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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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. The DOCter can also be used to measure the depth of surface-opening cracks, using a time domain analysis. IE investigations can also be performed to predict the strength of early age concrete if the member thickness is known. These drawbacks are eliminated by using the impact-echo method, which requires access to only one surface.
Subscription pricing is determined by: We have no amendments or corrections for this standard. A short-duration stress pulse is introduced into the member by mechanical impact.
The Spider multiple impactor unit can be purchased as an option to increase the operating range of the systems. 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 wave speed of a material.
The diffracted P-wave is detected by the transducer on the opposite side of the crack from the impact. 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: A negative reflection coefficient means that the stress adtm sign when the stress wave is reflected; for example, a compressive stress would be reflected as a tensile stress.
The P-wave speed is calculated by dividing the distance between the two transducers by the travel time. Work Asrm s – proposed revisions of this standard.
ASTM C Standard
Example The upper plot in this example shows the surface displacement waveform obtained from a test of a solid concrete slab. Thus, the impact-echo method is able to determine the location of internal defects as well as measure the thickness of a solid member.
These notes and footnotes excluding those in tables and figures shall not be considered as requirements of the standard. Impact-Echo Test— This procedure measures the frequency at which the P-wave generated by a short-duration, point impact is reflected between the parallel opposite surfaces of a plate. It is the responsibility of the asttm of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
If the wave speed is determined by the surface measurement method, the resulting value is multiplied by 0. Thus the P-wave undergoes multiple reflections between the two surfaces. 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.
These notes and footnotes excluding those in tables and figures shall not be considered as requirements of the standard. No other units of measurement are included in this standard. P-Wave Speed MeasurementThis procedure measures the time it takes for the P-wave generated by a short-duration, point impact to travel between two transducers positioned a known distance apart along the surface of a structure. All of Olson Instruments have been researched, tested, and used on-site daily by our sister company, Olson Engineeringworld reknowned for NDT consulting.
Depth of Surface-Opening Cracks The DOCter can also be used to measure the depth of surface-opening cracks, using a time domain analysis. Measurement of P-wave Speed The figure is an example of the measurement of P-wave speed by using two transducers a known distance apart.
Detection of delaminations and honeycomb in sewer pipe. The limits shall be specified by manufacturer of the apparatus, and the apparatus shall not be used beyond these limits.
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Furthermore, it is not possible to determine the depth to anomalies. If these conditions are not satisfied, the waveform will be of low amplitude and the amplitude spectrum will not include a dominant peak at the frequency corresponding to the thickness Eq 2. The frequency associated with the portion of the P-wave that travels around the defect will be shifted to a lower frequency value than the solid plate asrm frequency. A sensitive displacement transducer next to the impact point picks up c13883 disturbance due to the arrival of the P-wave.
The use of traditional stress wave methods, such as ultrasonic through transmission, to identify the presence of anomalies in structures aetm access to both faces of a member. You may delete a document from your Alert Profile at any time. This standard is also available to be included in Standards Subscriptions.
NDT System Add-On — Impact Echo
In impact-echo testing, the P-wave is used to obtain information about the member. The peak at The thickness is calculated from this measured frequency and the P-wave speed obtained from Procedure A. This impact generated three types of stress waves that propagate away from the impact point. Thus the correct equation for thickness calculation is: It is available on a consulting basis through our sister company, Olson Engineering.
No other units of measurement are included in this standard. CTG-2 requires Windows Device. Interface Reflection Coefficient Concrete-air Measure the thickness of pavements, asphalt overlays, slabs-on-ground and walls Detect the presence and depth of voids and honeycombing Detect voids below slabs-on-ground Evaluate the quality of grout injection in post-tensioning cable ducts Integrity of a membrane below an asphalt overlay protecting structural concrete Delamination surveys of bridge decks, piers, cooling towers and chimneystacks Detect debonding of overlays and patches Detect ASR damage and freezing-and-thawing damage Measure the depth of surface-opening cracks Estimate early-age strength development with proper correlation Principle A short-duration stress pulse is introduced into the member by mechanical impact.
The P-wave speed is determined by testing over a solid portion of a plate with known thickness. The figure is an example of the measurement of P-wave speed by using two transducers a known distance apart.
Please first log in with a verified email before subscribing to alerts. This standard is not included in any packages. The recorded waveform of surface displacement has a periodic pattern that is related to the thickness of the member and the wave speed.
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