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Utilizing recycled fibers as reinforcement in cement-based matrices is an effective means of promoting waste recycling and adopting a circular economy approach in the construction industry. Within this framework, the recycling and potential reutilization of textile residues can improve the pre- and post-cracking performance of cement-based matrices intended for building components with up to intermediate structural responsibilities (i.e., panels and cladding elements for buildings). This research is focused on the mechanical and durability -through forced aging of dry-wet and freeze-thaw cycles- experimental characterization of laminated fabric-reinforced cementitious matrices (FRCMs) containing 4 and 6 nonwoven fabric layers obtained from end-of-life fire-protecting t-shirts. For this purpose, both direct and flexural tensile tests were conducted to characterize the mechanical performance of the composite. The tests on the 6-fabric layers produced panels with Portland Cement (PC) matrix, after 28-day of curing, led to average values of the maximum tensile strength of 3.7 MPa with associated toughness index superior to 25 kJ/m2, and mean modulus of rupture of 11.6 MPa with a fracture energy index of 4.3 kJ/m2. After dry-wet accelerated aging, the post-cracking performance of the developed composites decreased (on average, 40% in toughness and 11% in strength) due to fiber embrittlement. To better understand the performance of aged composites, shredded fibers recovered from protective clothing (mainly consisting of meta-aramid fibers) were immersed in the binary matrix. Accordingly, the mechanical properties of the fibers after 5 and 10 cycles of dry-wet aging were studied. Based on the results, replacing partially PC by silica fume (between 30% and 50%) was seen as a sustainable alternative to improve the performance of the aged fibers by more than 10%.

Utilizing recycled fibers as reinforcement in cement-based matrices is an effective means of promoting waste recycling and adopting a circular economy approach in the construction industry. Within this framework, the recycling and potential reutilization of textile residues can improve the pre- and post-cracking performance of cement-based matrices intended for building components with up to intermediate structural responsibilities (i.e., panels and cladding elements for buildings). This research is focused on the mechanical and durability -through forced aging of dry-wet and freeze-thaw cycles- experimental characterization of laminated fabric-reinforced cementitious matrices (FRCMs) containing 4 and 6 nonwoven fabric layers obtained from end-of-life fire-protecting t-shirts. For this purpose, both direct and flexural tensile tests were conducted to characterize the mechanical performance of the composite. The tests on the 6-fabric layers produced panels with Portland Cement (PC) matrix, after 28-day of curing, led to average values of the maximum tensile strength of 3.7¿MPa with associated toughness index superior to 25¿kJ/m2, and mean modulus of rupture of 11.6¿MPa with a fracture energy index of 4.3¿kJ/m2. After dry-wet accelerated aging, the post-cracking performance of the developed composites decreased (on average, 40% in toughness and 11% in strength) due to fiber embrittlement. To better understand the performance of aged composites, shredded fibers recovered from protective clothing (mainly consisting of meta-aramid fibers) were immersed in the binary matrix. Accordingly, the mechanical properties of the fibers after 5 and 10 cycles of dry-wet aging were studied. Based on the results, replacing partially PC by silica fume (between 30% and 50%) was seen as a sustainable alternative to improve the performance of the aged fibers by more than 10%., The authors express their gratitude to the Agencia Estatal de Investigación, Spanish Ministry of Economy, Industry, and Competitiveness (Government of Spain) for the financial support received under the scope of the project RECYBUILDMAT (PID2019-108067RB-I00/AEI/10.13039/501100011033). Also, they acknowledge the funding of the research group TECTEX (2021 SGR 01056) from the Department de Recerca i Universitats de la Generalitat de Catalunya. The first author acknowledges the Banco Santander for the Research Scholarships (Postdoc-UPC 2022 Grant)., Peer Reviewed, Postprint (published version)

