Effects of Pulverized Fuel Ash (PFA) on the bond strength of Self Compacting Concrete (SCC) with different diameter of embedded steel bars

This project was done to determine the effects of Pulverized Fuel Ash (PFA) on the bond
strength of Self Compacting Concrete (SCC) with different diameter of embedded steel
bars. PFA act as cement replacement material used at different percentages such as 5%,
10% and 15% and there were three sizes of steel bars diameter used in this project such
as 10 mm, 12 mm and 16 mm. To establish the bond strength or stress of SCC to the steel
bar, 9 samples of cylinder for each mix with single bar embedded inside will undergo the
pull-out test. Two sets of sample were cast which set 1 has a constant embedded area
while set 2 with embedded length of steel bars equal to 15 times the diameter of bar. The
experimental bond strength value is given by pull out force divided by the effective
embedded area of the steel bar while the theoretical value is determined by 0.5 times the
square root of the compressive strength data. The results for slump flow are taken to
determine the flow ability of the SCC. Based on the results, addition of more PFA to SCC
did not affecting significantly to the bond strength at 28 days but have effects on the
slump flow of SCC. Addition of PFA improves the slump flow of SCC. By using 12 mm
steel bar, the bond strength value for both set are steadier compared to 10 mm and 16 mm
bars. For set 1 with constant embedded steel bar area, bigger bar diameter gives better
bond strength while for set 2 with embedded length of steel bar equal to 15 times the bar
diameter, 12 mm bar gives better bond strength