| Crack control is of great significance in reinforced concrete (RC) structures. but the control of crack width and length had not reached an ideal state as yet. Based on fracture mechanics theory, one kind of anti-cracking RC beams is fabricated by means of " filling cracks under loading ", namely, the RC beams are preliminary loaded to a certain crack width and then keep loaded while the cracks are being filled in the paper, performances of the RC beams with cracks filled under loading are tested and analyzed, and the following are the main conclusions:â‘ Compared with general RC beams, blow the loading level under which the cracks are being filled, the load-displacement relationship of the RC beams with cracks filled under loading present linearly elastic properties and much higher stiffness.â‘¡Cracking load of the RC beams with cracks filled under loading significantly increases, to a level equal to or even higher than the service loading level under which the cracks are being filled, and far higher than that of the general RC beams.â‘¢Generally, cracks of the RC beams with cracks filled under loading wouldn't appear just along the filled cracks, but on both sides of them. Both the RC beams with cracks filled under loading and general RC beams have some maximal crack heigh about 0.7 ~ 0.8 times the test beam height. There exist certain relationships among the crack widths and quantities before and after the crack filling.â‘£With the finite element software ANSYS, load- deflection curves and crack development of the general RC beams with different reinforcement ratios are calculated, and the results agree well with the tested data. At the same times, the finite element analysis verifies the theoretical analysis: at the same level of load, the crack-tip stress intensity factors of the RC beam is smaller than that of the plain concrete beam; higher the reinforcement ratio is, smaller the crack-tip stress intensity factor of the RC beam is.
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