In recent years, there has been an increased focus on the research of earthen construction, driven by the rising demand for low-cost and sustainable building materials. Numerous studies have investigated the properties of compressed earth blocks (CEBs), however, very few have examined the properties of earth-based mortar. Mortar is an essential component and further investigation is required to enhance the mechanical performance of CEB structures. The study focuses on raw earth mortar (REM), which is a rudimentary mix of water with natural earth consisting of sand, silt and clay. Through experimental investigation, the fresh and hardened properties of three REM mixes were examined to determine the influence of cement stabilisation and jute fibre reinforcement. Shear triplet CEB assemblages were manufactured and tested to determine the initial shear strength of each mortar mix. The addition of 20 mm jute fibre at 0.25 % by weight increased the compressive and flexural strength of cement-stabilised raw earth mortar by 12 % and 20 % respectively. The addition of jute fibre also enhanced the initial shear strength, angle of internal friction and coefficient of friction during shear triplet testing. Finite element analysis (FEA) was undertaken to model the failure mechanism of the CEB assemblages, employing the use of cohesive zone modelling. The results of the FEA provided a satisfactory correspondence to the behaviour observed during experimental analysis and were within +/- 5.0 % of the expected values. The outcome of this investigation demonstrates the potential of REM and contributes to the development of low-cost and sustainable earth construction.

Using ecological materials such as raw earth represents an ancestral building practice that has been revisited for modern construction, thanks to its availability, low cost, environmental friendliness, and thermal properties, which offer optimal insulation and thermal comfort. This article explores the development of a new composite based on raw earth reinforced with 15% mussel shells, a by-product of the aquaculture industry, combined with two stabilizers: lime or cement (3%, 5% and 8%), in distinct formulations. This study aims to characterize the chemical and mineralogical composition of the soil and mussel shells and the thermal and mechanical properties of the composites. The results indicate that the gradual addition of lime to the soil-mussel shell mixture decreases dry density, which reduces dry mechanical strength due to increased porosity but enhances thermal properties. Conversely, incorporating cement into the soil-mussel shell mixture improves significantly mechanical properties while limiting the thermal performances.

This research examines the influence of blast furnace slag (BFS) on the physico-mechanical properties of compressed earth blocks (CEBs) stabilised with cement and/or lime. A three-factor mixture design is employed to assess the effects of BFS, cement and lime on key properties such as dry density, water content and compressive strength at 28 and 90 days. The study maintains a constant dune sand proportion with soil substitutions up to 20% (420 grams), while the BFS, lime and cement proportions vary with soil substitutions up to 15% (315 g). The findings indicate that mixtures with over 7.5% cement and equal proportions of lime and BFS, as well as a ternary mixture of 10% cement, 2.5% lime and 2.5% BFS, deliver superior strength. Notably, the optimal compressive strength with a high desirability score of 0.93 is achieved using around 14% cement and 1% lime. Proctor curve analysis shows that BFS-cement-lime substitution reduces water content and increases dry density. Statistical analysis confirms the model's robustness in predicting compressive strength, supported by high F-values and low probabilities, and highlights its effectiveness in guiding design decisions. Additionally, the study's evaluation of rupture types offers further insights into material strength and validates adherence to testing standards.

Modern research is focused on the discovery of new compounds that meet the requirements of modern construction. An example of low energy consumption is that buildings consume between 20% and 40% of energy. In this research, the effect of fiber addition on the properties of compacted earth bricks composed of clay and sand and fixed with cement is studied. Fiberglass or palm are used in different proportions (0% and 0.4%). This is done by studying the change in mechanical and thermal properties. The study focuses on clarifying the role of fiber type and the amount of compressive force applied to the soil. To change the properties of bricks. This is studied using experimental methods and systematization criteria. The results showed a decrease in density by 9.1%, with a decrease in water absorption by 8%, an increase in brick hardness by 42.7%, and a decrease in thermal conductivity by 22.2%. These results show that the addition of fiber improves mechanical and thermal properties. Which reduces energy consumption. The results are important because they explain the changes that occur in the earth block when palm fibers and glass are added and how they are used to improve earthen buildings.

