Search Results (49)

Global interest in sustainable building materials is increasing due to growing concerns regarding the environmental impacts of conventional construction materials, particularly fired clay bricks. Compressed Stabilized Earth Blocks (CSEBs) have emerged as a viable, cost-effective, and environmentally sustainable alternative for building construction. The incorporation of waste-derived additives in CSEBs not only addresses waste management challenges but also enhances the functional performance of earthen materials. This study presents a comprehensive synthesis of existing research on the influence of fibers, binders, stabilizers, and production processes on the performance characteristics of CSEBs. A systematic literature review was conducted following the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) 2020 guidelines, resulting in the identification and analysis of 256 relevant studies. The selected literature was synthesized using the Theories, Contexts, Characteristics, and Methodologies (TCCM) framework to map research trends and methodological approaches. The review indicates that fiber reinforcement primarily improves flexural strength and thermal performance, while binders significantly enhance compressive strength and erosion resistance. The findings also demonstrate that selected waste materials can partially replace natural soil, provided minimum material and performance standards are satisfied. The study highlights the need for standardized manufacturing guidelines and testing protocols to improve the reliability, scalability, and wider adoption of CSEBs in sustainable building applications. Full article

Monosex culture has been shown to enhance farming productivity in several decapod crustaceans, and it has also been suggested that this approach holds high potential for the sustainable aquaculture of the Chinese mitten crab, Eriocheir sinensis. Pronounced sexual dimorphism in E. sinensis facilitates the implementation of a monosex culture. This study aimed to compare the growth, gonadal development, culture performance, and economic outcomes of two monosex culture modes, i.e., an all-female culture and an all-male culture, as well as a mixed-sex culture (males: females = 1:1) during an 8-month growth period in earthen ponds. The results showed that: (1) Throughout the grow-out period, the average body weight in both monosex culture treatments was consistently higher than in the mixed-sex treatment, with a significantly greater body weight in the all-female and all-male treatments than that of males and females in the mixed-sex treatment being detected during mid-June and October, respectively (p < 0.05). (2) The percentages of both sexes that had finished puberty molting were mostly similar between the monosex and mixed-sex treatments between July 20th to October 10th, although the all-female treatment had a significantly lower puberty molting percentage than the mixed-sex treatment on August 10th (p < 0.05). Gonadosomatic index (GSI) values were similar between the monosex and mixed-sex treatments for both males and females (p > 0.05). (3) At harvest period, the final body weight in the all-male treatment was significantly higher than that of the mixed-sex treatment (p < 0.05). In contrast, the all-female treatment exhibited a significantly higher survival rate and a lower limb injury rate compared with the mixed-sex treatment (p < 0.05). As a result, the yield of the all-male and all-female treatments exceeded that of the males and females in the mixed-sex treatment by 24% and 13%, respectively. Additionally, the mixed-sex treatment also had a significantly higher feed conversion ratio (p < 0.05). Finally, the monosex treatments had a higher proportion of large crabs (males ≥ 200 g, females ≥ 175 g) and a lower proportion of small crabs (males ≤ 150 g, females ≤ 100 g) compared to the mixed-sex treatment. (4) In terms of economic benefits, net profit and return on investment (ROI) were highest under the all-female treatment, while the mixed-sex treatment recorded the lowest total return, net profit, and ROI (p < 0.05). In conclusion, an all-female culture is recommended for the grow-out culture period of E. sinensis, as it led to a higher survival rate, produced larger-sized crabs and generated greater overall economic benefit. Full article

