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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-based model generated for this research can be straightforwardly used for assessing the sustainability performance of facade-cladding techniques made of any material and for any type of building (and location). The application of the MIVES model led to the sustainability index of this new material for facade-cladding ranging from 0.68 to 0.71 (/1.00) for different weighting scenarios. 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).

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).

The thermal and fire behaviour of calcium aluminate cement-based composites with a variable metakaolin content (from 0 to 40 wt% addition) reinforced with nonwoven flax fabrics has been examined. The fire behaviour was assessed using epiradiator and small-scale fire testing. The composites did not emit smoke or generate flames, nor did they produce spalling. Their integrity was maintained above 1000 ¿C. Samples having a higher metakaolin content revealed a delay in the temperature of the unexposed surface until reaching 760 ¿C. The effect of exposure to high temperatures (250 ¿C, 450 ¿C, and 950 ¿C) on bending behaviour was examined. The fibres were found to maintain their reinforcing capacity up to 250 ¿C, while the matrix maintained its performance up to 450 ¿C. The addition of metakaolin reduced conductivity and diffusivity. The results of the thermal and fire behaviour of the tested composites indicated that they may be suitable for façade panels for outdoor applications Objectius de Desenvolupament Sostenible::12 - Producció i Consum Responsables

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).

The aim of this work was to develop strain hardening cementitious composites (SHCC) and durable composites based on calcium-aluminate cement (CAC) with variable metakaolin (MK) content (from 0 to 50 wt%) and flax nonwoven natural textile reinforcement. For this purpose, three experimental packages were performed in order to: a) evaluate the effect of MK content on the mechanical performance and cement mixture microstructure of the matrix, b) analyze the effect of the cement mixture on the performance of the natural fibers, and c) determine the bending behavior and durability of the composites. It was found that the strength and modulus of the 28 days cured cement paste under compression and bending modes decreased with MK content. Low degradation of the natural fibers on the CAC-MK matrix was found and this degradation was lower for higher MK content. The developed composites presented a ductile behavior and high tensile strength and maintained this performance after subjecting them to a 250 cycles of accelerated aging. The authors acknowledge Prof. Claret Verdú and Prof. Maite Más from the DEAB-UPC for their help on the statistical analysis of the results in this study. This work was supported by the Ministerio de Economía, Industria y Competitividad (MINECO) of the Government of Spain [project BIA2014-59399-R]. The author Heura Ventura is a Serra Húnter Fellow

Nowadays, the most used construction solutions for building envelopes are “ventilated facade” systems, which have continuity between the thermic and impermeable envelopes, avoiding thermal bridges and consequently avoiding energy loss and the presence of water vapor condensation. The sheets or panels of this envelope system should fulfill certain requirements such as strength, flexibility, ductility, lightness, permeability, thermal insulation, and durability. In this sense, it is of practical importance to develop new materials with the maximum characteristics aforementioned, primarily strength, ductility, flexibility, and durability, using environmentally friendly and low-cost raw materials and processes. Over the last few years, many interesting works have been published describing the use of natural fibers as reinforcements for cement matrix composites. These fiber–cement composites exhibit improved toughness, ductility, flexural strength, and crack resistance. Nonetheless, in most of the research done the fibers are used in pulp or staple forms, limiting the improvement of the flexural strength and ductility of the composites due to the short length of the fibers and the maximum content that it is possible to mix with the cement matrix (around 4–8 wt.%). One possible solution to overcome these problems is the incorporation of the fibers in the form of textile structures, such as nonwovens. However, as far as we know, the incorporation of textile structures made of vegetable fibers in the form of nonwovens on cement-based matrix has been scarcely reported. This chapter focuses on the processing and characterization of high-performance cement-based composites reinforced with nonwoven flax fabrics intended for application in sheets for ventilated facades.

Layered double hydroxides (LDHs) are lamellar inorganic solids with a brucite-like structure similar to hydrotalcite, where the partial substitution of trivalent for divalent cations results in a positive sheet charge, compensated by anions situated in the interlayer galleries. Their layered structure enables the intercalation of polymer macromolecules, in some cases resulting in the exfoliation of their sheets, and hence in the formation of polymer nanocomposites. This chapter reviews the state-of-the-art preparation of hybrid LDHs and incorporation into polymers, the structure of these nanocomposites and the resulting properties: rheological, mechanical, and thermal. Particular attention is given to their possible applications and future trends.

The stiffness of a material has high impact when its industrial use is considered. Moreover, this property has interest in the case of short fiber reinforced materials due to its dependence on the orientation of the fibers against the loads. Due to nowadays-environmental concerns, greener alternatives to oil-based composites are under study and development showing some promising results. In this work, a polyamide 11 reinforced with lignocellulosic fiber composite is evaluated as such sustainable alternative. Previous works showed the suitability of PA11-based composites to replace glass fiber reinforced polypropylene. Nonetheless, there is a lack of information about the flexural modulus behavior of these composites. This is of interest because, under some conditions, flexural modulus is more representative of a material behavior than Young's modulus. The flexural moduli of these composites were analyzed under a three point bending test and the results were evaluated from macro and micromechanical points of view. The increment of the modulus with the fiber contents implied a good dispersion of the reinforcements. Nonetheless, the results were lower than those observed for the tensile modulus. This was unexpected due to the anisotropy of the bending test. The micromechanics analysis showed a lower performance of the fiber during the flexural test. These lower results were related with a non-optimal interface or with the non-adequate compression of the fibers. Additionally, the calculus of the void volume showed low void contents.

Textile industry produces a high amount of residues that, nowadays, are poorly managed. The majority of such wastes are dumped and landfilled. Among all the textile value chain, cotton yarning factories produce wastes in the shape of fiber flocks, with lengths smaller than 10 mm that prevent their reintroduction in the textiles manufacturing process. Nonetheless, such waste cotton flocks could be used as reinforcement for short fiber mould injected composites. This paper reports on the behavior of the interphase between the cotton flocks and a polypropylene matrix. It was found that the organic dyes present on the cotton flocks seem to affect the quality of the interphase in two ways: on the one hand by increasing the affinity between the cotton fibers and the matrix, and on the other hand by limiting the effect of the coupling agents. Micromechanic models are used to further research the quality of the interphase and the intrinsic properties of the composites.