Paper contribution

Using Blanco Mera granite as standard reference and benchmark material

Manuel Alejandro González-Fernández; Mauro Muñiz-Menéndez; Ignacio Pérez-Rey

Proceedings
EUROCK 2026
Pages
285-290
Submitted
28 January 2026
Accepted
15 June 2026
Published
12 August 2026

Summary

Abstract

In geotechnical engineering, researchers frequently rely on a set of well-known reference soils such as Toyoura sand, Ottawa sand, or London clay. These materials are widely used because of two essential characteristics: reproducibility and comparability. Reproducibility ensures that experiments can be repeated under nearly identical conditions, yielding results that are consistent across time and location. Comparability, on the other hand, makes it possible to benchmark results between different laboratories, testing methods, or equipment. Together, these attributes allow such soils to serve as reliable materials for validating numerical models, constitutive laws, or innovative experimental techniques. In what concerns rocks, the situation becomes more complex. Unlike soils, which are generally treated as homogeneous and isotropic materials, rocks are intrinsically heterogeneous and anisotropic, that greatly influence their behavior. Consequently, the establishment of “typical” or reference rocks is less straightforward. Despite this, a few candidates have gained recognition in the literature and in experimental studies. Examples include Lac du Bonnet granite from northern Canada, Berea sandstone from Ohio, and Westerly granite from Rhode Island. These rocks have been tested extensively and are often cited in studies dealing with fracture mechanics, hydraulic conductivity, or strength characterization. The key challenge lies in determining the threshold at which a rock can be legitimately considered a standard reference material. Unlike soils, where grain-size distribution is more uniform and mineralogical composition can be considered homogeneous, rocks display natural variability even within a single quarry. Therefore, a question arises: how much testing, and under which conditions, is enough to establish a rock as a benchmark for scientific and engineering purposes? Based on a large amount of tests performed by the authors on Blanco Mera granite, this document seeks to explore the aforementioned issue by examining existing practices and identifying the fundamental criteria that a standard rock should meet.

Contributors

Authors

  1. Manuel Alejandro González-Fernández Laboratorio de Geotecnia, CEDEX, Madrid, Spain ORCID 0000-0001-8495-7990
  2. Mauro Muñiz-Menéndez Laboratorio de Geotecnia, CEDEX, Madrid, Spain ORCID 0000-0001-5202-0044
  3. Ignacio Pérez-Rey CINTECX, Universidade de Vigo, GESSMin Group, Vigo, Spain ORCID 0000-0003-0883-7211

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References

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