Kei-ichi IMAMOTO: A novel approach towards conservation of the world heritage RC building in Japan

Kei-ichi ImamotoAbstract: The National Museum of Western Art (NMWA) of Japan, designed by Le Corbusier and constructed in 1959, has been the world heritage.  This paper reports on the degradation and deterioration of the structural concrete members of the NMWA, such as the steel corrosion due to carbonation of concrete.  Non-destructive test (NDT) methods were employed for measuring the air permeability of the concrete cover and the cover thickness in order to assess the steel bar corrosion risk due to carbonation.  It was found that this historical reinforced concrete structure would face to the significant degradation.  According to idealized steel corrosion reaction in concrete, it can be understood that prevention of moisture ingress into concrete would be effective to prevent steel corrosion.  Authors carried out round robin tests of impregnation agents from viewpoints of prevention capacity of moisture ingress into concrete and change of appearance of concrete surface. Finally, authors applied the selected agent to the exposed concrete of NMWA and evaluated the effectiveness of impregnation agent on-site NDT method with surface electric resistivity. This paper will provide a perspective to conserve historical buildings, whose authenticity should be maintained.