Can shotcrete be effectively used to repair holes in an old 8 ft (2.4 m) diameter storm sewer tunnel constructed of stone/brick/mortar? One of the holes is completely worn through to the earthen backfill material. The other two holes are missing the innermost layer of stone masonry, but the outer layer of masonry is still in place.

The friction coefficient n of well-finished shotcrete for use in Kutter’s equation (and, more streamlined, Manning’s equation) is generally used as 0.012. Shotcrete is used not only to improve flow characteristics of brick, corrugated metal, or any other pipe construction but can also be conventionally reinforced as a structural liner to eliminate the need for liner plates or other pipe-lining alternatives.