1、Designation: C 915 79 (Reapproved 2002)Standard Specification forPrecast Reinforced Concrete Crib Wall Members1This standard is issued under the fixed designation C 915; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of l
2、ast revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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-retaini
3、ngstructures 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 bea
4、ring 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 adeq
5、uate 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:A 370 Test Methods and Definitions for Mechanical Testingof Steel Products2A 615/A 61
6、5M Specification for Deformed and PlainBillet-Steel Bars for Concrete Reinforcement3A 616/A 616M Specification for Rail-Steel Deformed andPlain Bars for Concrete Reinforcement4A 617/A 617M Specification for Axle-Steel Deformed andPlain Bars for Concrete Reinforcement4C 31/C 31M Practice for Making a
7、nd Curing Concrete TestSpecimens in the Field5C 33 Specification for Concrete Aggregates5C 39/C 39M Test Method for Compressive Strength of Cy-lindrical Concrete Specimens5C 42/C 42M Test Method for Obtaining and Testing DrilledCores and Sawed Beams of Concrete5C 94/C 94M Specification for Ready-Mix
8、ed Concrete5C 150 Specification for Portland Cement6C 173/C 173M Test Method for Air Content of FreshlyMixed Concrete by the Volumetric Method5C 231 Test Method for Air Content of Freshly MixedConcrete by the Pressure Method5C 260 Specification for Air-Entraining Admixtures for Con-crete5C 309 Speci
9、fication for Liquid Membrane-Forming Com-pounds for Curing Concrete5C 330 Specification for Lightweight Aggregates for Struc-tural Concrete5C 494/C 494M Specification for Chemical Admixtures forConcrete5C 595 Specification for Blended Hydraulic Cements6C 618 Specification for Coal Fly Ash and Raw or
10、 CalcinedNatural Pozzolan for Use as a Mineral Admixture inConcrete53. 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 cr
11、ib 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 the manufac-turer, shall verify that
12、the cement, aggregate, admixtures, andreinforcing steel conform to 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
13、 by the cylinder compression tests shallbe as specified in 6.3, and the test method shall conform to therequirements of Test Method C 39. The manufacturers state-ment shall also certify adherence to tolerance dimensions ofSection 9.4.2 Acceptability of the concrete strength of completedcribbing prod
14、uced in accordance with Section 6 may also be1This specification is under the jurisdiction of ASTM Committee C27 on PrecastConcrete Products and is the direct responsibility of Subcommittee C27.20 onArchitectural and Structural Products.Current edition approved Nov. 5, 1979. Published January 1980.2
15、Annual Book of ASTM Standards, Vol 01.03.3Annual Book of ASTM Standards, Vol 01.04.4Discontinued; see 1998 Annual Book of ASTM Standards, Vol 01.04. Replacedby A 996/A 996M.5Annual Book of ASTM Standards, Vol 04.02.6Annual Book of ASTM Standards, Vol 04.01.1Copyright ASTM International, 100 Barr Har
16、bor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.determined by compressive tests of concrete cores in accor-dance with Test Method C 42.5. Materials5.1 CementPortland cement shall conform to the require-ments of Specification C 150 or shall be portland blast-furnaceslag cement
17、 or portland-pozzolan cement conforming to therequirements of Specification C 595.5.2 AggregatesAggregates shall conform to SpecificationC 33 or C 330. The nominal maximum size aggregate shall notbe greater than34 in. (19.0 mm).5.3 AdmixturesAir-entraining admixtures shall conformto Specification C
18、260. Chemical admixtures shall conform toSpecification C 494. Fly ash or other pozzolanic admixturesshall conform to the requirements of Specification C 618.5.4 WaterWater used for curing, washing aggregates, andmixing concrete shall be free of oils, organic materials, andother substances that may b
19、e 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 approval from the u
20、ser.5.5 Steel ReinforcementSteel reinforcement shall consistof bars conforming to Specifications A 615/A 615M, A 616/A 616M, or A 617/A 617M.6. Design6.1 Precast concrete crib wall members shall conform todetails and dimensions prescribed in Figs. 1-4, subject to theprovisions of this section and Se
21、ction 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 thereinforcement shall be 114 in.
22、 (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 C 173 or C 231.NOTE 1Surface drainage should not be permitted to flow directly against the face of the cribbing.NOTE 2Walls should be separated into
23、 96-ft sections by the 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 aggressiv
24、e environment, Type 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 WallC 915 79 (2002)27. Manufacture7.1 CertificationAt the
25、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 admixture (if a
26、ny), 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 to the tes
27、t and designrequirements of this specification.7.3 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 secu
28、red so as to remain in the 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 combinati
29、on thereof. They shall becured 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-saturate
30、d material or by a systemof 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 C 309 may be applied andshould be left intact until strength require
31、ments are met. Theconcrete 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.NOTE 1All reinforcing to be No. 3 bars placed 114 in. clear from surfa
32、ce 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 closely the erection of the successive tiers of units, and the wall should not be erected higher than 3 ft above thebackfilled
33、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 should be used to avoid damaging or dislodging the crib units. Clay or material having a large percentage of clay is not to be
34、 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 frost, unless on solid rock. If the stretchers are located directly above rock, a cushion of sand or gravel not less than 6 in.
35、 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 Crib WallC 915 79 (2002)37.4.4 Curing OptionsOther methods of curing may beused if approved by the purchaser.7.5 ReinforcementSt
36、eel 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 strong
37、 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 Cleaning
38、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 Concrete F
39、inishConcrete finishing shall be at theoption of the manufacturer 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
40、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 made in accordance with Practice C 31, cured in asimilar manner to the product, and
41、 tested in accordance withTest Method C 39. The average compressive strength of allcylinders tested for any one days production shall be equal toor greater than the design strength. In no case shall anycylinder tested fall below 80 % of the design strength.9. Tolerances and Permissible Variations9.1
42、 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 dimen
43、sions 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 process
44、ofmanufacture, and the finished crib wall members shall beFIG. 3 Closed-Face Concrete Crib WallC 915 79 (2002)4subject 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 testingl
45、aboratory, 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 conduct. All tests and inspection shall
46、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 without written approval bythe purcha
47、ser. 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 finished, and cured. The repaired section
48、sshall conform to the requirements of this specification.10.3 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 incorrec
49、t 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 orany continuous structural crack extending for a length of 12 in.(305 mm) or more, regardless of position in the section.11. Marking11.1 The following information shall be clearly marked oneach member:11.1.1 The date of manufacture of the member, and11.1.2 The concrete lot num
