Tsuyoshi Maruya

Degradation of concrete buried in soil with saline ground water

Abstract This study has been carried out to collect information on the degradation sequence of concrete buried in soil. We obtained concrete aged for 60 years and 100 years buried in soil saturated with saline ground water and investigated not only the physical properties but also the change in composition of the hydrated phases along the distance from the surface contacted with soil. Significant changes of pore size distribution, pH of concrete soak solution, CaO/Insoluble-fraction ratio of concrete, composition of hydrated phases and CaO/SiO2 ratio of C-S-H were observed along the distance from surface contacted with soil. From these results, it was possible to obtain important information for estimating the degradation sequence of concrete in soil saturated with saline ground water.

MAINTENANCE OF RC HOLLOW SLAB BRIDGE DAMAGED BY FREEZING PREVENTING AGENT AND CONTAMINATED SALT

内部塩分と凍結防止剤によって塩害を受けたRC中空床版橋に対し, 設計耐用年数100年を想定した包括的な維持管理の検討を行った. 対象とした橋りょうは, 鉄筋の腐食, コンクリートのひび割れ, はく離等が著しく, 早急な補修対策が必要になった. 現状の劣化状況およびニューラルネットワーク手法を用いた劣化予測により, 主筋背後30mm以上のはつりとかぶり55mm以上の断面修復が必要であることが判明した.