AbstractTo repair microcracks in cast-in-place concrete bridge decks and improve the quality of bridge deck pavement, low-viscosity epoxy grouting material was prepared. The effects of different diluent types and dosages on the viscosity, operable time, and mechanical properties of the epoxy grouting materials were compared. The variation of the bond strength, tensile strength, and engineering strain of the grouting material with the dosage of the active diluent (AD-I, AD-II, and AD-III) was explored. Based on the reconstruction data envelopment analysis (DEA) method, a model for optimizing the composition of the grouting material was established. The results show that the initial viscosity and 30-min average viscosity of the epoxy grouting material initially decreased rapidly, then declined more slowly. When the dosage of active diluent was 15%, the operable time increased more than 150% compared with the epoxy grouting material without active diluent. The tensile strength and engineering strain of the epoxy grouting material at low temperature first increased slightly and then decreased rapidly. The tensile strength at room temperature and high temperature was basically the same as that at low temperature, while the engineering strain increased overall. The bonding strength of the epoxy grouting material increased slightly first and then decreased rapidly with the addition of AD-I and AD-II active diluent and decreased rapidly with the increase of AD-III active diluent. Through reconstruction and optimization of the DEA method, the final optimal epoxy grouting material formulations were found to be AD-I-15, AD-II-15, AD-III-10, and the dosage of AD-I, AD-II, and AD-III active diluent accounts for 15%, 15%, and 10% of the epoxy resin, respectively. The low-viscosity epoxy grouting material prepared in this study had excellent groutability and mechanical properties, which can provide an effective guarantee for the repair of microcracks in cast-in-place concrete.