Elucidating the Alkali-Activated Dissolution Mechanisms in Boehmite-based Cementitious Composites Under Enhanced Geothermal Conditions Using In-situ Synchrotron Characterization

Abstract

The widespread adoption of enhanced geothermal systems has the potential to revolutionize global renewable electrical power access. However, its progress is currently obstructed by the inability of traditional cement formulations to endure high-temperature corrosive conditions. This study focuses on a novel alkali-activated boehmite cementitious system specially designed for enhanced geothermal wells, where rationalizing the thermal-induced phase transitions is pivotal for their mechanical performance under high-temperature and high-pressure environments. During the hardening process of alkali-activated cements, a complex interplay of dissolution and crystallization processes takes place, critically influencing the development of mechanical properties. Utilizing synchrotron-based hard X-ray diffraction, we investigate these dynamics in real-time to elucidate the mechanisms underpinning the solidification process under EGS relavent conditions. The solidification mechanism established in this work provides valuable insights for optimizing the performance of alkali-activated boehmite cementitious materials for high-temperature geothermal applications.