Geopolymers have garnered widespread attention due to their excellent mechanical properties, durability, and fire resistance. In this paper, we have conducted the design of a geopolymer coating, incorporating a specific proportion of solid waste manganese slag and polyvinyl alcohol (PVA) fibers. The geopolymer serves to stabilize the manganese slag, while the PVA fibers enhance the mechanical properties of the coating. The results demonstrate that the composite geopolymer coating becomes dense at high temperatures, exhibiting outstanding fire-resistant characteristics. Furthermore, the coating significantly enhances the mechanical performance of wood specimens, indicating promising application prospects in the field of building material fire protection.
{"title":"Preparation and property study of geopolymer composite fireproof coating with PVA fiber and manganese slag","authors":"Zhenyu Zhou , Chenxi Zeng , Hongqing Wei , Yanhuai Ding","doi":"10.1016/j.clema.2024.100289","DOIUrl":"10.1016/j.clema.2024.100289","url":null,"abstract":"<div><div>Geopolymers have garnered widespread attention due to their excellent mechanical properties, durability, and fire resistance. In this paper, we have conducted the design of a geopolymer coating, incorporating a specific proportion of solid waste manganese slag and polyvinyl alcohol (PVA) fibers. The geopolymer serves to stabilize the manganese slag, while the PVA fibers enhance the mechanical properties of the coating. The results demonstrate that the composite geopolymer coating becomes dense at high temperatures, exhibiting outstanding fire-resistant characteristics. Furthermore, the coating significantly enhances the mechanical performance of wood specimens, indicating promising application prospects in the field of building material fire protection.</div></div>","PeriodicalId":100254,"journal":{"name":"Cleaner Materials","volume":"15 ","pages":"Article 100289"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143133198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-01Epub Date: 2025-01-16DOI: 10.1016/j.clema.2025.100296
Hossein Sousanabadi Farahani , Amin Hosseini Zadeh , Jiong Hu , Chris Hawkins , Seunghee Kim
Concrete is a key building material around the world due to its excellent strength and durability. Recycling demolished concrete for new construction materials may play a significant role in sustainable development. Producing recycled concrete aggregates (RCA) from waste concrete is one approach for such an initiative. However, using RCA may pose challenges, such as reduced density, lower elastic modulus and strength, and increased water absorption. Recently, the carbonation of RCA has emerged as a method to address those concerns. This study explores the carbon sequestration capacity of RCA through carbonation, examining various parametric conditions, including initial CO2 pressure, relative humidity, temperature, and pre-treatment approach. Both lab-scale and large-scale carbonation tests were conducted. Additionally, a cost analysis and CO2 footprint assessment were performed. The findings showed that applying higher initial CO2 pressures (e.g., 40–60 psi) and optimal relative humidity (∼55 %) could significantly enhance the carbonation efficiency of RCA. Elevating temperature also led to accelerated CO2 consumption, being more effective on the lab scale. The economic analysis presented potential cost benefits when substituting natural aggregates with CO2-treated RCA. All in all, these results suggest that the carbonation of RCA may provide significant environmental benefits through carbon sequestration, promoting sustainable construction practices.
