Diagnosis, Preservation and Strengthening System for Concrete Structures in Cold Region

本研究的目的是对寒冷地区混凝土结构的现状进行诊断，并建立混凝土结构的保存和加固系统。现场评估项目包括肉眼检查、超声波测速、施密特锤法无损强度评估、碳化深度和保护层混凝土厚度。本次调查的结果表明，混凝土结构的劣化是通过这些无损检测来评估的。为了估计深度方向的劣化，进行了钻机的爆破试验。由于热分析预测的冻融循环次数与无损检测的强度相对应，因此这些试验将能够应用于使用寿命的预测、维修和加固设计。渗透性、氯离子含量、pH和强度试验是耐久性评估的主要试验方法。分别研究了涂装(面层)、FRP片材粘结、外索加固等加固方法，并对加固效果进行了评价。

The purpose of this study is initiated to diagnose the situation and develop preservation and strengthening systems for concrete structures in cold region.Actual structures were investigated to consider diagnosis method. Items in place assessment were visual inspection, velocity measurement of ultra sonic, non-destructive strength estimation by Schmidt hammer, depth of carbonation and thickness of cover concrete. The result of this investigation shows the deterioration of concrete structures is evaluated by these non-destructive tests.Excavation test by the drill was carried out for the purpose of estimating the deterioration of depth direction. As the result, the power expressed by the product of drilling speed and the force showed high correlation with the concrete strength.As predicted number of freeze-thaw cycles by thermal analysis corresponds to the strength of non-destructive tests, these tests will be able to apply for the prediction of service life, repairing and strengthening design.Tests for permeability, chloride content, pH and strength are major test methods for the durability assessment. These tests form a system of the diagnosis for concrete structures.The strengthening methods such as painting(surface coating), FRP sheet bonding and external cable are investigated and the effect of strengthening are evaluated, respectively.