Water quality plays a central role in determining the environmental performance of pond-based tropical aquaculture systems. This study aimed to evaluate the relative environmental performance of different tropical pond-based aquaculture systems by identifying multivariate water quality patterns that allow their discrimination and comparison under commercial production conditions. Four pond-based production systems were evaluated: an aquaponic system (APS), a recirculating aquaculture system (RAS), a conventional earthen pond system (CEP), and an integrated rice–chame system (RCS). Fourteen physicochemical water quality variables were monitored throughout the production cycle under real commercial conditions using a comparative observational design. Multivariate discriminant analysis was applied to identify the variables with the highest discriminatory power and evaluate the ability of water quality patterns to correctly classify observations among production systems. The results revealed a clear multivariate separation between technologically intensive systems (APS and RAS) and less intensive and integrated systems (CEP and RCS), reflecting distinct water quality structures and environmental functioning. Variables associated with mineralization and nutrient dynamics, including electrical conductivity, dissolved solids, turbidity, phosphates, chlorides, dissolved oxygen, nitrites, and temperature, contributed most strongly to system discrimination. The discriminant functions achieved a high overall correct classification rate, demonstrating the robustness of the multivariate approach. These findings support the use of water quality variables as consistent environmental signatures for distinguishing tropical pond-based aquaculture systems, providing an operational framework for assessing their relative environmental performance. Discriminant analysis emerges as a valuable tool for system characterization and comparative evaluation, supporting environmentally informed management and optimization of chame aquaculture under tropical conditions. Although water quality represents a robust integrative indicator, it captures only one dimension of environmental performance, and additional factors such as production efficiency, energy use, and effluent characterization should be incorporated in future studies to achieve a comprehensive sustainability assessment. Full article

This paper presents the results of research conducted as part of a bilateral cooperation project between National Research Council (Italy) and Chinese Academy of Cultural Heritage (China) for the conservation of the earthen walls of Ancient Ulanbay City (Xinjiang, China). In 2007 and 2012, conservation interventions were carried out on the remains of the ancient walls, focusing on areas at risk of collapse. This involved the construction of new adobe masonry (sun-dried earthen bricks and mud mortar) to support the ancient rammed-earth walls, which required consolidation treatments due to their exposure to weathering. In order to support the site’s conservation efforts, several nanoproducts were selected for testing as consolidants for the adobe bricks. Nano-silica (NanoEstel) and nano-lime (Calosil E25), with and without ethyl silicate, and a nano-calcium oxalate-functionalized ethyl silicate (SurfaPore FX WB) were tested and compared with commonly used products for surface consolidation. Ethyl silicate was applied alone as a reference treatment. The mixtures tested in this research had not been previously explored, thus offering new opportunities to identify suitable solutions for the consolidation of earthen structures exposed to environmental conditions. In this study, adobe bricks were sampled from the archaeological site, and the effectiveness of each treatment was assessed based on changes in chromatic appearance, cohesion, and water behaviour. The results showed different behaviours of nanoproducts. Nano-silica, alone or especially in combination with ethyl silicate, is overall more effective than nano-lime for the consolidation of earthen materials, thanks to its greater compatibility with these materials. Full article

The degradation of building foundations, underground structures, and historical fabrics in sulfate-laden environments poses a persistent threat to the durability and safety of the built environment. Developing effective, sustainable repair materials is of paramount importance. This study presents the development, systematic optimization, and performance validation of a novel micro-expansive grout designed for high durability in aggressive sulfate conditions. The grout formulation utilizes industrial by-product fly ash, quicklime, and site-compatible soils, emphasizing sustainability. Nine chemical admixtures were screened for sulfate resistance enhancement. Laboratory experiments rigorously characterized the effects of water-to-solid ratio and admixture dosage on fresh-state properties (fluidity, setting time) and hardened-state performance (volumetric stability). To resolve a multi-objective optimization problem balancing injectability, dimensional compatibility, and cost-effectiveness, an integrated multi-criteria decision-making (MCDM) framework combining FAHP, MII, CRITIC, and TOPSIS was employed. This data-driven methodology identified an optimal formulation incorporating 3% disodium hydrogen phosphate (DSP) at a 0.58 water-to-solid ratio. The optimized grout exhibited a flow value of 75 mm, ensuring excellent injectability within the target range (40–120 mm), and an expansion rate of 7.67%, which falls within the safe range (0%–10%) to ensure dimensional compatibility. Accelerated durability tests via cyclic immersion in sodium sulfate solution demonstrated the optimized grout’s exceptional resistance to sulfate attack, retaining approximately 88% of its compressive strength after 15 aggressive cycles. The balanced properties and validated durability indicate strong potential for this grout in demanding repair scenarios. One key example is the repair of fissures in earthen heritage structures, which requires extreme material compatibility and long-term performance. Full article

