इंटरनेटमानक Disclosure to Promote the Right To Information Whereas the Parliament of India has set out to provide a practical regime of right to information for citizens to secure access to information under the control of public authorities, in order to promote transparency and accountability in the working of every public authority, and whereas the attached publication of the Bureau of Indian Standards is of particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit of education and knowledge, the attached public safety standard is made available to promote the timely dissemination of this information in an accurate manner to the public. “जान1 का अ+धकार, जी1 का अ+धकार” “प0रा1 को छोड न' 5 तरफ” “The Right to Information, The Right to Live” “Step Out From the Old to the New” Mazdoor Kisan Shakti Sangathan Jawaharlal Nehru IS 13311-1 (1992): Method of Non-destructive testing of concret, Part 1: Ultrasonic pulse velocity [CED 2: Cement and Concrete] “!ान $ एक न' भारत का +नम-ण” Satyanarayan Gangaram Pitroda “Invent a New India Using Knowledge” “!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता ह” है” ह Bhartṛhari—Nītiśatakam “Knowledge is such a treasure which cannot be stolen” . . INDIAN STANDARDS 9 BAHADUR SHAH NEW DELHI 110002 ZAFAR MARO Price Group 4 .16 @ BIS.IS13311 (Part1 ):i992 ( Reaffirmed 2004 ) vITamT% Indian Standard NON-DESTRUCTIVE TESTING OF CONCRETE METHODS OF TEST PART 1 ULTRASONIC PULSE VELOCITY First ReprintSEPTEMBER 1996 UDC 666*972*620*179.‘:1992 BUREAU MANAK Junuury 1992 OF BHAVAN. It is more so. The various methods that can be adopted for in-situ assessment of strength properties of concrete depend upon the particular aspect of the strength in question. the combined use of these two methods is made in another way. no assessment of concrete strength is made from rebound indices.Cement and Concrete Sectional Committee. nuclear.characteristics of concrete in a structure are required to be assessed. However. mix and environmental factors. penetration. moisture condition. of concrete is assessed to be ‘excellent or good’ by pulse velocity method. also become important in others. characteristic of concrete and the measurements are influenced by materials. etc. after the draft finalized by the Cement and Concrete Sectional Committee had been approved by the Civil Engineeflng Division Council. the estimation of compressive extended to the entire mass only on the basis of other colateral measurements. In view of the limitations of the methods for predicting the strength of concrete in the structure it is preferable that both ultrasonic pulse velocity and rebound hammer methods given in Part 2 of the standard are used in combination to alleviate the errors arising out of influence of material. In addition. for example dynamic or vibration methods like resonance frequency and ultrasonic pulse velocity tests and those which involve measurement of parameters like surface hardness. surface texture. The correlation is valid only within the range of values of pulse velocity rebound number and compressive strength employed and any extrapolation beyond these is open to question. There are occasions when the various performance . rebound. However. In most of the cases. on the other hand when the actual compressive strength of concrete in the structure is to be measured. radiographic. For example. an estimate of strength of concrete in the structure is needed. which not only provide an estimate of the relative strength and overall quality of concrete in the structure but also help in deciding whether more rigorous tests like load testing or core drilling at selected locations are required. when the data on the materials and mix proportions used in the construction are not available. both these methods are relatively cumbersome and the latter method may leave the structure damaged locally in some cases. CED 2 FOREWORD This Indian Standard was adopted by the Bureau of Indian Standards. proper interpretation of the results calls for certain degree of expertise. There are va‘rious such non-destructive testing methods which can be broadly