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![Figure 4: Impact strength test setup [17]](profile/Federico-Antico-2/publication/344966847/figure/fig2/AS:952164981694467@1604025230461/Impact-strength-test-setup-17_Q320.jpg)
Adobe is an earthen-based material that consists of the use of a clayey soil and, most of the times, straw fibres to manufacture blocks that are afterwards sundried. This study reviews the use of three types of fibres: vegetal, industrial and animal, for the manufacture of adobe blocks. Overall, all the fibres increase at least one order of magnitu...
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Context 1
... impact strength test setup used in this study (Figure 4), consists of a projectile released from a specific height that impacts to the centre of a specimen, as suggested by ARAYA-LETELIER et al. [17,28]. The values obtained from the impact strength test can be considered as an indirect measure of the material toughness [27,29,30]. ...
Context 2
... evaluate the impact strength, the number of blows needed to fracture the specimen was counted, calculating the fracture energy with Equation 5. Three specimens were tested for each adobe mixture. (5) where I e is the impact energy at fracture, n is the number of times the projectile was thrown, m is the mass of the projectile (0.047 kg), g is the gravitational constant and h (496 mm) is the height of the drop (Figure 4). [17,26,31,32]. ...
Citations
... In view of the above, it is clear the large availability of wastes or low-value by-products from animal sources [11,14,18,20]. According to literature [8,9,13,17,19,[22][23][24][25] one of the main interests to study these natural sources has led to their use as animal reinforcing fibers in composite materials, which can be specifically composite CMs. It is worth noticing that there are other wastes or low-value by-products (e.g., oyster shell waste [26]) from industries such as the fishing industry that have been used into CMs as fillers and/or supplementary cementitious materials, but not as fibers. ...
Although natural fibers (NFs), among which animal fibers (AFs) are found, have been used for millennia as reinforcement scheme of some construction materials (CMs), it is not until recent decades when scientific studies have been carried out to quantitively evaluate the impact of adding NFs into CMs, but with a special focus on vegetal fibers (VFs) over AFs. Nevertheless, there have been several studies addressing the use of AFs in different CMs and, therefore, the need of a systematic review study is evident. To contribute to this research gap, this paper presents a comprehensive review study addressing available scientific information of different types of AFs (e.g., sheep wool fibers (SWFs), chicken feathers fibers (CFFs), human hair fibers (HHFs), pig hair fibers (PHFs), silk fibers (SFs), and dog hair fibers (DHFs)) and also their use in four specific different CMs matrices (i.e., cementitious, gypsum, soil and polymer matrices). This comprehensive search was conducted in Web of Science and Science Direct, two of the largest and more prestigious scientific databases, using specific keywords and Boolean operators and the selection of the papers was based on the provision of enough quantitative information of the mixtures (e.g., specific characteristic and dosages of AFs and matrix used) as well as experimental findings. As a result of this study, organized, summarized and sufficient information is provided to support the positive use of AF as reinforcement scheme to improve some physical/thermal/mechanical/damage/durability properties of CMs by taking advantage of the abundance of these resources worldwide. Moreover, the use of AFs might also provide environmental benefits and cost reductions, which are global objectives within the construction sector. Finally, this review study found that there are still several research gaps in the use of particular AFs (e.g., DHFs) as well as combinations between the AFs and the CMs addressed in this study (e.g., effects of PHFs in polymer matrices) and these gaps are recommended as future studies.
... La forma de estos bloques es variada y depende de la matriz empleada durante su fabricación, pudiendo ser macizos, huecos o encastrables.Existen numerosas publicaciones y líneas de investigación específicas sobre las tecnologías de BTC y adobes(Cabrera, 2022;Costantini Romero et al., 2021;Turco et al., 2021), siendo de particular interés para este trabajo aquellas abocadas el estudio de las propiedades físicas, químicas y mecánicas de mampuestos de tierra producidos con residuos industriales. En lo que respecta a la fabricación de adobes, pueden destacarse los estudios realizados sobre la utilización de residuos molidos de la industria ladrillera y la agroindustria de la yuca(Kumanan & Sofi, 2023), residuos de plantas de tratamientos de efluentes cloacales(Minh Trang et al., 2021), residuos de polímeros reforzados con fibra de vidrio(Gandia et al., 2019) y residuos de la industria porcina(Concha-Riedel et al., 2020). En lo que respecta a la producción de BTC con residuos industriales, se enfatizan las investigaciones realizadas sobre el empleo de materiales de descarte generado en canteras de áridos(Flament, 2012), residuos producidos por la industria petrolera(Khalifa et al., 2021), escombros generados durante la demolición de edificios(Malkanthi et al., 2021) y residuos de la minería de hierro(Nagaraj & Shreyasvi, 2017); como aquellas investigaciones abocadas al estudio de la estabilización de BTC con residuos de la industria ladrillera(Bediako, 2018;Cabrera et al., 2022), azucarera(Lima et al., 2012), arrocera(Laguna, 2011) ...
