Mechanical Properties and Evaluation of Concrete Beams Made of a Large Amount of Fine Fly Ash

Nine reinforced concrete beams were fabricated and tested under monotonic shear and bending to investigate effects of the fine fly ash content on ultimate shear strength and deformation capacity of concrete beams. Taking the fine fly ash content, the shear span ratio, and the section size of beams as primary experimental variables, all test beams were prismatic beams and made of concrete with a water-to-cement ratio as low as 65%. Test results have indicated that increasing the fly ash content can enhance both ultimate shear strength and deformation capacity. The larger the quantity of fine fly ash, the higher the shear strength and the rotation angle at the peak shear. The use of 455 kg/m³ fly ash per unit volume in a concrete beam, which had no transverse hoops and had shear span ratio of 1.0, could enhance the ultimate rotation angle of the beam up to 0.02 radian.