1、Designation: C 947 03Standard 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 year oforiginal adopt
2、ion or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers determination of the flexuralultimate strength i
3、n 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 forinformation only
4、.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
5、Documents2.1 ASTM Standards:C 1228 Practice for Flexural and Washout Tests on GlassFiber Reinforced Concrete2D 76 Specification for Tensile Testing Machines for Tex-tiles3E 4 Practices for Force Verification of Testing Machines43. Significance and Use3.1 Flexural properties determined by this test m
6、ethod 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 testing ma-chine that can be operate
7、d at constant rates of crosshead motionand in which the error in the force measuring system shall notexceed 6 1.0 % of the maximum force expected to bemeasured shall be used. The testing machine shall be equippedwith a deflection measuring and recording device. The stiffnessof the testing machine sh
8、all be such that the total elasticdeformation of the system does not exceed 1.0 % of the totaldeflection of the test specimen during the test, or appropriatecorrections shall be made. The force-indicating mechanismshall be essentially free of inertial lag at the crosshead rateused. The accuracy of t
9、he testing machine shall be verified inaccordance with Practices E 4 and Specification D 76.4.2 Loading Noses and SupportsThe loading noses andsupports shall have cylindrical surfaces. In order to avoidexcessive indentation or failure due to stress concentrationdirectly under the loading noses or su
10、pports, 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 thenoses. Neoprene pads, appr
11、oximately116 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 will distort the measureme
12、nts.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 apparatus willensure t
13、hat 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 0.005 in. (0.13 mm) andwidt
14、h 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 GlassFiber Reinforced
15、Concrete Made by the Spray-Up Process.Current edition approved June 10, 2003. Published July 2003. Originallyapproved in 1981. Last previous edition approved in 1999 as C 947 - 99.2Annual Book of ASTM Standards, Vol 04.05.3Annual Book of ASTM Standards, Vol 07.01.4Annual Book of ASTM Standards, Vol
16、03.01.1Copyright 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 withPractice C 1228.6.2 The test specimen shall have a ratio of the specimenmajor span length to the specime
17、n 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. Conditioning7.1 The sample or specimens shall be transported to thetesting laboratory packaged so that no damage will
18、 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. Remove specimens from water bath individually andtest. Do not allow specimen surfaces to dry out either prior t
19、oor 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 environment at 73 6 5F (23 6 3C).8. Procedure8.1 Set the major span of the test apparatus to correspondwith
20、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 parallelism of the loading noses and supports may bechecked by means of a plate containing parallel grooves into which
21、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 specimen perpendicular to the loading noses andsupports.8.5 Test three specimens with the mold face in tensio
22、n 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 to 756 25 times the crosshead speed being used. Set the initial loadmeasuring range such that the flexural yie
23、ld 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 outside theminor span, discard the specimen and specimen test data.NOTE 2The chart speed may be reduced or sto
24、pped 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 force-deflection curve deviates from linearity (Py).Also the deflections should be measured at the point where th
25、eforce-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 measurements to the nearest 0.005 in. (0.125 mm) at ornear the fracture location. Determine the specimen widt
26、h 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 at or near the fracture.9. Calculations9.1 Calculate flexural yield strength (Fy) as follows:Fy5 PyL/bd2(1)whe
27、re: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 = width of specimen, in. (or mm), andd = depth of specimen, in. (or mm).9.2 Use of testing machines with magnifica
28、tion 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 errors maybe corrected by the use of a factor determined by comparingresults from specimens from a variety of
29、 specimens yielding aFIG. 1 Loading Configuration for Flexural TestingFIG. 2 Force Deflection ChartC 947 032range of proportional elastic limit values tested on machineswith and without the recommended magnification factors.9.3 Calculate the flexural ultimate strength (Fu) as follows:Fu5 PuL/bd2(2)w
30、here: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 = depth of specimen, in. (or mm).10. Report10.1 Report the following information:10.1.1 Identification number of speci
31、men,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 0.005 in. (0.127 mm) andwidth to nearest 0.01 in. (0.254 mm), and10.1.9 Deflections at the point where the force-deflec
32、tioncurve 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 nearest 5 psi(0.03 MPa).11. Precision and Bias11.1 The precision and bias criteria are being developedand tests are b
33、eing run.12. Keywords12.1 flexural properties; GFRC; glassfiber reinforcedconcreteAPPENDIX(Nonmandatory Information)X1.X1.1 In certain circumstances a value for the Modulus ofElasticity is required. This can be calculated as follows:E 55PyL327Yybd3(X1.1)where:E = initial flexural modulus of elastici
34、ty, 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 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, i
35、n. (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 fixture stiffness, the flexural modulus of elasticity is thencalculated using the following equation:E 523PyL3108Yybd3(X1.2)ASTM International t
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39、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 947 033
