These values are used to determine the size of structural members, the quantity of reinforcements, and to compute the stress for observed strains. The modulus of elasticity under static rate will be less than values found under dynamic or seismic rate and greater than values under slow load application. This involves applying a compressive axial load until failure occurs. Place the specimen on the platen so the axis of the specimen is aligned with the center of thrust of the spherically seated bearing block. Ensure the specimen fails within the prescribed permissible time tolerances in the specification.
|Published (Last):||11 May 2016|
|PDF File Size:||15.31 Mb|
|ePub File Size:||10.89 Mb|
|Price:||Free* [*Free Regsitration Required]|
A number in parentheses indicates the year of last reapproval. 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. 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. Referenced Documents2. Significance and Use3.
Current edition approved March 1, Published April Originallyapproved in Last previous edition approved in as C— Order Adjunct No. 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.
At one point on the circumference of the rotating yoke,midway between the two support points, use a pivot rod see A,Fig. 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. 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.
Procedures for calibrating strain-measuring devices aregiven in Practice E 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. A combined compressometer andextensometer Fig. 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. 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.
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. Test Specimens5. 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. Requirementsrelative to storage and to ambient conditions immediately priorto test shall be the same as for molded cylindrical specimens.
If the specimen as cast does not meet theplaneness requirements, planeness shall be accomplished bycapping in accordance with Practice C, or by lapping, or bygrinding. Planeness will be considered within tolerance when a 0.
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. 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. 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.
Do not recordany data during the first loading. Base calculations on theaverage of the results of the subsequent loadings. This is the maximum loadfor the modulus of elasticity test. Correct any attachment or alignmentdefects that may be causing erratic readings prior to the secondloading. 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.
The transverse strain is themeasured change in specimen diameter divided by the originaldiameter.
ASTM C469/C469M - 14
ASTM A469 Grade 6 Quenched and Tempered; Stress Relieved