# ASTM C469C469M-14

Designation: C469/C469M − 14Standard Test Method forStatic Modulus of Elasticity and Poisson’s Ratio of Concretein Compression1This standard is issued under the fixed designation C469/C469M; the number immediately following the designation indicates the yearof original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers determination of (1) chordmodulus of elasticity (Young’s) and (2) Poisson’s ratio ofmolded concrete cylinders and diamond-drilled concrete coreswhen under longitudinal compressive stress. Chord modulus ofelasticity and Poisson’s ratio are defined in Terminology E6.1.2 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C31/C31M Practice for Making and Curing Concrete TestSpecimens in the FieldC39/C39M Test Method for Compressive Strength of Cylin-drical Concrete SpecimensC42/C42M Test Method for Obtaining and Testing DrilledCores and Sawed Beams of ConcreteC174/C174M Test Method for Measuring Thickness of Con-crete Elements Using Drilled Concrete CoresC192/C192M Practice for Making and Curing Concrete TestSpecimens in the LaboratoryC617 Practice for Capping Cylindrical Concrete SpecimensE4 Practices for Force Verification of Testing MachinesE6 Terminology Relating to Methods of Mechanical TestingE83 Practice for Verification and Classification of Exten-someter SystemsE177 Practice for Use of the Terms Precision and Bias inASTM Test Methods2.2 ASTM Adjuncts:Compressometers (two drawings) and Extensometers (twodrawings)33. Significance and Use3.1 This test method provides a stress to strain ratio valueand a ratio of lateral to longitudinal strain for hardenedconcrete at whatever age and curing conditions may bedesignated.3.2 The modulus of elasticity and Poisson’s ratio values,applicable within the customary working stress range (0 to40 % of ultimate concrete strength), are used in sizing ofreinforced and nonreinforced structural members, establishingthe quantity of reinforcement, and computing stress for ob-served strains.3.3 The modulus of elasticity values obtained will usuallybe less than moduli derived under rapid load application(dynamic or seismic rates, for example), and will usually begreater than values under slow load application or extendedload duration, given other test conditions being the same.4. Apparatus4.1 Testing Machine—Use a testing machine capable ofimposing a load at the rate and of the magnitude prescribed in6.4. The machine shall conform to the requirements of Prac-tices E4 (Constant-Rate of-Traverse CRT-Type Testing Ma-chines section). The spherical head and bearing blocks shallconform to the Apparatus Section of Test Method C39/C39M.4.2 Compressometer3—For determining the modulus ofelasticity use a bonded (Note 1) or unbonded sensing devicethat measures to the nearest 5 millionths the average deforma-tion of two diametrically opposite gauge lines, each parallel tothe axis, and each centered about midheight of the specimen.1This test method is under the jurisdiction of ASTM Committee C09 onConcrete and Concrete Aggregates and is the direct responsibility of SubcommitteeC09.61 on Testing for Strength.Current edition approved March 1, 2014. Published April 2014. Originallyapproved in 1961. Last previous edition approved in 2010 as C469–10. DOI:10.1520/C0469_C0469M-14.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at service@astm.org. For Annual Book of ASTMStandards volume information, refer to the standard’s Document Summary page onthe ASTM website.3Available from ASTM International Headquarters. Order Adjunct No.ADJC0469.*A Summary of Changes section appears at the end of this standardCopyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1The effective length of each gauge line shall be not less thanthree times the maximum size of the aggregate in the concretenor more than two thirds the height of the specimen; thepreferred length of the gauge line is one half the height of thespecimen. Either use gauge points embedded in or cemented tothe specimen, and read deformation of the two lines indepen-dently; or use a compressometer (such as is shown in Fig. 1)consisting of two yokes, one of which (see B, Fig. 1) is rigidlyattached to the specimen and the other (see C, Fig. 1) attachedat two diametrically opposite points so that it is free to rotate.At one point on the circumference of the rotating yoke,midway between the two support points, use a pivot rod (see A,Fig. 1) to maintain a constant distance between the two yokes.At the opposite point on the circumference of the rotating yoke,the change in distance between the yokes (that is, the gaugereading) is equal to the sum of the displacement due tospecimen deformation and the displacement due to rotation