1、Designation: C 900 06Standard Test Method forPullout Strength of Hardened Concrete1This standard is issued under the fixed designation C 900; 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 pa
2、rentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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
3、 and 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 re
4、garded as thestandard.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 method.1.4 This standard does not purport to address all of th
5、esafety 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. (WARNINGFresh hydraulic cementitious mixtures are caustic and maycaus
6、e chemical burns to skin and tissue upon prolongedexposure.)22. Referenced Documents2.1 ASTM Standards:3C 670 Practice for Preparing Precision and Bias Statementsfor Test Methods for Construction MaterialsE4 Practices for Force Verification of Testing MachinesE74 Practice of Calibration of Force-Mea
7、suring Instru-ments for Verifying the Force Indication of Testing Ma-chines3. Summary of Test Method3.1 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
8、 bearing ring. The pullout strength isdetermined by measuring the maximum 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.4. Significance and Use4.1 For a given con
9、crete and a given test apparatus, pulloutstrengths can be related to compressive strength test results.Such strength relationships depend on the configuration of theembedded insert, bearing ring dimensions, depth of embed-ment, and level of strength development in that concrete. Priorto use, these r
10、elationships must be established for each systemand each new combination of concreting materials. Suchrelationships tend to be less variable where both pullout testspecimens and compressive strength test specimens are ofsimilar size, compacted to similar density, and cured undersimilar conditions.NO
11、TE 1Published reports (1-17)4by different researchers presenttheir experiences in the use of pullout test equipment. Refer toACI 228.1R(14) for guidance on establishing a strength relationship and interpretingtest results. The Appendix provides a means for comparing pulloutstrengths obtained using d
12、ifferent configurations.4.2 Pullout tests are used to determine whether the in-placestrength of concrete has reached a specified level so that, forexample:(1) post-tensioning may proceed;(2) forms and shores may be removed; or(3) winter protection and curing may be terminated.In addition, post-insta
13、lled pullout tests may be used toestimate the strength of concrete in existing constructions.4.3 When planning pullout tests and analyzing test results,consideration should be given to the normally expected de-crease of concrete strength with increasing height within a1This test method is under the
14、jurisdiction of ASTM Committee C09 onConcrete and Concrete Aggregates and is the direct responsibility of SubcommitteeC09.64 on Nondestructive and In-Place Testing.Current edition approved Dec. 15, 2006. Published January 2007. Originallyapproved in 1978. Last previous edition approved in 2001 as C
15、900 01.2Section 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, ref
16、er to the standards Document Summary page onthe ASTM website.4The boldface numbers refer to the list of references at the end of this testmethod.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA
17、19428-2959, United States.given concrete placement in a structural element. The mea-sured pullout strength is indicative of the strength of concretewithin the region represented by the conic frustum defined bythe insert head and bearing ring. For typical surface installa-tions, pullout strengths are
18、 indicative of the quality of the outerzone of concrete members and can be of benefit in evaluatingthe cover zone of reinforced concrete members.4.4 Cast-in-place inserts require that their locations in thestructure be planned in advance of concrete placement. Post-installed inserts can be placed at
19、 any desired location in thestructure provided the requirements of 6.1 are satisfied.4.5 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 the cast-in-place test de
20、scribed in this test method(16).5. Apparatus5.1 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 grinding wheel to prepare a flat bearingsurface, a millin
21、g tool to undercut a groove to engage theinsert, and an expansion tool to expand the insert into thegroove.NOTE 2A center-pull hydraulic jack with a pressure gauge calibratedaccording to Annex A1 and a bearing ring have been used satisfactorily.5.1.1 Cast-in-place inserts shall be made of metal that
22、 doesnot react with cement. The insert shall consist of a cylindricalhead and a shaft to fix embedment depth. The shaft shall beattached firmly to the center of the head (see Fig. 1). The insertshaft shall be threaded to the insert head so that it can beremoved and replaced by a stronger shaft to pu
23、llout the insert,or it shall be an integral part of the insert and also function asthe pullout shaft. Metal components of cast-in-place inserts andattachment hardware shall be of similar material to preventgalvanic corrosion. Post-installed inserts shall be designed sothat they will fit into the dri
24、lled holes, and can be expandedsubsequently to fit into the grooves that are undercut at apredetermined 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.5.1.2 The loading system shall consist of a
25、bearing ring tobe placed against the hardened concrete surface (see Figs. 1and 2) and a loading apparatus with the necessary load-measuring devices that can be readily attached to the pulloutshaft.5.1.3 The test apparatus shall include centering features toensure that the bearing ring is concentric
