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.

Enhancement of the Properties of Compressed Stabilized Earth Blocks through the Replacement of Clay and Silt with Fly Ash

The use of earth as a building material, in different forms, such as unburnt and burnt bricks, rammed earth, mud blocks, and soil blocks, is a common practice globally. This study is focused on soil blocks stabilized with cement which are referred to as Cement Stabilized Earth Blocks (CSEBs). The strength and durability of CSEBs are primarily governed by the amount of silt and clay content (finer) in the soil. Many researchers have shown that low finer content improves the properties of CSEB and they have altered the finer content by adding different additives. The current study used a washing method to reduce the finer content and fly ash was utilized as finer to re-fill the soil to the required finer content amount. Also, soil grading was modified by adding larger particles that were separated from the same soil to fit the soil grading to the optimization curves mentioned in the literature. The finer content was changed to 5%, 7.5%, and 10%. Blocks were made by stabilizing the soil with 6%, 8%, and 10% cement and with the size of 150mm×150mm×150mm. The results revealed that fly ash addition up to 10% improves the properties of CSEBs and compressive strength changes from 4.28N/mm2 to 13.43N/mm2.

Artificial Neural Networks to Predict the Mechanical Properties of Natural Fibre-Reinforced Compressed Earth Blocks (CEBs)

The purpose of this study is to explore Artificial Neural Networks (ANNs) to predict the compressive and tensile strengths of natural fibre-reinforced Compressed Earth Blocks (CEBs). To this end, a database was created by collecting data from the available literature. Data relating to 332 specimens (Database 1) were used for the prediction of the compressive strength (ANN1), and, due to the lack of some information, those relating to 130 specimens (Database 2) were used for the prediction of the tensile strength (ANN2). The developed tools showed high accuracy, i.e., correlation coefficients (R-value) equal to 0.97 for ANN1 and 0.91 for ANN2. Such promising results prompt their applicability for the design and orientation of experimental campaigns and support numerical investigations.