ASTM C1176-2005 Standard Practice for Making Roller-Compacted Concrete in Cylinder Molds Using a Vibrating Table《使用振动台在筒模中制作碾实混凝土的标准实施规范》.pdf

《ASTM C1176-2005 Standard Practice for Making Roller-Compacted Concrete in Cylinder Molds Using a Vibrating Table《使用振动台在筒模中制作碾实混凝土的标准实施规范》.pdf》由会员分享，可在线阅读，更多相关《ASTM C1176-2005 Standard Practice for Making Roller-Compacted Concrete in Cylinder Molds Using a Vibrating Table《使用振动台在筒模中制作碾实混凝土的标准实施规范》.pdf（4页珍藏版）》请在麦多课文档分享上搜索。

1、Designation: C 1176 05Standard Practice forMaking Roller-Compacted Concrete in Cylinder Molds Usinga Vibrating Table1This standard is issued under the fixed designation C 1176; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the ye

2、ar of last 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 practice covers procedures for making cylindricaltest specimens from concrete when the standard procedures

3、 ofrodding and internal vibration, as described in Practice C 31,are not practicable. This practice is applicable to freshly mixedconcrete, prepared in the laboratory and the field, having anominal maximum size aggregate of 50 mm (2 in.) or less. Ifthe nominal maximum size aggregate is larger than 2

4、 in., thepractice is applicable only when performed on the fractionpassing the 50-mm (2-in.) sieve with the larger aggregate beingremoved in accordance with Practice C 172. This practice,intended for use in testing roller-compacted concrete, may beapplicable to testing other types of concrete such a

5、s cement-treated aggregate and mixtures similar to soil-cement.1.2 Two methods are provided for making concrete cylin-ders using a vibrating table:1.2.1 Method A is a procedure for making test specimens insteel reusable molds attached to a vibrating table.1.2.2 Method B is a procedure for making tes

6、t specimens insingle-use plastic molds that have been inserted into a metalsleeve attached to a vibrating table.1.3 The values stated in inch-pound units are to be regardedas the standard. The values given in parentheses are forinformation purposes only.1.4 This standard does not purport to address

7、all of thesafety 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.2. Referenced Documents2.1 ASTM Standards:2C 31/C 31M Practic

8、e for Making and Curing Concrete TestSpecimens in the FieldC 39/C 39M Test Method for Compressive Strength of Cy-lindrical Concrete SpecimensC 172 Practice for Sampling Freshly Mixed ConcreteC 192/C 192M Practice for Making and Curing ConcreteTest Specimens in the LaboratoryC 470/C 470M Specificatio

9、n for Molds for Forming Con-crete Test Cylinders VerticallyC 496/C 496M Test Method for Splitting Tensile Strengthof Cylindrical Concrete SpecimensC 1170 Test Methods for Determining Consistency andDensity of Roller-Compacted Concrete Using a VibratingTableE11 Specification for Wire Cloth and Sieves

10、 for TestingPurposes3. Summary of Practice3.1 This practice describes methods for making cylindricalconcrete test specimens using a vibrating table. Test specimensare made in cylindrical molds that are attached to the vibratingtable under a 20-lb (9.1-kg) surcharge to facilitate consolida-tion.4. Si

11、gnificance and Use4.1 This practice is intended to be used for stiff to extremelydry concrete mixtures commonly used in roller-compactedconcrete construction. This practice is used instead of roddingor internal vibration, which cannot properly consolidate con-crete of this consistency (Note 1).NOTE

12、1Further description of this concrete consistency is given inACI 207.5 Roller-Compacted Mass Concrete3and 211.3 Guide for Se-lecting Proportions for No-Slump Concrete3. The consistency of roller-compacted concrete may be determined in accordance with Test MethodC 1170.5. Apparatus5.1 Molds:5.1.1 Typ

13、e A MoldA cylindrical mold conforming to therequirements of Specification C 470 for 6-in. (152-mm) diam-eter by 12-in. (305-mm) high reusable molds. Molds shall be1This practice is under the jurisdiction of ASTM Committee C09 on Concreteand ConcreteAggregates and is the direct responsibility of Subc

14、ommittee C09.45 onRoller-Compacted Concrete.Current edition approved Dec. 15, 2005. Published January 2006. Originallyapproved in 1991. Last previous edition approved in 1998 as C 1176 92(1998).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at s

15、erviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3ACI Manual of Concrete Practice, Part 1, Materials and General Properties ofConcrete, 2005, American Concrete Institute (ACI), P.O. Box 9094, FarmingtonHills, MI 4833

16、3.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.made of steel or other hard metal not readily attacked by thecement paste. Aluminum molds shall not be used. Molds shallbe equipped with permanently affixed metal slotted brackets ont

