建立再碱化技术修复火害后钢筋混凝土之pH值控制模式

Abstract

由火害后钢筋混凝土内部钢筋腐蚀主要是因为钝化膜被破坏，而钝化膜破坏的主要原因是钢筋周围的碱性环境的消失。因此利用再碱化技术控制火害后钢筋混凝土周围的OH−的浓度。本研究主要建立以再碱化后钢筋周围溶液的pH值为目标的控制模型。根据试验建立了以控制混凝土保护层内的pH值为目标的再碱化控制模型为 ，j为电路流密度(A/m2)，T为通电时间(s)，d为中性化深度(mm)，fcu为火灾后混凝土实际强度(MPa)，k为孔隙率的参数。本研究估计火害普通强度的混凝土孔隙率参数k值为6.3 × 10−4，而火害高强度的 值2.5 × 10−5，该模式可应用于以再碱化技术修复火害后钢筋混凝土的pH的估计。 The passive film in internal reinforcement corrosion was destroyed by the fire-damaged of rein-forced concrete. However, the destruction of the passive film is caused by the disappearance of the alkaline environment around reinforced corrosion. This study was to establish the modeling pH value for electrochemical realkalisation to repair of fired-damaged reinforced concrete. The pH value of fire-damaged reinforced concrete is determined by the equation , in which j is the circuit current density (A/ m2), T is power-on time (s), d is neutral depth (mm), fcu is actual strength of concrete after fire-damaged (MPa), k is the parameter of porosity. The parameter of k of porosity for the or-dinary strength fire-damaged is 6.3 × 10−4, while the high-intensity fire-damaged is 2.5 × 10−5. This equation can be used to estimate the pH value for fire-damaged reinforced concrete to repair by electrochemical realkalisation.