Estuarine organisms experience frequent fluctuations in salinity and temperature, facing major challenges to their physiological homeostasis. Such variability can promote high energetic costs for osmoregulation, potentially reducing tolerance to additional stressors. We investigated the effect of salinity on the thermal tolerance of the estuarine amphipod Melita palmata (Montagu, 1804), a species of growing interest for aquaculture, either as live feed or as a potential source for essential fatty acids in formulated diets. The critical thermal maximum (CTmax) was determined for males and females collected from three sites within a temperate coastal lagoon (Ria de Aveiro, Portugal) characterized by different salinity regimes (15, 20, and 30). Individuals from lower-salinity environments exhibited significantly lower CTmax values than those from higher salinities, indicating that osmoregulatory costs may restrict thermal resistance. No significant sex-based differences in CTmax were detected. However, thermal safety margins (TSMs) increased with salinity, indicating greater thermal tolerance under higher salinity conditions, and differences in body condition index (BCI) between sites suggest salinity-related effects on growth performance. These results highlight that the elevated energetic demands of osmoregulation under hypo-osmotic conditions can constrain the thermal limits of M. palmata, underscoring the complex trade-offs between environmental variability and physiological performance in estuarine habitats. Beyond its ecological implications, understanding the physiological responses of M. palmata to salinity and temperature is key, optimising its use in aquaculture. The species’ physiological plasticity under such variable conditions reinforces its suitability for aquaculture production, particularly in earthen ponds in estuarine environments. Full article

The global demand for compost, produced through the bioconversion of organic waste into nutrient-rich soil amendments, is increasing due to the adverse environmental, health, and economic impacts of synthetic fertilizers. Compost use offers a cost-effective and sustainable alternative, improving soil fertility and long-term productivity. However, the potential of tobacco waste as a composting substrate remains insufficiently investigated. This study aimed to evaluate the feasibility of utilizing tobacco waste as a composting feedstock and to develop an optimized composting method. Tobacco waste (scrap leaves and midrib stems) was composted with cow manure in earthen pots to promote decomposition and nutrient mineralization, and its performance was compared with compost produced from cow manure and vegetable waste (vegetable leaves). Vermicomposting, which involves the addition of earthworms to conventional compost treatments, was also implemented to enhance composting efficiency and nutrient release. The final composts, both conventional and vermicompost, were analyzed for organic carbon (OC), nitrogen (N), phosphorus (P), potassium (K), sulfur (S), and the maturity duration. Among the three conventional compost variants, the mixture of cow manure and tobacco leaves had the highest nitrogen concentration at 1.45% and the cow manure and tobacco stems had 1.23% as the second best. Cow manure and tobacco stem compost had the highest K content of 1.13%, followed by tobacco leaves (0.99%). Sulfur levels were also found to be higher in the tobacco stem compost compared to the other compost types, with the highest value of 0.56%, followed by tobacco leaves (0.23%). All three vermicompost variants outperformed their conventional counterparts in terms of nutrient concentrations and achieved maturity in shorter durations. The cow manure with tobacco stem mixed vermicompost was notable for its elevated potassium (1.35%) and sulfur (0.89%) contents. The results indicate that vermicomposting offers a faster and more nutrient-enriched composting approach, particularly with tobacco waste. Incorporating tobacco waste into this process has the potential to produce high-quality compost, presenting a sustainable strategy for waste valorization and enhancing soil fertility. Full article