classified as those which measure the overall quality of concrete. uniformity. mix and environmental parameters on the respective measurements. core testing as per IS 516 : 1959 ‘Method of test for strength of concrete’ is more reliable. Since such radiometric. as is often the case. When the quality of concrete is doubtful. therefore. made of suitable nondestructive tests. cement content in the concrete or core testing. pull-out strength. carrying out a full-scale load test as per IS 456 : 1978 Code of practice for plain and reinforced concrete ( thirdrevision )’ or IS 1343 : 1980 Code of practice for prestressed concrete (first revision )’ is the most direct way. strength of site concrete cubes. non-destructive tests are at best indirect methods of monitoring the particulars. etc. rebound number and compressive strength of concrete are obtained by multiple regression of the measured values on laboratory test specimens. etc. Because of the above limitations. Relationships between pulse velocity. crete. In this. if the load-carrying capacity of a structural ensemble is to be assessed. if the quality ( Continued on third Cover ) . although parameters like overall quality. and are believed to be indirectly related to the compressive strength of concrete. for example. Use is. for example. only then the compressive strength is assessed from the rebound manner indices and this is taken as indicative of strength of concrete in the entire cross-section of the concrete member. When strength by rebound indices is the quality assessed is ‘medium’. magnetic and electrical methods are also available. presence of reinforcement. this approach has the limitation that the correlations are valid only for the materials and mix proportions The intrinsic difference between the laboratory test specimens and in-situ conused in trials. also affect the accuracy of results. . pulse velocity method is a convenient technique for investigating structural concrete. 4 the quality of the concrete in relation to standard requirements. If there is a crack.When the pulse is induced into the concrete from a transducer. lower velocities are obtained.a 700-l 500 above 1500 . b) the presence of cracks. 4 APPARATUS 4. b) Transducer - one pair. PULSE VELOCITY The underlying principle of assessing the quality of concrete is that comparatively higher velocities are obtained when the quality of concrete in terms of density. void or flaw inside the concrete which comes in the way of transmission of the pulses. Density and modulus of elasticity of aggregate also significantly affect the puise velocity.1 The ultrasonic pulse velocity method could be used to establish: 4 the homogeneity of the concrete.1. Piezoelectric and magneto-strictive types of transducers may be used. shear ( transverse ) and surface transducer ( rayleigh ) waves. cl changes in the structure of the concrete which may occur with time. NOTE . The actual pulse velocity obtained depends primarily upon the materials and mix proportions of concrete. and f) the values of dynamic elastic modulus of the concrete.1 The apparatus for ultrasonic pulse velocity measurement shall consist of the following: a) Electrical pulse generator. thereby making the path length longer. 1 Natural Frequency of Troasdncer (mm) up to 500 500-700 +JQ 150 . it undergoes multiple reflections at the boundaries of the differ&t material phases within the concrete.1 The ultrasonic pulse is generated by an electroacoustical transducer. which is the fastest. it is essen!ial that the results .a > 3.1992 Indian Standard NON-DESTRUCTIVETESTINGOFCONCRETE METHODS-OF TEST PART 1 ULTRASONIC 1 SCOPE 1. voids and other imperfections. In addition. Table 1 Natural Frequency of Transducers for Different Path Lengths Path Length Because the velocity of the pulses is almost independent of the geometry of the material through which they pass and depends only on its elastic properties. and d) Electronic timing device. the pulse strength is attenuated and it passes around the discontinuity. Consequently. 