EN 12504-4-2004 en Testing concrete - Part 4 Determination of ultrasonic pulse velocity《结构中的混凝土试验 第4部分 超音波脉冲速率的测定》.pdf

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1、BRITISH STANDARD BS EN 12504-4:2004 Testing concrete Part 4: Determination of ultrasonic pulse velocity The European Standard EN 12504-4:2004 has the status of a British Standard ICS 91.100.30 BS EN 12504-4:2004 This British Standard was published under the authority of the Standards Policy and Stra

2、tegy Committee on 13 October 2004 BSI 13 October 2004 ISBN 0 580 44584 4 National foreword This British Standard is the official English language version of EN 12504-4:2004. It supersedes BS 1881-203:1986 which is withdrawn. The UK participation in its preparation was entrusted by Technical Committe

3、e B/517, Concrete, to Subcommittee B/517/1, Concrete production and testing, which has the responsibility to: A list of organizations represented on this subcommittee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publica

4、tions referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the neces

5、sary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the inter

6、pretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 14, an inside back cover and a b

7、ack cover. The BSI copyright notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsEUROPEANSTANDARD NORMEEUROPENNE EUROPISCHENORM EN125044 August2004 ICS91.100.30 Englishversion TestingconcretePart4:Determinationofult

8、rasonicpulse velocity EssaispourbtondanslesstructuresPartie4: Determinationdelavitessedepropagationduson PrfungvonBetonTeil4:Bestimmungder Ultraschallgeschwindigkeit ThisEuropeanStandardwasapprovedbyCENon26February2004. CENmembersareboundtocomplywiththeCEN/CENELECInternalRegulationswhichstipulatethe

9、conditionsforgivingthisEurope an Standardthestatusofanationalstandardwithoutanyalteration.Uptodatelistsandbibliographicalreferencesconcernings uchnational standardsmaybeobtainedonapplicationtotheCentralSecretariatortoanyCENmember. ThisEuropeanStandardexistsinthreeofficialversions(English,French,Germ

10、an).Aversioninanyotherlanguagemadebytra nslation undertheresponsibilityofaCENmemberintoitsownlanguageandnotifiedtotheCentralSecretariathasthesamestatusast heofficial versions. CENmembersarethenationalstandardsbodiesofAustria,Belgium,Cyprus,CzechRepublic,Denmark,Estonia,Finland,France, Germany,Greece

11、,Hungary,Iceland,Ireland,Italy,Latvia,Lithuania,Luxembourg,Malta,Netherlands,Norway,Poland,Portugal, Slovakia, Slovenia,Spain,Sweden,SwitzerlandandUnitedKingdom. EUROPEANCOMMITTEEFORSTANDARDIZATION COMITEUROPENDENORMALISATION EUROPISCHESKOMITEEFRNORMUNG ManagementCentre:ruedeStassart,36B1050Brussels

12、 2004CEN Allrightsofexploitationinanyformandbyanymeansreserved worldwideforCENnationalMembers. Ref.No.EN125044:2004:EEN 12504-4:2004 (E) 2 Contents page Foreword3 1 Scope4 2 Normative references4 3 Terms and definitions .4 4 Method4 5 Apparatus.4 5.1 General4 5.2 Performance requirements.5 5.3 Trans

13、ducers.5 5.4 Apparatus for determination of arrival time of the pulse 5 6 Procedures.5 6.1 Determination of Pulse Velocity.5 7 Expression of result7 8 Test report7 9 Precision.8 Annex A (informative) Determination of pulse velocity indirect transmission 9 Annex B (informative) Factors influencing pu

14、lse velocity measurements .10 B.1 General10 B.2 Moisture content10 B.3 Temperature of the concrete 10 B.4 Path length.10 B.5 Shape and size of specimen.10 B.6 Effect of reinforcing bars 11 B.7 Cracks and voids.11 Annex C (informative) Correlation of pulse velocity and strength.12 C.1 General12 C.2 C

15、orrelation using moulded specimens .12 C.3 Correlation by tests on cores .12 C.4 Correlation with the strength of precast units13 Bibliography 14 EN 12504-4:2004 (E) 3 Foreword This document (EN 12504-4:2004) has been prepared by Technical Committee CEN/TC 104 “Concrete and related products”, the se

