1、Designation: C900 13aStandard Test Method forPullout Strength of Hardened Concrete1This standard is issued under the fixed designation C900; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in par
2、entheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers determination of the pulloutstrength of hardened concrete by measuring the force requiredto pull an embedded metal insert a
3、nd the attached concretefragment from a concrete test specimen or structure. The insertis either cast into fresh concrete or installed in hardenedconcrete. This test method does not provide statistical proce-dures to estimate other strength properties.1.2 The values stated in SI units are to be rega
4、rded as thestandard. No other units of measurement are included in thistest method.1.3 The text of this test method references notes andfootnotes which provide explanatory material. These notes andfootnotes (excluding those in tables and figures) shall not beconsidered as requirements of this test m
5、ethod.1.4 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. (WARNING
6、Fresh hydraulic cementitious mixtures are caustic and maycause chemical burns to skin and tissue upon prolongedexposure.)22. Referenced Documents2.1 ASTM Standards:3C125 Terminology Relating to Concrete and Concrete Ag-gregatesC670 Practice for Preparing Precision and Bias Statementsfor Test Methods
7、 for Construction MaterialsE4 Practices for Force Verification of Testing MachinesE74 Practice of Calibration of Force-Measuring Instrumentsfor Verifying the Force Indication of Testing Machines3. Terminology3.1 Definitions:3.1.1 For definitions of terms used in this practice, refer toTerminology C1
8、25.4. Summary of Test Method4.1 A metal insert is either cast into fresh concrete orinstalled into hardened concrete. When an estimate of thein-place strength is desired, the insert is pulled by means of ajack reacting against a bearing ring. The pullout strength isdetermined by measuring the maximu
9、m force required to pullthe insert from the concrete mass. Alternatively, the insert isloaded to a specified load to verify whether a minimum level ofin-place strength has been attained.5. Significance and Use5.1 For a given concrete and a given test apparatus, pulloutstrengths can be related to com
10、pressive strength test results.Such strength relationships are affected by the configuration ofthe embedded insert, bearing ring dimensions, depth ofembedment, and the type of aggregate (lightweight or normalweight). Before use, the relationships must be established foreach test system and each new
11、concrete mixture. Such rela-tionships are more reliable if both pullout test specimens andcompressive strength test specimens are of similar size, con-solidated to similar density, and cured under similar conditions.NOTE 1Published reports (1-17)4by different researchers present theirexperiences in
12、the use of pullout test equipment. Refer toACI 228.1R (14)for guidance on establishing a strength relationship and interpreting testresults. The Appendix provides a means for comparing pullout strengthsobtained using different configurations.5.2 Pullout tests are used to determine whether the in-pla
13、cestrength of concrete has reached a specified level so that, forexample:(1) post-tensioning may proceed;(2) forms and shores may be removed;(3) structure may be placed into service; or(4) winter protection and curing may be terminated.1This test method is under the jurisdiction of ASTM Committee C0
14、9 onConcrete and Concrete Aggregatesand is the direct responsibility of SubcommitteeC09.64 on Nondestructive and In-Place Testing.Current edition approved Dec. 1, 2013. Published January 2014. Originallyapproved in 1978. Last previous edition approved in 2013 as C900 13. DOI:10.1520/C0900-13a.2Secti
15、on on Safety Precautions, Manual of Aggregate and Concrete Testing,Annual Book of ASTM Standards, Vol. 04.02.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the sta
16、ndards Document Summary page onthe ASTM website.4The boldface numbers refer to the list of references at the end of this testmethod.*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. Uni
17、ted States1In addition, post-installed pullout tests may be used toestimate the strength of concrete in existing constructions.5.3 When planning pullout tests and analyzing test results,consideration should be given to the normally expected de-crease of concrete strength with increasing height withi
18、n agiven concrete placement in a structural element.5.4 The measured pullout strength is indicative of thestrength of concrete within the region represented by the conicfrustum defined by the insert head and bearing ring. For typicalsurface installations, pullout strengths are indicative of thequali
