Adobe Materials Research Articles

Study on seismic failure mechanism and damage model of unconstrained adobe block walls

Through the quasi-static cyclic in-plane loading test of three kinds of unconstrained adobe block walls, namely plain adobe wall, modified mud adobe wall and modified adobe wall, the failure mode and seismic performance of each specimen were clarified. Using residual deformation and cumulative energy dissipation as failure parameters, a two-parameter seismic damage model of unconstrained adobe block walls was established. and a calculation method for the adjustment coefficients of energy consumption items was provided. The results showed that the failure mode of the typical unconstrained adobe block wall under earthquake action was not affected by the modification of adobe materials, and the final failure mode was shear failure along the mud crack and the inclined crack extending through the block. Furthermore, the proposed seismic damage model can well reflect the evolution law of earthquake damage of adobe block walls, and the recommended damage index boundary values for five performance levels were given, providing a reference for performance-based seismic design and damage assessment of adobe block walls.

Leveraging Life Cycle Cost Analysis (LCCA) for Optimized Decision Making in Adobe Construction Materials

Adobe construction is a longstanding practice in South America and is characterized by its affordability, accessibility, and ecological sustainability. However, the decision-making process regarding the choice of construction materials often relies on subjective factors, disregarding economic implications throughout the life cycle of a building. This study aimed to introduce life-cycle cost analysis (LCCA) as a valuable tool for optimizing decision making in the context of adobe construction materials in South America. This study emphasizes the significance of considering the life-cycle costs associated with adobe construction materials and their impact on decision-making processes. A comprehensive case study was conducted in South America to examine the various adobe construction scenarios. The life-cycle costs of different adobe materials and their associated maintenance strategies were assessed over a period of several decades, considering factors such as material acquisition, construction, maintenance, and repair. The values used in this study are specific to Ecuador, the country where the investigation was conducted.

Performance degradation mechanism of adobe materials under freeze-thaw cycles based on moisture transportation characteristics and microstructural analysis

It is well known that the mechanical properties and appearance of adobe materials degrade significantly during freeze-thaw cycles due to the unique moisture absorption characteristics of soil particles. In order to clarify the performance degradation mechanism of adobe materials under freeze-thaw cycles, the evolution law of the pore structure, attack products, and capillary absorption characteristics were systematically studied when experiencing 10, 20, and 30 freeze-thaw cycles. The results showed that the flocculent hydration product around the Yellow River sediments and aggregate particles gradually reduced during adobe materials subjected to freeze-thaw cycles. Volume expansion caused by the growth of ettringite in macropores and cracks led to the deterioration in pore structure and more water participated in the subsequent freeze-thaw cycles. The porosity and pore volume of adobe materials increased with the increasing of freeze-thaw cycles, and the harmful pores of 50–200 nm rose significantly. After 20 freeze-thaw cycles, harmful pores accounted for 62.3% of the total pore volume of adobe materials, which induced an enlarged moisture transport capacity, and thus the capillary absorption coefficient increased by 18.52 g/(m2·s1/2). As a combined result of above factors, after 30 freeze-thaw cycles, the loss rates in mass and compressive strength of adobe materials were 6.2% and 15.4%, respectively.

Experiment on the Performance of Recycled Powder of Construction Waste on Adobe Materials

With the widespread use of adobe materials in buildings, their durability can deteriorate under harsh weather conditions such as long-term low temperatures and rainfall, which can easily lead to safety accidents. This article takes adobe material mixed with construction waste recycled powder as the research object and adds the prepared construction waste recycled concrete powder and recycled brick powder to the adobe material in different proportions to study the mechanical and durability properties of the adobe material. The results indicate that under normal temperature curing conditions, the compressive strength of the adobe sample significantly increases with the increase in the recycled powder content, and then decreases. Under high-temperature conditions, with the increase in the recycled powder content, the compressive strength of the adobe sample first significantly increases and then decreases. When the powder content is within the range of 6% to 10%, good moisture absorption and desorption performance can be achieved. When the content of recycled powder is between 2% and 10%, the effect on the dry–wet cycling performance of the adobe is weakest. When the content of grade I/II recycled brick powder is between 2% and 6%, and the content of grade I recycled concrete powder is between 2% and 6%, the negative impact on the freeze–thaw cycle performance is relatively weak. The research results provide theoretical data support for the mixed-use of recycled powder and adobe materials.

