This study examines the preparation of high-strength sleeve grout incorporating basalt and polypropylene fibers, with a focus on the effects of fiber content and freeze-thaw cycling on its fundamental properties. Results indicate that a mix containing 0.05% polypropylene fiber and 0.05% basalt fiber delivers optimal performance. An appropriate fiber dosage does not substantially compromise fluidity, yet it significantly improves flexural strength, enhances toughness, and reduces mass loss after freeze-thaw exposure. Furthermore, such a mix mitigates strength degradation under specific freeze-thaw conditions. It is also shown that a slow pressurization process following freeze-thaw cycles can effectively exploit the toughness of the fiber-reinforced material, consistent with conditions encountered in practical applications.