2 OBJECT 2.of tests obtained by one method should be complimented by other tests and each method should be aqopted very carefully. In case of poorer quality. 3 PRINCIPLE 3. 4. The receiving detects the onset of the longitudinal waves.1 This standard covers the object. homogeneity and uniformity is good. A complex system of stress waves is developed which includes longitudinal ( compressional ). lower velocities are obtained. the latter being more suitable for the lower part of the frequency range.In view of the limitations of each method of non-destructive testing of concrete. apparatus and test procedure of ultrasonic pulse velocity test method. c) Amplifier. the quality of one element of concrete in e) relation to another. principle.3 MinimumTransverse Dimensionsof Members (mm) 25 70 150 300 .1 Transducer Any suitable type of transducer operating within the frequency Lange of 20 kHz to 150 kHz ( see Table 1 ) may be used. influence of test conditions and some general guidance on the interpretation of test results are also given. it is desirable to measure pulse velocity over a longer path length than would normally be used. For good quality concrete. 5 PROCEDURE To ensure that the ultrasonic pulses generated at the transmitting transducer pass into the concrete and are then detected by the receiving transducer. However. V = L/T Once the ultrasonic pulse impinges on the surface of the material. grease. the ultrasonic pulse is produced by the transducer which is held in contact with one surface of the concrete member under test. 4. If it is necessary to work on concrete surfaces formed by other means. TWO forms of the electronic timing apparatus are possible.1 The electronic excitation pulse applied to the transmitting transducer should have a rise time of not greater than one quarter of its natural period. a difference of about 0. -for example trowelling.1. these times. Typical couplants are petroleum jelly.1 In this test method. If both the forms of timing apparatus are available. In such cases. liquid soap and kaolin glycerol paste. the pulse of vibrations is converted into an electrical signal by the second transducer held in contact with the other surface of the concrete member and an electronic 5. The indirect velocity is invariably lower than the direct velocity on the same concrete element.2 The interval between pulses should be low enough to ensure that the onset of the received signal in small concrete test specimens is free from interference by reverberations produced within the preceding working cycle. the maximum energy is propagated at right angles to the face of the transmitting transducer and best results are. A minimum path length of 150 mm is recommended for the direct transmission method involving one unmoulded surface and a minimum of 400 mm for the surface probing method along an unmoulded surface. it is necessary to check the overall performance by making measurements on two standard reference specimens in which the pulse transit times are known accurately. For this.2 Electronic Timing Device timing circuit enables the transit time ( T ) of the pulse to be measured.2.5 km/ set may generally be encountered. 2 . high frequency transducers are preferable for short path lengths and low frequency transducers for long path lengths. The shorter of the reference specimens should be used to set the zero for the apparatus and the longer one should be used to check the accuracy of transit time measurement of the apparatus.2 The natural frequency of transducers should preferably be within the range of 20 to 150 kHz ( see Table 1 ). Generally. the interpretation of results becomes more reliable. one of which uses a cathode ray tube on which the leading edge of the pulse is displayed in relation to the suitable time scale. This difference may vary from 5 to 20 percent depending largely on the quality of the concrete under test. 4. humidity and power supply voltage stated by the supplier. The measurement obtained should not differ from the known value for the reference specimen by more than’ kO. 4. it is essential that there be adequate acoustical coupling between the concrete and the face of each