Modeling Earthen Treatments for Climate Change Effects

Adobe has been used globally for millennia. In the US Southwest, cultural heritage sites made of adobe materials have lasted hundreds of years in an arid/semi-arid environment. A common prediction across multiple climate change models, however, is that rainfall intensity will increase in the US Southwest. This increased erosivity threatens the long-term protection and preservation of these sites, and thus resource managers are faced with selecting effective conservation practices. For this reason, modeling tools are needed to predict climate change impacts and plan for adaptation strategies. Many existing strategies, including patching damaged areas, building protective caps and shelter coating walls are already commonly utilized. In this study, we modeled adobe block construction, subjected extant walls to a local 100-year return interval rainfall intensity, and tested earthen-coat-based strategies to minimize the deterioration of earthen fabric. Findings from the resultant linear models indicate that the patching of earthen architecture alone will not prevent substantial damage, while un-amended encapsulation coats and caps provide similar, and significantly greater protection than patching. The use of this model will enable local heritage resource managers to better target preservation methods for a return on investment of the material and labor costs, resulting in better preservation overall and the retention of culturally valuable resources.

Kuzey Suriye’de İç Mülteciler İçin Konut Üretiminde Kerpiç Malzemenin Rolü

Many people are in ınternally displaced people status in many parts of the world due to various reasons. The traditional adobe house architectural style has begun to be revived in northern Syria by many ınternally displaced people and those seeking shelter. Adobe material was reused in housing production, both through individual efforts and institutions and organizations. Various problems are experienced in the unplanned or planned camp areas that meet the shelter needs of ınternally displaced people to a great extent. The fact that the people at the design and implementation stage do not have sufficient knowledge about traditional adobe architecture, ignoring location, climate, and topographic features, and lack of public services and infrastructure have shown that the projects are not fully successful. The study, it is aimed to develop a house community model that meets the sheltering needs of internal refugees and produces solutions for the problems. In this context, the return to traditional adobe houses in northern Syria was handled and the continuity of the use of adobe materials was evaluated. It has great importance that the adobe house communities planned for ınternally displaced people are designed in line with the needs of the people who will live and that they are accessible and sustainable.

Mechanical and durability properties of adobe blocks filled with date palm wastes

PurposeEarthen construction does not meet today’s requirements due to certain limitations such as low water resistance and its high vulnerability to cracking damage. The purpose of this study is to improve the mechanical properties and low durability of adobe blocks by incorporating date palm wastes as a natural reinforcement and lime as a stabilizer.Design/methodology/approachSoil from the region of Biskra in Algeria was mixed with sand and lime in suitable ratios. Then, date palm wastes were added to the previous mixture at different ratios (0.3%, 0.6% and 0.9%) by dry mix weight to manufacture adobes. Cubical and cylindrical specimens were prepared and tested in a laboratory to investigate the curing time, mechanical and durability characteristics of the formulated blocks. In addition, X-ray diffraction and scanning electron microscopy (SEM) tests were used to identify the materials.FindingsIt has been observed that the addition of lime to the soil is very beneficial for its stabilization, in particular for an optimum of 12%. The presence of date palm waste in the mixture (soil + lime) generated a significant improvement in tensile strength reaching a rate of about 67%. The same observation was made for the tests of resistance to dry abrasion, resistance to erosion, attack by external sulphate and wetting/drying. However, for cases of compressive strength, water absorption and swelling an unfavorable effect was recorded.Originality/valueBased on the above-mentioned findings, this paper presents a novel solution to increase the durability of adobe materials using date palm wastes with oven curing at 65°C for about nine days. Adopting such an approach would certainly encourage building durable mud housing on a large scale. This can contribute to solving the acute housing shortage, particularly in poor countries.

