Analysis of the current scenario of Compressed Earth Block (CEB) production

The main objective of this study is to identify the parameters that influence the quality of the production of compressed earth blocks (CEB). Thus, an analysis of the performance of the materials that make up the final product was carried out, such as the binders that act as chemical stabilizers and the different types of soils, also the mechanical resistance and durability tests and finally the technical standards for its manufacturing. For this aim, a literature review was carried out in three electronic databases, Scopus, Web of Science and Scielo. The results showed environmental concerns with the use of Portland cement for stabilization, therefore, 18% of the studies used agricultural residues and 25% used mineral by-products, for partial or total replacement of Portland cement. Soils with plasticity indexes between 15% and 30% have a stabilization success rate of 69%, while soils with plasticity index less than 15% have a stabilization greater than 93%, which can be increased to 100% if the soil have a percentage of clay and silt between 21 and 35%. On the other hand, a plasticity index above 30% negatively affects stabilization. The compaction energy applied in the manufacture of CEB is an important parameter, as it influences the density, thermal conductivity and mechanical strength. Among the sustainable construction techniques, CEB is a great option, as it can be done locally and with ease of construction.

Formulation of Compressed Earth Blocks Stabilized by Glass Waste Activated with NaOH Solution

Due to the increase in demand for building materials and their high prices in most developing countries, many researchers are trying to recycle waste for use as secondary raw materials. The aim of this study is the optimization of a mixture of compressed earth blocks based on two sediments. These sediments were tested through the Vicat test to determine the proportion of each one and the optimal water content. The mixtures were treated by adding 10% of blast furnace slag and different proportions of dissolved glass in a NaOH solution. The results indicated that the mixture of 70% Oran sediments with 30% Sidi Lakhdar sediments treated with 4% glass waste produced a CEB (compressed earth block) with high compressive strength with low porosity. In addition, formulated CEBs have a very good resistance to water immersion.

ELABORACIÓN DE ADOBE SOSTENIBLE

La presente investigación tiene como objetivo realizar la revisión del estado del arte del adobe como material de construcción sostenible y vernáculo. En este sentido la hipótesis se refiere al planteamiento de una nueva metodología de elaboración del adobe sostenible donde confluyan las técnicas manuales con las pruebas de laboratorio. Para ello, se realizó un análisis bibliográfico referente al estado del arte de la elaboración adobe en parte de la zona urbano – rural de la ciudad de Riobamba, y su impacto ambiental; además, se describen algunos materiales para estabilización del adobe en la parte introductoria. La segunda parte se refiere, a la propuesta de esta investigación que consiste en el planteamiento de una metodología para elaboración del adobe, partiendo de la adecuada identificación y recolección de las muestras de suelo, y seguidamente realizar las distintas pruebas manuales de campo que permitirán conocer empíricamente la calidad del suelo, mientras que las pruebas de laboratorio físicas, químicas y mineralógicas permitirán científicamente seleccionar el tipo de suelo. Finalmente se exponen los resultados de simular el bloque de tierra y su comportamiento térmico, luego se comparan los resultados simulados y experimentales. Luego de la selección del tipo de suelo, se estableció la Norma peruana E.080 (2017) para la elaboración del bloque de adobe, haciendo énfasis en los beneficios de la estabilización del adobe con fibras naturales. La investigación bibliográfica realizada se espera sirva como modelo metodológico para futuras investigaciones para elaboración del adobe sostenible, considerando que los sistemas constructivos en tierra son parte del patrimonio y saberes ancestrales de la zona andina que se deben recuperar. Palabras clave: Adobe, elaboración, fibras naturales, pruebas de laboratorio, pruebas manuales. AbstractThis research aims to review the state of the art of adobe as a sustainable and vernacular construction material. In this sense, the hypothesis refers to the proposal of a new methodology for the elaboration of sustainable adobe where manual techniques converge with laboratory tests. For this, a bibliographic analysis was carried out regarding the state of the art of adobe production in part of the urban - rural area of Riobamba, and its environmental impact. Furthermore, some materials for adobe stabilization are described in the introductory part. The second part refers to the proposal of this research, which consists of the proposal of a methodology to elaborate adobe, starting from the adequate identification and collection of soil samples, and then carrying out the different manual field tests that will allow to know empirically the quality of the soil. The physical, chemical and mineralogical laboratory tests will lead to a scientific selection of the type of soil. Finally, the results of simulating the earth block and its thermal behavior were shown. After, the simulated and experimental results were compared. After selecting the type of soil, the Peruvian Standard E.080 (2017) was established to elaborate the adobe block, emphasizing on the benefits of stabilizing the adobe with natural fibers. The bibliographic research carried out is expected to serve as a methodological model for future research for the elaboration of sustainable adobe by considering that the construction systems on land are part of the heritage and ancestral knowledge of the Andean area that must be recovered.Keywords Adobe, crafting, natural fibers, lab tests, manual tests.