{"title":"Carbonation reaction of recycled concrete aggregates (RCA): CO2 mass consumption under various treatment conditions","authors":"Hossein Sousanabadi Farahani , Amin Hosseini Zadeh , Jiong Hu , Chris Hawkins , Seunghee Kim","doi":"10.1016/j.clema.2025.100296","DOIUrl":"10.1016/j.clema.2025.100296","url":null,"abstract":"<div><div>Concrete is a key building material around the world due to its excellent strength and durability. Recycling demolished concrete for new construction materials may play a significant role in sustainable development. Producing recycled concrete aggregates (RCA) from waste concrete is one approach for such an initiative. However, using RCA may pose challenges, such as reduced density, lower elastic modulus and strength, and increased water absorption. Recently, the carbonation of RCA has emerged as a method to address those concerns. This study explores the carbon sequestration capacity of RCA through carbonation, examining various parametric conditions, including initial CO<sub>2</sub> pressure, relative humidity, temperature, and pre-treatment approach. Both lab-scale and large-scale carbonation tests were conducted. Additionally, a cost analysis and CO<sub>2</sub> footprint assessment were performed. The findings showed that applying higher initial CO<sub>2</sub> pressures (<em>e.g.</em>, 40–60 psi) and optimal relative humidity (∼55 %) could significantly enhance the carbonation efficiency of RCA. Elevating temperature also led to accelerated CO<sub>2</sub> consumption, being more effective on the lab scale. The economic analysis presented potential cost benefits when substituting natural aggregates with CO<sub>2</sub>-treated RCA. All in all, these results suggest that the carbonation of RCA may provide significant environmental benefits through carbon sequestration, promoting sustainable construction practices.</div></div>","PeriodicalId":100254,"journal":{"name":"Cleaner Materials","volume":"15 ","pages":"Article 100296"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143133203","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study investigated the influence of various manufacturing conditions – including moulding pressure, post-curing, and aging – on the microstructure and mechanical properties (flexural and tensile) of epoxy matrix composites incorporating recovered glass particles at weight fractions ranging from 84 wt% to 90 wt%. The study focused on understanding how these conditions affect the interfacial bonding between the glass particles, epoxy matrix, and void content to establish a correlation between microstructure and mechanical performance before and after ceramification. The findings revealed that increasing moulding pressure from 1.1 MPa to 6.6 MPa reduced void content, increased composite density, and significantly improved flexural properties. The impact of post-curing on the composites’ flexural performance was also examined, and it was found that adjusting the epoxy matrix weight fraction from 6 wt% to 12 wt% further influenced the composite’s mechanical properties. X-ray computed tomography (CT) and scanning electron microscopy (SEM) analyses revealed changes in composite porosity and interfacial bonding, enabling the correlation of these microstructural changes with variations in mechanical properties for both non-ceramified and ceramified composites. Ceramification induced additional microstructural changes, including the formation of voids, which influenced the composites’ mechanical properties. Additionally, the effect of integrating steel wire mesh with 6.5 mm apertures on the mechanical performance of the glass/epoxy composites, both before and after ceramification, was explored.
{"title":"Impact of manufacturing variables on the mechanical performance of recycled glass-enhanced composites","authors":"Nathaphon Buddhacosa , Thevega Thevakumar , Everson Kandare , Sujeeva Setunge , Dilan Robert","doi":"10.1016/j.clema.2025.100297","DOIUrl":"10.1016/j.clema.2025.100297","url":null,"abstract":"<div><div>This study investigated the influence of various manufacturing conditions – including moulding pressure, post-curing, and aging – on the microstructure and mechanical properties (flexural and tensile) of epoxy matrix composites incorporating recovered glass particles at weight fractions ranging from 84 wt% to 90 wt%. The study focused on understanding how these conditions affect the interfacial bonding between the glass particles, epoxy matrix, and void content to establish a correlation between microstructure and mechanical performance before and after ceramification. The findings revealed that increasing moulding pressure from 1.1 MPa to 6.6 MPa reduced void content, increased