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1 前言超声技术在混凝土中的应用受到工程技术界普遍重视,得到了迅速发展.目前超声技术主要应用于检测混凝土构件的强度,缺陷和裂缝.根据超声波原理,我们将此技术应用于大骨料大尺寸混凝土断裂韧性试验中,追踪测定三点弯曲试件的断裂过程.测定了加载过程中,与微裂缝等效的主裂缝的扩展长度,以及主裂缝形成后裂缝扩展过程和长度,取得了较多的数据,结果较好.特别是△α/h,α/W 和K_(IC),以及临界荷载与最大
1 Introduction The application of ultrasonic technology in concrete has received widespread attention from the engineering and technical community and has been rapidly developed. Currently, ultrasonic technology is mainly used to detect the strength, defects and cracks of concrete components. According to the ultrasonic principle, we apply this technology to large aggregates. In the fracture toughness test of large-size concrete, the fracture process of the three-point bending test piece was traced and measured. The extension length of the main crack equivalent to the micro-crack in the loading process was measured, and the crack propagation process and length after the formation of the main crack were obtained. More data, the result is better. Especially △α/h, α/W and K_(IC), and critical load and maximum