It is important to doubt common knowledge established in the past when we face difficulty to seek further development based on them. In this presentation the importance of doubting common knowledge is pointed out for further endless development of the field of study by discussing stagnation of chloride ion ingress and liquid water penetration into concrete, stagnation of water pass through a crack in concrete and the inconsistency between Carbonation depth and cover concrete spalling risk.

• Toshiharu Kishi(Institute of Industrial Science, The University of Tokyo)