This study examines the main earthen constructions—such as adobe, compressed earth blocks (CEBs), and rammed earth walls (REWs)—highlighting their potential to reduce the environmental impact compared to conventional materials. Through a systematic literature review (2013–2024) and a meta-analysis, the mechanical, thermal, and sustainability properties of these constructions are analyzed. Emphasis is placed on the use of additives, such as stabilizers and fibers from various industrial and agro-industrial by-products, as leading actors influencing the mechanical and environmental performance of earthen constructions (EnCs). Remarkable improvements in the compressive and flexural strength are found, especially in stabilized CEBs and REWs, where strengths of up to 24 MPa are reached in certain mixtures, comparable to conventional materials such as concrete. However, the impact of these admixtures on environmental aspects, as measured through metrics such as the global warming potential (GWP), remains poorly documented. This review also shows that numerical methods like finite element modeling (FEM) have been crucial to modeling and predicting the performance of these materials, contributing to the understanding of their dynamic and structural responses. The findings suggest that, although CEB is currently the most studied onshore technique, future challenges include the standardization of admixtures and regulation of sustainable practices globally. Full article

Traditional bricks are still the most widely used building material in Madagascar. Bricks are made from clay that is fired for weeks in open-air kilns (600–750 °C) by using rice husks, peat, charcoal, coal, and wood as fuels. This process contributes significantly to environmental pollution by emitting CO₂ and particles. In addition, the intensive use of wood and charcoal is partly responsible for the deforestation that still taking place on the “Red Island”. The development of sustainable building materials is therefore of global interest. This research provided a solution by implementing the oxyacetic acid derivative of cashew nut shell liquid (CNSL) as a binder to reduce energy consumption in the preparation of earthen materials. This product was obtained from cashew nut waste and was used in a proportion of 5 to 15% with the red soil of Madagascar. The materials were formulated at a much lower temperature (60 °C) compared to the traditional process for 24 to 48 hours in a custom-designed mold. The material with 10% oxyacetic binder from CNSL was a compact, hard solid with higher mechanical properties, including a twice higher compressive strength (5.6 MPa compared to 2.2 MPa) and a higher tensile strength (2.2 MPa compared to 1.6 MPa). This material also had better water resistance after 2 months of immersion; traditional clay bricks absorbed 36.65% of the water, and the material with binder only absorbed 12.62%. This research demonstrates that the utilization of local agricultural waste as a binder is a viable strategy for reducing the carbon footprint of traditional building materials while significantly improving their physico-mechanical properties. Full article

The aquaculture sector is developing sustainability measures to address resource limitations and environmental concerns. A key strategy is replacing fishmeal and fish oil with alternatives that can equally sustain fish health, growth, and water quality. This study compared a standard diet (STD) to an alternative diet (ALT) containing sustainable ingredients, such as plant-based proteins and animal by-products, for meagre raised in earthen ponds within a polyculture system. Over 150 days, 5400 meagre juveniles (174.9 ± 32.8 g) were fed these diets. Fish on the ALT diet showed superior growth, likely due to higher dietary protein content and reduced protein degradation in liver and muscle, leading to increased protein content and reduced levels of dry matter, lipid, ash, energy, and phosphorous. While muscle cohesiveness was affected, fiber area and density were unchanged. ALT-fed fish exhibited higher saturated (SFA) and polyunsaturated (PUFA) fatty acids, reflecting the diet. Water quality indicators, including ammonia, nitrites, nitrates, and phosphates, were similar across diets, though chlorophyll a was higher in ponds with STD-fed fish. Overall, the ALT diet emerges as a sustainable alternative to the STD diet, maintaining or enhancing protein levels while reducing fishmeal usage. This approach effectively supports meagre growth and fillet quality without significant additional environmental impact. Full article

Modern construction is largely dependent on steel and concrete, with natural materials such as earth being significantly underutilised. Despite its sustainability and accessibility, earth is not being used to its full potential in developed countries. This study explores innovative building materials using Alhambra Formation soil (Granada, Spain) reinforced with difficult-to-recycle agricultural waste: polypropylene fibres contaminated with organic matter and leachates. Fibres were added at a ratio between 0.20 and 0.80% of the soil mass, leachates at a ratio between 4.25 and 8.50%, and lime was incorporated at 2.00% and 4.00% for specimens with higher residue content. Physico-mechanical properties, including uniaxial compressive strength and longitudinal strain, were analysed together with the microstructure. The results showed that polypropylene fibres, in comparison to the use of leachates, improved compressive strength and ductility, reaching a compressive strength of 1.76 MPa with a fibre content of 0.40%. On the other hand, this value is 7.4% lower than the reference sample without additives. The fibre-reinforced samples showed a higher porosity compared to the samples with leachates or without additives. This approach highlights the potential of agricultural waste for the development of sustainable construction materials, offering enhancements in the strength and ductility of reinforced soils. Full article

