Porosity changes in a granite close to quarry faces: identification from ¹⁴C-PMMA autoradiographs and mineralogical cartographies

¹ EA 473 “Microanalyse des Matériaux” LRC-CEA (M07), Université de Franche-Comté, 25000 Besançon, France
² Laboratoire HYDR'ASA, UMR 6532 CNRS, Université de Poitiers, France
³ ERM Sarl, 86022 Poitiers, France
⁴ EA 2642 Géosciences, Université de Franche-Comté, 25000 Besançon, France
⁵ Department of Chemistry, Laboratory of Radiochemistry, University of Helsinki, Finland

Corresponding author: claude.dubois@univ-fcomte.fr

Received: 5 October 2001
Revised: 1 September 2002
Accepted: 17 September 2002
Published online: 29 November 2002

Abstract

In a previous study, the porosity of the “Granite des Crêtes” was quantified by ¹⁴C-MMA porosimetry. Autoradiographs of the granite close to quarry faces, freshly quarried (A) or weathered for 20 years (B), show an increase in porosity of B in comparison with A, localized in intragranular microcracks and grain joints and in millimetric grain zones [1]. In this study, mineralogical cartography-autoradiograph overlaps led to the identification of the alterated millimetric minerals of B, in which the porosity was higher. Moreover, the SEM analysis led to the quantification of an increase in porosity linked to an enlargement of the intragranular microcracks and the grain joints.