CNN captures microstructural features from SEM images, while the LSTM models temporal dependencies from sequential curing data samples. To enhance the prediction accuracy, PCA was performed on feature dimensionality reduction and GA optimized hyperparameters both for the model as well as the concrete mix design for improved strength with cost effectiveness. With an R² value of 0.92–0.95, the performance results of the presented model came out better than the baseline models, as well as reducing the MAE by 20 %. Besides, there existed a 5–8 % better compressive strength in GA-optimized mix designs. Robustness comes into play with the model that shows steady strength predictions, regardless of conditions of curing under multiple conditions and at different material composition levels. Furthermore, the reutilization of recycled aggregates and nano-silica gives a real environmental benefit as less waste is produced but the material performance is maximized. This kind of outcome indicates how the proposed model can be practically applied in optimizing concrete design in terms of strength and sustainability features, thus providing an accessible instrument for decision-making in the construction field. It is an effective tool to improve the performance of concrete while minimizing environmental and material wastes.

Flexible and transparent leaf-vein electrodes fabricated by liquid film rupture self-assembly AgNWs for application of heaters and pressure sensors

The leaf veins with hierarchically interconnected network structures have great potential as self-assembly templates for transparent and flexible electrodes. In this paper, a liquid membrane ruptured assisted AgNWs self-assembly method was adopted to obtain conductive veins, which show a low sheet resistance of 3.6Ω/□ and a high transparency of 79 % at a minimal materials waste. The figure of merit of conductive veins was as high as 433Ω-1 and can be further increased by increasing the number of soaking because the light transmittance is nearly immune to the AgNWs layer number. The veins maintained a good electrical conductivity even after bending 10,000 times at a 2 mm radius of curvature and exhibited a good corrosion resistance under harsh conditions. Heaters based on the conductive veins are shown as application examples. A high temperature of 104 °C was achieved at a low voltage of 2 V, which is enough to heat cold water. They still have good heating properties even in the bending state or tensile state. Furthermore, pressure sensors based on the conductive veins were fabricated as examples of wearable devices. The sensor exhibits a high sensitivity of 3.8 kPa−1 in the low-pressure range (0–15 kPa) and 17.4 kPa−1 in the high pressure range (15–50.96 kPa). It can monitor human actions such as finger bending, finger taping, throat swallowing and wrist pulse in real-time, which has promising potential for motion monitoring and information encryption applications.

Exploring the Utilization of Municipal Solid Waste in Sustainable Construction Materials: A Review

Municipal solid waste (MSW) is a growing problem worldwide, as populations increase, and consumption patterns change. It not only causes pollution and health hazards, but it also results in the depletion of resources. Considering this, the utilization of MSW in sustainable construction materials has become a critical area of research. The purpose of this review study is to explore the various ways in which MSW can be utilized in sustainable construction materials such as fired clay bricks, eco-cement, geo-polymer, fly ash (FA), bottom ash (BA), ceramic bricks, municipal solid waste incineration (MSWI), incineration bottom ash (IBA), and coal bottom ash (CBA). This article also helps to understand the properties of waste-based materials and the potential for their use in various applications. This information renders the construction sector to design and develop standard guidelines for the use of waste-based materials. The significance of this review article lies in its potential to transform the construction sector into a more sustainable and resource efficient sector by leveraging the resources that are already available. Integrating waste into construction materials not only averts the waste from landfills and incinerators, but also facilitates the necessity of raw materials and consequently sustains the natural resources. Additionally, the utilization of waste-based building materials can lead to a reduction in the carbon trace of the construction industry, as waste materials often have lower embodied energy compared to traditional building materials. The outcomes of this review will provide valuable insights into the potential of MSW as a resource in sustainable construction and contribute to the development of effective Municipal Solid Waste Management (MSWM) strategies.

Full‐Component Utilization of Cellulose Nanofibrils and Artificial Stone Waste for Cement Enhancement

With the concept of carbon neutrality, the value‐added utilization of biomass materials and solid waste becomes a cutting‐edge topic. Cellulose nanofibrils (CNFs) receive much attention due to their excellent properties in terms of high aspect ratio, specific strength, and specific surface area, but their large‐scale preparation remains a great challenge. Herein, a facile aqueous solution method is proposed for the fabrication of CNFs through artificial stone waste (ASW)‐assisted supramolecular interfacial interactions for the full‐component utilization in cement mortar materials. The strong hydrogen bonding interaction between ASW and CNFs can effectively prevent the intramolecular hydrogen bonding of CNFs and agglomeration of ASW, while improving the stability of CNF/ASW suspensions. The resulting CNFs/ASW with active hydroxyl or carboxyl group can improve the flexural and compressive strength of cement (30.8% and 37.8% higher than that of pristine cement, respectively) by embedding into the defects of cement mortar and promoting the hydration process of cement. In this work, not only a new idea is provided for the large‐scale preparation of biomass nanomaterials, but also the full‐component value‐added utilization of biomass and solid waste in cement materials is opened up.