17、he baseplate so the molds can be rigidly clamped to a vibratingtable. The top rim of the mold shall be smooth, plane, andparallel to the bottom of the mold. The bottom of the mold shallprovide a watertight seal.5.1.2 Type B MoldA single-use plastic, cylindrical mold 6in. (152 mm) in diameter and 12

18、in. (305 mm) in height. Themold specifications shall conform to Specification C 470 forsingle-use plastic molds.5.1.2.1 Mold SleeveA Type B cylindrical mold shall beinserted into a rigid cylindrical sleeve with a bottom baseplatethat is clamped to the vibrating table. The mold sleeve shall bemade of

19、 steel or other hard metal that does not react withconcrete containing portland or other hydraulic cement. Thesleeve shall be capable of firmly and vertically holding theplastic mold in place without deformation and shall be slottedvertically with adjustable clamps for tightening around themold. The

20、 sleeve shall be hinged so that it can be opened toremove the mold (Fig. 1) and shall also have permanentlyaffixed slotted metal brackets so the sleeve may be rigidlyclamped to the vibrating table. The mold sleeve shall have aminimum wall thickness of18 in. (3.2 mm), and a minimumbaseplate thickness

21、 of14 in. (6.4 mm). The inside diameter ofthe mold sleeve shall be18 6116 in. (3.2 6 1.6 mm) largerthan the outside diameter of the Type B mold and have aheight12 to14 in. (12.8 6 6.4 mm) less than the height of theType B mold.5.2 Vebe Vibrating TableA vibrating table with a34-in.(19-mm) thick steel

22、 deck with dimensions of approximately 15in. (381 mm) in length, 1014 in. (260 mm) in width, and 12 in.(305 mm) in height. The vibrating table shall be constructed insuch a manner as to prevent flexing of the table duringoperation. The table deck shall be activated by an electrome-chanical vibrator.

23、 The total mass of the vibrator and table shallbe approximately 210 lb (95 kg). The table shall be level andclamped to a concrete floor or base slab that has sufficient massto prevent displacement of the apparatus during specimenpreparation (Note 2).NOTE 2The recommended vibrating table for these pr

24、ocedures is theVebe vibrating table. Testing to date has been performed using thisapparatus. An alternative vibrating table may be substituted for the Vebeapparatus provided it meets the specifications for the sinusoidal vibrationgiven in 7.1.5.3 Swivel Arm and Guide SleeveA metal guide sleevewith a

25、 clamp assembly or other suitable holding devicemounted on a swivel arm. The swivel arm and guide sleevemust be capable of holding a metal shaft attached to a 20-lb(9.1-kg) cylindrical mass in a position perpendicular to thevibrating surface and allowing the shaft to slide freely when theclamp is re

26、leased. The swivel arm must be capable of main-taining the guide sleeve in a locked position directly over thecenter of the specimens to be vibrated. The swivel arm shallalso be capable of being rotated away from the center of thetable (Note 3).NOTE 3The Vebe vibrating table comes equipped with the

27、swivel armand guide sleeve.5.4 SurchargeA cylindrical steel mass with a metal shaftat least 18 in. (457 mm) in length and58 6116 in. (16 6 2mm) in diameter attached perpendicularly to and embedded inthe center of the mass. The shaft shall slide through the guidesleeve without binding. The surcharge

28、shall have a diameter of534 618 in. (146 6 3 mm). The surcharge assembly shallhave a mass of 20 6 0.5 lb (9.1 6 0.25 kg) including the massof the metal shaft (Fig. 1). If the surcharge is to be hand held,the length of the shaft may be reduced to about 12 in. (305 mm)and fabricated with a “T” or “D”

29、handle for gripping thesurcharge shaft to avoid slipping.5.5 SieveA 50-mm (2-in.) sieve conforming to Specifica-tion E11.5.6 Small ToolsTrowels, square-ended shovel and handscoops, steel trowel, wooden float, wrench, tamping rod, andflashlight as required.6. Sampling6.1 Samples of fresh concrete sha

30、ll be obtained in accor-dance with Practice C 172.6.2 Concrete samples shall have a nominal maximum sizeaggregate of 50 mm (2 in.) or less. If the concrete has aggregatelarger than 50 mm (2 in.), samples shall be obtained by wetsieving over a 50-mm (2-in.) sieve in accordance with PracticeC 172.6.3

31、Concrete test specimens shall be made within 45 minafter the completion of mixing concrete unless otherwisestipulated.FIG. 1 Vibrating TableCylinder Preparation (Type B Mold)C11760527. Calibration and Standardization7.1 The vibrating table shall produce a sinusoidal vibratorymotion with a frequency

32、of at least 3600 6 100 vibrations permin (60 6 1.67 Hz) and a double amplitude of vibration of0.0170 6 0.0030 in. (0.43 6 0.08 mm) when a 60.0- 6 2.5-lb(27.2- 6 1.1-kg) surcharge is rigidly bolted to the center of thetable.7.1.1 Determine the frequency and double amplitude4of thevibrating table unde

