Recent advances in grouting materials and their reinforcement mechanisms

Grouting materials, typically dense liquids, play a crucial role in reinforcing and sealing structures by effectively filling and repairing the pores in existing building systems. This paper provides a comprehensive overview of recent advancements in physical, chemical, composite, and environmentally friendly grouting materials. Emphasis is placed on the modifications of physical grouting materials, including silicate cement, sulfoaluminate cement, and ultrafine cement-based variants, which are widely used due to their robust performance. Among these, ultrafine cement-based grouts exhibit injection properties similar to those of chemical grouts, yet without the need for chemical additives, presenting significant potential for application. The paper also explores the latest advancements in the modification of chemical grouting materials, such as acrylic salts, epoxy resins, and polyurethanes, which offer diverse properties tailored to specific engineering needs, progressively replacing traditional cement-based solutions. Additionally, the paper synthesizes key grouting reinforcement theories, including permeation, fracturing, and compaction grouting, which together optimize the overall effectiveness of the grouting process. Finally, the paper identifies current challenges in the research on grouting materials and proposes promising directions for future development.