composite density, and significantly improved flexural properties. The impact of post-curing on the composites’ flexural performance was also examined, and it was found that adjusting the epoxy matrix weight fraction from 6 wt% to 12 wt% further influenced the composite’s mechanical properties. X-ray computed tomography (CT) and scanning electron microscopy (SEM) analyses revealed changes in composite porosity and interfacial bonding, enabling the correlation of these microstructural changes with variations in mechanical properties for both non-ceramified and ceramified composites. Ceramification induced additional microstructural changes, including the formation of voids, which influenced the composites’ mechanical properties. Additionally, the effect of integrating steel wire mesh with 6.5 mm apertures on the mechanical performance of the glass/epoxy composites, both before and after ceramification, was explored.</div></div>","PeriodicalId":100254,"journal":{"name":"Cleaner Materials","volume":"15 ","pages":"Article 100297"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143133205","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-01Epub Date: 2025-03-04DOI: 10.1016/j.clema.2025.100303
Dong Li , Meritxell Asensio , Nello Russo , Mariacristina Cocca , Stefan Brandt , Maike Rabe , Patricia A. Holden
Synthetic textile fiber fragments (sFFs) shed via laundering including washing and drying—historically, but perhaps less accurately, known as synthetic microfibers—are microplastics contaminating environmental biota, ecosystems, and human food supplies. Reducing sFF emissions is of global concern, but there are few source reduction options. sFF emissions vary by fixed factors such as the type of garment edge treatment, the type of fiber or fabric (e.g. staple vs. filament, or surface treatment such as fleece), washing machine type, water conditions, and drying conditions. However, detergent effects are less studied and, while using any detergent—especially powder—may increase sFF emissions, the concept of liquid detergents formulated to reduce sFF emissions remains unexplored. Here, we report a novel “low shed” detergent’s comparative effects on sFF mass emissions, from two studies. First, four institutions washed each of four fabric types using either a conventional detergent or a novel (low shed) detergent, finding that the latter decreased sFF mass emissions despite institutional—operational and methodological—differences. The masses of sFFs per mass of textiles averaged, for each of four institutions, 0.08 ± 0.06, 0.07 ± 0.07, 0.05 ± 0.04, and 0.08 ± 0.04 g/kg when using the novel detergent, versus 0.23 ± 0.13, 0.16 ± 0.11, 0.14 ± 0.05, and 0.11 ± 0.05 g/kg for the conventional detergent. Despite multiple fixed differences in washing conditions across the institutions, the sFF shedding amounts significantly differed according to detergent. Second, for studies at one institution, textile fiber fragment (FF) mass emissions from laundering whole garments comprised of mixed synthetic and cotton fibers were also comparatively decreased with the low shed detergent during washing, wherein the novel detergent resulted in significantly less FF (0.37 g/kg) than the conventional detergent (0.50 g/kg; Wilcoxon test, p = 0.02, n = 8). Although whole garment FF masses captured from the machine dryer (lint trap plus dryer exhaust) did not vary by antecedent detergent (0.50 and 0.49 g/kg, using the novel versus conventional detergent, respectively), the overall garment laundering process across washing and drying emitted relatively decreased FF masses with the low shed detergent (0.87 g/kg) compared to the conventional detergent (0.99 g/kg, p = 0.02). Taken together, the results of this study demonstrated that detergent type could be an important factor in determining the release of sFFs and FFs during laundering, with a possible way to reduce the release being intentional detergent formulation.
合成纺织纤维碎片（sFFs）通过洗涤（包括洗涤和干燥）脱落——历史上，但可能不太准确，被称为合成微纤维——是污染环境生物群、生态系统和人类食物供应的微塑料。减少sFF排放是全球关注的问题，但减少来源的选择很少。sFF排放量因固定因素而异，如服装边缘处理的类型、纤维或织物的类型（如短纤维与长丝，或表面处理如羊毛）、洗衣机类型、水条件和干燥条件。然而，洗涤剂的影响研究较少，而使用任何洗涤剂，特别是粉状洗涤剂，可能会增加sFF排放，而制定的液体洗涤剂的概念，以减少sFF排放仍未探索。在这里，我们报告了一种新型的“低棚”洗涤剂对sFF质量排放的比较影响，来自两项研究。首先，四家机构使用传统洗涤剂或新型（低棚）洗涤剂洗涤四种织物类型中的每一种，发现后者减少了sFF的大量排放，尽管在制度操作和方法上存在差异。使用新型洗涤剂时，每质量纺织品的sFFs质量平均值分别为0.08±0.06、0.07±0.07、0.05±0.04和0.08±0.04 g/kg，而传统洗涤剂的sFFs质量平均值分别为0.23±0.13、0.16±0.11、0.14±0.05和0.11±0.05 g/kg。尽管各机构的洗涤条件存在多种固定差异，但根据洗涤剂的不同，sFF脱落量显着不同。其次，在某机构的研究中，洗涤由合成纤维和棉纤维混合组成的整件服装时，低含量洗涤剂在洗涤过程中也相对减少了纺织纤维碎片（FF）的质量排放，其中新型洗涤剂的FF （0.37 g/kg）显著低于传统洗涤剂（0.50 g/kg）；Wilcoxon检验，p = 0.02, n = 8)。尽管从机器烘干机（棉捕集器加烘干机废气）中捕获的整个衣物FF质量没有因先前使用的洗涤剂而变化（使用新型洗涤剂和传统洗涤剂分别为0.50和0.49 g/kg），但与传统洗涤剂（0.99 g/kg, p = 0.02）相比，使用低浓度洗涤剂（0.87 g/kg）在洗涤和干燥的整个衣物洗涤过程中排放的FF质量相对较少。综上所述，本研究的结果表明，洗涤剂类型可能是决定洗涤过程中sFFs和FFs释放的重要因素，而减少释放的可能方法是有意识的洗涤剂配方。
