Experimental Assessment on the Flexural Bonding Performance of Concrete Beam with GFRP Reinforcing Bar under Repeated Loading

Table 2

Stress levels in the fatigue bond test.

Specimens	Bond strength at static test (MPa)	Applied stress level (%)	Applied bond stress (MPa)	Slip at ultimate load (mm)	Number of cycles	Residual bond strength after 2 million loadings (MPa)	Failure mode
(45 mm)	15.1	70; 75; 80; 90	11.4; 12.2; 13.0; 14.7	0.175; —; —; —	2,000,000; 1,516,231; 29,268; 3,804	10.5; —; —; —	P
(90 mm)	10.2	70; 80	7.7; 8.8	0.083; —	2,000,000; 81,063	6.4; —	P
(135 mm)	7.5	60; 75; 80; 85	4.8; 6.0; 7.2; 7.7	—; —; —; —	2,000,000; 1,981,582; 193,972; 114,413	3.9; —; —; —	CS

Pullout failure and concrete splitting failure.