16、cretariat of which is held by DIN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by February 2005, and conflicting national standards shall be withdrawn at the latest by February 2005. A draft stan

17、dard was submitted in 1998 to CEN enquiry as prEN 13296. It was one of a series of individually numbered test methods for fresh or hardened concrete. For convenience it has now been decided to combine these separate draft standards into three new standards with separate Parts for each method, as fol

18、lows: Testing fresh concrete (EN 12350) Testing hardened concrete (EN 12390) Testing concrete in structures (EN 12504) This series, EN 12504, includes the following Parts where the brackets give the numbers under which particular test methods were submitted to CEN enquiry: EN 12504, Testing concrete

19、 in structures Part 1: Cored specimens Testing, examining and testing in compression (former prEN 12504:1996) Part 2: Non-destructive testing Determination of rebound number (former prEN 12398:1996) Part 3: Determination of pull-out force (former prEN 12399:1996) Part 4: Determination of ultrasonic

20、pulse velocity (former prEN 12396:1998) This European Standard is based on ISO/DIS 8047 “Concrete hardened Determination of ultrasonic pulse velocity“. It is recognised that the ultrasonic pulse velocity determined using this standard is a convention in as much that the path length over which the pu

21、lse travels may not strictly be known. The measurement of pulse velocity can be used for the determination of the uniformity of concrete, the presence of cracks or voids, changes in properties with time and in the determination of dynamic physical properties. These subjects were considered to be out

22、side the scope of this standard, but some information is given in Annex B and more information can be found in the technical literature. The measurement may also be used to estimate the strength of in-situ concrete elements or specimens. However, it is not intended as an alternative to the direct me

23、asurement of the compressive strength of concrete. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, G

24、reece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EN 12504-4:2004 (E) 4 1 Scope This document specifies a method for the determination of the velocity of propagation

25、 of pulses of ultrasonic longitudinal waves in hardened concrete, which is used for a number of applications. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references

26、, the latest edition of the referenced document (including any amendments) applies. EN 206-1:2000, Concrete Part 1: Specification, performance, production and conformity. 3 Terms and definitions For the purposes of this document, the terms and definitions given in EN 206-1:2000 and the following app

27、ly. 3.1 transit time time taken for an ultrasonic pulse to travel from the transmitting transducer to the receiving transducer, passing through the interposed concrete 3.2 onset leading edge of the pulse detected by the measuring apparatus 3.3 rise time time for the leading edge of the first pulse t

28、o rise from 10 % to 90 % of its maximum amplitude 4 Principle A pulse of longitudinal vibrations is produced by an electro-acoustical transducer held in contact with one surface of the concrete under test. After traversing a known path length in the concrete, the pulse of vibrations is converted int

29、o an electrical signal by a second transducer and electronic timing circuits enable the transit time of the pulse to be measured. 5 Apparatus 5.1 General The apparatus consists of an electrical pulse generator, a pair of transducers, an amplifier and an electronic timing device for measuring the tim

30、e interval elapsing between the onset of a pulse generated at the transmitting transducer and the onset of its arrival at the receiving transducer. A calibration bar is provided to provide a datum for the velocity measurement. Two forms of the electronic timing apparatus are available: a) an oscillo

31、scope on which the first front of the pulse is displayed in relation to a suitable time scale. b) an interval timer with a direct reading digital display. EN 12504-4:2004 (E) 5 NOTE An oscilloscope provides the facility for monitoring the wave form of the pulse, which can be advantageous in complex

32、testing situations or in automatic system measurements. 5.2 Performance requirements The apparatus shall conform to the following performance requirements: It shall be capable of measuring transit times in the calibration bar to a limit deviation of 0,1 s and an accuracy of 2 %. The electronic excit

33、ation pulse applied to the transmitting transducer shall have a rise time of not greater than one-quarter of its natural period. This is to ensure a sharp pulse onset. The pulse repetition frequency shall be low enough to ensure that the onset of the received signal is free from interference by reve