{"title":"Detergent-mediated reduction of fiber fragment emissions during conventional machine laundering of textiles and garments","authors":"Dong Li , Meritxell Asensio , Nello Russo , Mariacristina Cocca , Stefan Brandt , Maike Rabe , Patricia A. Holden","doi":"10.1016/j.clema.2025.100303","DOIUrl":"10.1016/j.clema.2025.100303","url":null,"abstract":"<div><div>Synthetic textile fiber fragments (sFFs) shed via laundering including washing and drying—historically, but perhaps less accurately, known as synthetic microfibers—are microplastics contaminating environmental biota, ecosystems, and human food supplies. Reducing sFF emissions is of global concern, but there are few source reduction options. sFF emissions vary by fixed factors such as the type of garment edge treatment, the type of fiber or fabric (e.g. staple vs. filament, or surface treatment such as fleece), washing machine type, water conditions, and drying conditions. However, detergent effects are less studied and, while using any detergent—especially powder—may increase sFF emissions, the concept of liquid detergents formulated to reduce sFF emissions remains unexplored. Here, we report a novel “low shed” detergent’s comparative effects on sFF mass emissions, from two studies. First, four institutions washed each of four fabric types using either a conventional detergent or a novel (low shed) detergent, finding that the latter decreased sFF mass emissions despite institutional—operational and methodological—differences. The masses of sFFs per mass of textiles averaged, for each of four institutions, 0.08 ± 0.06, 0.07 ± 0.07, 0.05 ± 0.04, and 0.08 ± 0.04 g/kg when using the novel detergent, versus 0.23 ± 0.13, 0.16 ± 0.11, 0.14 ± 0.05, and 0.11 ± 0.05 g/kg for the conventional detergent. Despite multiple fixed differences in washing conditions across the institutions, the sFF shedding amounts significantly differed according to detergent. Second, for studies at one institution, textile fiber fragment (FF) mass emissions from laundering whole garments comprised of mixed synthetic and cotton fibers were also comparatively decreased with the low shed detergent during washing, wherein the novel detergent resulted in significantly less FF (0.37 g/kg) than the conventional detergent (0.50 g/kg; Wilcoxon test, <em>p</em> = 0.02, n = 8). Although whole garment FF masses captured from the machine dryer (lint trap plus dryer exhaust) did not vary by antecedent detergent (0.50 and 0.49 g/kg, using the novel versus conventional detergent, respectively), the overall garment laundering process across washing and drying emitted relatively decreased FF masses with the low shed detergent (0.87 g/kg) compared to the conventional detergent (0.99 g/kg, <em>p</em> = 0.02). Taken together, the results of this study demonstrated that detergent type could be an important factor in determining the release of sFFs and FFs during laundering, with a possible way to reduce the release being intentional detergent formulation.</div></div>","PeriodicalId":100254,"journal":{"name":"Cleaner Materials","volume":"15 ","pages":"Article 100303"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143579112","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study investigates the compressive strength, porosity, water absorption, chloride penetration, and corrosion resistance of mortar in a ternary blended cementitious system that substitutes Portland Cement Type 1 (PCT) with varying proportions (15%, 20%, 25%, 30%, and 40%) of finely ground ceramic electrical insulator (CE) and silica fume (SF). To enhance the workability of the mortar, a superplasticizer (SP) was used, maintaining a consistent water-to-binder ratio (W/B) of 0.50. SEM-EDS microstructural analysis revealed a homogeneous composition with a high content of calcium silicate hydrate (C-S-H) gel, particularly notable in samples combining CE and SF. The incorporation of 5% to 20% by weight of CE and SF into the cementitious materials resulted in mortars that exhibited superior compressive strength compared to both the control sample and those containing only 10% SF. The use of very fine CE and SF also improved the mortars’ properties in terms of water absorption and chloride penetration. Furthermore, the addition of CE and SF significantly enhanced the mortar’s porosity and increased its corrosion resistance. These findings demonstrate the viability of ground ceramic electrical insulators as a cementitious material and emphasize the environmental benefits of reducing waste and alleviating disposal burdens by repurposing industrial by-products.
