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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No other units of measurement are included in this standard. Measurement of P-wave speed by surface method. Historical Version s – view previous versions of standard.
The limits shall be specified by manufacturer of the apparatus, and the apparatus shall not be used beyond these limits. The frequency of P-wave arrival is determined as the frequency with a high peak in the amplitude spectrum.
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. These notes and footnotes excluding those in tables and figures shall not be considered as requirements of the standard. Furthermore, it is not possible to determine the depth to anomalies.
When the P-wave reaches the tip of the crack, the crack tip acts as a P-wave source, a process called diffraction.
The P-wave is then reflected back into the member and the astn begins again. 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. Impact-Echo TestThis 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.
NDT System Add-On — Impact Echo
Proceed to Checkout Continue Shopping. With the LONGSHIP two-transducer assembly, the transducers are placed mm apart and the impactor is about mm from one of the transducers one the line passing through the transducers. This assumes that the P-wave speed is uniform with depth.
Lastly, the IE method will provide information on the depth of a flaw or defect, in addition to mapping its lateral location and extent. Click here for Agents. If the document is revised or amended, you will be notified by email.
These minimum lateral dimensions are necessary to prevent other modes 3 of x1383 from interfering with the identification of the thickness mode frequency in the amplitude spectrum. Astn, Cp may be determined by measuring the time for the P-wave to travel between two transducers with a known separation.
If the interface between the concrete and subgrade is rough, the amplitude spectrum will have a rounded peak instead of a sharp peak associated with a flat surface. Thus the c13833 equation for thickness calculation is: 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 ast, 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.
Testing for quality of grout injection in cable ducts located by ground penetrating radar.
Thus the P-wave undergoes multiple reflections between the two surfaces. The recorded waveform of surface displacement has a periodic pattern that is related to the thickness of the member and the wave speed. The same principle applies to reflection from an internal defect delamination or void.
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 thickness frequency. If the defect is just large enough to be detectable, the amplitude spectrum will show two peaks: It is available on a consulting basis through our sister company, Olson Engineering.
ASTM C Standard
DOCter Purpose 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. Subscription pricing is determined by: All of Olson Instruments have been researched, tested, and used on-site daily by our sister company, Olson Engineeringworld reknowned for NDT consulting. As explained in Note 12the minimum lateral dimensions and acceptable sampling period are related.
Complete Docter Brochure Docter Publications. The explanation for this 0. These drawbacks are eliminated by using the impact-echo method, which requires access to only one surface. The Viking software allows the user to place cursors at the points corresponding to the P-wave arrivals, and calculates the value of Cp. Work Item s – proposed revisions of xstm standard. Please first verify your email before subscribing to alerts.
Thus, the impact-echo method is able to determine the location of internal defects as well as measure the thickness of a solid member. Please first log in with a verified email before subscribing to alerts.