Nondestructive Controlled Failure of Concrete based on Elastic-Wave Methods

应用弹性波方法研究了混凝土的受控破坏，主要包括声发射、冲击回波和超声波。针对既有混凝土结构，无损监测，破坏机理和损伤评估已经阐明。取得的成果总结如下：1。混凝土破坏机理的声发射（AE）识别AE技术已被应用于各种胶凝材料的破坏过程。从而阐明了混凝土及混凝土结构的破坏机理.混凝土结构断裂的无损监测裂缝和缺陷的无损监测已被研究。特别是，广泛研究了冲击回波和超声波的应用。通过SIBIE（基于冲击回波的频谱振幅叠加成像）程序实际执行内部缺陷的可视化3。基于弹性体的动力破坏机理 ...更多信息 对纤维混凝土的爆破破坏进行了理论研究，阐明了共振对破坏模式的影响。因此，可以监测混凝土在冲击载荷下的破坏过程，以及脉冲放电引起的动态破裂。后一种技术基本上应用于再生骨料的制造。断裂力学和损伤力学在可控破坏中的应用在国际研究人员的合作下，对水泥基材料的断裂力学和损伤力学进行了研究。SiGMA程序已开发的AE源（裂纹）的矩张量分析。现在可以直观地显示裂纹位置、裂纹类型和裂纹方向。通过边界元分析和声发射分析，阐明了细观尺度和宏观尺度下的开裂机理.混凝土受控破坏的无损监测基于弹性波法的测量技术已被建立用于受控破坏。根据混凝土的破坏模式从静力学到动力学，发展了相应的测试和分析技术。少

Controlled failure of concrete has been studied by applying the elastic-wave methods, which primarily include acoustic emission, impact echo and ultrasonic. Targeting existing concrete structures, nondestructive monitoring, failure mechanisms and damage evaluation have been clarified. Results achieved are summarized, as follows;1. Identification of failure mechanisms of concrete by acoustic emission (AE)AE techniques have been applied to failure process of a variety of cementitious materials. Thus, the failure mechanisms of concrete and concrete structures are clarified.2. Fracture monitoring of concrete structures by nondestructive evaluationMonitoring of cracks and defects has been nondestructively investigated. In particular, applications of the impact echo and ultrasonics are extensively studied. Visualization of internal defects by the SIBIE(Stack Imaging of spectral amplitudes Based on Impact Echo)procedure is practically performed3. Mechanisms of dynamic failure based on elastod … More ynamicsBlasting failure of fiber-reinforced concrete has been theoretically studied, and the effect of resonant vibration on failure modes is clarified. Thus, failure process of concrete can be monitored under impact loading, and dynamic fracturing due to pulse-discharge. The latter technique is substantially applied to fabrication of recycled aggregate.4. Application of fracture mechanics and damage mechanics to controlled failureWith the collaboration of international researchers, fracture mechanics and damage mechanics have been studied in cementitious materials. The SiGMA procedure has been developed for the moment tensor analysis of AE sources(cracks). Visualized presentation of crack location, crack type and crack orientation is now available. Cracking mechanisms at the meso-scale and the macro-scale are clarified by applying the boundary element method(BEM)analysis and AE analysis.5. Nondestructive monitoring for controlled failure in concreteMeasurement techniques based on the elastic-wave methods have been established for controlled failure. Depending on failure modes of concrete from statics to dynamics, proper measuring and analyzing techniques are developed. Less