Alternative construction materials can allow the modern built environment to abide by sustainability and circularity. This snapshot review highlights some advances made in the stabilization of compressed earth blocks (CEB) using alternative binders in the context of Burkina Faso. The review put forward the considerations of the reactivity and processing of earth materials and binders to produce stabilized CEB. Moreover, it highlights the effects of the changes at chemico-micro-scale of materials to the macro-scale densification, strengthening, and hardening of stabilized CEB. Furthermore, it relates the physical and mechanical properties through the coefficient of structural efficiency and correlates the resistance to surface abrasion with the resistance to bulk compression of stabilized CEB. This could later be extended to the structural efficiency of CEB masonry and allow to easily assess the strength from the quasi-non-destructive test of abrasion.

Rammed earth blocks have recently gained substantial popularity in construction materials due to their environmental benefits, energy saving, and financial effectiveness. These benefits are even more pronounced if waste materials such as olive waste ash (OWA) are incorporated in rammed earth blocks. There is limited information on the use of OWA in rammed earth blocks. This paper investigates the use of OWA and cement in improving rammed earth block characteristics. OWA was incorporated to partially replace the soil by 10, 20, 30 and 40% of its weight and cement was added in percentages of 2, 4, 6 and 8% by the dry weight of the composite soil. Proctor, unconfined compressive strength (UCS), and California Bearing Ratio (CBR) tests were performed at 7, 28, and 56 days. Results indicated that OWA inclusion decreased the maximum dry density while it increased the optimum moisture content. However, cement addition improved the maximum dry density of soil. The UCS results revealed that OWA possessed cementitious and pozzolanic behavior, and soil mechanical properties improved by up to 30% due to OWA inclusion, after which there was a significant drop of 40%. The trend in the CBR results was similar to those of UCS. To further clarify the experimental results, a mathematical model was proposed to determine the variation in strength as a function of time. Furthermore, correlations between soil mechanical properties were conducted. Predicted equations were developed to determine the properties of rammed earth block. All in all, the inclusion of OWA in cement stabilized earth block suggests the potential to improve the properties of rammed earth blocks.

This paper investigates the effect of integrating Alfa fibers into compressed earth blocks (CEBs) stabilized with varying Portland cement contents. CEB composites were manufactured with earth stabilized using different cement contents (5% and 10% by weight) and Alfa fibers reinforcement (0-0.4% by weight), compressed at 10 MPa with a compaction loading press. After 28 days of drying, the CEBs underwent diverse experimental tests to evaluate their physical, mechanical, and durability properties. The findings indicated that incorporating fibers led to a diminution in unit weight, ultrasonic pulse velocity, and dry compressive strength. Moreover, an increase in water absorption was linked with higher fiber content and less cement stabilizer. Despite the drop in mechanical strength, CEBs with lower cement (5%) and higher fiber content (0.4%) show better thermal performance. Thermal conductivity values were decreased from 0.5166 W/m.K (10% cement without fibers) to 0.3465 W/m.K (5% fibers with 0.4% fibers). The findings show also satisfactory erosion resistance, which could play a crucial role in areas prone to extreme weather events (floods and storms). According to the findings of this research, this material has potential as a promoting composite for the building materials industry.

This comprehensive literature review investigates the impact of stabilization and reinforcement techniques on the mechanical, hygrothermal properties, and durability of adobe and compressed earth blocks (CEBs). Recent advancements in understanding these properties have spurred a burgeoning body of research, prompting a meticulous analysis of 70 journal articles and conference proceedings. The selection criteria focused on key parameters including construction method (block type), incorporation of natural fibers or powders, partial or complete cement replacement, pressing techniques, and block preparation methods (adobe or CEB). The findings unearth several significant trends. Foremost, there is a prevailing interest in utilizing waste materials, such as plant matter, construction and demolition waste, and mining by-products, to fortify or stabilize earth blocks. Additionally, the incorporation of natural fibers manifests in a discernible reduction in crack size attributable to shrinkage, accompanied by enhancements in durability, mechanical strength, and thermal resistance. Moreover, this review underscores the imperative of methodological coherence among researchers to facilitate scalable and transposable results. Challenges emerge from the variability in base soil granulometry and disparate research standards, necessitating concerted efforts to harness findings effectively. Furthermore, this review illuminates a gap in complete lifecycle analyses of earthen structures, underscoring the critical necessity for further research to address this shortfall. It emphasizes the urgent need for deeper exploration of properties and sustainability indicators, recognizing the inherent potential and enduring relevance of earthen materials in fostering sustainable development. This synthesis significantly contributes to the advancement of knowledge in the field and underscores the continued importance of earth-based construction methodologies in contemporary sustainable practices.

