Shear Behavior of High-volume Fly Ash Concrete as Replacement of Portland Cement in RC Beam

An experimental program was conducted to study the shear behavior of high-volume fly ash concrete as replacement Portland cement of Reinforced Concrete (RC) beams. Eight beam specimens were tested in this study. Two beams used normal concrete as control beams, while six others beams used High-Volume Fly Ash Concrete (HVFAC) as a replacement of Portland cement by mass (two beams with 50% of fly ash; two beams with 60% fly ash; and two beams with 70% of fly ash). The beams had longitudinal bars, and with stirrups were kept constant in the bending-test region. There were no shear reinforcements in the shear-test regions. The results showed that increasing substitutions of fly ash as replacement of Portland cement tend towards a reduction of shear strength and led the HVFAC beams became brittle. Comparing all the series of HVFAC beams that better results could be achieved by the beams with 50% of fly ash due to the higher shear strength than the beam with 60% and 70% of fly ash. The HVFAC beams failed in shear due to low shear strength of the beams.