Influence of Ground Temperature on Shotcrete-to-Rock Adhesion in Tunnels

Table 5

Designed mix proportions for the bond strength improvement test [47].

Designed mix proportions	Description
BP	Basic mix proportion (no mineral admixture or the fiber material): cement: 400 kg/m^3; sand: 814 kg/m^3; gravel: 666 kg/m^3; water: 200 kg/m^3; accelerator: 20 kg/m^3
25% SP	25% of cement replaced by slag powder
25% FA	25% of cement replaced by fly ash
SF	1% (volume ratio) of steel fiber mixed
PF	0.9 kg/m^3 of polypropylene fiber mixed
DF	Double mix of 1% (volume ratio) of steel fibers and 0.9 kg/m^3 of polypropylene fiber