1、Designation: C915 79 (Reapproved 2018)Standard Specification forPrecast Reinforced Concrete Crib Wall Members1This standard is issued under the fixed designation C915; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of las
2、t 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 specification covers open- and closed-face precastreinforced concrete crib walls intended to act as earth-retainings
3、tructures or as protection against stream encroachment.NOTE 1This specification is a manufacturing and purchase specifica-tion only, with examples and suggestions for usage. Successful perfor-mance of this product depends on the proper selection and assembling ofmembers, proper foundation and bearin
4、g material, and consideration ofbackfill heights, backfill material, drainage, and other engineering andconstruction considerations. The purchaser of the crib wall membersspecified herein is cautioned that he must properly correlate the fieldrequirements with the members selected and provide adequat
5、e inspectionat the construction site.1.2 The values stated in inch-pound units are to be regardedas the standard. The values given in parentheses are forinformation only.1.3 This international standard was developed in accor-dance with internationally recognized principles on standard-ization establ
6、ished in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2A370 Test Methods and Definitions for Mechanical Testingof Steel
7、 ProductsA615/A615M Specification for Deformed and Plain Carbon-Steel Bars for Concrete ReinforcementA616/A616M Specification for Rail-Steel Deformed andPlain Bars for Concrete Reinforcement (Withdrawn1999)3A617/A617M Specification for Axle-Steel Deformed andPlain Bars for Concrete Reinforcement (Wi
8、thdrawn1999)3C31/C31M Practice for Making and Curing Concrete TestSpecimens in the FieldC33/C33M Specification for Concrete AggregatesC39/C39M Test Method for Compressive Strength of Cylin-drical Concrete SpecimensC42/C42M Test Method for Obtaining and Testing DrilledCores and Sawed Beams of Concret
9、eC94/C94M Specification for Ready-Mixed ConcreteC150/C150M Specification for Portland CementC173/C173M Test Method forAir Content of Freshly MixedConcrete by the Volumetric MethodC231/C231M Test Method forAir Content of Freshly MixedConcrete by the Pressure MethodC260/C260M Specification for Air-Ent
10、raining Admixturesfor ConcreteC309 Specification for Liquid Membrane-Forming Com-pounds for Curing ConcreteC330/C330M Specification for Lightweight Aggregates forStructural ConcreteC494/C494M Specification for Chemical Admixtures forConcreteC595/C595M Specification for Blended Hydraulic CementsC618
11、Specification for Coal Fly Ash and Raw or CalcinedNatural Pozzolan for Use in Concrete3. Classification3.1 Cribbing manufactured in accordance with this specifi-cation shall be of open- or closed-face design and shallconform to the standard designs shown in Figs. 1-4.4. Ordering Information4.1 Accep
12、tability of the crib wall members in all crosssections and lengths produced in accordance with Section 6shall be determined by the results of cylinder compression testsof the placed concrete and mill certificates for the reinforcingsteel and cement. A written statement, signed by themanufacturer, sh
13、all verify that the cement, aggregate,admixtures, and reinforcing steel conform to the specificationsfor materials in Section 5 and that the preparation ofequipment, mixing, conveying, placing, consolidating, andcuring meet requirements of the applicable standard specifica-tions. The concrete streng
14、th as determined by the cylinder1This specification is under the jurisdiction ofASTM Committee C27 on PrecastConcrete Products and is the direct responsibility of Subcommittee C27.20 onArchitectural and Structural Products.Current edition approved July 1, 2018. Published July 2018. Originally approv
15、edin 1979. Last previous edition approved in 2010 as C915 79 (2010). DOI:10.1520/C0915-79R18.2For 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 standards Document
16、Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internatio
17、nally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1compression tests shall be as specified in 6.3, and t
18、he testmethod shall conform to the requirements of Test MethodC39/C39M. The manufacturers statement shall also certifyadherence to tolerance dimensions of Section 9.4.2 Acceptability of the concrete strength of completedcribbing produced in accordance with Section 6 may also bedetermined by compress
19、ive tests of concrete cores in accor-dance with Test Method C42/C42M.5. Materials5.1 CementPortland cement shall conform to the require-ments of Specification C150/C150M or shall be portlandblast-furnace slag cement or portland-pozzolan cement con-forming to the requirements of Specification C595/C5
