Rock fracturing using expansive mortar

• Main Author: Lim, Xuan Ni
• Other Authors: Wu Wei (CEE)
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2024
• Subjects: Engineering; Civil engineering; Geotechnical
• Online Access: https://hdl.handle.net/10356/177589
• Institution: Nanyang Technological University

Expansive mortar, identified as a soundless chemical demolition agent (SCDA), provides a safe and efficient alternative to explosives, applicable in tasks such as concrete structure removal, surface rock breaking and underground excavation. Primarily composed of calcium oxide (CaO), expansive mortar undergoes hydration with water, leading to significant volumetric expansion and subsequent generation of expansive pressures capable of fracturing rock and concrete within predrilled holes. However, challenges persist due to inefficient expansion pressure generation, hampering its practical effectiveness. In this investigation, experimental research was undertaken to optimise expansive mortar performance specifically for rock fracturing applications in the context of Singapore. The study focused on enhancing expansive pressure generation by strategically adjusting expansive mortar configuration and experimental methodologies, including specimen standardisation, borehole diameter expansion, enhanced confining pressure with steel elements and substitution of commercial mortar. These enhancements resulted in consistent and predictable rock fracturing observed across limestone and granite specimens. Digital Image Correlation (DIC) analysis served as a critical tool, providing insights into deformation and fracturing behaviours exhibited by rock specimens subjected to expansive mortar, facilitating accurate interpretation of experimental outcomes and confirming the efficacy of optimised expansive mortar configurations tailored to Singapore's geological conditions.