transducer. obtained when the receiving transducer is placed on the opposite face of the concrete member ( direct transmission or cross probing ).2 Performance of the Assembly of Apparatus The apparatus should be capable of measuring transit times to an accuracy of f 1 percent over a range of 20 microseconds to 10 milliseconds. the receiving transducer is also placed on the same face of the concrete members (surface probing ).3 The apparatus should maintain its performance over the range of ambient temperature. After traversing a known path length Q in the concrete. in many situations two opposite faces of the structural member may not be accessible for measurements.2.5 percent. 4.2 microsecond. Transducers with a frequency of 50 to 60 kHz are useful for most all-round applications. This is to ensure a sharp pulse onset. therefore. If there is very rough concrete surface. the other uses an interval timer with a direct reading digital display. The two reference specimens ( usually steel bars ) should have pulse transit times of about 25 microseconds to 100 microseconds respectively. Surface probing is not so e5cient as cross probing.fs~l3311( Part 1) : 1992 4. being specified by the supplier of the equipment to an accuracy of f0. The pulse velocity (V) is given by: It shall be capable of measuring the time interval elapsing between the onset of a pulse generated at the transmitting transducer and the onset of its arrival at the receiving transducer. because the signal produced at the receiving transducer has an amplitude of only 2 to 3 percent of that produced by cross probing and the test results are greatly influenced by the surface layers of concrete which may have different properties from that of concrete inside the structural member. it is required to smoothen and level an area of the surface where the transducer is to be placed. 5.2. drying of concrete may result in somewhat lower pulse velocity. ultrasonic pulse velocity is measured on one face of the structural member by surface probing.4 In view of the inherent variability in the test results. 6 INFLUENCE OF TEST CONDITIONS 6. probing in general gives lower pulse velocity than in case of cross probing and depending on number of parameters. the pulse velocity may be reduced due to the development of micro-cracks. this does not pose any difficulty as the pulse velocity measurements are carried out on thick structural concrete However.5 percent.1 Influence of Surface Conditions and Moisture Content of Concrete Smoothness of contact surface under test affects the measurement of ultrasonic pulse velocity. The shape and size of the concrete member do not influence the pulse velocity unless the least lateral dimension is less than a certain minimum value. the free water freezes within concrete. The apparent increase in pulse velocity depends upon the proximity of the measurements to the reinforcing bar. under certain conditions.3 Influence of Temperature of Concrete Variations of the concrete temperature between 5 and 30°C do not significantly affect the pulse velocity measurements in concrete. sufficient number of readings are taken by dividing the entire structure in suitable grid markings of 30 x 30 cm or even smaller. This influence is more for low strength concrete than high strength concrete. for example the minimum lateral dimension of about 80 mm for 50 kHz natural frequency of the transducer. it is essential that path lengths be sufficiently long so as to avoid any error introduced due to its heterogeneity. it is recommended that the minimum path length should be 100 mm for concrete in which the nominal maximum size of aggregate is 20 mm or less and 150 mm for concrete in which the nominal maximum size of . When concrete is subjected to a stress which is abnormally high for the quality of the concrete.41 Surface. aggregate is between 20 to 40 mm.accessible. The pulse velocity of saturated concrete may be up to 2 percent higher than that of similar dry concrete. In field work.in pulse velocity up to 7. the finish is usually sufficiently smooth to ensure good acoustical contact by the use of a coupling medium and by pressing the transducer against the concrete surface.1 The ultrasonic pulse velocity of concrete is mainly related to its density and modulus of elasticity. 