{"title":"Strength, pore and corrosion characteristics of ceramic insulator powder-silica fume based ternary blended mortar","authors":"Sumrerng Rukzon , Suthon Rungruang , Udomvit Chaisakulkiet , Patcharapol Posi , Prinya Chindaprasirt","doi":"10.1016/j.clema.2024.100284","DOIUrl":"10.1016/j.clema.2024.100284","url":null,"abstract":"<div><div>This study investigates the compressive strength, porosity, water absorption, chloride penetration, and corrosion resistance of mortar in a ternary blended cementitious system that substitutes Portland Cement Type 1 (PCT) with varying proportions (15%, 20%, 25%, 30%, and 40%) of finely ground ceramic electrical insulator (CE) and silica fume (SF). To enhance the workability of the mortar, a superplasticizer (SP) was used, maintaining a consistent water-to-binder ratio (W/B) of 0.50. SEM-EDS microstructural analysis revealed a homogeneous composition with a high content of calcium silicate hydrate (C-S-H) gel, particularly notable in samples combining CE and SF. The incorporation of 5% to 20% by weight of CE and SF into the cementitious materials resulted in mortars that exhibited superior compressive strength compared to both the control sample and those containing only 10% SF. The use of very fine CE and SF also improved the mortars’ properties in terms of water absorption and chloride penetration. Furthermore, the addition of CE and SF significantly enhanced the mortar’s porosity and increased its corrosion resistance. These findings demonstrate the viability of ground ceramic electrical insulators as a cementitious material and emphasize the environmental benefits of reducing waste and alleviating disposal burdens by repurposing industrial by-products.</div></div>","PeriodicalId":100254,"journal":{"name":"Cleaner Materials","volume":"15 ","pages":"Article 100284"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143133622","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Municipal solid waste incineration bottom ash (MSWIBA) emerges as a potential alternative to natural aggregates due to its similar mineral composition and engineering properties as embanking fillings. However, the instability and environmental pollution risks of MSWIBA limit its large-scale application. This study proposes to employ Enzyme Induced Carbonate Precipitation (EICP) technology to enhance the mechanical properties of MSWIBA and reduce its environmental impact. Initial analyses focused on the basic physicochemical properties and morphological changes of MSWIBA before and after modification. Then the modified MSWIBA exhibited improvements in shear resistance, resilient modulus, and permanent deformation behavior. It was also found that existing resilient modulus and permanent deformation predicting models for soils are applicable to EICP-modified MSWIBA. The column leaching tests were conducted on samples subjected and not subjected to freeze–thaw and dry-wet cycles. The results revealed the modified MSWIBA released reduced heavy metal concentrations in both water and acid leaches. These findings establish a solid theoretical foundation for employing EICP-modified MSWIBA as an embankment fill material, highlighting the potential for wider adoption of this eco-friendly alternative in road constructions.
{"title":"The engineering performance of EICP-modified municipal solid waste incineration bottom ash for road construction","authors":"Zeng Yuan , Tingjun Wu , Linbing Wang , Yucheng Huang , Qiang Tang","doi":"10.1016/j.clema.2024.100285","DOIUrl":"10.1016/j.clema.2024.100285","url":null,"abstract":"<div><div>Municipal solid waste incineration bottom ash (MSWIBA) emerges as a potential alternative to natural aggregates due to its similar mineral composition and engineering properties as embanking fillings. However, the instability and environmental pollution risks of MSWIBA limit its large-scale application. This study proposes to employ Enzyme Induced Carbonate Precipitation (EICP) technology to enhance the mechanical properties of MSWIBA and reduce its environmental impact. Initial analyses focused on the basic physicochemical properties and morphological changes of MSWIBA before and after modification. Then the modified MSWIBA exhibited improvements in shear resistance, resilient modulus, and permanent deformation behavior. It was also found that existing resilient modulus and permanent deformation predicting models for soils are applicable to EICP-modified MSWIBA. The column leaching tests were conducted on samples subjected and not subjected to freeze–thaw and dry-wet cycles. The results revealed the modified MSWIBA released reduced heavy metal concentrations in both water and acid leaches. These findings establish a solid theoretical foundation for employing EICP-modified MSWIBA as an embankment fill material, highlighting the potential for wider adoption of this eco-friendly alternative in road constructions.</div></div>","PeriodicalId":100254,"journal":{"name":"Cleaner Materials","volume":"15 ","pages":"Article 100285"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143133623","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study investigated the optimal design of double-layer rubber composites for eco-friendly laminates. A comprehensive methodology was used, combining material selection, manufacturing processes, and structural optimization to create composites with improved conductivity, strength, durability, and environmental sustainability. The Box-Behnken design methodology was utilized to optimize the formulation of these composites, yielding an optimal solution characterized by a desirability score of 0.714. This optimal formulation consists of a blowing agent content of 12 parts per hundred rubber (phr), wood sawdust content of 80 phr, and a processing temperature of 110 °C. The projected performance characteristics for this optimal composite formulation include a thermal conductivity of 0.023 watts per meter-kelvin (W/mK), a peeling force of 0.728 kN, a puncture force of 97.84 N, and a shearing force of 0.344 kN. Furthermore, an analysis of dimensionless parameters identified a favorable thickness ratio of 0.5 for the double-layer laminate wall panels, which corresponds to a total thickness of 10 mm. This finding is consistent with the principles of green building, facilitating resource efficiency. By adopting a holistic design approach, this study demonstrates a viable strategy for developing high-performance and sustainable double-layer rubber composites tailored for eco-friendly laminates, thus contributing to advancements in green building solutions.