26、with the insert, andthat the applied load is axial to the pullout shaft, perpendicularto the bearing ring, and uniform on the bearing ring.5.2 Equipment dimensions shall be determined as follows(see Fig. 1):5.2.1 The diameter of the insert head (d2) is the basis fordefining the test geometry. The th
27、ickness of the insert head andthe yield strength of the metal shall be sufficient to preventyielding of the insert during test. The sides of the insert headshall be smooth (see Note 5). The insert head diameter shall begreater than or equal to23 of the nominal maximum size ofaggregate.NOTE 4Typical
28、insert diameters are 25 and 30 mm, but largerFIG. 1 Schematic Cross Section of Cast-in-Place Pullout TestC900062diameters 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 relationships. L
29、arger 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 minimizeside frict
30、ion 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 checked prior to in
31、stallation 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.5.2.2 For cast-inplace inserts, the length of the pulloutinsert shaft
32、 shall be such that the distance from the insert headto the concrete surface (h) equals the diameter of the inserthead (d2). The diameter of the insert shaft at the head (d1) shallnot exceed 0.60 d2.5.2.3 For post-installed inserts, the groove to accept theexpandable insert shall be cut so that the
33、distance between thebearing surface of the 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
34、extracted during the test (see Note6). The expanded insert shall bear uniformly on the entirebearing area of the groove.NOTE 6A core hole diameter of 18 mm and an undercut groovediameter of 25 mm have been used successfully.5.2.4 The bearing ring shall have an inside diameter (d3)of2.0 to 2.4 times
35、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.FIG. 2 Schematic of Procedure for Post-Installed Pullout TestC9000635.2.5 Tolerances for dimensio
36、ns 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.5.2.6 The loading apparatus shall have sufficient capacity toprovide
37、 the loading rate prescribed in 7.4 and exceed themaximum load expected.NOTE 8Hydraulic pumps that permit continuous loading may givemore uniform test results than pumps that apply load intermittently.5.2.7 The gauge to measure the pullout force shall have aleast division not larger than 5 % of the
38、minimum value in theintended range of use.5.2.8 The force gauge shall have a maximum value indica-tor that preserves the value of the maximum load duringtesting.5.2.9 Pullout apparatus shall be calibrated in accordancewith Annex A1 at least once a year and after all repairs.Calibrate the pullout app
39、aratus using a testing machine verifiedin accordance with Practices E4 or a Class A load cell asdefined in Practice E74. The indicated pullout force based onthe calibration relationship shall be within 62 % of the forcemeasured by the testing machine or load cell.6. Sampling6.1 Pullout test location
40、s 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 times the head diameter.Inserts shall be placed so that reinforcement is outside theexpected con
41、ical failure surface by more than one bar diameter,or the maximum size of aggregate, whichever is greater.NOTE 9Areinforcement locator is recommended to assist in avoidingreinforcement when planning the locations of post-installed tests. Followthe manufacturers instructions for proper operation of s
42、uch devices.6.2 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 least five individual pullout tests shall beperformed as follows:6.2.1 For a given placement
43、, every 115 m3, or a fractionthereof, or6.2.2 For slabs or walls, every 470 m2, or a fraction thereof,of the surface area of one face.NOTE 10More than the minimum number of inserts should beprovided in case a test result is not valid or testing begins before adequatestrength has developed.6.2.3 Inse
44、rts shall be located in those portions of thestructure that are critical in terms of exposure conditions andstructural requirements.6.3 When pullout tests are used for other purposes, thenumber of tests shall be determined by the specifier.7. Procedure7.1 Cast-in-Place Inserts:7.1.1 Attach the pullo
45、ut inserts to the forms using bolts orby other acceptable methods that firmly secure the insert in itsproper location prior to concrete placement.All inserts shall beembedded to the same depth. The axis of each shaft shall beperpendicular to the formed surface.7.1.2 Alternatively, when instructed by
46、 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 planesurface perpendicular to the axis of the insert shaft. Installationof inserts shall be performed or
47、 supervised by personnel trainedby the manufacturer or manufacturers representative.NOTE 11Experience indicates that pullout strengths are of lowervalue and more variable for manually-placed surface inserts than forinserts attached to formwork (12).7.1.3 When pullout strength of the concrete is to b
48、e mea-sured, remove all hardware used for securing the pullout insertsin position. Before mounting the loading system, remove anydebris or surface abnormalities to ensure a flat bearing surfacethat is perpendicular to the axis of the insert.7.2 Post-Installed Inserts:7.2.1 The selected test surface
49、shall be flat to provide asuitable working surface for drilling the core and undercuttingthe groove. Drill a core hole perpendicular to the surface toprovide a reference point for subsequent operations and toaccommodate the expandable insert and associated hardware.The use of an impact drill is not permitted.7.2.2 If necessary, use a grinding wheel to prepare a flatsurface so that the base of the milling tool is supported firmlyduring subsequent test preparation and so that the bearing ringis supported uniformly during testing. The ground surface shallbe perpendicula