6. When the concrete surface is rough and uneven. in the laboratory where members. 6. it is necessary to smoothen the surface velocity measurement to make the pulse possible. 6. 7 INTERPRETATION OF RESULTS 7. This is because. depends upon the materials and mix proportions ti in making 3 . generally small specimens are used. 6.2 to 1.e.. the diameter and number of the bars and their orientation with respect to the path of propagation.IS 13311( Part 1 ) : 1992 5.9 times the velocity in plain concrete and. This in turn. In general. If one of the faces is not.2 Influence of Path Length. resulting in an increase . Shape and Size of the Concrete Member As concrete is inherently heterogeneous.5 Effect of Reinforcing Bars The pulse velocity measured in reinforced concrete in the vicinity of reinforcing bars is usually higher than in plain concrete of the same composition. In general. This influence is generally insignificant unless the stress is greater than about 60 percent of the ultimate strength of the concrete. At temperatures between 30 to 60°C there can be reduction in pulse velocity up to 5 percent. This influence is likely to be the greatest when the pulse path is normal to the predominent direction of the planes of such micro-cracks. cross probing. Table 1 gives the guidance on the choice of the transducer natural frequency for different path lengths and minimum transverse dimensions of the concrete members. Transducers are held on corresponding points of observation on opposite faces of a structural element to measure the ultrasonic pulse velocity by direct transmission. Each junction point of the grid becomes a point of observation. This occurs when the pulse path is perpendicular to the direction of a uniaxial compressive stress in a member.4 Influence of Stress 5. the path length can affect the pulse velocity readings. the pulse velocity in steel is 1.3 Since size of aggregates influences the pulse velocity measurement. 5. the difference could be of the order of about 1 km/set. Below freezing temperature. the first pulse to arrive at the receiving transducer travels partly in concrete and partly in steel. i. For most concrete surfaces. pulse velocity through concrete increases with increased moisture content of concrete. 24 as average.0 where Young’s Modulus of elasticity E = :~uI. although the same materials and mix proportions are used. However. 7. which have been evolved for characterising the quality of concrete in structures in terms of the ultrasonic pulse velocity. if actual concrete materials ’ and mix proportions adopted in a particular structure are available. which influence the pulse velocity and compressive strength of concrete to different extents. etc. However. if the concrete is not compacted as thoroughly as possible. compaction and curing of concrete. How- f (+ ( Sal 1’ VS where n = fundamental resonant frequency cycles per second. Pulse Velocity by Cross Probing ( km/= 1 Above 4. For example.4 The dynamic Young’s modulus of elasticity (E) of the concrete may be determined from the pulse velocity and the dynamic Poisson’s ratio (&. 4. the assessment of quality becomes more meaningful and reliable. 3. incidence or absence of internal flaws.n.: Excellent Good Medium Doubtful it may w-WV1 ( l+r) ‘-12 Concm~d?.5 ‘3.1. indicative of the level of workmanship employed. when the comparison is made amongst different parts of a structure. in 4 3 . depend on a number of parameters. supervision. the factor f (.5 to 4. 