34、rberations. The apparatus shall be used within the operating conditions stated by the manufacturer. 5.3 Transducers The natural frequency of the transducers should normally be within the range 20 kHz to 150 kHz. NOTE Frequencies as low as 10 kHz and as high as 200 kHz can sometimes be used. High fre

35、quency pulses have a well defined onset, but, as they pass through the concrete, they become attenuated more rapidly than pulses of lower frequency. It is therefore preferable to use high frequency transducers (60 kHz to 200 kHz) for short path lengths (down to 50 mm) and low frequency transducers (

36、10 kHz to 40 kHz) for long path lengths (up to a maximum of 15 m). Transducers with a frequency of 40 kHz to 60 kHz are found to be useful for most applications. 5.4 Apparatus for determination of arrival time of the pulse The apparatus shall be capable of determining the time of arrival of the firs

37、t front of the pulse with the lowest possible threshold, even though this may be of small amplitude compared with that of the first half wave of the pulse. 6 Procedures 6.1 Determination of Pulse Velocity 6.1.1 Factors influencing pulse velocity measurements In order to provide a measurement of puls

38、e velocity which is reproducible, it is necessary to take into account various factors which can influence the measurements. These are set out in Annex B. 6.1.2 Transducer arrangement Although the direction in which the maximum energy is propagated is at right angles to the face of the transmitting

39、transducer, it is possible to detect pulses which have travelled through the concrete in some other direction. It is therefore possible to make measurements of pulse velocity by placing the two transducers on opposite faces (direct transmission), or on adjacent faces (semi-direct transmission), or t

40、he same face (indirect or surface transmission) (see Figure 1) of a concrete structure or specimen. NOTE 1 Where it is necessary to place the transducers on opposite faces but not directly opposite each other such arrangement shall be regarded as a semi-direct transmission (see Figure 1.b) NOTE 2 Th

41、e indirect transmission arrangement is the least sensitive and should be used, when only one face of the concrete is accessible, or when the quality of the surface concrete relative to the overall quality is of interest. NOTE 3 The semi-direct transmission arrangement is used when the direct arrange

42、ment cannot be used, for example at the corners of structures. EN 12504-4:2004 (E) 6 Key R is the receiver transducer T is the transmitter transducer Figure 1 Transducer positioning 6.1.3 Path length measurement For direct transmission, the path length is the shortest distance between the transducer

43、s. The accuracy of measurement of the path length shall be recorded to an accuracy of 1 %. For semi-direct transmission, it is generally found to be sufficiently accurate to take the path length as the distance measured from centre to centre of the transducer faces. The accuracy of path length is de

44、pendent upon the size of the transducer compared with the centre to centre distance. With indirect transmission, the path length is not measured, but a series of measurements is made with the transducers at different distances apart (see Annex A). 6.1.4 Coupling the transducer onto the concrete Ther

45、e shall be adequate acoustical coupling between the concrete and the face of each transducer. For many concrete surfaces, the finish is sufficiently smooth to ensure good acoustical contact by the use of a coupling medium such as petroleum jelly, grease, soft soap and kaolin/glycerol paste and by pr

46、essing the transducer against the concrete surface. Repeated readings of the transit time should be made until a minimum value is obtained, indicating that the thickness of the couplant has been reduced to a minimum. When the concrete surface is very rough and uneven, the area of the surface should

47、be smoothed and levelled by grinding, or by the use of a quick-setting epoxy resin. NOTE Special transducers are available for use on very rough surfaces. EN 12504-4:2004 (E) 7 6.1.5 Measurement of transit time Using the electronic device the time interval indicated shall be determined in accordance

48、 with the manufacturers instruction (see 5.2). 7 Expression of result For direct and semi-direct transmissions the pulse velocity shall be calculated from the formula: 1 T L V = where: V is the pulse velocity, in km/s; L is the path length, in mm; T is the time taken by the pulse to transverse the length, in s. For the velocity by indirect transmission, see Annex A. The resultant determination of the pulse velocity shall be expressed to the nearest 0,01 km/s. 8 Test report The test report shall include the following: identification of the concre