Study on Curing Kinetics of Low‐Viscosity Epoxy Grout Under Frontal Water Condition

ABSTRACT Low‐viscosity epoxy grout (LER) is susceptible to interference from frontal water during application, but the quantitative relationship between LER curing and frontal‐water conditions remains unclear. This study introduces the frontal water‐to‐grout ratio ( x ) as a quantitative parameter and examines LER curing under different frontal water conditions. Focused beam reflectance measurement (FBRM), isothermal microcalorimetry (TAM), rheological testing, in situ attenuated total reflectance infrared spectroscopy (ATR‐IR), and molecular simulation (MS) were employed. FBRM and TAM indicated phase separation within 3 min across the investigated x range of 0%–80%, while epoxy ring opening remained the dominant curing reaction. MS indicated that frontal water increased the curing energy barrier from 1800 to 2100 kcal mol −1 . ATR‐IR analysis identified two distinct curing stages: the induction period and the post‐induction period. At x = 80%, the apparent activation energy increased by 10.5 kJ mol −1 during induction and by 4 kJ mol −1 after induction. A novel LER curing‐kinetics model incorporating frontal water content over x = 0%–80% was established. The model provides a theoretical basis for analyzing and predicting the curing performance of organic grouting materials under water‐rich engineering conditions.