2. can thus be assessed using the guidelines given in Table 2. the pulse velocity will be lower.1 The quality of concrete in terms of uniformity. then estimate of concrete strength can be made by establishing suitable correlation between the pulse velocity and the compressive strength of concrete specimens made with such materials and mix proportions.5 3. P = density in kg/ms.In case of *adoibtful*9 quality necessary to carry out further tests. The dynamic Poisson’s ratio may be obtained from measurements on concrete test-beams of the pulse velocity ( V) alongwith length ( I ) of the beam and the fundamental resonant frequency ( n ) of the beam in longitudinal mode of vibration.lity Note . any criterion for assessing the quality of concrete on the basis of pulse velocity as given in Table 2 can be held as satisfactory only to a general extent. )is calculated by the relation: 7. using the following relationship: E = P Table 2 Velocity Criterion for Concrete Quality Grading S1 No.IS 13311( Part 1) : 1992 concrete as well as the method of placing. under environmental conditions similar to that in the structure.2 Since actual values of the pulse velocity obtained. it is desirable to have an independent measure of it for the particular type of concrete under test.. The estimated strength may vary from the actual strength by f 20 percent. The reason is that a large number of parameters are involved. may be expressed as: (l+p)(l-2cr) 1-P The value of the dynamic Poisson’s ratio varies from 0. From these measurements. cracks and segregation.20 to O-35. ever. 7.3 The assessment of compressive strength of concrete from ultrasonic pulse velocity values is not adequate because the statistical confidence of the correlation between ultrasonic pulse velocity and the compressive strength of concrete is not very high.5 Below 3. and V = pulse velocity in m/second.0 to 3.. 1. The above relationship I$= Pf (A V where be f(p)= 7. The correlation so obtained may not be applicable for concrete of another grade or made with different types of materials. which have been built at the same time with supposedly construction practices and similar materials. or if there is segregation of concrete during placing or there are internal cracks or flaws. with 0. and I = length of specimen in m.. N. H. GHANEKAR Structural Engineering Research Centre The India Cements Limited. Research Institute Research. K. GOPINATH SI~I R. MEHTA SHRI J. Roorkce 247667 ) Chairman DR H. K. MIC+LANI( Alternate ) Roads Wing. SIIANKARANARAYANAN ( AIternale ) Gannon Dunkerley Bombay DR IRSHADMASOOD DR MD KHALID ( Alternate Central Building SHRI S. Buildings Bombay New Delhi ) SHRI G. KELKAR( AIrernare ) SHRI D. New Delhi Industries Limited. KILISHNAMLIRTHY SHRI S. Lucknow Standards ( CSIR ). New Delhi ( Ministry of Survey of India. S. JOSHI SHRI P. K. 0. RANGARI( Afrernare Hospital Services New Delhi Consultancy Corporation ( India ) Lid. D. R. SHRI B. Research Laboratories. BHARTIKAR SHRI U. Calcutta ) SHRI P. GUHA THAKURTA SHRIS.QCC ( Alternare ) Sardar Sarovar Public Works Department. SUBRAMANIAN ( AIrernare ) Orissa Cement Limited. MUKHER~EE SHIU M. G. Madras ( CSIR ). SANGANEIIIA ( Alternafe ) MEMBERSECRETARY DIIIE~TOR( CIVIL ) ( Afrernare ) SHRI NIRMAL SINOH SHRI S. Roorkee ) JOINTDIRECTOR. CHATTERJ~~ SHRIS. Amritsar Hyderabad Hyderabad ) SHRI V. CED 2 Representing capacity ( University of Roorkee. S. GHOSH ( Afrernare ) SHRI P. Ghaziabad SHRIS. GANGWAL SHRIV.NAVAGAMDAM SUPERINTENDING ENGINEER. C. K. K. Narmada CHIEFENGINEPR( RESEARCH-CUMDIRECTOR) RESEARCH OFFICER( CONCRETE TECHNOLOGY) ( AIrernare ) Irrigation DIRECTOR JOINT DIRECTOR( Alfernate ) DIRECTOR( CMDD ) ( N & W ) DEPUTYDIRECTOR( CMDD ) ( NW & S ) ( A/ternafe ) A. Calcutta Board of Irrigation Development Industry Transport Commissioner ) and Power.STANDARDS( B & S ) (CB-I) JOINTDIRECTORSTANDARDS( B & S )/ ( CB-II ) ( Alrernare ) SHRI N. Bombay Nigam Ltd.Is 13311( Part 1 ) : 1992 Cement and Concrete Sectional Committee. Puoe ) SHRIH. RATH ( Afternate B. KANUNOO . P. H. BHATTACIIARYA DR A. PAI-IABIII( Alternate Central New Delhi Companies Ltd. K. P. LAL SHRI T. Engineering SHRIK. National Organization ( Ministry of Bombay Test House. for Cement New Delhi Industry ( Ministry of . Commission. MEENA( Alternate Indian Hume Pipes Co Limited. TA~~LAKARAN( AIternare ) & Company Limited. K. VISVESVARAYA In personal Members SHRI B. R. N. SHRI A. ) !