19、ty of the outer zone of concrete members and can be ofbenefit in evaluating the cover zone of reinforced concretemembers.5.5 Cast-in-place inserts require that their locations in thestructure be planned in advance of concrete placement. Post-installed inserts can be placed at any desired location in
20、 thestructure provided the requirements of 7.1 are satisfied.5.6 This test method is not applicable to other types ofpost-installed tests that, if tested to failure, do not involve thesame failure mechanism and do not produce the same conicfrustum as for the cast-in-place test described in this test
21、method (16).6. Apparatus6.1 The apparatus requires three basic sub-systems: a pull-out insert, a loading system, and a load-measuring system(Note 2). For post-installed inserts, additional equipmentincludes a core drill, a planing tool to prepare a flat bearingsurface, a grinding tool to undercut a
22、groove to engage theinsert, and an expansion tool to expand the insert into thegroove.NOTE 2A center-pull hydraulic jack with a pressure gauge that hasbeen standardized according to AnnexA1 and that reacts against a bearingring has been used satisfactorily.6.1.1 Cast-in-place inserts shall be made o
23、f metal that doesnot react with the constituents of the concrete. The insert shallconsist of a cylindrical head and a shaft to fix embedmentdepth. The shaft shall be attached firmly to the center of thehead (see Fig. 1). The insert shaft shall be threaded to the inserthead so that it can be removed
24、and replaced by a stronger shaftto pullout the insert, or it shall be an integral part of the insertand also function as the pullout shaft. Metal components ofcast-in-place inserts and attachment hardware shall be ofsimilar material to prevent galvanic corrosion. Post-installedinserts shall be desig
25、ned so that they will fit into the drilledholes, and can be expanded subsequently to fit into the groovesthat are undercut at a predetermined depth (see Fig. 2).NOTE 3A successful post-installed system uses a split ring that iscoiled to fit into the core hole and then expanded into the groove.6.1.2
26、The loading system shall consist of a bearing ring tobe placed against the hardened concrete surface (see Figs. 1and 2) and a tensile loading apparatus, with a load-measuringdevice that can be attached to the pullout shaft.6.1.3 The test apparatus shall include centering features toensure that the b
27、earing ring is concentric with the insert, andthat the applied load is axial to the pullout shaft, perpendicularto the bearing ring, and uniform on the bearing ring.6.2 Equipment dimensions shall be determined as follows(see Fig. 1):6.2.1 The diameter of the insert head (d2) is the basis fordefining
28、 the test geometry. The thickness of the insert head andthe yield strength of the metal shall be sufficient to preventFIG. 1 Schematic Cross Section of Cast-in-Place Pullout TestC900 13a2yielding of the insert during test. The sides of the insert headshall be smooth (see Note 5). The insert head dia
29、meter shall beat least23 of the nominal maximum size of aggregate.NOTE 4Typical insert diameters are 25 and 30 mm, but largerdiameters have been used (1, 3). Tests (15) have shown that nominalmaximum aggregate sizes up to 1.5 times the head diameter do not havesignificant effects on the strength rel
30、ationships. Larger aggregate sizesmay result in increased scatter of the test results because the large particlescan interfere with normal pullout of the conic frustum.NOTE 5Cast-inplace inserts may be coated with a release agent tominimize bonding with the concrete, and they may be tapered to minim
31、izeside friction during testing. The insert head should be provided with themeans, such as a notch, to prevent rotation in the concrete if the insertshaft has to be removed prior to performing the test. As a furtherprecaution against rotation of the insert head, all threaded hardware shouldbe checke
32、d prior to installation to ensure that it is free-turning and can beeasily removed. A thread-lock compound is recommended to preventloosening of the insert head from the shaft during installation and duringvibration of the surrounding concrete.6.2.2 For cast-inplace inserts, the distance from the in
33、serthead to the concrete surface (h) shall equal the diameter of theinsert head (d2).The diameter of the insert shaft at the head (d1)shall not exceed 0.60 d2.6.2.3 For post-installed inserts, the groove to accept theexpandable insert shall be cut so that the distance between thebearing surface of t
34、he groove and concrete surface equals theinsert diameter after expansion (d2). The difference betweenthe diameters of the undercut groove (d2) and the core hole (d1)shall be sufficient to prevent localized failure and ensure that aconic frustum of concrete is extracted during the test (see Note6). T
