• To study the changes of rock structural properties during sampling by comparing porosities in samples whose pore space was preserved by in-situ resin impregnation experiment results with those which were drilled and taken to the laboratory before resin impregnation.
  
   
• To study rock porosity and morphology of pore space in intact rock matrix (i.e. tortuosity and constrictivity, the connected porosity and accessible pore space).
  
   
• To use spatial porosity distribution provided by the 14C-PMMA method for the new development of modelling tools of the heterogeneous matrix diffusion.

Experimental Concept

The experiment is based on the previously developed 14C-PMMA method which consists the following steps during impregnation in the laboratory:

• Drying of centimetre scale rock samples under vacuum
   
• Impregnation with 14C-PMMA under vacuum
   
• Radiation induced polymerisation using a ⁶⁰Co source
   
• Detection of 14C-PMMA in the rocks with autoradiography
   
• Digital image analysis of beta autoradiographs (*) to provide spatial porosity distribution of the rocks

The following steps were performed during the in-situ experiment at the GTS:

• Drying of the intact rock by air ventilation
   
• Injection of 14C-PMMA into the rock matrix
   
• Polymerisation of 14C-PMMA by heating
   
• Overcoring of the resin impregnated matrix
   
• Detection of the 14C-PMMA in the granite matrix using beta autoradiography techniques (*)

(*) The location of the 14C-PMMA on the rock samples can be determined by placing a thin, plastic film over the rock sample. The beta particles from the 14C-PMMA in the rock matrix interact with the film and leave a unique signal. The films are analysed in an instrument that converts the area where beta particles interacted with the film into an optical density in a technique called beta autoradiography. The images produced are called beta autoradiographs.

Pore Space Geometry (PSG) Experiment