1、Designation: C900 14C900 15Standard 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
2、in parentheses 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 pullout strength of hardened concrete by measuring the force required to pullan embedded metal i
3、nsert and the attached concrete fragment from a concrete test specimen or structure. The insert is either castinto fresh concrete or installed in hardened concrete. This test method does not provide statistical procedures to estimate otherstrength properties.1.2 The values stated in SI units are to
4、be regarded as the standard. No other units of measurement are included in this testmethod.1.3 The text of this test method references notes and footnotes which provide explanatory material. These notes and footnotes(excluding those in tables and figures) shall not be considered as requirements of t
5、his test method.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.
6、(WarningFresh hydraulic cementitious mixtures are caustic and may cause chemical burns to skin andtissue upon prolonged exposure.2)2. Referenced Documents2.1 ASTM Standards:3C125 Terminology Relating to Concrete and Concrete AggregatesC670 Practice for Preparing Precision and Bias Statements for Tes
7、t Methods for Construction MaterialsE4 Practices for Force Verification of Testing MachinesE74 Practice of Calibration of Force-Measuring Instruments for Verifying the Force Indication of Testing Machines3. Terminology3.1 Definitions:3.1.1 For definitions of terms used in this practice, refer to Ter
8、minology C125.4. Summary of Test Method4.1 A metal insert is either cast into fresh concrete or installed into hardened concrete. When a measure of the in-place pulloutstrength is desired, the insert is pulled by means of a jack reacting against a bearing ring. The pullout strength is determined bym
9、easuring the maximum force required to pull the insert from the concrete mass. Alternatively, the insert is loaded to a specifiedload to verify whether a minimum level of in-place pullout strength has been attained.5. Significance and Use5.1 For a given concrete and a given test apparatus, pullout s
10、trengths can be related to compressive strength test results. Suchstrength relationships are affected by the configuration of the embedded insert, bearing ring dimensions, depth of embedment, andthe type of aggregate (lightweight or normal weight). Before use, the relationships must be established f
11、or each test system and1 This test method is under the jurisdiction of ASTM Committee C09 on Concrete and Concrete Aggregates and is the direct responsibility of Subcommittee C09.64 onNondestructive and In-Place Testing.Current edition approved Oct. 1, 2014May 1, 2015. Published November 2014June 20
12、15. Originally approved in 1978. Last previous edition approved in 20132014 asC900 13a.C900 14. DOI: 10.1520/C0900-14.10.1520/C0900-15.2 Section on Safety Precautions, Manual of Aggregate and Concrete Testing, Annual Book of ASTM Standards, Vol 04.02.3 For referencedASTM standards, visit theASTM web
13、site, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indicati
14、on of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be consi
15、dered the official document.*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. United States1each new concrete mixture. Such relationships are more reliable if both pullout test specimen
16、s and compressive strength testspecimens are of similar size, consolidated to similar density, and cured under similar conditions.NOTE 1Published reports (1-17)4 by different researchers present their experiences in the use of pullout test equipment. Refer to ACI 228.1R (14)for guidance on establish
17、ing a strength relationship and interpreting test results. TheAppendix provides a means for comparing pullout strengths obtainedusing different configurations.5.2 If a strength relationship has been established experimentally and accepted by the specifier of tests, pullout tests are usedto determine
18、 whether estimate the in-place strength of concrete to establish whether it 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.In addition
19、, post-installed pullout tests may be used to estimate the strength of concrete in existing constructions.construction.5.3 When planning pullout tests and analyzing test results, consideration should be given to the normally expected decrease ofconcrete strength with increasing height within a given
20、 concrete placement in a structural element.5.4 The measured pullout strength is indicative of the strength of concrete within the region represented by the conic frustumdefined by the insert head and bearing ring. For typical surface installations, pullout strengths are indicative of the quality of
21、 theouter zone of concrete members and can be of benefit in evaluating the cover zone of reinforced concrete members.5.5 Cast-in-place inserts require that their locations in the structure be planned in advance of concrete placement. Post-installedinserts can be placed at any desired location in the
22、 structure provided the requirements of 7.1 are satisfied.5.6 This test method is not applicable to other types of post-installed tests that, if tested to failure, do not involve the same failuremechanism and do not produce the same conic frustum as for the cast-in-place test described in this test
23、method (16).6. Apparatus6.1 The apparatus requires three basic sub-systems: a pullout insert, a loading system, and a load-measuring system (Note 2).For post-installed inserts, additional equipment includes a core drill, a planing tool to prepare a flat bearing surface, a grinding toolto undercut a
24、groove to engage the insert, and an expansion tool to expand the insert into the groove.NOTE 2A center-pull hydraulic jack with a pressure gauge that has been standardized according to Annex A1 and that reacts against a bearing ringhas been used satisfactorily.6.1.1 Cast-in-place inserts shall be ma
25、de of metal that does not react with the constituents of the concrete. The insert shallconsist of a cylindrical head and a shaft to fix embedment depth. The shaft shall be attached firmly to the center of the head (seeFig. 1). The insert shaft shall be threaded to the insert head so that it can be r
26、emoved and replaced by a stronger shaft to pulloutthe insert, or it shall be an integral part of the insert and also function as the pullout shaft. Metal components of cast-in-place insertsand attachment hardware shall be of similar material to prevent galvanic corrosion. Post-installed inserts shal
