1、Designation: C 947 03 (Reapproved 2009)Standard Test Method forFlexural Properties of Thin-Section Glass-Fiber-ReinforcedConcrete (Using Simple Beam With Third-Point Loading)1This standard is issued under the fixed designation C 947; the number immediately following the designation indicates the yea
2、r oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers determination of the flexuralul
3、timate strength in bending and the yield strength of glass-fiber reinforced concrete sections by the use of a simple beamof 1.0 in. (25.4 mm) or less in depth using third-point loading.1.2 The values stated in inch-pound units are to be regardedas the standard. The values given in parentheses are fo
4、rinformation only.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 u
5、se.2. Referenced Documents2.1 ASTM Standards:2C 1228 Practice for Preparing Coupons for Flexural andWashout Tests on Glass Fiber Reinforced ConcreteD76 Specification for Tensile Testing Machines for TextilesE4 Practices for Force Verification of Testing Machines3. Significance and Use3.1 Flexural pr
6、operties determined by this test method areuseful for quality control of glass-fiber reinforced concreteproducts, ascertaining compliance with the governing specifi-cations, research and development, and generating data for usein product design.4. Apparatus4.1 Testing MachineA properly calibrated te
7、sting ma-chine that can be operated at constant rates of crosshead motionand in which the error in the force measuring system shall notexceed 61.0 % of the maximum force expected to be measuredshall be used. The testing machine shall be equipped with adeflection measuring and recording device. The s
8、tiffness of thetesting machine shall be such that the total elastic deformationof the system does not exceed 1.0 % of the total deflection ofthe test specimen during the test, or appropriate correctionsshall be made. The force-indicating mechanism shall beessentially free of inertial lag at the cros
9、shead rate used. Theaccuracy of the testing machine shall be verified in accordancewith Practices E4and Specification D76.4.2 Loading Noses and SupportsThe loading noses andsupports shall have cylindrical surfaces. In order to avoidexcessive indentation or failure due to stress concentrationdirectly
10、 under the loading noses or supports, the radius of thenoses and supports shall be at least 0.25 in. (6.35 mm). See Fig.1 for loading configuration. The arc of the loading noses andsupports, in contact with the specimen, shall be sufficientlylarge to prevent contact of the specimen with the sides of
11、 thenoses. Neoprene pads, approximately116 in. (1.6 mm) thick,may be placed between the loading noses and the test specimenfor uniform load distribution across the width of the specimen.However, neoprene pads should not be used if deflectionmeasurements are to be made, as the compression of theneopr
12、ene will distort the measurements.4.3 Loading Head and Support ApparatusLoading noses,supports, and their respective holding devices shall be designedto allow rotation to occur about axes that lie in horizontalplanes of the loading apparatus as shown in Fig. 1. Thisconfiguration of loading head and
13、support apparatus willensure that forces applied to the specimen will be initiallyperpendicular to the surfaces of the specimen and appliedwithout eccentricity.4.4 Specimen Depth and Width Measuring DeviceA cali-per or micrometer or other suitable device that is able tomeasure sample depth accurate
14、to 0.005 in. (0.13 mm) andwidth accurate to 0.01 in. (0.25 mm).5. Sampling5.1 Test boards shall be manufactured in accordance withgoverning specifications.1This test method is under the jurisdiction of ASTM Committee C27 on PrecastConcrete Products and is the direct responsibility of Subcommittee C2
15、7.40 on GlassFiber Reinforced Concrete.Current edition approved May 1, 2009. Published May 2009. Originallyapproved in 1981. Last previous edition approved in 2003 as C 947 03.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. Fo
16、r Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6. Test Specimen6.1 Six test specimens shall be prepared in accordance
17、 withPractice C 1228.6.2 The test specimen shall have a ratio of the specimenmajor span length to the specimen depth between 16 to 1 and30 to 1. The total specimen length shall be a minimum of 1 in.(25 mm) longer than the specimens major span. Nominalspecimen width shall be 2 in. (50 mm).7. Conditio
18、ning7.1 The sample or specimens shall be transported to thetesting laboratory packaged so that no damage will take place.7.2 Condition the samples or specimens in water at 73 65F (23 6 3C) for a period of minimum 24 h and maximum72 h to ensure complete saturation and test immediately uponremoval. Re
19、move specimens from water bath individually andtest. Do not allow specimen surfaces to dry out either prior toor during the test. Specimen surfaces may be sprayed withwater during testing if indications of surface drying are present.7.3 Samples or specimens shall be tested in a temperaturecontrolled
