Huaca de la Luna is a monumental earthen complex near Trujillo, Peru built by the Moche civilization from 200 to 850 C.E. Its principal structure, a stepped pyramid constructed with millions of adobe bricks on sloping bedrock and sandy soil, presents severe structural damage at the northwest corner. A sensitivity study of the static and dynamic response of the pyramid is conducted in Abaqus/CAE Explicit using 2D and 3D nonlinear finite element models derived from archaeological, material, and geotechnical data. Concrete damaged plasticity and Mohr-Coulomb formulations are adopted to represent adobe and sandy soil, respectively. Models undergo quasi-static gravitational loading followed by dynamic application of lateral ground accelerations. Lateral capacity is defined as the applied acceleration that produces collapse and is identified from the time-evolution of elastic strain and plastic dissipation energies. Initial 2D sensitivity analysis investigates the effect on lateral capacity of adobe tensile strength, bedrock/soil configuration, west fa & ccedil;ade profile, eastward architecture, and plastic dilation angle. Critical configurations identified from 2D analysis are expanded into 3D models. All results show stability under gravitational load. At dynamically induced failure, damage corresponds closely to the extant collapse of the northwest corner of the pyramid, suggesting that present damage is due to seismic activity.

This study addresses the challenges of adobe in Peru, a material widely used in rural areas but with limitations in mechanical strength and durability, particularly in seismic and humid regions. To bridge this gap, a combination of sugarcane bagasse fiber (SBF) and rice husk (RH) was added at percentages of 0.5%, 1%, and 1.5% (by dry soil weight), and the experimental adobe walls were reinforced with galvanized metal mesh. At 28 days, mechanical properties were evaluated through cube compression, prism compression, and diagonal wall compression tests, while durability was assessed at 56 days using wetting-drying wear and suction tests. The findings showed that adding 1% SBF + 0.5% RH to the adobe mixture increased compressive strength by up to 30.8%, and reinforcing this mixture with metal mesh further enhanced the strength by 26.4% at 28 days. Additionally, a 37.12% improvement in wetting-drying wear resistance and a 26% reduction in suction were observed at 56 days. This sustainable solution meets local regulatory standards and is particularly beneficial for seismic and humid regions, offering a practical alternative for safer and more resilient adobe housing in vulnerable areas of Peru and beyond, adaptable to on-site conditions. The results demonstrate a strong synergy between these agricultural byproducts and the galvanized metal mesh in enhancing adobe performance.

This paper presents the results of experimental testing of adobe masonry assemblages to study their flexure and bond behaviors. The properties of soil and water absorption of adobe units also were investigated. The plasticity index of the soil was 7.56, which was higher than that reported for the adobe soil in a few regions of the world. The silt and clay contents of the soil also were higher than those of the soil used by researchers elsewhere. High water absorption of the adobe units (27.37%) indicated their low cohesion characteristic, which was evidenced by low bond strength. The flexural strength of the wallettes tested in a direction parallel to the bed joints was less than that of those tested perpendicular to the bed joints. The tensile bond strength determined by the bond wrench method was considerably smaller than the flexural strength of the wallettes. The observed flexural and bond strengths of the adobe masonry also were smaller than those reported in the literature.

In the surrounding rural region of Hawassa village houses are constructed by using soil, wood, teff straw, and water which is called chika in the local name, although its degradable materials prompt a shift to adobe brick for durability. Adobe brick, prevalent in rural locales, offers social, economic, and cultural advantages. However, its inherent flaws include brittleness, low compressive, and tensile strength, along with moisture sensitivity. This research aims to enhance the native soil attributes of Hawassa villagers by integrating sisal fiber for brick production. The investigation employed soil, water, and sisal fiber to create enhanced adobe bricks. A displacement controlled uniaxial testing machine was utilized to evaluate the compressive strength of the bricks. Findings indicated that a 0.9% sisal fiber inclusion achieved a maximum compressive strength of 13.44 MPa, outperforming conventional samples by 3.4 times, alongside a flexural strength of 0.097 MPa, exceeding conventional results by 3.34 times. The study includes a comparative analysis of mechanical properties and a cost evaluation between traditional and enhanced approaches.

This study contributes to the understanding of the vernacular raw-earth heritage of the Champagne region in France, where such structures are currently being documented. The research investigates the mineral composition, grain size distribution, and physico-chemical, mechanical, thermal, and hydric properties of seven adobe types derived from soils with varying compositions (predominantly silicate or limestone-based soils). In particular, the influence of calcite content, which spans a wide range from 0 % to 84.9 %, was examined. The results indicate a strong dependency of peak compressive strength on calcite content: higher CaCO3 levels correspond to lower peak compressive strength. Additionally, the study reveals that the metal oxide content of soils is a critical factor directly associated with mechanical performance. Interestingly, it was observed that historical builders often used weaker adobes for load-bearing purposes and stronger ones for filling, likely without adherence to formal construction standards. Rather than compressive strength, wall design appears to have played a more critical role in structural stability. Regarding thermal properties, calcite content showed minimal influence on diffusivity, specific heat capacity, and thermal conductivity across all adobe samples. Furthermore, all adobes demonstrated excellent to very good moisture regulation performance, with corresponding Moisture Buffer Values varying from 1.65 to 3.09 g/(m2.%RH). The findings of this study underscore the potential of traditional raw-earth techniques in rediscovering and evaluating earthen architecture, with implications for promoting sustainable and environmentally friendly contemporary earthen construction and renovation practices.