This study investigates the potential of integrating areca fiber as a reinforcement agent in Compressed Stabilized Earth Blocks (CSEBs), used in combination with cement. Traditional earth-based construction methods, once prevalent, have seen a decline in industrialized nations with the advent of modern building materials. However, there is a growing resurgence in the use of earth-based materials, motivated by their economic, social, and environmental sustainability benefits. This renewed interest in CSEBs is primarily due to their superior energy efficiency and lower greenhouse gas emissions, especially when compared to conventional materials like fired clay bricks or concrete blocks. Areca catechu, widely recognized as the areca palm, thrives in the tropical regions of the Pacific, Asia, and East Africa. The fibers derived from areca nutshells, often regarded as agricultural waste, present an intriguing material for study. While the application of areca fiber in soil reinforcement has been previously acknowledged in scholarly literature, its specific role in enhancing the engineering properties of CSEBs represents a novel area of exploration, which this research aims to address comprehensively. In this research endeavor, CSEBs were manufactured with varying proportions of areca fibers, spanning from 0 % to 3 %, based on the dry mass of soil. Subsequently, these blocks underwent comprehensive testing to assess their strength and durability characteristics. Strength properties were evaluated through unconfined compression, split tensile strength, and flexural strength tests, while durability was meticulously examined using wet strength, water absorption, submersion, and efflorescence tests. Here, CSEBs displayed increases in compressive strength (107.04-436.38 %), split tensile strength (208.66-358.08 %), and flexural strength (16.49-82.47 %). Durability tests revealed enhanced wet compressive strength (up to 100.42 % increase) and optimized water absorption rates. A notable finding is identifying 2 % areca fiber content as optimal, yielding significant improvements in strength and durability parameters. Microstructural analysis using Scanning Electron Microscopy (SEM) further confirmed the benefits of 2 % fiber content, showing a compact and cohesive internal structure with reduced voids and fissures. This microstructural integrity underlines the enhanced bonding and stability imparted by the areca fibers. Another essential aspect of the study was evaluating the compliance of CSEBs with various international standards on earthen construction. The fiber-reinforced blocks met or exceeded several standards, demonstrating their suitability for broader construction applications. Finally, this study underscores the promise of areca fiber as a valuable reinforcement material in CSEBs stabilized with cement. This innovative approach offers a sustainable and eco-friendly building material option, aligning with the growing emphasis on environmentally conscious construction practices.

The interest in earth construction is growing increasingly as society becomes more aware of the importance of sustainable building. A considerable number of investigations have been devoted to studying the mechanical properties of compressed earth blocks (CEBs). However, most of these studies were conducted in laboratory settings. Little focus has been directed at studying the performance of CEBs that use on-site soil and other local materials to construct small-scale housing at the same location. A total of 120 CEBs were manufactured on-site from four block mixes: coarse soil with and without Phragmites Australis (Phragmites) and fine soil with and without Phragmites. By comparing the results achieved with minimum strength requirements from different building codes, the dry compressive strengths of all four block mixes were deemed adequate for single-storey structures. The addition of Phragmites caused a slight increase in the compressive strength and a slight decrease in the flexural strength of the CEBs. A formula to estimate the flexural strength of the blocks given the compressive strength is proposed based on a database of test results from the literature and this investigation's results. CEBs can create a sustainable building solution, especially in remote areas and Indigenous communities with limited access to conventional building materials.