Highly powder-resistant backfill grout and its backfill grout material

摘要

To provide a backfill group having enhanced resistance to pulverization by repeated load, and a backfill group material thereof.SOLUTION: There are provided a backfill grout material containing a base grout material consisting of cement, a rapid hardening material, a short fiber, a water reducing agent and a setting modifier, with milling them to have content of the rapid hardening material of 1 to 6 mass%, content of the water reducing agent of 0.05 to 1.0 mass%, content of the setting modifier of 0.0 to 3.0 mass%, content of the short fiber of 0.01 to 0.5 vol.% based on volume of the backfill grout, and a water grout material ratio (W/B) of 35 to 65%, in which flow-down time of a JA funnel test is 26 sec. or less, bleeding is not generated, and compression strength at material age of 7 days after hydration hardening is 25 N/mmor more, and a backfill grout formed by the backfill group material.SELECTED DRAWING: Figure 1