Influence of synthetic waste fibres on drying shrinkage cracking and mechanical properties of adobe materials

Earthen construction materials are often vulnerable to cracking due to excessive drying shrinkage deformations because of the high content of fine particles. Thus, fibrous materials can beneficially be added, not only to reduce such crack formation but also to improve the mechanical performance. In this study, recycled polyethylene fibres (R-PE) obtained from discarded fishing nets are added to adobe bricks in different fractions (1–5% by weight). Besides a chemical and geotechnical characterization of the raw materials used for the adobe production (Fine-grained Greenlandic sediments (GP) and a coarser gravel fraction (KG)), the investigation described in this paper includes the mechanical properties and restrained drying shrinkage deformations in manufactured, laboratory-scale adobe specimens. The crack formation due to restrained shrinkage is analysed using a digital image correlation (DIC) technique, which allows detailed, continuous monitoring and quantification of surface deformations. The results show that the evaluated adobe material can provide adequate mechanical properties, which makes the raw materials suitable for adobe brick production. From the mechanical tests, the addition of R-PE fibres resulted in improved flexural toughness, flexural strength and compressive strength. A detailed analysis using the DIC technique revealed that the addition of R-PE fibres significantly and quantitatively reduces the degree of shrinkage cracking.

Improving the adobe material properties by laser material processing

Many of the old heritage buildings and even many current buildings in the world are made of adobe, which is a sustainable, inexpensive, and environmentally friendly material. The adobe buildings react harmoniously against gravity or lateral forces, but structural fractures and sudden forces such as natural disasters or moisture leakage are the main causes of making them vulnerable, especially against earthquakes. Strengthening and reinforcement of adobe materials have long been discussed, and techniques such as adding materials to adobe or plastering adobe walls have been used to increase its resistance. Here, laser shock processing operation is exploited to analyze the extent of change in mechanical strength and moisture resistance of adobe material and ultimately to test its applicability to heritage buildings. The distance between the focal point of the laser beam and the surface of the adobe is optimized while an optimum value is also obtained for laser intensity. Laser radiation increases the compressive strength and flexural strength of the adobe by 348% and 12%, with respect to the raw material, whereas no significant difference is observed in the tensile strength. Nevertheless, the hydrophobicity of the samples increases by upper defocus and increasing the defocus, improves the soil adhesion, and escalates the homogeneity and integrity of the surface. Microstructural analysis such as SEM, EDAX and XRD of raw, and laser-treated adobe material confirm these improvements and overall render laser treatments an interesting, beneficial candidate among adobe reinforcement techniques.

Dynamic behaviour of adobe bricks in compression: The role of fibres and water content at various loading rates

This paper presents the results of an experimental research aimed at assessing the material performance of adobe bricks in compression for a wide range of induced strain rates, from statics to high velocity impact. Adobe connotes a traditional masonry whose bricks are made of sundried soil mixtures possibly reinforced with natural fibres and joined together using mud mortar. The inclusion of fibre and the presence of water in the mixture have a dominant effect on the mechanical performance of adobe bricks and masonry. Their influence on the dynamic behaviour of this material is quantified and interpreted in this study at high strain rates also with data produced through Hopkinson bar testing. Appropriate dynamic increase factors and constitutive equations for adobe materials in dynamics are also investigated. The paper presents the experimental campaign, shows the main results and offers qualitative and quantitative interpretations for the principal damage patterns observed.

Comprehensive study of projectile impact on lightweight adobe masonry

We conduct a comprehensive experimental and numerical study of the impact response of lightweight adobe masonry with a density of 1.2 g/cm3. Based on two independent test cases, a simulation model for lightweight adobe is validated and applied. First, we investigate the impact of a spherical projectile on finite and semi-infinite targets. Then, the penetration behavior of a generic hollow projectile is studied. In each case, the data from the ballistic experiments is compared to the results of corresponding numerical simulations. The employed numerical model utilizes a p-α-equation of state, recently derived from planar plate impact experiments on the same lightweight adobe material [Sauer et al., Journal of Dynamic Behavior of Materials 4 (2018) 231–243]. Strength and failure modeling are based on a validated numerical description of another adobe material that has a density of 1.8 g/cm3. The simulation model for lightweight adobe is capable of simultaneously reproducing all experimental results in a quantitatively appropriate way. This reveals that, although the phenomenology and quantitative properties differ significantly, lightweight adobe (1.2 g/cm3) and adobe (1.8 g/cm3) can be described by the same approach. Hence, this work suggests that the utilized model is applicable for analyses of impact loading of the entire class of adobe materials.

