This standard is issued under the fixed designation C ; the number 1 This test method is under the jurisdiction of ASTM Committee C-9 on Concrete. Purchase your copy of ASTM C – 15 as a PDF download or hard copy directly from the official BSI Shop. All BSI British Standards available. mm. Thickness Measurement by ASTM C Accurate measurement of thickness requires knowledge of the in-place P- wave speed. ASTM C, “Test .
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This assumes that the P-wave speed is uniform with depth. The following lists the reflection coefficients of a P-wave travelling through concrete and incident normal to an interface with air, water, soil, or steel:. In impact-echo testing, the P-wave is used to obtain information about the member.
The impact-echo method is based on monitoring the periodic arrival of reflected stress waves and is able to obtain information on the depth of the internal reflecting interface or the thickness of a solid member.
Zstm Version s – view previous versions of standard. When the P-wave reaches the back side of the member, it is reflected and travels back to the surface where the impact was generated. Already Subscribed to this document.
NDT System Add-On — Impact Echo
Powered by WordPress Theme Designed by: If the document is revised or amended, you will be notified by email. The thickness T of the member is related to this thickness frequency f and wave speed Cp by this simple approximate equation see below: Furthermore, it is not possible to determine the depth to anomalies.
The use of traditional stress wave methods, such as ultrasonic through transmission, to identify the presence of anomalies in structures requires access to both faces of a member. Impact Echo IE investigations are performed to assess the condition or thickness of slabs, beams, columns, walls, pavements, runways, tunnels, and dams.
Standards Subscriptions from ANSI provides a money-saving, multi-user solution for accessing standards. Lastly, the IE method will provide information on the depth of a flaw or defect, in addition to mapping its lateral location and extent. Thus the P-wave undergoes multiple reflections between the two surfaces.
The upper plot in this example shows the surface displacement waveform obtained from a test of a solid concrete asrm. The DOCter is a versatile, portable system based on the impact-echo method, and can be used for the following applications: These minimum lateral dimensions are necessary to prevent other modes 3 of vibration from interfering with the identification of the thickness mode frequency in the amplitude spectrum.
Docter | GERMANN
Olson offers Impact Echo systems for use with three different platforms as shown in the chart below. Standards Subsctiption may be the perfect solution.
Accurate measurement of thickness requires knowledge of the in-place P-wave speed. The diffracted P-wave is detected by the transducer on the opposite aastm of the crack from the impact. The LONGSHIP transducers are placed on opposite sides of the crack as shown in the sketch to the right and impact is generated on the line passing through the transducers.
ASTM C Standard
These notes and footnotes excluding those c1338 tables and figures shall not be considered as requirements of the standard. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. When the P-wave reaches the tip of the crack, the crack tip acts as a P-wave source, a process called diffraction. The frequency shift is a good indicator of the presence of a flaw if it is known that the plate thickness is constant.
The distance L mm between the transducers, is divided by c1833 difference t between arrival satm the P-wave at the second and first transducers. The displacement waveform is transformed into the frequency domain to produce an amplitude spectrumwhich shows the predominant frequencies in the waveform.
You may delete a document from your Alert Profile at any time. The thickness is calculated from this measured frequency and the P-wave speed obtained from Procedure A.
Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard. Detection of Internal Defects The P-wave generated by impact will reflect at interfaces within the concrete where there is a change in acoustic impedancewhich is defined as the product of the density and atsm speed of a material.
We have no amendments or corrections for this standard. The Spider multiple impactor unit can be purchased as an option to increase the operating range f1383 the systems. The figure is an example of the measurement of P-wave speed by using two transducers a known distance apart.