In this article, we will briefly present and discussImpact-Echo(IE)混凝土结构测试方法。我们将回顾这项技术背后的概念。我们还将研究IE方法的应用和局限性How to Test Concrete Using Impact-Echo Method.该测试方法已被美国测试材料学会(ASTM C1383) (1), “Standard Test Method for Measuring the P-Wave Speed and the Thickness of Concrete Plates Using the Impact-Echo Method.”
What is Impact-Echo Method?
Impact-Echo是评价混凝土和砖石结构的一种无损检测方法。该测试利用冲击器(Impact)撞击混凝土时通常产生的应力波(声音)，并记录来自内部缺陷和其他边界(Echo)的反射和折射。一般来说，脉冲是由单点的撞击产生的。由此产生的应力波向四面八方传播。在这方面，所产生的波缺乏由大型换能器产生的脉冲的方向性超声波脉冲速度)．由于反射来自各个方向，所以这种测试方法在细长的单元中最有效，例如外部边界引导波穿过桩的桩。在这种特殊的应用中，测试被标准化为低应变桩完整性测试。阅读更多关于桩完整性测试。
The Concept Behind Impact-Echo Method
冲击-回波测试的概念在图吹中得到了说明。对混凝土表面的机械冲击被用来产生应力波。The generate stress pulse propagates throughout the concrete along spherical wave fronts as P- and S-waves.Another component is the surface wave (R) which travels along the surface.
As P- and S- waves propagate within concrete element, they get reflected by internal interfaces (concrete-crack, concrete-air, concrete-rebar) or external boundaries.The arrival of these echos on the surface induces displacement.This displacement can be measured by placing a sensitive transducer (which then converts displacement or acceleration into electrical voltage).Data is recorded by a data acquisition and data logging system.
分析Impact-Echo数据
Data analysis can either be done in Time Domain, or the Frequency Domain.While time-domain analysis looks to be a very good an easy way of data interpretation for slender elements (as in the case of pile integrity test), it can be way too complicated in the case of thin slabs.For these components, analysis of the signal in frequency domain is preferred.
Fast Fourier transform (FFT) technique is used to analyze the frequency content of the digitally recorded wave.In this method, a waveform can be represented as a sum of sine curves, each with a particular amplitude, frequency, and phase shift.According to N. J. Carino (2) The method is used to calculate the amplitude spectrum of the waveform, which gives the relative amplitude of the component frequencies in the waveform.
Applications of Impact-Echo Technique
冲击回波是一种非常实用的测试方法，在混凝土结构状态评估中有着广泛的应用。该测试可用于:
1-测量混凝土板和墙的厚度
2-测量混凝土墙和隧道衬砌的厚度
3-查找混凝土桥面分层等缺陷。
4- Evaluate the condition of concrete retaining walls, dams, tunnel linings, sea walls.
由罗格斯大学、德克萨斯大学埃尔帕索分校和联邦材料研究与测试研究所(BAM)的研究人员最近进行的一项研究发表在国家科学、工程和医学科学院(简称为SHRP2(3)总结了Impact-Echo方法的一些最广泛的应用。
参考文献
1- ASTM C1383-15，用冲击回声法测量混凝土板p波速度和厚度的标准试验方法，ASTM International, West Conshohocken, PA, 2015，www.astm.orgDOI:10.1520 / C1383-15
2- M.马尔霍特拉，V &卡里诺，尼古拉斯。(2004)。混凝土无损检测手册。CRC出版社公司。
3-美国国家科学、工程和医学科学院，2012。Nondestructive Testing to Identify Concrete Bridge Deck Deterioration．华盛顿:美国国家科学院出版社。https://doi.org/10.17226/22771。
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I like how you mention that using the impact-echo technique can be used to measure the thickness of concrete slabs and walls as well as tunnel lining and bridge decks.The impact-echo method is a non-destructive method that’s used to evaluate standing concrete and masonry structures to determine their structural soundness to check whether or not they are up to quality standards.While I haven’t the faintest idea on how to use this method, at least I can say from the information given that it can prove to be potentially beneficial for building safety in the long run.
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好文章!我发现这非常有用，特别是对我们的业务。
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