This project consists of manufacturing a highly sustainable fiber cement made of textile waste and mining industries and analyzing its properties., Aquest projecte consisteix en la fabricació d'un fibrociment altament sostenible a partir de residus de les indústries tèxtil i de la mineria i en analitzar les seves propietats., Este proyecto consiste en en la fabricación de un fibrocemento altamente sostenible a partir de residuos de las industrias textil y de la minería y en analizar sus propiedades., Objectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles, Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura

Towards more eco-friendly building materials, nonwoven fabrics from natural-based (flax) and recycled (textile waste) fibers were produced and incorporated into the cementitious composite panels. The textile waste fibers were recovered from two different clothing sources including fashion and fire-proofing garments. The flexural and durability (through forced wet-dry aging cycles) properties of the laminated sandwich-like cement panels reinforced with four different nonwoven fabrics (flax, treated flax, hybrid fashion textile waste/flax, and fire-proofing textile waste) were analyzed. Based on the results, all four different composites showed promising flexural-hardening behaviors in unaged conditions, especially those reinforced with the treated flax or hybrid fabrics which reached flexural strength of more than 16 MPa and energy ab-sorption index of more than 10 kJ/m2. After wet-dry aging, the post-cracking performance of all composites degraded due to fiber embrittlement, this was more evident for untreated flax composite (reduced by ~65%). Nonetheless, the treated flax fabric composite and hybrid fabric composite containing silica fume could show a better performance after aging., The authors express their gratitude to the Agencia Estatal de Investigación, Spanish Ministry of Economy, Industry, and Competitiveness (Government of Spain) for the financial support received under the scope of the projects RECYBUILDMAT (PID2019-108067RB-I00/AEI/10.13039/501100011033); 3D-Crete (2019PROD00066/IU68-017262-Codi project: J-02696); and CREEF (PID2019-108978RB-C32/AEI/10.13039/501100011033). The first author acknowledges the Banco Santander for the Research Scholarships (Postdoc-UPC 2022 Grant)., Postprint (published version)

Towards the sustainable development goals in the built environment, the use of waste and recycled sources has been attaining great interest among researchers and policy-makers, especially in concrete as the most used construction material. Excess use of natural aggregates, as one of the main components of concrete, causes the depletion of natural resources and the associated environmental problems, thus, the use of artificial and recycled aggregates is of great importance. In this regard, the production of lightweight artificial aggregates from industrial and hazardous wastes may be a promising solution that not only mitigates the depletion of natural resources but also stabilize those kinds of wastes. This study aimed to investigate the production of concrete with recycled aggregates from industrial wastes, mainly municipal solid waste incineration fly ash (MSWI-FA). To this end, different kinds of mix designs to manufacture the aggregates were developed based on MSWI-FA, ground granulated blast furnace slag (GGBFS), marble sludge (MS), and cement. The concrete samples containing different artificial aggregates, as well as recycled polyethylene terephthalate (PET) in the sand form, were produced and the properties, including compressive strength and thermal insulation, were evaluated. The obtained results of the lightweight concrete demonstrated enhanced thermal property (up to 30%), but at least 30% lower resistance with respect to the normal concrete produced from the natural aggregate., Postprint (author's final draft)

