1、Designation: C915 79 (Reapproved 2010)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.2. Referenced Documents2.1 ASTM Standards:2A370 Test Methods and Definitions for Mechanical Testingof Steel ProductsA615/A615M Spe
6、cification for Deformed and PlainCarbon-Steel Bars for Concrete ReinforcementA616/A616M Specification for Rail-Steel Deformed andPlain Bars for Concrete Reinforcement3A617/A617M Specification for Axle-Steel Deformed andPlain Bars for Concrete Reinforcement3C31/C31M Practice for Making and Curing Con
7、crete TestSpecimens in the FieldC33 Specification for Concrete AggregatesC39/C39M Test Method for Compressive Strength of Cy-lindrical Concrete SpecimensC42/C42M Test Method for Obtaining and Testing DrilledCores and Sawed Beams of ConcreteC94/C94M Specification for Ready-Mixed ConcreteC150 Specific
8、ation for Portland CementC173/C173M Test Method for Air Content of FreshlyMixed Concrete by the Volumetric MethodC231 Test Method for Air Content of Freshly Mixed Con-crete by the Pressure MethodC260 Specification for Air-Entraining Admixtures for Con-creteC309 Specification for Liquid Membrane-Form
9、ing Com-pounds for Curing ConcreteC330 Specification for Lightweight Aggregates for Struc-tural ConcreteC494/C494M Specification for Chemical Admixtures forConcreteC595 Specification for Blended Hydraulic CementsC618 Specification for Coal Fly Ash and Raw or CalcinedNatural Pozzolan for Use in Concr
10、ete3. 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 Acceptability of the crib wall members in all crosssections and lengths produced in acco
11、rdance 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 the manufac-turer, shall verify that the cement, aggregate, admixtures, andreinforcing steel conform t
12、o the specifications for materials inSection 5 and that the preparation of equipment, mixing,conveying, placing, consolidating, and curing meet require-ments of the applicable standard specifications. The concretestrength as determined by the cylinder compression tests shallbe as specified in 6.3, a
13、nd the test method shall conform to the1This 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, 2010. Published August 2010. Last pre
14、viousedition approved in 2002 as C915 79 (2002). DOI: 10.1520/C0915-79R10.2For 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 Summary page onthe
15、ASTM website.3Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.requirements of Test Method C39/C39M. The manufacturersstatement shall also certify adherence to tolerance dimensionsof Section 9.4.2 Acceptability of the concre
16、te strength of completedcribbing produced in accordance with Section 6 may also bedetermined by compressive 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 or shall be portland blast-furna
17、ceslag cement or portland-pozzolan cement conforming to therequirements of Specification C595.5.2 AggregatesAggregates shall conform to SpecificationC33 or C330. The nominal maximum size aggregate shall notbe greater than34 in. (19.0 mm).5.3 AdmixturesAir-entraining admixtures shall conformto Specif
18、ication C260. Chemical admixtures shall conform toSpecification C494/C494M. Fly ash or other pozzolanic ad-mixtures shall conform to the requirements of SpecificationC618.5.4 WaterWater used for curing, washing aggregates, andmixing concrete shall be free of oils, organic materials, andother substan
19、ces that may be deleterious to concrete or steel; itshould not contain 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 appro
20、val from the user.5.5 Steel ReinforcementSteel reinforcement shall consistof 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 t
21、he provision of double rows of headers.NOTE 3In using these typical sections 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
22、II cement or protective coatings, or both, may need to be used to avoid 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 (2010)26. Design6.1 Precast concrete crib wall members shall confo
23、rm todetails and dimensions prescribed in Figs. 1-4, subject to theprovisions 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
24、 MPa) in 28 days.6.4 Concrete CoverThe minimum concrete cover over thereinforcement 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 C231.7. Manufacture7.1 Certificati
25、onAt the request of the purchaser, themanufacturer shall, prior 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 admixt
26、ure (if any), and mill certificates for thereinforcing steel used in the manufacture.7.2 MixtureThe aggregates shall be sized, graded, propor-tioned, and thoroughly mixed with proportions of cement andwater as will produce a concrete mixture of a quality such thatthe crib wall members will conform t