33、r simulated test conditions prior to initialuse and annually thereafter.Avibrating reed tachometer shouldbe used to check the frequency of vibration.7.2 Recalibrate the vibrating table after any event (includingrepairs) that might affect its operation, or whenever test resultsare questionable.8. Tec

34、hnical Precautions8.1 When obtaining samples, ensure that the samples arerepresentative of the material being sampled.8.2 Concrete with stiff to extremely dry consistency ishighly susceptible to segregation during handling. To minimizesegregation, use care in obtaining samples and during trans-porti

35、ng, remixing, and testing of the concrete.8.3 After at least every three months of continued use,inspect and clean the underside of the vibrating table top of anyhardened concrete or cement paste which may interfere withfree movement of the table top.9. Procedure9.1 Method AType A Molds:9.1.1 Coat T

36、ype A molds with a suitable lubricant or bondbreaker prior to casting the test specimens to facilitate removalfrom the mold.9.1.2 Place the mold on the vibrating table, and center thesurcharge so that the edges of the plastic plate do not touch thewalls of the mold. Lower the surcharge into the mold

37、 to checkfor proper clearance.Attach the mold to the vibrating table, andfirmly tighten the wing nuts. Move the surcharge away fromthe mold.9.1.3 Place enough concrete in the mold so that the moldwill be filled to one-third of its volume after consolidationapproximately 9.5 lb (4.3 kg). A tamping ro

38、d may be used todistribute the loose concrete as it is added. During filling, usesquare-ended shovels and scoops to obtain representativesamples, and handle the concrete in such a manner that largersized coarse aggregate particles do not separate from themortar.9.1.4 Move the surcharge over the cent

39、er of the mold,release the guide sleeve clamp, and place the surcharge gentlyon the loose concrete. The surcharge shall be able to verticallyslide free without binding on the guide sleeve.9.1.5 If the surcharge cannot be centered in the moldwithout binding on the inside wall of the mold, place thesu

40、rcharge directly onto the specimen in the mold without use ofthe guide sleeve, and hold the surcharge shaft perpendicular tothe top of the table. Hold the surcharge shaft manually whilevibrating the specimen. Do not apply any additional handpressure to the surcharge when manually holding the sur-cha

41、rge.9.1.6 Start the vibrator table, and allow the concrete toconsolidate under the surcharge. Using a flashlight, observe theconcrete in the annular space between the edge of the surchargeand the inside wall of the mold. As the concrete consolidates,mortar will fill in the annular space between the

42、outer edge ofthe surcharge and the inside mold wall. Observe the mortaruntil it forms a ring around the total perimeter of the surcharge.When the mortar ring forms completely around the surcharge,stop the vibrator. If the wing nuts loosen while casting thespecimen, retighten the wing nuts, then cont

43、inue vibrating toensure complete consolidation of the specimen.9.1.7 If a rock pocket prevents the mortar ring from formingat one small location, even though it has formed in all otherlocations, the vibrator can be stopped and another layer ofconcrete added. If a significant portion of the mortar ri

44、ng doesnot form, this indicates the concrete may have insufficientmortar due to either improper sampling, segregation, or im-proper mixture proportioning. In these instances, the concretespecimen should be visually inspected after stripping from themold, and a decision then made whether to accept or

45、 reject thespecimen.9.1.8 Repeat the procedure in 9.1.3 through 9.1.7 for thesecond lift of concrete, filling the mold to approximatelytwo-thirds of its volume. For the third lift, overfill the mold bymounding the concrete above the top of the mold. Again, placethe surcharge on the loose concrete an

46、d consolidate. If thesurcharge consolidates concrete below the top level of themold, turn off the vibrating table. Place additional concrete inthe mold so that, when consolidated, the concrete will beabout18 in. (3 mm) above the top of the mold. Continuevibrating, and slide the surcharge back and fo

47、rth across the topof the mold until the compacted concrete is level with the topof the mold. This replaces strikeoff with a float since stiffconcrete cannot be easily floated. Do not allow the surcharge toremain in one position when the concrete is being finishedbecause this can cause aggregates to

48、be forced down andmortar to be forced out of the mold resulting in a nonrepre-sentative test specimen. After the surface has been screededwith the surcharge, vibrate the specimen for 4 6 1 s withoutthe surcharge to fill in minor surface tears unless damage to thespecimen by large-amplitude oscillati

49、ons of the vibrator isanticipated.9.1.8.1 When making test specimens using an alternativevibrating table, it may not be possible to vibrate the specimenwithout a surcharge. This is due to the disturbance of thecompacted specimen when large-amplitude, low-frequencyoscillations occur after the vibrator has been turned off. If thisoccurs, keep the surcharge in place until the vibrating table hascompletely stopped.9.1.9 Remove the mold with the consolidated specimenfrom the vibrating table, and finish the top surface of thespecimen with a steel trowel or wooden