In the search of more environmentally-friendly construction materials, the use of natural-based fibers has gained much attention as reinforcement in the inorganic-based matrix. In this paper, the nonwoven flax fabric reinforced lime composites are created using a dewatering technique, and the serviceability parameters –thermal conductivity, sound absorption coefficient, and residual flexural resistance after exposure to elevated temperature– are determined experimentally. The tests are carried out on two different lime composites prepared under two distinct curing regimens, i.e., accelerated carbonation in a CO2 chamber and natural carbonation in laboratory conditions, to evaluate the effect of forced carbonation. In addition, the experimental results of the serviceability parameters are included in the MIVES model (Integrated Value Model for Sustainability Assessment) to evaluate the social sustainability of the developed material as an interior drywall panel. MIVES, a type of multi-criteria decision-making method, is based on the value function concept and seminars with experts. According to the results of experimental tests, the accelerated cured sample has higher thermal conductivity (~4 times) and lower sound absorption coefficients (~20%) than the naturally cured one. Nonetheless, the flexural performance of the former is 50% (at room temperature) and 100% (at elevated temperature) better. As for the social sustainability index assessed by the MIVES-based multi-objective approach, it ranges between 0.65 and 0.75 (out of 1.0) for both lime composite panels, at least 20% higher than the control lime panel with no reinforcement. The sustainability model designed for this research can be used for assessing the social sustainability performance of other materials although the weights assigned by the experts could be adapted to reflect the perceptions and local preferences., This work was supported through the project grants PID2019-108067RB-I00/AEI/10.13039/501100011033 and PID2020-117530RB-I00/MCIN/AEI/10.13039/501100011033 by the Ministerio de Ciencia e Innovación (MCIN)/Agencia Estatal de Investigación (AEI) of the Spanish Government. The author Payam Sadrolodabaee acknowledges the Banco Santander for the Research Scholarships (Postdoc-UPC 2022 Grant)., Peer Reviewed, Objectius de Desenvolupament Sostenible::12 - Producció i Consum Responsables, Postprint (published version)

To reach carbon neutrality, the use of more eco-friendly building materials derived from recycled resources and industrial by-products has been widely encouraged. The use of Portland cement (PC) and concrete as the most used material in the world, after water, ends in the release of million tonnes of CO2 into the atmosphere. On the other hand, fast fashion in the garment industry has resulted in a massive volume of textile waste (TW) that ends up in landfills worldwide. In this regard, a cementitious composite containing industrial by-products as a partial replacement of PC reinforced with recycled TW fibers could be a viable option in terms of both durability and sustainability. In this study, the durability of the hybrid TW/falx nonwoven fabric-reinforced cement composite modified with 30% Silica Fume (SF) was investigated by determining the effect of accelerated wet /dry cycles on the mechanical behavior (through the flexural test) and microstructural characteristics (through scanning and backscat-tered electron microscope). The results show that there was a negligible difference between the mechanical properties of the laminated composite treated with SF with respect to the one without SF in unaged conditions. Nonetheless, after accelerated aging, the fibers in the former could maintain their strength and flexibility, resulting in the composite with better post-cracking mechanical parameters by 40%. © 2022, fib. The International Federation for Structural Concrete. All rights reserved., Postprint (author's final draft)

Incorporating eco-friendly substances obtained from recycled resources and industrial by-products is gaining increased acceptance among building materials. In this context, a cementitious matrix containing supplementary cementitious materials (SCMs) reinforced by recycled fibers may be a promising solution from both a durability and sustainability perspective. This study presents an extensive experimental program carried out on a cement- based composite with Silica Fume (SF), reinforced with recycled textile waste (TW) nonwoven fabric. Initially, the mechanical strength (compression and flexure) of the Portland cement paste substituted with variable SF content (0%–30%) was characterized. Based on the results, laminate plates having six TW fabric layers impregnated with three different cement pastes, Postprint (published version)