FGD-Gypsum Waste to Capture CO2 and to Recycle in Building Materials: Optimal Reaction Yield and Preliminary Mechanical Properties.

The use of waste to capture CO2 has been on the rise, to reduce costs and to improve the environmental footprint. Here, a flue gas desulfurization (FGD) gypsum waste is proposed, which allows us to obtain a CaCO3-based solid, which should be recycled. The CO2 capture stage has primarily been carried out via the direct carbonation method or at high temperature. However, a high energy penalty and/or long reaction times make it unattractive from an industrial perspective. To avoid this, herein an indirect method is proposed, based on first capturing the CO2 with NaOH and later using an aqueous carbonation stage. This allows us to capture CO2 at a near-ambient temperature, improving reaction times and avoiding the energy penalty. The parameters studied were Ca2+/CO32- ratio, L/S ratio and temperature. Each of them has been optimized, with 1.25, 100 mL/g and 25 °C being the optimal values, respectively, reaching an efficiency of 72.52%. Furthermore, the utilization of the produced CaCO3 as a building material has been analyzed. The density, superficial hardness and the compressive strength of a material composed of 10 wt% of CaCO3 and 90 wt% of commercial gypsum, with a water/solid ratio of 0.5, is measured. When the waste is added, the density and the mechanical properties decreased, although the compressive strength and superficial hardness are higher than the requirements for gypsum panels. Thus, this work is promising for the carbonation of FGD-gypsum, which involves its chemical transformation into calcium carbonate through reacting it with the CO2 of flue gasses and recycling the generated wastes in construction materials.

Development of phase change eco-composite materials from eggshell waste

ABSTRACT The consumption of eggshell powder (ES) as an affluent source of calcium carbonate (CaCO3) can efficiently solve both ecological and financial interest. The use of eggshell waste in eco-composite materials (ECPCMs) is an attempt to reduce waste's negative effects. Eco-composite powders of polyethylene glycol (PEG) and calcium carbonate (CaCO3) were obtained by mechanical grinding. Compression molding was used to produce plates from the ground powders. FTIR spectroscopy and X-ray diffraction analysis showed that the ECPCMs were physically combined and the crystallinity of the two components was affected. According to TGA, the thermal stability of ECPCMs was improved, thanks to the use of eggshell waste powder. On the other hand, the results of the DSC showed that ECPCM with the addition of 90 wt% of PEG in the mixture provides excellent thermal stability and high energy storage density. In light of its high latent heat storage capacity of 156.1 J/g as well as its ability to prevent PEG exudation. Significant enhancement in melting-solidification time shows an improvement in Thermal Energy Storage (TES) response time by adding ES to the PCM. The obtained results indicate a good potential for industrially applied ECPCMs.

Effect of Recycled Fibers on the Mechanical Properties and Durability of Sand Concrete

Recycling waste in construction materials is part of a sustainable development approach aimed at creating new materials with characteristics that have been shown to be competitive with traditional materials. In this context, this study aims to recover steel, copper and aluminum wastes from blacksmiths’ workshops together with the reuse thereof in the form of reinforcing fibers in sand concrete. However, in order to assess the impact of this waste on the concrete properties, we introduced such wastes in the form of fibers at different proportions (0.4 %, 0.8 % and 1.2 %). Further, a series of tests was then carried out to determine the evolution of the concrete characteristics in the fresh state (workability and density) and in the hardened state (compressive strength, flexural strength, compressive strength obtained using a sclerometer and the speed of ultrasonic waves), as well as the concrete’s durability (absorption coefficient by immersion, by capillarity and the porosity accessible to water). In closing, the behavior of the concrete was assessed in the face of a chemical attack by H2SO4 and HCl by measuring mass loss. In virtue of thus, the results obtained demonstrated a positive evolution of certain properties of sand concrete as a function of the type and percentage of fibers incorporated into the composition of the concrete.

A pathway for plastic waste in construction materials

A pathway for plastic waste in construction materials

Versatile Hyper-Cross-Linked Polymers Derived from Waste Polystyrene: Synthesis, Properties, and Intentional Recycling.