&RI M. G. MAJUMDAR SHRIS. Transport Geological Central Department of Surface ). Designs and Railways ). BHATIA ( Alternate National Organization. The Associated Cement CHIEFENGINEER( DESIQNS) SUPERINTENDINO ENGINEER( S & S ) ( Alternale ) Central CIIIEPENGINEER. CHAKRAVARTII~ ( Alternarr ) Larsen and Toubro Limited. Gandhinagar and Power Research Water Hyderabad New Delhi Institute. R. Shirke & Co. K. BIS ( Ex-ojkio Member ) Director ( Civil Engg ) Secretary !%a~ N.P.utMA( AIrernate ) SHRI T. PHULL SHRIR. New Delhi DR M. Bombay In personal capacity ( 36 finch Nagar. PENLL SHRI S. VISWANATHA ( Alternate ) DEPUIY DIRWTOR (EH ) ASSISTANTDIRECTOR( Torsteel Research Foundation DIRICTOR JOINTDIRECTOR ( Alternate Central Water Commission. GHANEKAR SHRI D. New Delhi Central Road Research Institute ( CSIR ). Bombay Smu S. CED 2 : 2 Convener DR National Council for Cement and Building Materials. SHARMA ( Alternate ) National Council for Cement and Building Materials. in India. HARIDW S-I N. C. C. A.‘~HANDRASEKARAN( Alternate ) iBa H. S. New Delhi SHRI Y. SEIZHRA ( Alterna/e ) Indian Roads Congress. RAMDAS SHRI R. EH ) ( Alternate DlRl!CTOR( C & MDD ) Depun DIRE~IOR ( Alternate SEIU S. KAMAIAH DR A. SHARMA ( Alternate ) DR C. REDDI ( Alternate ) SUPT ENOINEER ( DEVIANT ) EXIZCUTIVE ENGINEER ( S. PASRICHA Engineer-in-Chief’s Branch. SUBBARAO Research Ccntre ( CSIR ). Bombay )1 Gammon India Limited. Engineering Research Laboratories. Ghaziabad ) SHRI S. New Delhi Smu Y. S. CHOWDHURY DR C. MU.Is 13311(Pad 1) : 1992 Representing Members SHRI R.LLICK NOW Delhi Members SHRI Stup Consultants C. SHRI J.C. Calcutta National Buildings Organization. C.. C. H. Nagpur 15 ) 6 . N. S. P. GUPT~ GUHA THAKURTA New Delhi ) ) S-1 V. MADHAVA RAO ( Alternate ) Structural Engineering REPR~. K. Limited. B. RAMAN.WNTATIVB Builders Association of India. ALIMCHANDANI SHRI S. SANKARNARAYANAN ( Alternate SHRI G. Bombay Cement Corporation of India. PRAKASHRAO ( Alternate K. DM~ION ) ( Alternate ) SHRI S. S. R. New Delhi Directorate General of Supplies and Disposals. Rangarajan ( Alternate ) DR P. Roorkoo Gannon Dunkerloy & Company Limited. RAI~UMAR DR S. G. SINoH ( Alternate SHRI H. REMEDIOS ( Alternate ) SHRI LALIT KUMAR JAIN New Delhi ) Central Building Research Institute ( CSIR ). Army Headquarters ) Hindustan Prefab Ltd. Wardha Road. CHATIJIWW ( Alternate ) Public Works Department. Now Delhi The Institution SBRI G. A.R. Hyderabad Structural Engineering Research Con&o ( CSIR ). RUHSIN~HANI Sxw C. Government of Tamil Nadu Central Soil and Materials Research Station. K. HINOORANI SHRI A: P. BANDYOPADHYAY Joint Director ( Civil Engg ). SURI SHRI N. PARAIR COL R.M. C. A. S. Bombay Associated Consulting Services. Madras Gammon India Limited. K. U. PRABHAKAR ( Alternate ) . R. VIWESVARAYA SHRI D. AHLUWALIA( Alternate ) SHRI 0. C. Calcutta Director General. SH. of Engineers ( India ). BIS Concrete Subcommittee. R. S. Bombay SHRI B. S. R. New Delhi SHIU A. GUPTA (Afrernate ) Indian Institute v. S. SHRI N. New Delhi ) Structural Engineering SHRI Research Centre ( CSIR ). JOINT DIFGZCXOR. KETKAR ( Alfernate SHRI Y. New Delhi ) Public Works Department. . PRASAIIA RAO SHRI K. KUNDU ( Afternate Materials. MALEKAR (Alternate DR S. D. MUKHERJEE SHRI N. v. K.IS 13311( Part 1 ) : 1992 JOINT DIRECTORSTANDARDS ( B & S )/(CB-I) Designs and Standards Railways ). ) SHRI S. SINHA( Alternute) SHRI B. MANI ( Alternate of Technology. Lucknow SHm K. PAI SHRI A. of K. BHA~ACHARYA Engineer-in-Chief’s ( Alfernale ) 7 Branch. Rustom Barcg. ( Ministry Engineers India Limited. C. S. Madras ) SIJPERINTENDINOENGINEER ( DESIGNS ) EXFCUTIVE ENGINEER ( DESIGNS ) 1x1 ( Alfernate ) Central Public Works Department. B. K. New Delhi Road. New Delhi MAITI MANAQINO DIRECTOR SHRI M. M. SHRI B. Bombay ) Central Road Research Institute. Bombay ) National Council for Cement and Building Hindustan Prefab Limited. MADoE The Hindustan New Delhi Construction Co Ltd. VOMBATKARE SHRI N. New Delhi KARAMCHANDANI PROF S. New Delhi SHRI N. C. V. SEFHRA ( Alternate A. G. UNWALLA In personal capacity New Delhi ( 1519. M~RANI M. K. KRISHNAMOORTHY SHRI K. Victoria Bombay 2 7 ) BRIG (DR) S. K:NAYAR (Alfernate SIIRI Organization Research. PHULL SHRI SHRI S. Army