This study presents a comprehensive bibliometric analysis of the earthen architecture and construction scientific literature production at present, analysing the historical evolution, research patterns and trends and the investigation of the different existing earthen building technologies. Utilising the SCOPUS database, this study analysed 3804 documents published between 1968 and 2023, with an annual growth of 16.92% since the year 2001. Key findings include the identification of top authors, institutions and collaborative networks, the co-citation analysis and the main keyword analysis and classification into different clusters. Regarding the building technologies, the results indicate a prevalence of research on vernacular earthen building techniques, mainly rammed earth and adobe masonry. Nevertheless, a growing interest in innovative methods using earth-based materials can be spotted. The bibliometric analysis identifies the development of the academic interest and emphasises the importance of interdisciplinary collaboration and the need for international recognition of earthen buildings. Future research should continue to explore the environmental benefits of using earthen materials, the development of earthen building techniques and systems in modern industry and the preservation of the architectural heritage and vernacular knowledge of contemporary technology. Full article

Aquaculture in rural areas, carried out in accordance with current EU requirements, aims to contribute significantly to the conservation of the biodiversity of aquatic resources, the protection of which is a prerequisite for sustainable economic and social development. The objective of this study was to present the conceptual and technical framework and to analyze the costs and profitability of producing the consumer-attractive Eurasian perch (Perca fluviatilis L.) based on the untapped potential of hatchery infrastructure and dedicated earthen ponds for common carp (Cyprinus carpio L.) production. The experiments were conducted under Polish conditions, but the results/methods can be successfully applied in other countries, mainly in Central and Eastern Europe, where production in earthen ponds is the basis of aquaculture production. The analysis of the profitability of the venture shows that the cost structure was dominated by labor and feed inputs. Despite high variable costs, this type of production can be profitable and contribute to food security and economic development in line with the EU’s Blue Growth Strategy. The article also analyzes the potential opportunities and risks of fish production based on the Recirculating Aquaculture System (RAS) and the Recirculating Aquaculture Multitrophic Pond System (RAMPS). Full article

For past societies on the Iberian Peninsula, one of the most prolific architectures was earthen construction, with a wealth of typologies and solutions derived from the legacy of local construction and materials. However, its study within the field of archaeology has been limited. The challenges posed by conservation, archaeological identification and social recognition have traditionally limited the dissemination of this type of architecture. Its low profile is perceived as fragile once the original protections collapse. The ethnological information preserved and linked to past ways of life and societies is crucial to the interpretation of the cultural development handed down over generations by different communities and now transmitted to the general public through archaeological sites. This research aims to provide an overview of the main earthen vestiges from domestic, productive and funerary architecture dating from the prehistoric, protohistoric, Roman and medieval periods. For this, a bibliographical review and data collection through fieldwork were conducted for numerous case studies. These included the classification of materials, compositions and construction techniques, creating an integrated comprehensive database with information on geography, measurements and the general state of conservation. Full article

The present work aims to evaluate the macroinvertebrate community associated with macroalgae in earthen pond systems to better understand their potential in detritus recycling and as an accessory production. Sampling took place on the settling pond of an aquaculture research station, where macroalgae permanently occurred at high densities. The results suggest differentiation between seasons but not between sites within the settling pond. Seasonal variation was observable in terms of macroinvertebrate density, biomass, and diversity. Two non-indigenous species of invertebrates were found, the crustaceans Grandidierella japonica and Paracerceis sculpta Amphipods were the most abundant group, and their high nutritional value can be exploited. Detritus and the epiphyte layer are the main food items for the invertebrates, reinforcing the advantages of these organisms being present to enhance the recycling of excess detritus and to transfer organic matter to upper trophic levels. These species, naturally present in aquaculture facilities, can improve the water quality and increase the variability of food nutrients for reared species. Full article