En este trabajo se evalúa la factibilidad de emplear la arena y arcilla residuales generados por la minería de arena para fabricar bloques de tierra comprimida (BTC) y adobes.Para ello, se caracterizaron los subproductos generados por una mina en la provincia de Río Negro (Argentina) y se confeccionaron diferentes series de probetas, determinando su retracción por secado, densidad seca, resistencia a compresión y resistencia a erosión húmeda. Los resultados indican que, con una dosificación en peso de 74.25% arcilla, 24.75% arena y un 1% de paja, pueden producirse adobes portantes con una resistencia a compresión de 18.63 kgf/cm2, mientras que, empleando una dosificación de 71.3% de arcilla, 23.7% arena y 5% de cemento Portland, pueden producirse BTC con una resistencia a compresión superior a 30 kgf/cm2 y una elevada resistencia a la erosión húmeda, aptos para emplearse en la construcción de muros de carga y muros exteriores sin revoque.
... Specifically, the use of natural fibers, both vegetal and (to a lesser extent) animal fibers, on EBCMs has attracted more research attention than the implementation of synthetic fibers [7,17,18], mainly due to the higher cost and environmental impacts associated to the production of synthetic fibers [19]. However, since synthetic fibers are more standardized and often exhibit a superior technical performance when compared to natural fibers, detailed studies assessing the use of different synthetic fibers into EBCMs have been performed, especially monofilament micro polypropylene fibers (MPFs). ...
This study assesses the feasibility of the incorporation of fibrillated polypropylene fibers (FPFs), an engineered multidimensional and multifilament fiber mostly used to reinforce concrete mixtures, into adobe mixtures (AMs), a traditional and manually-made material used to produce adobe blocks. The incorporation of FPFs was assessed using increasing dosages (0%, 0.25%, 0.5%, and 1% in wt% of clay soil) of FPFs. These fibers were gradually added and mixed with the clayey soil prior to incorporation of water to promote uniform mixtures with adequate fiber distribution to reduce the formation of fiber clusters. The impact of FPFs was evaluated in terms of its effects on the bulk density (physical), compressive and flexural strength (mechanical), flexural toughness indices (fracture) and water erosion resistance (durability) of AMs. Results indicate that increasing dosages of FPFs monotonically reduce average values of bulk density, as well as compressive and flexural strength of AMs. On the other hand, these increasing dosages of FPFs monotonically increase average values of water erosion resistance as well as flexural toughness indices, varying the flexural failure mode from brittle (unreinforced AM) to ductile (reinforced AMs) because of the adequate bonding and FPF-bridging effect after the crack generation as confirmed by instrumentation as well as digital image correlation evaluations implemented in this study. The significant reductions of bulk densities and compressive and flexural strengths obtained for fiber-reinforced AMs were related to the increasing number of fiber clusters found for increasing dosages of FPFs within the fiber-reinforced mixtures, which was evaluated using scanning electron microscopy analyses. For example, positively the AM incorporating 1% of FPFs increased, on average, the flexural toughness by 674% and reduced the bulk density and water erosion depth by, on average, 9% and 64%, respectively, when compared to the unreinforced AM. However, this large dosage of FPFs also generated a significant reduction of the compressive strength (60% on average) and the flexural strength (43% on average) when compared to the plain mixture. On the other hand, a small dosage of FPFs (0.25%) generated less significant improvements in terms of flexural toughness, bulk density, and water erosion (on average, increment of 58% and reductions of 2% and of 38%, respectively, when compared to the unreinforced AM). Yet, the latter mixture presented reductions, on average, of compressive and flexural strengths of 24% and 16%, respectively, when compared to the plain mixture, and these reductions were significantly smaller than the reductions obtained by the largest FPF dosage, due to the significantly smaller number of fiber clusters presented by the 0.25% dosage when compared to the 1% dosage. Finally, the mechanical performance limitations exhibited by the incorporation of FPFs, especially in large dosages, are related to generated fiber clusters due to the inherent morphology of these FPFs as well as the traditional manual confection process of AMs. Therefore, this study recommends the implementation of FPFs in AMs, but in small dosages and/or suggests the implementation of a mechanical mixing/compaction process that guarantee a more uniform fiber distribution that reduces the generation of fiber clusters.