27、o the test and designrequirements of this specification.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 noncorrosive tips.NOTE 3Blocks shall be set in cement-sand mortar (1 to 3).NOTE 4Backfilling should follow c
28、losely 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 material meeting the users specifications may be used as backfill material. Rock may also be used,but care
29、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 material. This foundation should be at least 3 ft below the surface of the ground,beyond all danger of f
30、rost, 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. center to center.NOTE 8Details of steps are similar to those shown on Fig. 4.FIG. 2 Open-Faced Concrete Cr
31、ib WallC915 79 (2010)37.3 PlacingConcrete shall be placed in the forms asnearly as possible in its final position. Special care should betaken to fill all parts of the forms, and to place concrete underand around all reinforcing steel. Reinforcement shall be ad-equately secured so as to remain in th
32、e proper position duringthe placing 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.7.4 CuringCrib wall members shall be cured by one ofthe following methods or combination thereof. They shall be
33、cured so that the concrete will develop the required compres-sive strength.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 system
34、of perforated pipes, mechanical sprinklers, porous hose, or byany other 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
35、 at the time of application shall be within 10F (6C)of the atmospheric 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 Reinforc
36、ementSteel reinforcement shall conform tothe requirements set forth 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
37、 strong tosupport the weight of the concrete without deformation ordeflection 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 Cl
38、eaning and OilingForms shall be cleaned beforeeach use. New forms shall 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 Con
39、crete FinishConcrete finishing shall be at theoption of the manufacturer and shall produce a finish compa-rable to a steel form finish.8. Physical Requirements Physical Requirements8.1 Compression TestsCompression tests for satisfyingthe design concrete strength shall be made on standard concreteFIG
40、. 3 Closed-Face Concrete Crib WallC915 79 (2010)4cylinders. Test specimens shall be identified with crib wallmembers. Two cylinders will be required for each 10 yd3(8 m3)with a minimum of two cylinders for each day of productionand shall be made at random from different batches. Cylindersshall be ma
41、de in accordance with Practice C31/C31M, cured ina similar manner to the product, and tested in accordance withTest Method C39/C39M. The average compressive strength ofall cylinders tested for any one days production shall be equalto or greater than the design strength. In no case shall anycylinder
42、tested fall below 80 % of the design strength.9. Tolerances and Permissible Variations9.1 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 parall
43、el tothe centerline of the member more than14 in. (6 mm).9.3 DimensionsThe finished dimensions 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.
44、(38 mm).10. Inspection and Rejection10.1 InspectionThe quality of materials, the process 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
45、 services of an independent testinglaboratory, the cost shall be borne by the purchaser. 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 cond
46、uct. All tests and inspection shall be soconducted as not to interfere unnecessarily with 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 w
47、ithout 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. Theywill be acceptable if, in the opinion of the purchaser, the repairsare sound, properly finis
48、hed, and cured. The repaired sectionsshall conform to the requirements of this specification.* Where changes of height occur, units of 68-49,68-59,68-89 or 68-109 are required depending on header size.NOTE 1For general notes and details not shown refer to open-faced details.FIG. 4 Closed-Face Concre
49、te Crib WallC915 79 (2010)510.3 RejectionMembers shall be subject to rejection onaccount of failure to conform to any of the specificationrequirements. Individual members may also be rejected be-cause of any of the following reasons:10.3.1 Defects that indicate incorrect proportioning, mixing,and molding.10.3.2 Surface defects that indicate honeycombed or opentexture.10.3.3 Damaged or cracked areas where such damage wouldcause the member not to perform as designed.10.3.4 Fractures or cracks passing through the section