Headquarters. Bombay Ministry of Transport ( Roads Wing ).STANDARDS ( B & S )/ ( CB-II ) ( AIternafe ) The Associated Cement Companies Limited. R. B. T. the final value. in line with the current limit state concepts of design. an approach is taken that if the same . expressing the result of a test or analysis.materials and similar mix proportions and level of workmanship were employed for the two situations. The composition of the technical given in Annex A. The test results on ultrasonic pulse velocity and rebound indices -are analysed statistically and plotted as histograms and the lower fractiles of results are taken for assessing the . shall be rounded off in accordance with IS 2 : 1960 ‘Rules for rounding off numerical values (revised)‘. considerable improvisation has to be done in evolving the testing scheme and use is made of comparative measurements made on adjoining portions of the structure or even other structures in the vicinity of the one in question. committee responsible for the formulation of this standard is For the purpose of deciding whether a particular requirement of this standard is complied with. The number of-significant places retained in the rounded off value should be the same as that of the specified value in this standard. . any significant difference in the ultrasonic pulse velocity or rebound indices between them must be due to some inherent differences in the overall quality.quality. In doing so. If the nominal grades of concrete or mix proportions are known to be different in either case. Therefore. suitable allowance is made for the same in interpretation of results. the records of the original materials or mix proportions used in the structure are not available.( Continued from second Cover ) In-most of the situations. observed or calculated. or ‘characteristic’ strength of concrete. 9 Bahadur Shah Zafar Marg NEW DELHI 110002 Eastern : l/14 C. BANGALORE. LUCKNOW. IV Cross Road.Bureau of Indian Standards BIS is a statutory institution established under the Bureau ofIndian Standards Acr. BIS.832 78 58 832 78 91. Standards are also reviewed periodically.337 26. This Indian Standard has been developed from Dot : No.235 04 23 42 15 Western : Manakalaya. New Delhi 110002 Telephones : 323 0131. MADKAS 600113 1 235 02 15 16. Marol.235 19. 9 Bahadur Shah Zafar Marg. Campus. a standard~along with amendments is reaffirmed when such review indicates that no changes are needed. marking and quality certification of goods and attending to connected matters in the country. of necessary details. CED 2 ( 3889 ) Amendments Amend No. BHUBANESHWAR. KANPUR. Users of Indian Standards should ascertain that they are in possession of the latest amendments or edition by referring to the latest issue of ‘BIS Handbook’ and ‘Standards Monthly Additions’. 1. if the review indicates that changes are needed. Andheri (East) MUMBAI 400093 832 92 95.832 78 92 Branches : AHMADABAD. T.T.337 9120 85 61 cALculTA700054 Northern : SC0 335-336. Scheme VII M.323 94 02 Telegrams : Manaksanstha (Common to all offices) Telephone Regional Offices : Central { 323 76 38 41 17 : Manak Bhavan. CHANDIGARH 160022 1 60 38 20 43 25 Southern : C. No part of these publications may be reproduced in any form without the prior permission in writing of BIS. Issued Since Publtiation Text Affected Date of Issue BUREAU OF INDIAN STANDARDS Headquarters: Manak Bhavan. GHAZIABAD. JAIPUR. I. India. such as symbols and sizes. Maniktola 1 337 84 86 99. Review of Indian Standards Amendments are issued to standards as the need arises on the basis of comments. This does not preclude the free use. V. BHOPAL. COIMBATORE.323 83 75. Enquiries relating to copyright be addressed to the Director (Publications). E9 MIDC. Road. GUWAHATI. Printed at Dee Kay Printers. 1986 to promote harmonious development of the activities of standardization. THIRUVANANTIIAPU’RAM. in the course of implementing the standard. . Sector 34-A. Copyright BIS has the copyright of all its publications. I. FARIDABAD. HYDERABAD. PATNA. P. type or grade designations. New Delhi-l 10015. it is taken up for revision.