{"title":"Optimizing double-layer rubber composites for eco-friendly laminates: A thermal-mechanical characterization","authors":"Thanwit Naemsai , Chatree Homkhiew , Theerawat Petdee , Chainarong Srivabut","doi":"10.1016/j.clema.2024.100290","DOIUrl":"10.1016/j.clema.2024.100290","url":null,"abstract":"<div><div>This study investigated the optimal design of double-layer rubber composites for eco-friendly laminates. A comprehensive methodology was used, combining material selection, manufacturing processes, and structural optimization to create composites with improved conductivity, strength, durability, and environmental sustainability. The Box-Behnken design methodology was utilized to optimize the formulation of these composites, yielding an optimal solution characterized by a desirability score of 0.714. This optimal formulation consists of a blowing agent content of 12 parts per hundred rubber (phr), wood sawdust content of 80 phr, and a processing temperature of 110 °C. The projected performance characteristics for this optimal composite formulation include a thermal conductivity of 0.023 watts per meter-kelvin (W/mK), a peeling force of 0.728 kN, a puncture force of 97.84 N, and a shearing force of 0.344 kN. Furthermore, an analysis of dimensionless parameters identified a favorable thickness ratio of 0.5 for the double-layer laminate wall panels, which corresponds to a total thickness of 10 mm. This finding is consistent with the principles of green building, facilitating resource efficiency. By adopting a holistic design approach, this study demonstrates a viable strategy for developing high-performance and sustainable double-layer rubber composites tailored for eco-friendly laminates, thus contributing to advancements in green building solutions.</div></div>","PeriodicalId":100254,"journal":{"name":"Cleaner Materials","volume":"15 ","pages":"Article 100290"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143133199","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-01Epub Date: 2025-01-08DOI: 10.1016/j.clema.2025.100293
Joud Hwalla , Hilal El-Hassan , Joseph J. Assaad , Tamer El-Maaddawy
The increase in greenhouse gas emissions from cement production, along with limited landfill capacity for construction waste, has driven research into finding sustainable alternatives to replace cement and natural aggregates. While cement replacement with geopolymeric binders in mortar and concrete has been proven feasible, replacing natural aggregates with recycled counterparts has led to performance losses. To offset this drawback, different additives, including fibers, have been incorporated into such construction materials. This study evaluates the feasibility of using steel fiber (SF)-reinforced geopolymer (GP) composites incorporating recycled fine aggregates (RFA) for screed flooring and repair applications. GP mixes were prepared with RFA mass substitution up to 100 %, alongside SF volume of 0.5 % and 1 %. Flow values of 125 ± 25 mm were attained within 35 to 70 min. The 7-day compressive strength of GP composites reached 74.0 % to 96.2 % of their 28-day values. RFA substitution reduced compressive strength, elastic modulus, tensile strength, pull-off bond strength, and energy absorption and increased impact indentation and abrasion mass loss by up to 56, 69, 60, 23, 68, 266, and 2025 %, respectively. Conversely, SF addition improved most of these properties except for compressive and pull-off bond strength, which slightly decreased. GP composites made with 0 %, 25 %, and 50 % RFA satisfied the strength requirements for use in structural repair, while those with higher RFA replacement were suitable for non-structural use. Based on BS 8204, GP mixes were categorized as Category A screed flooring except the plain mix made with 100 % RFA, which was categorized as Category B.
