Physical-chemical, mechanical and durability characterization of historical adobe buildings from the State of Michoacan, Mexico

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 t
Authors want to acknowledge the economic support of the research project DBMC 2020 through the 1st International Contest for Cooperation and Development of the XV International Conference on Durability of Building Materials and Components— DBMC 2020; the CIC Projects of the Universidad Michoacana de San Nicolas de Hidalgo (UMSNH); the Consejo Nacional de Ciencia y Tecnología (CONACYT), through the Becas Nacionales program; and the the project “Proyecto TED2021-129705B-C31” funded by MCIN/AEI/10.13039/501100011033 and European Union NextGeneration EU/PRTR. The authors also thank the technical support of the Laboratory “Ing. Luis Silva Ruelas”, in the Faculty of Civil Engineering of UMSNH. The authors from SEMB (UdL) would like to thank Generalitat de Catalunya for the project awarded to their research group (2021 SGR 01370)
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