20、95M.5.2 AggregatesAggregates shall conform to SpecificationC33/C33M or C330/C330M. The nominal maximum sizeaggregate shall not be greater than34 in. (19.0 mm).5.3 AdmixturesAir-entraining admixtures shall conform toSpecification C260/C260M. Chemical admixtures shall con-form to Specification C494/C4
21、94M. Fly ash or other pozzo-lanic admixtures shall conform to the requirements of Speci-fication C618.5.4 WaterWater used for curing, washing aggregates, andmixing concrete shall be free of oils, organic materials, andother substances that may be deleterious to concrete or steel; itshould not contai
22、n concentrations of chlorides in excess of1000 ppm or sulfates in excess of 1000 ppm.5.4.1 If water of higher chloride content is used by reason ofnonavailability of water of recommended quality, the manu-facturer must obtain approval from the user.5.5 Steel ReinforcementSteel reinforcement shall co
23、nsistof bars conforming to Specifications A615/A615M, A616/A616M,orA617/A617M.NOTE 1Surface drainage should not be permitted to flow directly against the face of the cribbing.NOTE 2Walls should be separated into 96-ft sections by the provision of double rows of headers.NOTE 3In using these typical s
24、ections for designing walls of intermediate height, the drawing should be read from the top down until the desiredheight is reached. Base details are repeated for intermediate heights.NOTE 4In areas of aggressive environment, Type II cement or protective coatings, or both, may need to be used to avo
25、id deterioration of the walls.NOTE 5Metric Conversion: 1 ft = 304.8 1 in. = 25.4 mm 1 lb = 0.453592 kg 1 ft3= 0.028317 m3FIG. 1 Open-Faced Concrete Crib WallC915 79 (2018)26. Design6.1 Precast concrete crib wall members shall conform todetails and dimensions prescribed in Figs. 1-4, subject to thepr
26、ovisions of this section and Section 10.6.2 ReinforcementMinimum reinforcement shall be asshown in Fig. 2 and Fig. 4 and shall be Grade 40 or 60.6.3 ConcreteConcrete shall have a minimum design com-pressive strength of 4000 psi (28 MPa) in 28 days.6.4 Concrete CoverThe minimum concrete cover over th
27、ereinforcement shall be 114 in. (32 mm).6.5 Air EntrainmentUnless otherwise specified by thepurchaser, all concrete shall have an air content of 612 6 112 %as measured by Test Method C173/C173M or C231/C231M.7. Manufacture7.1 CertificationAt the request of the purchaser, themanufacturer shall, prior
28、 to the actual delivery of the crib wallmembers, furnish a statement to the purchaser giving thesource and type of cement, the sources and specific gravities ofthe aggregates, the concrete mix proportions, type, amount, andname of admixture (if any), and mill certificates for thereinforcing steel us
29、ed in the manufacture.7.2 MixtureThe aggregates shall be sized, graded,proportioned, and thoroughly mixed with proportions of ce-ment and water as will produce a concrete mixture of a qualitysuch that the crib wall members will conform to the test anddesign requirements of this specification.7.3 Pla
30、cingConcrete shall be placed in the forms as nearlyas possible in its final position. Special care should be taken tofill all parts of the forms, and to place concrete under andaround all reinforcing steel. Reinforcement shall be adequatelysecured so as to remain in the proper position during thepla
31、cing of the concrete. Tie wires, if used to fasten thereinforcing steel, shall be bent down to provide the maximumprotective cover of concrete over the wires.NOTE 1All reinforcing to be No. 3 bars placed 114 in. clear from surface of concrete.NOTE 2Bars to be held in position by chairs having noncor
32、rosive tips.NOTE 3Blocks shall be set in cement-sand mortar (1 to 3).NOTE 4Backfilling should follow closely the erection of the successive tiers of units, and the wall should not be erected higher than 3 ft above thebackfilled portion at any time.NOTE 5Gravel, crushed stone, or other granular mater
33、ial meeting the users specifications may be used as backfill material. Rock may also be used,but care should be used to avoid damaging or dislodging the crib units. Clay or material having a large percentage of clay is not to be used.NOTE 6Cribbing should be placed on a foundation of firm bearing ma
34、terial. This foundation should be at least 3 ft below the surface of the ground,beyond all danger of frost, unless on solid rock. If the stretchers are located directly above rock, a cushion of sand or gravel not less than 6 in. thick shouldbe provided.NOTE 7All headers are placed at 6 ft 0 in. cent