Tesi en modalitat de compendi de publicacions, Cementitious materials have one of the highest compressive strength-to-weight ratios compared to other construction materials. Nonetheless, both tensile strength capacity and toughness result to be an order of magnitude less respect to the former, which thereby leads to cracking under tensile stresses caused by service loads. This lack of tensile strength capacity of the material leads to cracking and fragile failure in case the material is insufficiently reinforced. Within this context, fibers can be used in cementitious matrices aiming at enhancing the toughness, energy absorption capacity, post-cracking behavior as well as flexural and tensile strength. Although during the past decades, various types of fibers such as asbestos, steel, glass, and polymeric have been tested in brittle matrices, there have been some disadvantages such as detrimental health effects, high cost, and specifically, substantial environmental footprint. Likewise, based on the statistics, the construction sector is responsible for about 40% of the European Union's total final energy consumption, 35% of its total CO2 emissions, and 45% of waste generation. That is why significant efforts should be devoted to applying the ‘3Rs’ concept of reducing, reusing, and recycling in the building sector and material fabrication. On the other hand, the textile leftover is one of the predominant waste resources worldwide while only less than 20% is being recycled. The textile industry produces textile wastes (TW) from the primary stages of garment production (pre-consumer waste such as fiber, yarn, and fabric) to the end of its useful life (post-consumer waste: discarded clothes). Thus, the reuse of this textile waste in construction is becoming interesting and convenient due to the shortage of natural mineral resources and increasing waste disposal costs. Recently, sustainable fibers produced from renewable, biodegradable, waste, recycled, available, and low-cost resources becoming a focal point. In thi, Los materiales cementosos tienen una de las más altas resistencias a la compresión comparada con la de otros materiales de construcción. No obstante, tanto la capacidad de resistencia a la tracción como la tenacidad resultan ser un orden de magnitud menor que la primera, lo que conduce a la fisuración bajo los esfuerzos de tracción provocados por las bajas cargas de servicio. Esta falta de capacidad de resistencia a la tracción puede provocar grietas y roturas frágiles.. Por esta razón, las fibras se han utilizado predominantemente en matrices cementosas con el objetivo de mejorar la tenacidad, la capacidad de absorción de energía, el comportamiento posterior al agrietamiento y la resistencia a la flexión y a la tracción. Aunque durante las últimas décadas, se han probado varios tipos de fibras como asbesto, acero, vidrio y polímeros en matrices frágiles. Algunas de ellas presentan algunas desventajas como efectos perjudiciales para la salud, alto costo y, específicamente, una huella ambiental sustancial. Asimismo, según las estadísticas, el sector de la construcción es responsable de cerca del 40% del consumo total de energía final de la Unión Europea, el 35% de sus emisiones totales de CO2 y el 45% de la generación de residuos. Es por eso que se deben dedicar esfuerzos significativos a aplicar el concepto de las '3R' de reducción, reutilización y reciclaje en el sector de la construcción y la fabricación de materiales. Por otro lado, el sobrante textil es uno de los residuos predominantes a nivel mundial del cual se recicla menos del 20%. La industria textil produce residuos textiles (TW) desde las etapas primarias de la producción de prendas de vestir (restos previos al consumo, como fibras, hilados y telas) hasta el final de su vida útil (excedentes posteriores al consumo: ropa desechada). Así, la reutilización de estos residuos textiles en la construcción se está volviendo interesante y conveniente debido a la escasez de recursos minerales naturales y al aument, Postprint (published version)

As the building sector is one of the leading responsible for energy consumption and CO2 emissions, criteria of sustainability, availability, and recyclability should be considered for developing materials even in the envelopes. Façade, as the first element against the undesirable external impact, may contribute to building sustainability by reducing the amount of energy consumption and providing indoor environment quality for the inhabitants. The envelope excluding its aesthetic function should fulfill certain requirements such as strength, flexibility, ductility, lightness, thermal and acoustical insulation, durability, and sustainability. Fiber/Textile cement sheets as an interesting architectural material attract great interest during the last decade, especially those reinforced with more sustainable fibers like vegetables or textile wastes. In this sense, this paper presents a novel model to evaluate the sustainability index of façade cladding panel, especially the fiber/textile cement board. To this end, a new model for assessing objectively the façade cladding sustainability was designed and developed based on MIVES according to the value function concept and seminars of experts., The authors wish to express their gratitude to the Spanish Ministry of Economy and Competitiveness for the financial support in the scope of the project eFIB (reference: RTC-2016-5236-5) which was carried out along with SACYR Ingeniería e Infraestruturas. The first author also thanks the Department of Enterprise and Education of Catalan Government for providing support through the PhD Industrial Fellowship (2018 DI 77) in collaboration with Smart Engineering Ltd., Peer Reviewed, Postprint (published version)

