Experimental Study of Friction Resistance between Steel and Concrete in Prefabricated Composite Beam with High-Strength Frictional Bolt

Table 1

Summary of the test specimens.

Group	Specimen	Concrete	Steel	Surface treatment of steel
Group 1	S1–S3	C40	Q235	Shot-blasted
Group 2	S4–S6	C50
Group 3	S7–S9	C60
Group 4	S10–S12	C60 + PP fiber
Group 5	S13–S15	C60	Q345
Group 6	S16–S18	C60	Q235	Rusty
Group 7	S19–S21	C60	Q235	Cleaned by metal brush