20、 environment at 73 6 5F (23 6 3C).8. Procedure8.1 Set the major span of the test apparatus to correspondwith 6.2.8.2 Set the minor span to correspond with one third of themajor span.8.3 Align the loading noses and supports so that the axes ofthe cylindrical surfaces are parallel.NOTE 1The parallelis
21、m of the loading noses and supports may bechecked by means of a plate containing parallel grooves into which theloading noses and supports will fit when properly aligned.8.4 Center the specimen on the supports with equal lengthsof specimen projecting outside of the supports with the longaxis of the
22、specimen perpendicular to the loading noses andsupports.8.5 Test three specimens with the mold face in tension andthree specimens with the opposite face (or trowelled face) intension.8.6 Set the crosshead speed of the testing machine at 0.05to 0.20 in./min (1.27 to 5.1 mm/min). Set the chart speed t
23、o 756 25 times the crosshead speed being used. Set the initial loadmeasuring range such that the flexural yield strength (Fy) loadoccurs at not less than 30 % of full scale. Apply force at aconstant crosshead speed to specimen failure. Examine thefailure location of the specimen. If failure occurs o
24、utside theminor span, discard the specimen and specimen test data.NOTE 2The chart speed may be reduced or stopped after the force-deflection curve reaches its point of deviation from linearity (Pyin Fig. 2)to conserve chart paper.8.7 Record the maximum force attained (Pu) and the forcewhere the forc
25、e-deflection curve deviates from linearity (Py).Also the deflections should be measured at the point where theforce-deflection curve deviates from linearity (Yy) and at failure(Yu). See Fig. 2 for a typical force-deflection chart recording.8.8 Determine and record the average of three specimendepth
26、measurements to the nearest 0.005 in. (0.125 mm) at ornear the fracture location. Determine the specimen width to thenearest 0.01 in. (0.25 mm) at or near the failure location. Usea measuring device as described in 4.4.NOTE 3Observe caution to avoid measurements at locations that havebeen expanded a
27、t or near the fracture.9. Calculations9.1 Calculate flexural yield strength (Fy) as follows:Fy5 PyL/bd2(1)where:Fy= flexural yield strength psi (or MPa),Py= force at the point on the force-deflection curve wherethe curve deviates from linearity, lbf (or N),L = major support span, in. (or mm),b = wid
28、th of specimen, in. (or mm), andd = depth of specimen, in. (or mm).9.2 Use of testing machines with magnification factors(ratio of chart speed to crosshead speed) of less than 50:1 maylead to systematic errors in identifying the point at which theforce-deflection curve deviates from linearity. Such
29、errors maybe corrected by the use of a factor determined by comparingresults from specimens from a variety of specimens yielding aFIG. 1 Loading Configuration for Flexural TestingFIG. 2 Force Deflection ChartC 947 03 (2009)2range of proportional elastic limit values tested on machineswith and withou
30、t the recommended magnification factors.9.3 Calculate the flexural ultimate strength (Fu) as follows:Fu5 PuL/bd2(2)where:Fu= flexural ultimate strength, psi (or MPa),Pu= maximum force achieved by the specimen, lbf (or N),L = major support span, in. (or mm),b = width of specimen, in. (or mm), andd =
31、depth of specimen, in. (or mm).10. Report10.1 Report the following information:10.1.1 Identification number of specimen,10.1.2 Sample description and age,10.1.3 Sample conditioning,10.1.4 Date of testing,10.1.5 Crosshead speed,10.1.6 Chart speed,10.1.7 Major span,10.1.8 Specimen depth to nearest 0.0
32、05 in. (0.127 mm) andwidth to nearest 0.01 in. (0.254 mm), and10.1.9 Deflections at the point where the force-deflectioncurve deviates from linearity and at failure.10.1.10 Test Results:10.1.10.1 Flexural yield strength to the nearest 5 psi (0.03MPa), and10.1.10.2 Flexural ultimate strength to the n
33、earest 5 psi(0.03 MPa).11. Precision and Bias11.1 The precision and bias criteria are being developedand tests are being run.12. Keywords12.1 flexural properties; GFRC; glassfiber reinforcedconcreteAPPENDIX(Nonmandatory Information)X1. MODULUS OF ELASTICITYX1.1 In certain circumstances a value for t
34、he Modulus ofElasticity is required. This can be calculated as follows:E 55PyL327Yybd3(X1.1)where:E = initial flexural modulus of elasticity, psi (Mpa),Yy= deflection at the point where the load-deflection curvedeviates from linearity,Py= force at the point on the force-deflection curve wherethe cur
35、ve deviates from linearity, lbf (or N),L = major support span, in. (or mm),b = width of specimen, in. (or mm), andd = depth of specimen, in. (or mm).NOTE X1.1If a deflectometer is used at the center of the major spanto measure specimen deflection in order to minimize the effects ofmachine and fixtur
36、e stiffness, the flexural modulus of elasticity is thencalculated using the following equation:E 523PyL3108Yybd3(X1.2)ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly
37、 advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, ei
38、ther reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may atten
39、d. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).C 947 03 (2009)3