This study aimed to investigate the recycling opportunities for industrial byproducts and their contribution to innovative concrete manufacturing processes. The attention was mainly focused on municipal solid waste incineration fly ash (MSWI-FA) and its employment, after a washing pre-treatment, as the main component in artificially manufactured aggregates containing cement and ground granulated blast furnace slag (GGBFS) in different percentages. The produced aggregates were used to produce lightweight concrete (LWC) containing both artificial aggregates only and artificial aggregates mixed with a relatively small percentage of recycled polyethylene terephthalate (PET) in the sand form. Thereby, the possibility of producing concrete with good mechanical properties and enhanced thermal properties was investigated through effective PET reuse with beneficial impacts on the thermal insulation of structures. Based on the obtained results, the samples containing artificial aggregates had lower compressive strength (up to 30%) but better thermal performance (up to 25%) with respect to the reference sample made from natural aggregates. Moreover, substituting 10% of recycled aggregates with PET led to a greater reduction in resistance while improving the thermal conductivity. This type of concrete could improve the economic and environmental aspects by incorporating industrial wastes—mainly fly ash—thereby lowering the use of cement, which would lead to a reduction in CO2 emissions., Peer Reviewed, Postprint (published version)

Within the building construction sector, fiber cement boards have attracted interest as facade cladding materials in the last ten years, especially those that incorporate –for reinforcing purposes– natural and/or recycled synthetic fibers (i.e, from the textile industry). So far, the design-governing parameters of facade cladding panels have been mechanical strength, durability, constructability, aesthetics, insulation capacity, and fire resistance. From the sustainability perspective, the impact of the facade on the economic and energy efficiency performance is most often the parameter that leads the decision-making process. Within this context, the quantification of the sustainability performance of the facade –accounting for economic, environmental, and social indicators– is unfrequently carried out in design and project phases, this being attributed to the lack of methodologies that allow considering and quantifying some relevant indicators representative of the facade sustainability performance. As consequence, decisions made based on solely economic and on some of the environmental indicators might lead to solutions with lower sustainability performance than that required (or expected). Recycled textile waste fabric-reinforced cement board as a facade-cladding material for building envelopes is the focus of this research. In order to characterize the fire resistance, and thermal and acoustic insulation –as relevant serviceability parameters– of this material, an experimental program was carried out. Likewise, the sustainability performance of this facade-cladding is assessed through a method based on the Integrated Value Model for Sustainability Assessment (MIVES). This multi-criteria decision making (MCDM) model relies on the value function concept and the multi-disciplinary participation of experts to identify and quantify the relevant indicators of the facade sustainability performance and the relative importance of indicators and requirements. The MIVES-ba, The authors express their gratitude to the Spanish Ministry of Economy, Industry, and Competitiveness for the financial support received under the scope of the projects CREEF (PID2019-108978RB-C32) and RECYBUILDMAT (PID2019-108067RB-I00)., Peer Reviewed, Postprint (published version)

Large amounts of nonrenewable resources are depleted by the construction industry in addition to the generation of million tons of mineral waste and carbon dioxide gas every year. For the sake of a more sustainable consumption pattern of building materials, as well as for reducing the waste flux to landfills, the use of recycled materials and wastes should be researched and motivated. One of the promising wastes is textile waste from residues of the garments and textile industries. The recycling and reusing of textile waste would be beneficial for reducing CO2 emissions and energy intake. In this sense, there are already some studies regarding the thermal behavior of this type of material, however, the engineering design properties of textile waste fiber reinforced cement composites to identify the proper application have not been deeply investigated. Hence, the objective of this study was to evaluate the potentiality of using textile waste fiber as reinforcement in the cement paste. To this end, the composites with three different treatments were made and the optimum treatment was chosen based on the flexural test. The result is the feasibility of using this kind of fiber as reinforcement of mortar elements with dewatering treatment., This work was supported by the Spanish Government, Ministerio de Ciencia e Innovación [grant number PID2019-108067RB-I00]., Objectius de Desenvolupament Sostenible::12 - Producció i Consum Responsables, Postprint (published version)

