Assessment of the efficacy of ethyl silicate and dibasic ammonium phosphate consolidants in improving the durability of two building sandstones from Andalusia (Spain)

  • Eduardo Molina
  • Caterina Fiol
  • Giuseppe Cultrone
Thematic Issue
Part of the following topical collections:
  1. Stone in the Architectural Heritage: from quarry to monuments – environment, exploitation, properties and durability


We performed a comparative study of the effectiveness of ethyl silicate (TEOS) and dibasic ammonium phosphate (DAP) on two varieties of natural stone used in the architectural heritage of Andalusia (Spain): Arenisca Ronda (calcarenite) and Molinaza Roja (arkose). The consolidants were applied on healthy samples with a paintbrush, a method frequently used in real building works, and the study was divided into three phases: (a) petrophysical analysis and analysis of the porous system prior to application of the consolidants; (b) evaluation of the changes that have taken place after each application; (c) evaluation of the durability of the two varieties of treated rock when subjected to the salt crystallization ageing test. The results obtained show that there is a compositional affinity between the consolidant and the rock and that this affinity has an influence on the efficacy of the product. This explains why DAP performed better in Arenisca Ronda, which is rich in carbonates, while TEOS was more effective for Molinaza Roja, which is rich in silicates. The change in the porous system was not important, although it showed positive aspects such as an improvement in the drainage of the water during the drying process. We also measured the level of penetration of both products, which reached a depth of 3–5 mm depending on the product applied. We also noticed a negative result, namely the change in the colour of both rocks after treatment with the consolidants, especially in the case of DAP. Finally, the stones were subjected to a salt crystallization test, the results of which show that the consolidants increased the durability of the materials.


Carbonated sandstone Siliceous sandstone Dibasic ammonium phosphate (DAP) Ethyl silicate (TEOS) Consolidation 



This study was financially supported by Research Group RNM179 of the Junta de Andalucía and by Research Project MAT2016-75889-R. We are grateful to Nigel Walkington for his assistance in translating the original text.


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Department of Structural and Geotechnical EngineeringPontificia Universidad Católica de ChileSantiagoChile
  2. 2.Centro de Excelencia en Geotermia de los Andes (CEGA, FONDAP-CONICYT)Universidad de ChileSantiagoChile
  3. 3.Department of Mineralogy and Petrology, Faculty of SciencesUniversity of GranadaGranadaSpain

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