This paper discusses the bond characteristics of GFRP bars in high performance concrete (HPC) 

by pullout testing of GFRP bars embedded in concrete cube samples. Two types of GFRP bars 

with ribbed or sand-coated surface were used with or without casted head. The nominal bar 

diameters used for sand-coated bars were 15.875 and 19.05 mm and for ribbed surface bars were 

16 and 20 mm. The surface dimension of concrete cubes was 300×300 mm for headed end bars 

and was 200×200 mm for straight end bars. Three embedment lengths of 4, 6, and 8db were used 

for straight end bars, while it was 0 or 4db plus the head length for headed end bars, where db is 

the bar diameter. To investigate the effect of concrete clear cover on the bond behaviour, three 

cases of centric, 40 and 60 mm clear cover were used for 16 mm bars, while only centric and 40 

mm clear cover were used for 19 and 20 mm bars. Five identical cube samples were casted for 

each case as prescribed by the code. In total, 250 concrete cube samples were casted due to 

different bar type, head, and diameter and also embedment depths and concrete clear cover. 

Pullout tests were carried out to obtain associated failure loads. Experimental results were 

compared with available formulas for development lengths in the building and bridge codes and 

application of any adjustment factor was discussed. Load-slip behaviour of the bars on both free 

and loaded end was also studied.