35、er to center.NOTE 8Details of steps are similar to those shown on Fig. 4.FIG. 2 Open-Faced Concrete Crib WallC915 79 (2018)37.4 CuringCrib wall members shall be cured by one of thefollowing methods or combination thereof. They shall be curedso that the concrete will develop the required compressives
36、trength.7.4.1 Accelerated CuringThe crib wall members may becured with either steam or radiant heat in a moist atmosphere.7.4.2 Water CuringCrib wall members may be water-cured by covering with water-saturated material or by a systemof perforated pipes, mechanical sprinklers, porous hose, or byany o
37、ther approved method that will keep the members moist.7.4.3 Membrane CuringA curing membrane conformingto the requirements of Specification C309 may be applied andshould be left intact until strength requirements are met. Theconcrete at the time of application shall be within 10F (6C)of the atmosphe
38、ric temperature. All surfaces shall be keptmoist prior to the application of the compounds and shall bedamp when the compound is applied.7.4.4 Curing OptionsOther methods of curing may beused if approved by the purchaser.7.5 ReinforcementSteel reinforcement shall conform tothe requirements set forth
39、 in this specification and shall beplaced in position in the form within specified tolerances. Theminimum reinforcement shall be No. 3 bars placed symmetri-cally about the principal axis.7.6 FormsForms shall be rigid and sufficiently strong tosupport the weight of the concrete without deformation or
40、deflection within specified tolerances. Seepage of water fromthe form should be minimized. All forms shall be so con-structed that they can be removed without damaging theconcrete. All exposed concrete edges shall be beveled.7.6.1 Cleaning and OilingForms shall be cleaned beforeeach use. New forms s
41、hall be free of paint or other protectivecoatings that might cling to the surface of the members. Formsshall have a suitable release agent applied as necessary to aidin breaking the bond between the form wall and the concrete.7.7 Concrete FinishConcrete finishing shall be at theoption of the manufac
42、turer and shall produce a finish compa-rable to a steel form finish.8. Physical Requirements8.1 Compression TestsCompression tests for satisfyingthe design concrete strength shall be made on standard concretecylinders. Test specimens shall be identified with crib wallmembers. Two cylinders will be r
43、equired for each 10 yd3(8m3) with a minimum of two cylinders for each day ofproduction and shall be made at random from different batches.Cylinders shall be made in accordance with Practice C31/C31M, cured in a similar manner to the product, and tested inFIG. 3 Closed-Face Concrete Crib WallC915 79
44、(2018)4accordance with Test Method C39/C39M. The average com-pressive strength of all cylinders tested for any one daysproduction shall be equal to or greater than the design strength.In no case shall any cylinder tested fall below 80 % of thedesign strength.9. Tolerances and Permissible Variations9
45、.1 Cross SectionThe cross section of the member shallnot be out of square more than18 in. (3 mm).9.2 Horizontal AlignmentThe longitudinal straightness ofthe four faces shall not deviate from a straight line parallel tothe centerline of the member more than14 in. (6 mm).9.3 DimensionsThe finished dim
46、ensions of the membershall not deviate more than14 in. (6 mm) from the nominaldesign dimensions.9.4 Tolerance of ReinforcementCover over reinforcementshall not be less than 114 in. (32 mm) nor greater than 112 in.(38 mm).10. Inspection and Rejection10.1 InspectionThe quality of materials, the proces
47、s ofmanufacture, and the finished crib wall members shall besubject to inspection and approval by the inspector employedby the purchaser, if the purchaser so desires. If the manufac-turer is required to obtain the services of an independent testinglaboratory, the cost shall be borne by the purchaser
48、. Themanufacturer shall afford the inspector all reasonable access,without charge, for making necessary checks of the productionfacilities and for performing any tests the purchaser may directhis inspector to conduct. All tests and inspection shall be soconducted as not to interfere unnecessarily wi
49、th the manufac-ture and delivery of the member. The manufacturer shall haveraw members out of the forms available for inspection.10.2 RepairThe manufacturer shall not apply any cos-metic treatment to the members without written approval bythe purchaser. Sections may be repaired, if necessary, becauseof occasional imperfections in manufacture or damage duringhandling, but only after authorization by the purchaser. They* Where changes of height occur, units of 6-49, 6-59, 6-89 or 6-109 are required depending on header si
