Mechanical and Thermal Performance Characterisation of Compressed Earth Blocks

Elisabete R Teixeira,Jorge Fernandes,Adilson De P Junior,Sandra M Silva,Christiane Guarnier,Gilberto Machado,Ricardo Mateus

doi:10.3390/en13112978

Elisabete R Teixeira, Jorge Fernandes + Show 5 more

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https://doi.org/10.3390/en13112978

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Abstract

The present research is focused on an experimental investigation to evaluate the mechanical, durability, and thermal performance of compressed earth blocks (CEBs) produced in Portugal. CEBs were analysed in terms of electrical resistivity, ultrasonic pulse velocity, compressive strength, total water absorption, water absorption by capillarity, accelerated erosion test, and thermal transmittance evaluated in a guarded hotbox setup apparatus. Overall, the results showed that compressed earth blocks presented good mechanical and durability properties. Still, they had some issues in terms of porosity due to the particle size distribution of soil used for their production. The compressive strength value obtained was 9 MPa, which is considerably higher than the minimum requirements for compressed earth blocks. Moreover, they presented a heat transfer coefficient of 2.66 W/(m2·K). This heat transfer coefficient means that this type of masonry unit cannot be used in the building envelope without an additional thermal insulation layer but shows that they are suitable to be used in partition walls. Although CEBs have promising characteristics when compared to conventional bricks, results also showed that their proprieties could even be improved if optimisation of the soil mixture is implemented.

Highlights

Earth has been used as a building material since ancient times in several different ways around the world [1,2,3,4]
Electrical resistivity was measured to analyse the porosity of Compressed earth blocks (CEBs), and the results are presented in of the sample similar results for all samples
The results presented in this study show a strong relationship between soil and mixture preparation and compaction with CEB properties

Summary

Introduction

Earth has been used as a building material since ancient times in several different ways around the world [1,2,3,4]. Industrialised building systems and the dissemination of materials, like concrete [5], have replaced earthen construction. The continuous increase in the energy cost of some building materials (cement and ceramic bricks) and environmental issues are promoting the use of sustainable materials, such as the earthen materials known by their abundance and low-cost production [5,6,7]. Compressed earth blocks (CEBs) are one of the most widespread earthen building techniques. They represent a modern descendent of the moulded earth block, commonly called as the adobe block [7]. Regarding the environmental advantages of using earthen products, a previous study showed that in a cradle-to-gate analysis of Energies 2020, 13, 2978; doi:10.3390/en13112978 www.mdpi.com/journal/energies

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