27、l be designed so thatthey will fit into the drilled holes, and can be expanded subsequently to fit into the grooves that are undercut at a predetermineddepth (see Fig. 2).NOTE 3A successful post-installed system uses a split ring that is coiled to fit into the core hole and then expanded into the gr
28、oove.6.1.2 The loading system shall consist of a bearing ring to be placed against the hardened concrete surface (see Figs. 1 and 2)and a tensile loading apparatus, with a load-measuring device that can be attached to the pullout shaft.6.1.3 The test apparatus shall include centering features to ens
29、ure that the bearing ring is concentric with the insert, and thatthe applied load is axial to the pullout shaft, perpendicular to 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 b
30、asis for defining the test geometry. The thickness of the insert head and theyield strength of the metal shall be sufficient to prevent yielding of the insert during test. The sides of the insert head shall besmooth (see Note 5). The insert head diameter shall be at least 23 of the nominal maximum s
31、ize of aggregate.NOTE 4Typical insert diameters are 25 and 30 mm, but larger diameters have been used (1, 3). Tests (15) have shown that nominal maximumaggregate sizes up to 1.5 times the head diameter do not have significant effects on the strength relationships. Larger aggregate sizes may result i
32、nincreased scatter of the test results because the large particles can interfere with normal pullout of the conic frustum.NOTE 5Cast-inplace inserts may be coated with a release agent to minimize bonding with the concrete, and they may be tapered to minimize sidefriction during testing. The insert h
33、ead should be provided with the means, such as a notch, to prevent rotation in the concrete if the insert shaft has tobe removed prior to performing the test. As a further precaution against rotation of the insert head, all threaded hardware should be checked prior toinstallation to ensure that it i
34、s free-turning and can be easily removed. A thread-lock compound is recommended to prevent loosening of the insert headfrom the shaft during installation and during vibration of the surrounding concrete.4 The boldface numbers refer to the list of references at the end of this test method.C900 1526.2
35、.2 For cast-inplace inserts, the distance from the insert head to the concrete surface (h) shall equal the diameter of the inserthead (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 the expandable insert shall be
36、 cut so that the distance between the bearingsurface of the groove and concrete surface equals the insert diameter after expansion (d2). The difference between the diametersof the undercut groove (d2) and the core hole (d1) shall be sufficient to prevent localized failure and ensure that a conic fru
37、stumof concrete is extracted during the test (see Note 6). The expanded insert shall bear uniformly on the entire bearing area of thegroove.NOTE 6A core hole diameter of 18 mm and an undercut groove diameter of 25 mm have been used successfully.6.2.4 The bearing ring shall have an inside diameter (d
38、3) of 2.0 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 the pulloutinsert head diameter. For a given test system, the same bearing ring dimensions shall be used.
39、6.2.5 Tolerances for dimensions of the pullout test inserts, bearing ring and embedment depth shall be 62 % within a givensystem.NOTE 7The limits for dimensions and configurations for pullout test inserts and apparatus are intended to accommodate various systems.6.2.6 The loading apparatus shall hav
40、e sufficient capacity to provide the loading rate prescribed in 8.4.NOTE 8Hydraulic pumps that permit continuous loading may give more uniform test results than pumps that apply load intermittently.6.2.7 The gauge to measure pullout force is permitted to be of the analog or digital type. Analog gaug
41、es shall be designed sothat the pullout force can be estimated to the nearest 0.5 kN. Digital gauges shall display the pullout force to the nearest 0.1 kN.6.2.8 The force gauge shall have a means to preserve the maximum value of the load during a test.6.2.9 Pullout apparatus shall be standardized in
42、 accordance with AnnexA1 at least once a year and after all repairs. Standardizethe pullout apparatus using a testing machine verified in accordance with Practices E4 or using a Class A load cell as defined inPractice E74. The indicated pullout force based on the developed relationship shall be with
43、in 62 % of the force measured by thetesting machine or load cell.7. Sampling7.1 Pullout test locations shall be separated so that the clear spacing between inserts is at least seven times the pullout inserthead diameter. Clear spacing between the inserts and the edges of the concrete shall be at lea
44、st 3.5 times the head diameter. Insertsshall be placed so that reinforcement is outside the expected conical failure surface by more than one bar diameter, or the maximumsize of aggregate, whichever is greater.FIG. 1 Schematic Cross Section of Cast-in-Place Pullout TestC900 153NOTE 9A reinforcement
45、locator is recommended to assist in avoiding reinforcement when planning the locations of post-installed tests. Follow themanufacturers instructions for proper operation of such devices.7.2 When pullout test results are used to assess the in-place strength in order to allow the start of critical con
46、struction operations,such as formwork removal or application of post tensioning, at least five individual pullout tests shall be performed as follows:7.2.1 For every 115 m3, or a fraction thereof, of a given placement; or7.2.2 For every 470 m2 , or a fraction thereof, of the surface area of one face
47、 of a slab or wall.NOTE 10More than the minimum number of inserts should be provided in case a test result is not valid or testing begins before adequate strengthhas developed.7.2.3 Inserts shall be located in those portions of the structure that are critical in terms of exposure conditions and stru
48、cturalrequirements.7.3 When pullout tests are used for other purposes, the number of tests 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 or by other methods that firmly secure the insert in its proper
49、locationprior to concrete placement. All inserts shall be embedded to the same depth. The axis of each shaft shall be perpendicular to theformed surface.FIG. 2 Schematic of Procedure for Post-Installed Pullout TestC900 1548.1.2 Alternatively, when instructed by the specifier of tests, manually place inserts into unformed horizontal concrete surfaces.The inserts shall be embedded into the fresh concrete by means that ensure a uniform embedment depth and a surface to supportthe bearing ring that is plane and perpendicular to the axis of the insert shaft. Install
