The paper surveys a great deal of old concrete buildings which were built eighty years ago,measures the rebound value of old concrete components that bear differ stress,and designs a simulated experiment on aging concrete components,in order to analyze the cause of surface carbonization of old concrete.

Key elements have been presented including the investigation and analysis of resilience number of the old concrete and surface carbonization depth,the experimental contrast between th.

Based on that surface carbonization destroys passivation menbrane and the concrete s carbonizated layer(CaCO3) transfers from brittleness to plasticity gradually,the spreading of plastic crack causes corrosion of the steel bar,thus reduces bearing capacity of the concrete structure.