Waste polystyrene contributes considerably to environmental pollution due to its persistent nature, prompting a widespread consensus on the urgent need for viable recycling solutions. Owing to the aromatic groups structure of polystyrene, hyper-cross-linked polymers can be synthesized through the Friedel-Crafts cross-linking reaction using Lewis acids as catalysts. In addition, hyper-cross-linked polystyrene and its carbonaceous counterparts can be used in several important applications, which helps in their efficient recycling. This review systematically explores methods for preparing multifunctional hyper-cross-linked polymers from waste polystyrene and their applications in sustainable recycling. We have comprehensively outlined various synthetic approaches for these polymers and investigated their physical and chemical properties. These multifunctional polymers not only exhibit structural flexibility but also demonstrate diversity in performance, making them suitable for various applications. Through a systematic examination of synthetic methods, we showcase the cutting-edge positions of these materials in the field of hyper-cross-linked polymers. Additionally, we provide in-depth insights into the potential applications of these hyper-cross-linked polymers in intentional recycling, highlighting their important contributions to environmental protection and sustainable development. This research provides valuable references to the fields of sustainable materials science and waste management, encouraging further exploration of innovative approaches for the utilization of discarded polystyrene.

Opportunities to reduce environmental burden by recycling fabric waste in a woollen fabric company

PurposeWool fiber is accepted as one of the natural and renewable sources and has been used in the apparel and textile industry since ancient times. However, wool fiber has the highest global warming potential value among conventional fibres due to its high land use and high methane gas generation. This study aimed to recycle the wool fabric wastes and also to create a mini eco-collection by using the produced yarns.Design/methodology/approachThis manuscript aimed to evaluate the fabric wastes of a woolen fabric producer company. Fabric wastes were opened with two different opening systems and fiber properties were determined. First, conventional ring yarns were produced in the company’s own spinning mill by mixing the opened fibres with the long fiber wastes of the company. In addition, opening wastes were mixed with different fibres (polyester, long wool waste, and Tencel fibres) between 25% and 70% in the short-staple yarn spinning mill and used in the production of conventional ring and OE-rotor yarns. Most of the yarns contained waste fibres at 50%. Recycled and virgin yarns were used as a weft and warp yarn and a total of 270 woven fabric samples were obtained and fabric properties were examined. Also, a fabric collection was created. A life cycle assessment (LCA) was made for one of the selected yarns.FindingsAt the end of the study, it was determined that it was possible to produce yarn and fabric samples from fiber blends containing high waste fiber ratios beyond 50%. All the woven fabric samples produced from conventional ring and OE-rotor yarns gave higher breaking, tearing and stitch slip strength values in the weft and warp direction than limit quality values of the company. In addition, abrasion resistance and WIRA steam stability properties of the fabric samples were also sufficient. Environmental analysis of the recycling of the wastes showed a possible decrease of about 9940034.3 kg CO2e per year in the global warming potential. In addition, fiber raw material expenses reduced yarn production cost about 50% in case of opened fabric waste usage. However, due to insufficient pilling resistance results, it was decided to evaluate the woven fabrics for the product groups such as shawls and blankets, where pilling resistance is less sought.Originality/valueThe original aspects of the article can be summarized under two headings. First, there are limited studies on the evaluation of wool wastes compared to cotton and polyester fibres and the number of samples examined was limited. However, this study was quite comprehensive in terms of opening type (rag and tearing), spinning systems (long and short spinning processes), fiber blends (waste 100% and blends with polyester, long wool waste and Tencel fibres) and yarn counts (coarser and finer). Recycled and virgin yarns were used as a weft and warp yarn and a total of 270 woven fabric samples were obtained using different colour combinations and weave types. All processes from fabric waste to product production were followed and evaluated. Life cycle assessment (LCA) and cost analysis was also done. The second unique aspect is that the problem of a real wool company was handled by taking the waste of the woolen company and a collection was created for the customer group of the company. Production was made under real production conditions. Therefore, this study will provide important findings to the research field about recycling, sustainability etc.

Circular Economy Approach: Recycling Toner Waste in Cement-Based Construction Materials

Based on a waste generated survey by companies in the area of the city of Bahia Blanca (Argentina), the possibility of incorporating part of them in a Portland cement matrix was examined. Among the waste is toner (TW), which is obtained from cartridges used in photocopiers, laser printers, and faxes. This paper aims to analyze the physical and mechanical properties of cement pastes and mortars using toner as a Portland cement replacement compared to a reference sample without toner. The mixes were made with 2.5, 5, 10, and 15 wt.% replacement of cement by toner, and it was measured the flow, normal consistency, setting time, calorimetry, and Frattini test in pastes and mechanical strengths in mortars employing standardized tests. Also, an analysis of the leachate in the curing water was carried out after 56 days to look for contaminating materials. The replacement of up to 5% cement with toner did not produce substantial alterations in the final setting time or mechanical properties. No heavy metals were found in the leachate, so TW can be immobilized in a cementitious matrix as it does not cause leaching above the established limits. Therefore, TW from a local industry can be used in construction materials and could contribute to a reduction of up to 14% of CO2 emissions with a cement replacement of 15% in cement-based materials.