{"title":"Fiber-reinforced geopolymers made with recycled aggregates for screed flooring and repair applications","authors":"Joud Hwalla , Hilal El-Hassan , Joseph J. Assaad , Tamer El-Maaddawy","doi":"10.1016/j.clema.2025.100293","DOIUrl":"10.1016/j.clema.2025.100293","url":null,"abstract":"<div><div>The increase in greenhouse gas emissions from cement production, along with limited landfill capacity for construction waste, has driven research into finding sustainable alternatives to replace cement and natural aggregates. While cement replacement with geopolymeric binders in mortar and concrete has been proven feasible, replacing natural aggregates with recycled counterparts has led to performance losses. To offset this drawback, different additives, including fibers, have been incorporated into such construction materials. This study evaluates the feasibility of using steel fiber (SF)-reinforced geopolymer (GP) composites incorporating recycled fine aggregates (RFA) for screed flooring and repair applications. GP mixes were prepared with RFA mass substitution up to 100 %, alongside SF volume of 0.5 % and 1 %. Flow values of 125 ± 25 mm were attained within 35 to 70 min. The 7-day compressive strength of GP composites reached 74.0 % to 96.2 % of their 28-day values. RFA substitution reduced compressive strength, elastic modulus, tensile strength, pull-off bond strength, and energy absorption and increased impact indentation and abrasion mass loss by up to 56, 69, 60, 23, 68, 266, and 2025 %, respectively. Conversely, SF addition improved most of these properties except for compressive and pull-off bond strength, which slightly decreased. GP composites made with 0 %, 25 %, and 50 % RFA satisfied the strength requirements for use in structural repair, while those with higher RFA replacement were suitable for non-structural use. Based on BS 8204, GP mixes were categorized as Category A screed flooring except the plain mix made with 100 % RFA, which was categorized as Category B.</div></div>","PeriodicalId":100254,"journal":{"name":"Cleaner Materials","volume":"15 ","pages":"Article 100293"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143133200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The substitution of natural coarse aggregates (NCA) by recycled coarse aggregates (RCA) is part of the environmental approach aimed at reducing waste and preserve natural resources. Unfortunately, RCA is of poor quality due to the presence of old mortar attached to its surface. It is characterized by its low density, high absorption, low rigidity and a poor quality interfacial transition zone (ITZ) which results in a lower quality concrete. This experimental study aims to introduce together with RCA aggregates supplementary cementitious materials (SCM) in order to reduce the decrease in mechanical performance, durability and microstructure of concrete. In a concrete based on RCA aggregates, ordinary cement was replaced with 20% natural pozzolan (NP), 10% limestone powder (LP), 20% ground granulated blast furnace slag (GGBFS) or 10% fumed silica (SF). Concrete was studied in terms of workability, superplasticizer requirements, mechanical strength, water absorption and microstructure. The results reveal that SCM significantly improves the performance of RAC concrete by promoting filling effects, nucleation, pozzolanic reactions and hydraulic activity. In the long term, RAC concrete has a 12% lower strength than OAC concrete. This decrease is reduced to only 3% when using LP and even results in 9% and 28% higher strengths when using GGBFS or SF. Similarly, an improvement in structural porosity up to 28% is observed, which led to a significant reduction in shrinkage strain, ranging from 20% to 44%.
{"title":"Enhancing performance of recycled aggregate concrete with supplementary cementitious materials","authors":"Abba Fatiha , Ezziane Karim , Adjoudj Mhamed , Abed Farid","doi":"10.1016/j.clema.2025.100298","DOIUrl":"10.1016/j.clema.2025.100298","url":null,"abstract":"<div><div>The substitution of natural coarse aggregates (NCA) by recycled coarse aggregates (RCA) is part of the environmental approach aimed at reducing waste and preserve natural resources. Unfortunately, RCA is of poor quality due to the presence of old mortar attached to its surface. It is characterized by its low density, high absorption, low rigidity and a poor quality interfacial transition zone (ITZ) which results in a lower quality concrete. This experimental study aims to introduce together with RCA aggregates supplementary cementitious materials (SCM) in order to reduce the decrease in mechanical performance, durability and microstructure of concrete. In a concrete based on RCA aggregates, ordinary cement was replaced with 20% natural pozzolan (NP), 10% limestone powder (LP), 20% ground granulated blast furnace slag (GGBFS) or 10% fumed silica (SF). Concrete was studied in terms of workability, superplasticizer requirements, mechanical strength, water absorption and microstructure. The results reveal that SCM significantly improves the performance of RAC concrete by promoting filling effects, nucleation, pozzolanic reactions and hydraulic activity. In the long term, RAC concrete has a 12% lower strength than OAC concrete. This decrease is reduced to only 3% when using LP and even results in 9% and 28% higher strengths when using GGBFS or SF. Similarly, an improvement in structural porosity up to 28% is observed, which led to a significant reduction in shrinkage strain, ranging from 20% to 44%.</div></div>","PeriodicalId":100254,"journal":{"name":"Cleaner Materials","volume":"15 ","pages":"Article 100298"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143208219","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-01Epub Date: 2025-01-11DOI: 10.1016/j.clema.2025.100294