ofthe yoke about the pivot rod (see Fig. 2).4.2.1 Measure deformation by a dial gauge used directly orwith a lever multiplying system, by a wire strain gauge, or bya linear variable differential transformer. If the distances of thepivot rod and the gauge from the vertical plane passing throughthe support points of the rotating yoke are equal, the deforma-tion of the specimen is equal to one-half the gauge reading. Ifthese distances are not equal, calculate the deformation asfollows:d 5 ger/~er1eg! (1)where:d = total deformation of the specimen throughout the effec-tive gauge length, µm [µin.],g = gauge reading, µm [µin.],er= the perpendicular distance, measured to the nearest 0.2mm [0.01 in.] from the pivot rod to the vertical planepassing through the two support points of the rotatingyoke, andeg= the perpendicular distance, measured to the nearest 0.2mm [0.01 in.] from the gauge to the vertical planepassing through the two support points of the rotatingyoke.Procedures for calibrating strain-measuring devices aregiven in Practice E83.NOTE 1—Although bonded strain gauges are satisfactory on dryspecimens, they may be difficult, if not impossible, to mount on specimenscontinually moist-cured until tested.4.3 Extensometer3—If Poisson’s ratio is desired, the trans-verse strain shall be determined (1) by an unbonded extensom-eter capable of measuring to the nearest 0.5 µm [25 µin.] thechange in diameter at the midheight of the specimen, or (2)bytwo bonded strain gauges (Note 1) mounted circumferentiallyat diametrically opposite points at the midheight of thespecimen and capable of measuring circumferential strain tothe nearest 5 millionths. A combined compressometer andextensometer (Fig. 3) is a convenient unbonded device. Thisapparatus shall contain a third yoke (consisting of two equalsegments) located halfway between the two compressometeryokes and attached to the specimen at two diametricallyopposite points. Midway between these points use a short pivotrod (A , see Fig. 3), adjacent to the long pivot rod, to maintaina constant distance between the bottom and middle yokes.Hinge the middle yoke at the pivot point to permit rotation ofthe two segments of the yoke in the horizontal plane. At theopposite point on the circumference, connect the two segmentsFIG. 1 Suitable Compressometerd = displacement due to specimen deformationr = displacement due to rotation of the yoke about the pivot roda = location of gaugeb = support point of the rotating yokec = location of pivot rodg = gauge readingFIG. 2 Diagram of DisplacementsC469/C469M − 142through a dial gauge or other sensing device capable ofmeasuring transverse deformation to the nearest 1.27 µm [50µin.]. If the distances of the hinge and the gauge from thevertical plane passing through the support points of the middleyoke are equal, the transverse deformation of the specimendiameter is equal to one-half the gauge reading. If thesedistances are not equal, calculate the transverse deformation ofthe specimen diameter in accordance with Eq 2.d 5 g e h/~e h1e g! (2)where:d = transverse deformation of the specimen diameter, µm[µin.],g = transverse gauge reading, µm [µin.],e h= the perpendicular distance, measured to the nearest 0.2mm [0.01 in.] from the hinge to the vertical planepassing through the support points of the middle yoke,ande g= the perpendicular distance, measured to the nearest 0.2mm [0.01 in.] from the gauge to the vertical planepassing through the support points of the middle yoke.4.4 Balance or Scale, accurate to 50 g [0.1 lb] shall be usedif necessary.5. Test Specimens5.1 Molded Cylindrical Specimens—Mold test cylinders inaccordance with the requirements for compression test speci-mens in Practice C192/C192M, or in Practice C31/C31M.Subject specimens to the specified curing conditions and test atthe age for which the elasticity information is desired. Testspecimens within 1 h after removal from the curing or storageroom. Specimens removed from a moist room for test shall bekept moist by a wet cloth covering during the interval betweenremoval and test.5.2 Drilled Core Specimens—Cores shall comply with therequirements for drilling, and moisture conditioning applicableto compressive strength specimens in Test Method C42/C42M,except that only diamond-drilled cores having a length-to-diameter ratio greater than 1.50 shall be used. Requirementsrelative to storage and to ambient conditions immediately priorto test shall be the same as for molded cylindrical specimens.5.3 The ends of the test specimens shall be made perpen-dicular to the axis 60.001 rad [60.5°] and plane within 0.05mm [0.002 in.]