2014 Volume 70 Issue 2 Pages 153-165
In order to evaluate the utilization of anti-washout underwater concrete for RC marine submerged structures, RC beam specimens and cylindrical specimens prepared in artificial seawater have been exposed into actual marine environment in Tokyo bay for 20 years. RC beam specimens were arranged for four types of beam specimens (with or without flexural cracks, with a concrete cover 40mm or 70mm). This report describes a series of test including tests on flexural capacity and reinforcement corrosion of RC beam specimens, and physical properties of concrete such as compressive strength, Young's modulus, ultrasonic wave propagation velocity and chloride content. The results of test showed RC beam specimens have kept on sufficient flexural capacity as compare with the design requirement after 20 years marine exposure. The prediction the future change of flexural capacity of RC beam specimens was conducted, and it can be said RC beam specimens could maintain sufficient performance over 100 years long. Furthermore, the progressive period until the initiation of longitudinal cracking on RC beam specimens could be estimated approximately 69 years.