Olden adobe structures had been commonly built on raw clayey earth hence the technique was exposed to be an eco-green and globally sustainable construction. Nowadays, modern construction materials lack long-lasting stability, affordability, and eco-friendliness. On the other hand, overutilization of earth-based materials led to the depletion of natural resources. So, global construction societies were raised to develop organic construction for an eco-friendly environment. This paper reviewed the recent research on the earthen clay adobe bricks and mortar stabilized with Agro-wastes and how they contended with adaptability and stability standards. The literature study focuses on the ability of the rejuvenated clay adobes rather than the traditional clay adobes of historical times. Agro-waste, non-agro-waste, and some synthetic components were used to enhance the adobe's mechanical, durable, and thermal behavior. This review emphasized altering raw clay and Agro-waste or waste additives by endorsing W/B proportions. From the literature, the scientific interpretations were conferred to attain possible usage of alternate binders and Agro-waste additives with viable W/B ratio. The prime findings of this review were subjected to define modifications of raw clay by adding disposal wastes and alternate binders to resolve the shortage of raw clay resources. Nominal mixing strategies of altered clay bricks are to be prescribed since adobes have no specific standards. The renovations of earthen adobe construction are essential to progress and to satisfy commercial needs as an environmentally sustainable material.

The objective of this study was to improve the physical and mechanical properties of adobes reinforced by cement-metakaolin mixtures. For this purpose, a raw clayey material from Burkina Faso consisting of kaolinite (62 wt%), quartz (30 wt%), and goethite (6 wt%) and belonging to the category of sandy-silty soils with medium plasticity has been used for adobe manufacturing. Metakaolin was produced by thermal activation of a local raw clayey material at 680 degrees C for 2 h. Adobes were first formulated with cement up to 12 wt%. It appears from this formulation that 10 and 12 wt% cement offer good mechanical strength elaborated adobes. Taking into account the high cost of cement in Burkina Faso, 10 wt% of cement was retained to be replaced by 2, 4, 6, 8, and 10 wt% metakaolin. The microstructural (by SEM-EDS), physical (apparent density, porosity, linear shrinkage, water absorption test by capillarity, spray test), and mechanical (compressive and flexural strengths) characteristics of formulated adobes were evaluated. The obtained results showed that this substitution improved adobe microstructure with pores reduction leading to composite densification. The presence of metakaolin slows down the phenomenon of capillary rise of water in adobes. Also, the metakaolin presence within the cementitious matrix improves the mechanical behavior and reduces rain erosion effect. The improvement of different properties was mainly due to formation of calcium silicate hydrates (CSH) resulting by cement hydration and metakaolin's pozzolanic reaction. Adobes reinforced with 6 wt% cement and 4 wt% metakaolin have suitable technological characteristics to be used as building materials for developing countries.

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.

Most earthen historical buildings have been abandoned for decades, exposed to the weathering and the passage of time. In Mexico, the low status of earthen constructions has increased these deterioration processes, resulting into the risk of disappearance of this significant architectural heritage. Historical adobes from monumental buildings in the State of Michoacan were sampled and collected in the localities of La Huacana (H) and Santa Cruz de Morelos (SC). The specimens were characterized in the materials laboratory, assessing their physical-chemical, mechanical and durability properties. An interdisciplinary methodology was designed through institutional cooperation and the application of different test methods. The adobes showed totally different compositions and proportions, and stabilizers like vegetal fibers, nevertheless, the mechanical performance of both samples was very similar, achieving respectable values in the context of historical adobe structures. Several correlations were found through the analyses: the physical properties like the density, the color or the electrical resistivity were related with the mechanical and durability ones; the non-destructive testing (NDT) allowed to calculate the dynamic elasticity modulus and infer the mechanical behavior; the chemical characterization enabled to obtain the elemental and mineralogical composition; and the Atterberg limits gave the soil classification. The research showed the broad diversity of earthen solutions and demonstrated how the granulometry is not a limitation to the adobe production, since the local soils can achieve similar mechanical and durability behaviors. Furthermore, H presented very different composition than the guidelines for earthen construction; nevertheless, the samples showed better durability performance and lower capillarity absorption rates. It is hoped that the results obtained with this research can help the further development of the earthen materials characterization and the decision-making process for the restoration and conservation of historical and vernacular constructions.

The underutilization of natural waste from date palm plantation maintenance presents an opportunity for the production of sustainable building materials. This study investigates the mechanical properties and environmental sustainability of adobe bricks reinforced with date palm waste (DPW) and a small percentage of cement. Adobe bricks were stabilized using 7% cement by weight and varying proportions of DPW (0%, 0.5%, 1%, and 1.5% by weight), followed by curing under two distinct conditions: moist storage (MS) and open-air (AF). It was observed that bricks cured under MS conditions significantly outperformed those cured in AF, evidenced by a 47.05% reduction in capillary absorption coefficient compared to the reference brick. Despite a decrease in compressive strength due to DPW incorporation, the bricks exhibited increases in capillary and total absorption while still satisfying earth construction standards. Notably, flexural strength improved by 41.66% under MS curing. Enhanced erosion and abrasion resistance, as well as improved performance throughout wetting/drying cycles, were also recorded. These enhancements underscore the potential of DPW as a renewable additive in the formulation of adobe bricks for ecological and durable housing. The study not only proposes a novel use for date palm byproducts but also contributes to the advancement of environmentally -friendly construction methodologies.