... This soil was previously used by a construction company that specializes in the restoration of heritage earthen buildings in Chile. Araya-Letelier et al. [37][38][39][40] used this soil to address the mechanical strength of reinforced adobe blocks. To measure the particle size distribution of the soil used in this work, a sieve analysis was performed in accordance with ASTM D 6913/D 6913 M [41], which can be seen in Fig. 1 (black dashed-dotted line and square symbols). ...
Earthen construction represents almost 30% of the housing in developing countries, partially because of its low cost compared to steel and concrete construction, and also because the raw materials are available almost everywhere. One of the biggest disadvantages of earthen materials is the lack of information and variety on their constitutive materials, specifically their soil type. This work addresses the physical and mechanical properties of adobe matrices containing different concentrations of kaolin, which is a specific type of clay, as well as different proportions of fine particles of the original soil of the adobe matrix. All adobe matrices were manufactured with a SM-SC soil obtained from Santiago, Chile, and had concentrations of 0, 10, 30, and 50% of kaolin and 0, 10, 20, and 30% fines of the original soil content. It is concluded that the compressive strength of the studied earthen mixtures improves when kaolin is added to the mixture. The shrinkage of adobe matrices with kaolin compared to plain adobe matrices was reduced during the first days of age and stayed stable after that. This work shows that the inclusion of fines from the original soil (other than kaolin) did not significantly affect any of the studied properties. It also shows that the Unified Soil Classification System is not sufficient to characterize soils for adobe matrices.
... Initially, a calibration of the dimensions of the unloaded specimen is required to capture the displacements of the specimens and during the tests images were taken every 4 s over the specimens painted with a white background over which a random black paint pattern was generated (speckle pattern) as shown in Fig. 4. Then, images were analyzed using MATLAB Ò [56] and the Ncorr 2D-DIC toolbox [57] to estimate displacement and strain values, complementing the LVDT measurements, and to observe the failure modes as previously reported [26]. ...
Due to their sustainability as well as physical and mechanical performance, different natural fibers, both vegetal and animal fibers, have been successfully used in adobe mixtures (AMs) to enhance properties such as cracking control, flexural toughness and water erosion resistance, among others. However, the use of jute fibers (JFs), one of the most largely produced vegetal fiber worldwide, has not been extensively studied on AMs. Consequently, this study evaluates the effects of the incorporation of varying dosages
(0.5 and 2.0 wt%) and lengths (7, 15, and 30 mm) of JFs on the physical/thermal/mechanical/fracture and durability performance of AMs, a specific type of earth-based construction material widely used globally. Experimental results showed that the incorporation of 2.0 wt% dosages of JFs increased the capillary water absorption of AMs, which might affect AM durability. The latter result could be explained by the additional porosity generated by the spaces left between the JFs and the matrix of adobe, as well as the inherent water absorption of the JFs. The incorporation of JFs significantly improved the behavior of AMs in terms of thermal conductivity, drying shrinkage cracking control, flexural toughness and water erosion performance, without affecting their compressive and flexural strength. For example, flexural toughness indices were increased by 297% and crack density ratio as well as water erosion depth values
were reduced by 93% and 62%, respectively, when 2.0 wt%-15 mm length JFs were incorporated into AM. Since the latter combination of JF dosage and length provided the overall best results among AMs, it is recommended by this study as JF-reinforcement scheme for AMs for construction applications such as adobe masonry and earth plasters.
... As mentioned by previous studies (e.g., [58][59][60][61]), the fracture toughness of composite materials, including earthen mixes, can be modified due to fiber-reinforcement and the impact strength test has been suggested as a way of measuring this damage-absorption capacity. This research implemented a setup consisting of beam specimens supported at two points by a metallic base (20 cm distance between supports) and a metallic projectile was thrown at the midspan of the beam specimens at increasing heights (see Figure 6). ...
