Evaluation of Micro- and Macroporosity in Bentonil-WRK Bentonite

Compacted bentonite buffer material plays a critical role in engineered barrier systems (EBSs) for high-level radioactive waste (HLW) disposal. Upon groundwater infiltration, the micro- and macropores within the bentonite structure undergo changes that induce swelling. Therefore, understanding the swelling behavior and hydraulic properties of compacted bentonite, considering both micro- and macropores contributions, is essential. In this study, the micro- and macroporosity of Bentonil-WRK bentonite, which has not been previously characterized, were determined using X-ray diffraction analysis. Additionally, the saturated hydraulic conductivity of compacted Bentonil-WRK bentonite was measured at various dry densities and compared with predictions from a modified Kozeny–Carman model that incorporates both micro- and macropore effects. The modified model accurately predicted saturated hydraulic conductivity, especially under low dry density conditions, highlighting the significance of considering macroporosity.