Chloride attack Ⅱ/ Alkali silica reaction

[1127] THE EFFECT OF SEAWATER MIXING ON CORROSION OF STEEL BAR IN 36-YEARS OLD RC BEAMS UNDER MARINE TIDAL ENVIRONMENT

Dahlia Patah¹, Hidenori HAMADA², Yasutaka SAGAWA², Daisuke YAMAMOTO² (1.Kyushu University, 2.九州大学)

Keywords:seawater mixing、 corrosion、 corroded area、 microstructure、 RC beam、海水練り混ぜ、腐食、腐食面積、微細構造、鉄筋コンクリート梁

Visual observation, chloride ingress, porosity, and corrosion of steel bars in RC beam made with seawater and tap water were investigated in this paper based on 36 years of exposure under marine tidal environment. After long-term exposure, seawater mixing shows better performance against corrosion of steel bar as well as strength, concrete resistance, oxygen permeability and microstructure compared with tap water mixing. It shows high possibility to use seawater as mixing water with precautions, such as minimum 50mm in cover depth which has influence significantly for the service life of RC structure.