The poultry industry, highly prevalent worldwide, generates approximately 7.7 × 10 6 metric tons of chicken feathers (CFs), which become a major environmental challenge due to their disposal when considered waste or due to their energy transformation consumption when considered by-products. CFs are mainly composed of keratin (approximately 90%), which is one of the most important biopolymers whose inherent characteristics make CFs suitable as biopolymer fibers (BPFs). This paper first assesses the morphological and chemical characteristics of these BPFs, through scanning electron microscopy and energy dispersive X-ray spectroscopy, and then evaluates the waste valorization of these BPFs as a sustainable alternative for fiber-reinforcement of earthen mixes intended for earthen construction, such as adobe masonry, rammed earth, and earthen plasters. In particular, four earthen mixes with increasing doses of BPFs (i.e., 0%, 0.25%, 0.5%, and 1% of BPFs by weight of soil) were developed to evaluate the impact of BPF-reinforcement on the capillary, mechanical, impact, and abrasion performance of these earthen mixes. The addition of BPFs did not significantly affect the mechanical performance of earthen mixes, and their incorporation had a statistically significant positive effect on the impact performance and abrasion resistance of earthen mixes as the BPF dose increased. On the other hand, the addition of BPFs increased the capillary water absorption rate, possibly due to a detected increment in porosity, which might reduce the durability of water-exposed BPF-reinforced earthen mixes, but a statistically significant increment only occurred when the highest BPF dose was used (1%).
El presente estudio se evaluó el comportamiento de la adición de fibra de maguey y cal hidratada con el objetivo de mejorar las propiedades físico-mecánicas del adobe para viviendas rurales, asimismo, el estudio es de naturaleza aplicada y diseñada experimentalmente, como objetivos específicos se evaluó las propiedades de variación dimensional, compresión por unidad de albañilería, axial y diagonal, de los cuales, se examinó el efecto de las siguientes dosificaciones: 0.30% Paja que corresponde a la muestra patrón y los tres grupos experimentales con adiciones de Fibra de Maguey (FM) y Cal Hidratada (CH) en proporciones de 0.75% FM + 1.80% CH, 1.15% FM + 1.80% CH y 1.30% FM + 1.80% CH. Se desarrollo en dos etapas; primero se evaluó caracterización y extracción de los materiales para la elaboración del adobe y en la segunda etapa se realizaron los ensayos de variación dimensional y resistencia a compresión. En base a los resultados obtenidos se concluyo que existe incidencia significativa en las propiedades del adobe al adicionar la Fibra de Maguey y Cal Hidratada.
A mechanical and physicochemical characterisation of soil used for adobe block production is presented in this paper, considering a geomechanical framework. The main research objectives were to apply the partially saturated soil mechanics theory and obtain some of the soil's physicochemical characteristics. The soil used in this research was extracted from Putaendo, Chile, as it is representative of the vernacular building of that region. The soil was classified as silty sand, of low plasticity. Further inspection showed a 7% content of organic matter. The unsaturated shear strength of the soil was obtained using a conventional shear box test, coupled with the soil–water characteristic curve (which was obtained using the filter paper technique) to estimate suction values. The soil–water characteristic curve had a similar shape as for other sands previously reported in the literature, but with a higher air entry and residual values. Results show that shear strength increases for drier soil samples, reaching an asymptotic value after the air entry suction of the soil. It is concluded that shear box tests without suction control can be used to estimate the unsaturated strength of soils and that the organic matter in soils can influence its cohesive strength, although further research on this aspect is required.
The strength characteristics of the sand and gravel are influenced by the size of the grains, their distribution and packaging. The theoretical approach states that the sand angle of internal friction decreases if the uniformity coefficient increases. There are insufficient data for gravel correlation between the uniformity coefficient and the angle of internal friction. Consolidated drained triaxial compression tests (CD) were conducted to determine the strength parameters of remolded sand and gravel samples. These samples were classified as sands and gravels. The optimal water content and density were determined by standard Proctor compaction test and used for these samples. Consolidated drained triaxial compression test gives more reliable data that idealize the soil behavior in the real situation. Three different confining pressures of 20, 50 and 70 kPa were applied to restore horizontal stresses for the soil specimens imitating embankment behavior affected with traffic load. The results indicate that the sand angle of internal friction decreases if the uniformity coefficient is increased. The gravel angle of internal friction does not correlate with the uniformity coefficient.
