1、Designation: C947 03 (Reapproved 2016)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 C947; the number immediately following the designation indicates the year
2、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 flexuralulti
3、mate 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 fori
4、nformation 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 use
5、.2. Referenced Documents2.1 ASTM Standards:2C1228 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 prope
6、rties determined by this test method areuseful for quality control of glass-fiber reinforced concreteproducts, ascertaining compliance with the governingspecifications, research and development, and generating datafor use in product design.4. Apparatus4.1 Testing MachineAproperly calibrated testing
7、machinethat can be operated at constant rates of crosshead motion andin 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 stiffness
8、 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 crosshead ra
9、te used. Theaccuracy of the testing machine shall be verified in accordancewith Practices E4 and 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 under
10、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 thenos
11、es. 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 theneoprene wil
12、l 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 support
13、 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 to 0.00
14、5 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 C27.40 on
15、 GlassFiber Reinforced Concrete.Current edition approved April 1, 2016. Published May 2016. Originallyapproved in 1981. Last previous edition approved in 2009 as C947 03(2009). DOI:10.1520/C0947-03R16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Servi
16、ce at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States16. Test Specimen6.1 Six test specimens shall b
17、e prepared in accordance withPractice C1228.6.2 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
18、in. (50 mm).7. Conditioning7.1 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 imme
19、diately uponremoval. Remove 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
20、a temperaturecontrolled 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 parall
21、el.NOTE 1The parallelism 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 wi
22、th the longaxis of the 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 0.05 to0.20 in./min (1.27 to 5.1 mm/min)
23、. Set the chart speed to 75 625 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 specim
24、en. If failure occurs outside theminor span, discard the specimen and specimen test data.NOTE 2The chart speed may be reduced or stopped after theforce-deflection curve reaches its point of deviation from linearity (PyinFig. 2) to conserve chart paper.8.7 Record the maximum force attained (Pu) and t
25、he forcewhere the force-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 o
26、f three specimendepth 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 th
27、at havebeen expanded at 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 spa
28、n, in. (or mm),b = width of specimen, in. (or mm), andd = depth of specimen, in. (or mm).FIG. 1 Loading Configuration for Flexural TestingFIG. 2 Force Deflection ChartC947 03 (2016)29.2 Use of testing machines with magnification factors(ratio of chart speed to crosshead speed) of less than 50:1 mayl
29、ead to systematic errors in identifying the point at which theforce-deflection curve deviates from linearity. Such errors maybe corrected by the use of a factor determined by comparingresults from specimens from a variety of specimens yielding arange of proportional elastic limit values tested on ma
30、chineswith and without 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,
31、 in. (or mm), andd = 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
32、 depth to nearest 0.005 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 ultim
33、ate strength to the nearest 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 reinforced con-creteAPPENDIX(Nonmandatory Information)X1. MODULUS OF ELASTICITYX1.1 In certain circ
34、umstances a value for the 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-deflec
35、tion curve wherethe curve 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 effec
36、ts ofmachine and fixture 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
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38、s andif not revised, either 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 committ
39、ee, which you may attend. 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
40、-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). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 03 (2016)3
