Use of electrodeposition to realise the crack-healing and pore-filling of weathered rock: A small specimen case

Abstract

Medium- to long-term weathering phenomena is one of the major causes of rock instability. Although many geo-protection technologies have been developed to mitigate the hazards such as slope failures of natural rock weathering, these techniques provide no self-healing function of the rock around the facilities. The status quo in rock instability problems is to provide rock maintenance and to constantly monitor the situation depending on the particular conditions. Improper rock maintenance comes with the risk of critical accidents which may result in human casualties as well as significant environmental destruction. It is therefore necessary to develop novel techniques to realise the continuous healing of weathered rock in the medium- and long-term. In this study, the electrodeposition method was applied for the first time to heal weathered rock mass in a series of fundamental experiments, using volcanic tuff sampled in Japan as the weathered rock model. It was noted that a reduction reaction occurs around the cathode side, and the electrodeposits fill the pores and cracks in the rocks selectively, thereby improving the surface hardness in a small specimen scale. Moreover, the application of a weak current over a lengthy period was shown to facilitate the deposition of stable crystals, such as calcite and magnesian calcite. The results of this study on electrodeposition on unstable rock formations show the potential of crack-healing and pore-filling in a self-organised manner.