. If the specimen as cast does not meet theplaneness requirements, planeness shall be accomplished bycapping in accordance with Practice C617, or by lapping, or bygrinding. It is not prohibited to repair aggregate popouts thatoccur at the ends of specimens, provided the total area ofpopouts does not exceed 10 % of the specimen area and therepairs are made before capping or grinding is completed (Note2). Planeness will be considered within tolerance when a 0.05mm [0.002 in.] feeler gauge will not pass between thespecimen surface and a straight edge held against the surface.NOTE 2—Repairs may be made by epoxying the dislodged aggregateback in place or by filling the void with capping material and allowingadequate time for it to harden.5.4 Measure the diameter of the test specimen by caliper tothe nearest 0.2 mm [0.01 in.] by averaging two diametersmeasured at right angles to each other near the center of thelength of the specimen. Use this average diameter to calculatethe cross-sectional area. Measure and report the length of amolded specimen, including caps, to the nearest 2 mm [0.1 in.].Measure the length of a drilled specimen in accordance withTest Method C174/C174M; report the length, including caps,to the nearest 2 mm [0.1 in.].6. Procedure6.1 The temperature surrounding the specimen shall notvary by more than 2°C [4°F] during a test.6.2 Except as provided in 6.5, use at least two companionspecimens to determine the compressive strength in accordancewith Test Method C39/C39M prior to the test for modulus ofelasticity.6.3 Place the specimen, with the strain-measuring equip-ment attached, on the lower platen or bearing block of thetesting machine. Carefully align the axis of the specimen withthe center of thrust of the spherically-seated upper bearingblock. Note the reading on the strain indicators. Beforeapplying the load on the specimen, tilt the movable portion ofthe spherically seated block by hand so that the bearing faceappears to be parallel to the top of the test specimen based onvisual observation.FIG. 3 Suitable Combined Compressometer-ExtensometerC469/C469M − 1436.4 Load the specimen at least three times. Do not recordany data during the first loading. Base calculations on theaverage of the results of the subsequent loadings.6.4.1 Apply the load continuously and without shock. Settesting machines of the screw type so that the moving headtravels at a rate of about1 mm/min [0.05 in./min] when the machine is running idle. Inhydraulically operated machines, apply the load at a constantrate within the range 250 6 50 kPa/s [35 6 7 psi/s]. Load thespecimen until the applied load is 40 % of the average ultimateload of the companion specimens. This is the maximum loadfor the modulus of elasticity test.6.4.2 During the first loading, observe the performance ofthe gauges (Note 3). Correct any attachment or alignmentdefects that may be causing erratic readings prior to the secondloading. For the second and subsequent loadings, obtain eachset of readings as follows: Record, without interruption ofloading, the applied load and longitudinal strain at the point (1)when the longitudinal strain is 50 microstrain and (2) when theapplied load is equal to 40 % of the ultimate load of thecompanion specimens (see 6.5). Longitudinal strain is definedas the measured longitudinal deformation of the specimendivided by the effective gauge length.NOTE 3—The first loading is primarily for the seating of the gauges. Ifa dial gauge is used to measure longitudinal deformation, it is convenientto set the gauge before each loading so that the indicator will pass the zeropoint at a longitudinal strain of 50 microstrain.6.4.3 If Poisson’s ratio is to be determined, record thetransverse strain at the same points. The transverse strain is themeasured change in specimen diameter divided by the originaldiameter.6.4.4 If a stress-strain curve is to be determined, takereadings at two or more intermediate points without interrup-tion of loading; or use an instrument that makes a continuousrecord of the gauge readings.6.4.5 Upon reaching the maximum load, except on the finalloading, reduce the load to zero at the same rate at which it wasapplied.6.5 It is not prohibited to obtain the modulus of elasticityand strength on the same loading provided that the gauges areexpendable, removable, or adequately protected so that it ispossible to comply with the requirement for continuous loadinggiven in Test Method C39/C39M. In this case, record severalintermediate readings to obtain a stress-strain curve up to atleast 40 % of the ultimate load and determine the strain valueat 40 % of the ultimate by interpolation.6.6 If intermediate readings are taken, plot the results ofeach of the tests with the longitudinal strain as the abscissa andt