The Dynamic Properties of Historic Timber‐Framed Masonry Structures in Bursa, Turkey

Timber‐framed masonry structures are known as an effective earthquake load resisting system in high seismicity regions such as Bursa, Turkey. Intense earthquakes have occurred throughout history; however, many of the traditional timber structures have been able to survive without significant damage until the present day. In this study, six historic two‐storied timber‐framed masonry structures dating from the nineteenth century in Bursa City are investigated by using laboratory and in situ structural health monitoring tests. Although the houses have the same construction techniques, different masonry infill materials are used inside the timber frames. Stone, adobe, and brick are used as infill materials. Mud and lime mortars are used as binding materials. Mud mortar is used with stone and adobe materials. Lime mortar is used with brick material. The physical, mechanical, and dynamic parameters such as density, specific gravity, porosity, elastic modulus, frequencies, mode shapes, and damping ratios of the studied structures were investigated and the results were comparatively discussed. It is understood that the use of different infill materials affects the dynamic behaviors of these structures.

Use of zinc stearate to produce highly-hydrophobic adobe materials with extended durability to water and acid-rain

This paper presents a novel solution to increase the durability of adobe materials using zinc stearate at doses ranging from 0.25% to 2.00% w/w. Shrinkage, apparent density and ultrasonic propagation speed measurements were performed on the cured samples. In addition, water absorption and durability features were determined by capillary tests, Karsten tube measurements, immersion in water, hydrochloric acid (5% w/w) and sulphuric acid (5% w/w) solutions. The durability study was complemented by rain erosion and acid-rain erosion tests. The capillary water absorption was comparable to that of hydrophobic cement renders and the acid-rain erosion was negligible in samples containing 1.00–2.00% w/w zinc stearate. Besides, SEM examination confirmed the protective action of zinc stearate in front of acid-rain. To conclude, zinc stearate was found to be was an excellent choice to increase the durability of adobe materials.

Geomechanical characterization of some adobe materials

The influence of the material properties in the physical and numerical modelling of historical buildings suggests identifying proper laboratory procedures for their mechanical characterization. In the following some aspects are discussed of the geotechnical laboratory tests suitable for the characterization of some adobe materials used in historical heritage.Apart from the conventional identification and classification procedures, the direct shear and the uniaxial compression tests are considered. The study intends to provide additional experimental information that could be used in subsequent studies for the development of constitutive laws applicable in the numerical analysis aimed, for instance, at comparing the effectiveness of various alternative solutions applicable in the field for the restoration of buildings that characterize monument sites.

Fibre reinforcement in earthen construction materials

Earthen construction materials are generally brittle with low tensile strength. To deal with this in practice, it is often proposed that reinforcement be added in the form of fibres of various materials. Construction in earthquake-prone parts of the world is thought to benefit from this form of reinforcement, and indeed fibres (in the form of straw) are a key part of many adobe (unit-based) materials. To remain in harmony with the generally excellent environmental credentials of these materials, the reinforcement should be obtained from a natural material ideally obtained as a waste stream, so natural fibres are often chosen. While some studies have been published on the macroscopic mechanical behaviour of reinforced earthen materials, little is known of what is happening at the interface between the soil matrix and the fibres. In this paper, the authors present laboratory-based studies that attempt to fill this gap, covering pull-out behaviour of natural fibres embedded in earthen construction materials, both stabilised and unstabilised.