David Henriques Bento , Maria Leonor Matias , Maria Magalhães , Catarina Quitério , Ana Pimentel , Dora Sousa , Pedro Amaral , Carlos Galhano , Elvira Fortunato , Rodrigo Martins , Daniela Nunes
This study explores the development and characterization of self-cleaning coatings using titanium dioxide (TiO2) nanoparticles for natural stone façades, particularly limestone. An energy-efficient, eco-friendly, fast (30 min), and low temperature (110 °C) microwave-assisted solvothermal method is reported for synthesising TiO2 nanoparticles. These nanoparticles were integrated into coatings that were further applied to limestone substrates via spray-coating, maintaining the stone’s appearance while enhancing its self-cleaning properties. Characterization techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), energy-dispersive X-ray spectroscopy (EDX), UV–VIS spectroscopy and Brunauer-Emmett-Teller (BET) surface area analysis were used to fully characterize the nanopowder. The anatase phase of TiO2 nanoparticles and a band gap energy of about 3.24 eV were confirmed. SEM and STEM observations revealed that the nanopowder is formed by spherical particles with very fine nanocrystals highly agglomerated, however ensuing a high specific surface area of 199 m2/g. The self-cleaning properties of the coated limestone were assessed using static contact angle measurements. The results showed a significant enhancement in hydrophilicity, with the static contact angle of the coated limestone substrate reducing to nearly zero even without UV exposure, indicating complete wettability. The coating was also subjected to adhesion tests, confirming the presence of TiO2 nanoparticles even after multiple cycles. The photocatalytic activity of the developed coating was evaluated using rhodamine B and methyl orange as model pollutants under solar radiation. The coating effectively degraded both model pollutants, and the photocatalytic cycling tests revealed a stable performance after multiple cycles. This research provides a promising approach for creating sustainable and low-maintenance building materials, contributing to preserving natural stone façades and reducing environmental impact in the construction industry.
{"title":"Self-cleaning stone Façades using TiO2 Microwave-Synthesised Coatings","authors":"David Henriques Bento , Maria Leonor Matias , Maria Magalhães , Catarina Quitério , Ana Pimentel , Dora Sousa , Pedro Amaral , Carlos Galhano , Elvira Fortunato , Rodrigo Martins , Daniela Nunes","doi":"10.1016/j.clema.2025.100294","DOIUrl":"10.1016/j.clema.2025.100294","url":null,"abstract":"<div><div>This study explores the development and characterization of self-cleaning coatings using titanium dioxide (TiO<sub>2</sub>) nanoparticles for natural stone façades, particularly limestone. An energy-efficient, eco-friendly, fast (30 min), and low temperature (110 °C) microwave-assisted solvothermal method is reported for synthesising TiO<sub>2</sub> nanoparticles. These nanoparticles were integrated into coatings that were further applied to limestone substrates via spray-coating, maintaining the stone’s appearance while enhancing its self-cleaning properties. Characterization techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), energy-dispersive X-ray spectroscopy (EDX), UV–VIS spectroscopy and Brunauer-Emmett-Teller (BET) surface area analysis were used to fully characterize the nanopowder. The anatase phase of TiO<sub>2</sub> nanoparticles and a band gap energy of about 3.24 eV were confirmed. SEM and STEM observations revealed that the nanopowder is formed by spherical particles with very fine nanocrystals highly agglomerated, however ensuing a high specific surface area of 199 m<sup>2</sup>/g. The self-cleaning properties of the coated limestone were assessed using static contact angle measurements. The results showed a significant enhancement in hydrophilicity, with the static contact angle of the coated limestone substrate reducing to nearly zero even without UV exposure, indicating complete wettability. The coating was also subjected to adhesion tests, confirming the presence of TiO<sub>2</sub> nanoparticles even after multiple cycles. The photocatalytic activity of the developed coating was evaluated using rhodamine B and methyl orange as model pollutants under solar radiation. The coating effectively degraded both model pollutants, and the photocatalytic cycling tests revealed a stable performance after multiple cycles. This research provides a promising approach for creating sustainable and low-maintenance building materials, contributing to preserving natural stone façades and reducing environmental impact in the construction industry.</div></div>","PeriodicalId":100254,"journal":{"name":"Cleaner Materials","volume":"15 ","pages":"Article 100294"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143133202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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