35、he expanded insert shall bear uniformly on the entirebearing area of the groove.NOTE 6A core hole diameter of 18 mm and an undercut grooveFIG. 2 Schematic of Procedure for Post-Installed Pullout TestC900 13a3diameter of 25 mm have been used successfully.6.2.4 The bearing ring shall have an inside di
36、ameter (d3)of2.0 to 2.4 times the insert head diameter (d2), and shall have anoutside diameter (d4) of at least 1.25 times the inside diameter.The thickness of the ring (t) shall be at least 0.4 times thepullout insert head diameter. For a given test system, the samebearing ring dimensions shall be
37、used.6.2.5 Tolerances for dimensions of the pullout test inserts,bearing ring and embedment depth shall be 62 % within agiven system.NOTE 7The limits for dimensions and configurations for pullout testinserts and apparatus are intended to accommodate various systems.6.2.6 The loading apparatus shall
38、have sufficient capacity toprovide the loading rate prescribed in 8.4.NOTE 8Hydraulic pumps that permit continuous loading may givemore uniform test results than pumps that apply load intermittently.6.2.7 The gauge to measure pullout force is permitted to beof the analog or digital type. Analog gaug
39、es shall be designedso that the pullout force can be estimated to the nearest 0.5 kN.Digital gauges shall display the pullout force to the nearest 0.1kN.6.2.8 The force gauge shall have a means to preserve themaximum value of the load during a test.6.2.9 Pullout apparatus shall be standardized in ac
40、cordancewith Annex A1 at least once a year and after all repairs.Standardize the pullout apparatus using a testing machineverified in accordance with Practices E4 or using a ClassAloadcell as defined in Practice E74. The indicated pullout forcebased on the developed relationship shall be within 62%o
41、fthe force measured by the testing machine or load cell.7. Sampling7.1 Pullout test locations shall be separated so that the clearspacing between inserts is at least seven times the pullout inserthead diameter. Clear spacing between the inserts and the edgesof the concrete shall be at least 3.5 time
42、s the head diameter.Inserts shall be placed so that reinforcement is outside theexpected conical failure surface by more than one bar diameter,or the maximum size of aggregate, whichever is greater.NOTE 9A reinforcement locator is recommended to assist in avoidingreinforcement when planning the loca
43、tions of post-installed tests. Followthe manufacturers instructions for proper operation of such devices.7.2 When pullout test results are used to assess the in-placestrength in order to allow the start of critical constructionoperations, such as formwork removal or application of posttensioning, at
44、 least five individual pullout tests shall beperformed as follows:7.2.1 For every 115 m3, or a fraction thereof, of a givenplacement; or7.2.2 For every 470 m2, or a fraction thereof, of the surfacearea of one face of a slab or wall.NOTE 10More than the minimum number of inserts should beprovided in
45、case a test result is not valid or testing begins before adequatestrength has developed.7.2.3 Inserts shall be located in those portions of thestructure that are critical in terms of exposure conditions andstructural requirements.7.3 When pullout tests are used for other purposes, thenumber of tests
46、 shall be determined by the specifier of the test.8. Procedure8.1 Cast-in-Place Inserts:8.1.1 Attach the pullout inserts to the forms using bolts orby other methods that firmly secure the insert in its properlocation prior to concrete placement. All inserts shall beembedded to the same depth. The ax
47、is of each shaft shall beperpendicular to the formed surface.8.1.2 Alternatively, when instructed by the specifier of tests,manually place inserts into unformed horizontal concretesurfaces. The inserts shall be embedded into the fresh concreteby means that ensure a uniform embedment depth and a surf
48、aceto support the bearing ring that is plane and perpendicular tothe axis of the insert shaft. Installation of inserts shall beperformed or supervised by personnel trained by the manufac-turer or manufacturers representative.NOTE 11Experience indicates that pullout strengths are of lower valueand mo
49、re variable for manually-placed surface inserts than for insertsattached to formwork (12).8.1.3 When pullout strength of the concrete is to bemeasured, remove all hardware used for securing the pulloutinserts in position. Before mounting the loading system,remove any debris or surface abnormalities to ensure a flatbearing surface that is perpendicular to the axis of the insert.8.2 Post-Installed Inserts:8.2.1 The selected test surface shall be flat to provide asuitable working surface for drilling the core and undercuttingthe groove. Drill a core hole perpendicula