A Review on the Effects of Waste Textile Polymer Fiber on Concrete Strength: Exploring the Key Parameters

The construction industry is one of the largest users of natural resources and can, thus, lead to significant environmental issues. Therefore, there is elevated interest worldwide in developing sustainable construction materials and techniques that can reduce these associated environmental impacts. In this context, one substantial area of focus is the incorporation of textile waste in construction materials, such as concrete. Textile waste is generated in large quantities from the production stage through to the consumption and end-of-life disposal periods. Hence, it is prudent to devise effective ways of recycling this waste, which can, in turn, reduce the environmental implications of textile production and cut down the quantity of waste sent to landfills. Furthermore, fibers obtained from recycled textile waste can be used to reinforce concrete, thus replacing the need for synthetic fibers. This review focuses on the use and effects of incorporating polymer fibers from recycled textile waste in concrete and the use of textile polymer fiber in the construction of various structures, and challenges in the use of recycled fibers in concrete and the parameters affecting the resultant strength of concrete structures, such as stress transfer, crack control, bond strength, and spalling, etc., are discussed.

Utilization of polypropylene waste and zeolitic by-product in composite materials

Polypropylene is a widely used polymer that generates a lot of polypropylene waste. This study presents composite materials with matrix made from polypropylene waste reinforced with zeolitic powder (ZP). This zeolite is a waste from the oil industry. The relationships between the density, compressive strength, microstructure, durability for UV radiation and incorporation of ZP in the polypropylene waste matrix were observed. The durability in UV environmental increased due to powder acting as screen of UV radiation in polypropylene composites. This composite could be used as a civil engineering building material for light structures.

Lodo do Curtimento de couro em Argamassa: Valorização Sustentável

Purpose: This study aims to investigate the valorisation of sludge from Leather Tannery Wastewater Treatment Plants (LTWWTP) by incorporating it into cement mortars. Theoretical framework: The substantial quantity of waste generated by industries coupled with the scarcity of natural resources calls for the analysis, development, and implementation of treatment methods to recover and reuse materials, thereby minimising the environmental impact of waste disposal. The leather tanning industry, a significant polluter due to its use of hazardous and heavy materials, requires sustainable solutions for waste management. One promising approach is the incorporation of waste into cementitious matrices. Method: Three scenarios were examined: low-moisture sludge, ash obtained via incineration, and wet oxidation. Test specimens were prepared with varying proportions of cement replacement (0, 3, 5, 7, and 10%), and their flexural and compressive strengths were evaluated. Additionally, chemical analyses were conducted to assess solubility. Results and Conclusion: The results indicate that sludge can be used in small proportions without compromising the mechanical strength of the mortar. Substituting 10% cement with ash using the INC-2 incineration method improved mortar quality, exhibiting a higher compressive strength of 41 MPa and minimal water absorption (3.28%). Research implications: Drawing from these promising findings, it can be confidently asserted that utilising WWTP sludge in mortar is a practical, eco-conscious solution for civil construction. Furthermore, it is a pivotal step towards addressing the challenge of hazardous sludge disposal. Originality/value: The findings from this research will contribute to sustainable waste management practices and pave the way for responsible and eco-friendly utilisation of industrial waste in cementitious materials, thus minimising environmental burdens.

Using industrial waste in porous building materials for indoor humidity control

This study uses waste bricks and waste catalyst as raw materials in the synthesis of humidity control building materials with high structural strength. This paper explores the feasibility of producing porous humidity control materials (PHCM) through the billet sintering of waste brick with various quantities of waste catalyst (0 %–40 %) for indoor construction. N2 adsorption and desorption isotherms revealed that PHCM exhibits Type-IV adsorption with H3 hysteresis loops, indicating a network of interconnected mesopores with diameters ranging from 3 to 17 nm. Humidity control analysis revealed that increasing the waste catalyst content significantly enhanced the equilibrium moisture content and moisture adsorption and desorption capacity. This study determined that the adsorption of moisture within the PHCM relies on capillary condensation within the mesopores. Under 95 % relative humidity (RH), the highest equilibrium moisture content (2.97 kg/kg) and 12-h moisture adsorption capacity (72.41 g/m2) were obtained in specimens prepared at a sintering temperature of 1000 °C with a 40 % spent catalyst. This excellent adsorption capacity can be attributed to the high surface area of the waste catalyst, which increased the surface area of PHCM from 0.013 to 8.529 m2/g. This study demonstrates the benefits of synthesizing PHCM using waste bricks and catalysts in terms of porous properties, mechanical properties, and humidity control performance.