Improved Performance Of Earth Structures By Lime And Gypsum Addition

Studies have been carried out to resolve the housing problems of poor people all around the world. Low-priced and fast construction systems, which can be built with local materials, have always been required. Adobe buildings have the capacity to meet this need and are the most suitable systems fulfilling the housing needs of almost 50% of the world’s population (Houben, 1994). Interest in adobe buildings, first built in Mesopotamia c. 7000 BCE, has recently increased due to needs for energy conservation, reduced pollution, environmental concerns and increased standards of living. Thus, studies and researchers have gained new perspectives. Adobe buildings have been reevaluated in numerous studies under current conditions and compared with modern materials. Not only are adobe buildings environmentally friendly, but they are also advantageous regarding production and service costs compared to buildings made from burned bricks (CID, 1993, Riza et al. 2010). Adobe constructions, besides their superiority, are criticized as needing repair (Kerali, 2001), having thick and heavy walls, relatively low compressive and shear strengths and in particular the possibility of becoming damaged under earthquake effects (Ural et al., 2011, Maheri et al., 2005). Damages in adobe buildings are associated with material quality, ground motion acceleration, wall slenderness, structural design and geometry which have an effect on building performance (Bariola and Sozen, 1990, Samali et al., 2011). In particular, it is recommended to take precautions to improve the performance of adobe buildings under earthquake risk. Using natural fibers (Vargas et al., 1986, Vega et al. 2011, Lertwattanaruk and Choksiriwanna, 2011), wooden reinforcements or welded steel reinforcements improves the strength of adobe materials and the performance of a building which presents nonlinear behavior. Stabilizing the earth with some additives in adobe manufacture, as well as the use of fibers and reinforcements, presents positive effects on building performance depending on better material performance. Many stabilization methods have been practiced IMPROVED PERFORMANCE OF EARTH STRUCTURES BY LIME AND GYPSUM ADDITION

Heat Transfer Coefficient Analysis of the Chamber of Cyprus Turkish Architects Office Building on the Zahra Street in the Walled City of Nicosia in Cyprus

This study analyses and calculates the heat transfer coefficient values of the 134 years old historical building in the walled city of Nicosia. The build ing is the typical example of the Tradit ional Turkish House and built by the tradi- tional adobe materials and stones. The ceiling, external walls, roof and the windows of the building were analysed to esti- mate the heat transfer coefficient values of the house and to demonstrate the influence of the climate conditions of Cyprus on the physics of the building. The estimated U values of this old building are, 0,49 W/m 2 K for the e xterior adobe walls , 0,27 W/m 2 K for the ceiling, 0, 13 W/m 2 K for the roof and 2,0 W/m 2 K for the windows. The co mparison of these values with the modern concrete build ing under the same climatic conditions demonstrate that the adobe building p rovides better inner environment for the house life and also decreases the energy costs for the thermal insulation.

The Properties of Modified Adobe Materials with Desulfurization Waste

As a modifier, desulfurization waste can improve the performance of traditional adobe materials. The results show that it was possible effectively to modify properties of adobe materials by means of DHG and DFA. When the molding pressure is 15 MPa, the compressive strength of modified adobe materials arrived at 7.5MPa at 28 days. Moreover, modified adobe materials remain a better volume stability and water resistance observed in the drying shrinkage (0.6mm/m) and softness coefficient (0.52), respectively.

How to Build Affordable but High Quality Houses for Villagers: Appropriate Design for Aini Vernacular Houses in Xishuangbanna

Yunnan is very rich in natural resources, and using natural materials for building is an ancient tradition in local minority. In the remote poverty national areas, we always concern about making use of appropriate technical means, following the tradition of local construction, and efficiently applying local natural building materials. In addition, we pay close attention to improving their living quality effectively by the techniques. In this article, from a specific practice casethe United Nations GEF small grants programme, we make multiple detailed comparative analysis with traditional houses at the first, next we discuss appropriate design in the new residential construction of Aini in Xishuangbanna. And then we focus on using the local natural building materials such as bamboo, wood, adobe and other materials, by which we can make the improved design on roof system, wall system and floor system, so as to reduce construction costs and technical complexity, as well as we can effectively improve the living quality of construction at the same time. A demo project was constructed to show how these natural materials were integrated into a system to form the whole building. Joint team consists of local craftsmen and engineers constructed the demo-project so that the technology can be localized.

Texture of nopal treated adobe: restoring Nuestra Señora del Pilar mission

Materials eroded, non-eroded, and treated with the local nopal mucilage adobe, from the Nuestra Señora del Pilar mission located in Sonora Mexico, are compared. The treatment of adobe bricks with an alcohol–water solution prior to the nopal application is proposed in order to increase their resistance to erosion. Using X-ray diffraction, small angle X-ray scattering, scanning electron microscopy and nitrogen adsorption techniques, we compared the structural and textural properties of eroded and non-eroded adobe materials. In the samples treated with nopal it is shown how the nopal coats the adobe small particles. The nopal impregnated material is stable up to 200 °C. A non-conventional distinction among these materials is made through fractal geometry and nitrogen adsorption. We also show through XRD measurements that erosion is homogeneous and not selective.