広島で被爆したrc造建篵物における材齢70年のコンクリートの謙物性

摘要

The purpose of the experiments in this paper is to clarify the physical and dynamic properties of the concrete at seventy years age which was suffered from atomic bombing at 1945 in Hiroshima The compressive strength and Young's modulus of the concrete by the side of an atomic bombed place showed the value lower than the other concrete specimens. The coefficient of water absorption of the concrete was very high and it became clear that there was almost no freeze dissolution resistance. And neutralization of concrete was progressing very unusually. Moreover, as concerns the concrete by the side of an atomic bombed place, neutralization from the outdoors side was higher than that of inner side. It is considered to have influenced the above-mentioned examination result greatly that especially concrete temperature rose in 500 degrees C - 750 degrees C . The necessity for performing carefully the maintenance of the RC building which was suffered from atomic bombing was shown by this research.%筆者らの調査では広島市には22件の被爆RC造建築物が現存 しており、これらの被爆建築物を平和モニュメントとして有効活 用しながら保存するか、構造安全性の見地から解体・建替えを行 うかは、慎重に議論をすべきところである。戦前に建設され60 ～70年が経過した被爆建築物の多くは老朽化が進み、本朝で示す 広島県立広島商業高等学校本館（以下、調査建築物と記す）も生 徒や職員の安全性確保の観点から一昨年に解体された。解体に当 たり広島県教育委員会の協力を得てコンクリートや鉄筋の試験 片を入手でき、当時の建築構造材料の物理的、化学的な品質につ いて基礎的な試験を行うことができた。