Fiber reinforced mortars (FRM) are growingly used in several fields of building technology (e.g., façade panels, roofing, raised floors and masonry structures) as building elements. One of the promising type of fiber for these composite materials can be textile waste originated from cloth wastes. The use of this sort of recycled materials and wastes as cement reinforcement within the building sector can play a relevant role in sustainability, both the environmental, economic and social perspectives. In this paper, the design mechanical properties (flexural and compressive strengths at 7, 28 and 56 days as well as toughness and stiffness) together with durability properties of cement pastes reinforced with short Textile Waste Fiber (TWF) in contents ranging from 6 to 10 % by weight fraction cement was investigated. The results were compared with those obtained from Kraft Pulp pine Fiber (KPF), taken as reference. The main conclusion is the feasibility of using this type of fiber as potential reinforcement in construction materials with the optimum dosage of 8%. Although the flexural resistance and toughness of the TWF composite are lower than KPF control by almost 9%, the compressive strength and stiffness together with durability properties have proven to be enhanced respect to the reference composite., The authors express their gratitude to the Spanish Ministry of Economy, Industry and Competitiveness for the financial support received under the scope of the projects RECYBUILDMAT (PID2019-108067RB-I00) and CREEF (PID2019-108978RB-C32)., Peer Reviewed, Postprint (published version)

Currently, millions of tons of textile waste from the garment and textile industries are generated worldwide each year. As a promising option in terms of sustainability, textile waste fibers could be used as internal reinforcement of cement-based composites by enhancing ductility and decreasing crack propagation. To this end, two extensive experimental programs were carried out, involving the use of either fractions of short random fibers at 6–10% by weight or nonwoven fabrics in 3–7 laminate layers in the textile waste-reinforcement of cement, and the mechanical and durability properties of the resulting composites were characterized. Flexural resistance in pre- and post-crack, toughness, and stiffness of the resulting composites were assessed in addition to unrestrained drying shrinkage testing. The results obtained from those programs were analyzed and compared to identify the optimal composite and potential applications. Based on the results of experimental analysis, the feasibility of using this textile waste composite as a potential construction material in nonstructural concrete structures such as facade cladding, raised floors, and pavements was confirmed. The optimal composite was proven to be the one reinforced with six layers of nonwoven fabric, with a flexural strength of 15.5 MPa and a toughness of 9.7 kJ/m2., This research was funded by the Spanish Ministry of Economy, Industry, and Competitiveness, RECYBUILDMAT (PID2019-108067RB-I00) and CREEF (PID2019-108978RB-C32)., Peer Reviewed, Objectius de Desenvolupament Sostenible::12 - Producció i Consum Responsables, Postprint (published version)

Large amounts of nonrenewable resources are depleted by the construction industry in addition to the generation of million tons of mineral waste and carbon dioxide gas every year. For the sake of a more sustainable consumption pattern of building materials, as well as for reducing the waste flux to landfills, the use of recycled materials and wastes should be researched and motivated. In this sense, textile waste (TW) nonwoven fabric from residues of the garments and textile industries are investigated as internal reinforcement for cement-based matrices to enhance ductility and cracking control. To this end, an extensive experimental program was carried out to characterize both the mechanical and durability properties of the composite. The results were compared with those obtained from flax nonwoven fabric, taken as a reference (FNH and FH composites). All the composites showed a remarkable improvement in terms of toughness and post-cracking stress-bearing capacity, six being the optimum number of TW reinforcing layers. Through the analysis of the results obtained, the feasibility of using TW composite as a potential construction material in non-structural applications was confirmed. The extension to structural applications of low-medium responsibility is still required further research; nonetheless, the results are promising to this respect., The authors express their gratitude to the Spanish Ministry of Economy, Industry and Competitiveness for the financial support received under the scope of the projects RECYBUILDMAT (PID2019-108067RB-I00) and CREEF (PID2019-108978RB-C32)., Peer Reviewed, Postprint (author's final draft)