Two-Dimensional Modeling of Heat Transfers in a Ventilated Test Cell Built with Various Local Materials

The main objective of this work is to find a material that attenuates heat transfer and provides an acceptable indoor environment in the habitat of countries with a hot and dry climate like Burkina Faso. The absence of thermal regulations in Burkina Faso leads to the development of buildings constructed with materials that do not provide thermal comfort. This study therefore aims to compare the thermal performance of local materials such as BLT, BTC, concrete block and adobe in order to propose a material adapted to the hot climate. In this work, a modelling and simulation is conducted with the COMSOL software. The modelling is done on a building of dimensions 4m×3m×3m, built successively with cut laterite block (BLT), compressed earth block (BTC), hollow concrete block, and adobe. As for the simulation, it concerns the evolution of the internal and external temperature of the building. The heat flows on the Northern and Southern sides are neglected due to the overhang of the roof. The results obtained show that the cell built with BTC allows a 4°C reduction, the one built with BLT a 2°C reduction and the one built with adobe a 1.5°C gain compared to the one built with concrete block. Thus, the material that best meets the criteria is BTC.

Compressed stabilized earth block: environmentally sustainable alternative for villages housing

Construction materials contribute to environmental pollution and the impoverishment of natural raw materials. The villages of Upper Egypt were exposed to high thermal loads owing to their geographical location. Moreover, the current building materials do not comply with the principles of sustainability and environmental adaptation of the residents of these buildings. Therefore, attaining admission to one sustainable building material in Upper Egypt and using it as an environmentally compatible, inexpensive, accessible, and easy building material for the users of these blocks is essential. In this study, the author selected various sites in Upper Egypt, analyzed climate and urban data, and after that, suggested prototypes with many variables and measured using the DesignBuilder V5 computer simulation program to select an optimal building type. Reached that can be saved energy about 40:50% and decreased annual discomfort hours more than 50%, finally, discussed with community members by a questionnaire on societal acceptance. The research concluded that building with compressed stabilized earth block is an environmentally sustainable solution applied in residential areas in the villages of Upper Egypt to reduce deficiencies in environmental adaptation.

An Innovative Approach to Produce Soil-Based Building Products

Soil has been used as a building material in different forms, such as mud, adobe, rammed earth, and bricks. Compressed Stabilized Earth Block (CSEB), a form of soil blocks with different additives including cement, fly ash, and lime, is a sustainable building material with many advantages compared to other conventional building materials. The usual practice of past researchers in producing CSEB was to add different materials like sand to the soil to control its clay and silt (finer) content. A high level of finer content is not desirable when it comes to the strength and durability of CSEB. This study proposes to reduce/ extract the finer content in the soil by washing it using a conventional concrete mixing machine.

Methods to Test the Compressive Strength of Earth Blocks

The efficient design of new earth structures and the restoration of old structures both require a reliable assessment of the compressive strength of earth materials. However, there is still much debate on the best method to accurately measure the compressive strength of earth blocks. To solve the problem of measuring the compressive strength of the earth block, the cube specimen, the half-block stacked specimen, and the full-size block specimen are used to measure the compressive strength of the molded adobe and rammed adobe, respectively, considering the influence of the specimen preparation process, loading direction, capping, and other factors. By comparing and analyzing the stress state, failure mode, and compressive strength of the specimen under various test methods, a compressive strength test method of earth blocks is determined, which is simple to operate, easy to standardize, and as close as possible to the actual strength of the blocks. The results show that the full-size block compression test method along the block thickness direction should be preferred to test the compressive strength of the earth block. The standard specimen obtained by cutting the full-size block is not suitable for the test of the compressive strength of the earth block; it can effectively solve the problem that the compressive strength of the small-thickness earth block cannot be directly measured by cutting the full-size block in half and stacking it, but it is not recommended to use the binder to bond the two half-blocks. When comparing the compressive strength of the earth blocks, the conversion coefficient related to the height-to-thickness ratio of the specimen cannot be used to convert the compressive strength. Still, the anisotropy of the material strength should be considered.

Sustainable construction for affordable housing program in Kabul

Afghanistan suffers from four decades of war, caused a massive migration of the rural population to the cities. Kabul was originally designed for 1,5 million people, where now 5 million people live. The importation of modern western styles housing for rapid reconstruction reveals apparent cultural conflict and significant environmental footprint. The new constructive cultures for sustainable reconstruction should necessary consider the use of local materials combined with modern technologies. Earthen architecture underlies the embodiment of Afghanistan architecture. The aim of this research is to revisit traditional afghan earthen construction with the tools of industrial modernity. Three soils of the Kabul region were first characterized. Then, sun-dried mud brick and compressive earth block, with and without stabilization have been prepared and tested in the laboratory to develop the most suitable earth construction element which is cost effective and easily available compared to the imported modern products.