ASTM C1849 C1849M-2017 Standard Test Method for Density and Air Content (Pressure Method) of Freshly Mixed Roller-Compacted Concrete《新拌碾压混凝土密度和含气量的标准试验方法(加压法)》.pdf

《ASTM C1849 C1849M-2017 Standard Test Method for Density and Air Content (Pressure Method) of Freshly Mixed Roller-Compacted Concrete《新拌碾压混凝土密度和含气量的标准试验方法(加压法)》.pdf》由会员分享，可在线阅读，更多相关《ASTM C1849 C1849M-2017 Standard Test Method for Density and Air Content (Pressure Method) of Freshly Mixed Roller-Compacted Concrete《新拌碾压混凝土密度和含气量的标准试验方法(加压法)》.pdf（5页珍藏版）》请在麦多课文档分享上搜索。

1、Designation: C1849/C1849M 17Standard Test Method forDensity and Air Content (Pressure Method) of Freshly MixedRoller-Compacted Concrete1This standard is issued under the fixed designation C1849/C1849M; the number immediately following the designation indicates theyear of original adoption or, in the

2、 case of revision, the year of last revision. A number in parentheses indicates the year of lastreapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of density andair content of freshly mixed ro

3、ller-compacted concrete (RCC)using the apparatus described in Test Method C231/C231Mand the vibrating hammer described in Test Method C1435/C1435M.1.2 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system may not be exact e

4、quivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.NOTE 1Sieve size is identified by its standard designation in Speci-fication E11. The alternative designation given in parentheses is forinf

5、ormation only and does not represent a different standard sieve size.1.3 The text of this test method references notes andfootnotes that provide explanatory information. These notesand footnotes (excluding those in tables and figures) shall notbe considered as requirements of this standard.1.4 This

6、standard does not purport to address 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. (WarningFreshhydraulic

7、cementitious mixtures are caustic and may causechemical burns to skin and tissue upon prolonged exposure.)21.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of Inter

8、national Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:3C31/C31M Practice for Making and Curing Concrete TestSpecimens in the FieldC125 Terminology Relating to Concrete and Concrete A

9、g-gregatesC138/C138M Test Method for Density (Unit Weight), Yield,and Air Content (Gravimetric) of ConcreteC172/C172M Practice for Sampling Freshly Mixed Con-creteC192/C192M Practice for Making and Curing Concrete TestSpecimens in the LaboratoryC231/C231M Test Method forAir Content of Freshly MixedC

10、oncrete by the Pressure MethodC670 Practice for Preparing Precision and Bias Statementsfor Test Methods for Construction MaterialsC1067 Practice for Conducting a Ruggedness Evaluation orScreening Program for Test Methods for ConstructionMaterialsC1170/C1170M Test Method for Determining Consistencyan

11、d Density of Roller-Compacted Concrete Using a Vi-brating TableC1435/C1435M Practice for Molding Roller-CompactedConcrete in Cylinder Molds Using a Vibrating HammerE11 Specification for Woven Wire Test Sieve Cloth and TestSieves3. Terminology3.1 Definitions:3.1.1 For definitions of terms used in thi

12、s test method, referto Terminology C125.4. Significance and Use4.1 The test determines the air content of freshly mixedRCC exclusive of any air that may exist inside voids withinaggregate particles. For this reason, it is applicable to concretemade with normal-density or high-density aggregate parti

13、cles1This test method is under the jurisdiction of ASTM Committee C09 onConcrete and Concrete Aggregates and is the direct responsibility of SubcommitteeC09.45 on Roller-Compacted Concrete.Current edition approved June 15, 2017. Published July 2017. DOI: 10.1520/C1849_C1849M-17.2Section on Safety Pr

14、ecautions, Manual of Aggregate and Concrete Testing,Annual Book of ASTM Standards, Vol 04.02.3For 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

15、Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Princi

16、ples for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1and requires determination of the aggregate correction factordescribed in Test Method C231/C231M.4.2 If the concrete being tested contain

17、s aggregate thatwould be retained on a 50-mm (2-in.) sieve, the air content ofthe total mixture is only approximated by the test.4.3 The test determines the density of freshly mixed RCCcontaining aggregate with a maximum size not greater than50-mm (2-in.).4.4 The air content of hardened RCC may be e

18、ither higheror lower than that determined by this test method. This dependsupon the methods and amount of consolidation effort applied tothe RCC from which the hardened concrete specimen is taken;uniformity and stability of the air bubbles in the fresh RCC;accuracy of the microscopic examination, if

19、 used; stage in thedelivery at which the air content of the unhardened RCC isdetermined; and other factors.5. Apparatus5.1 Air MeterType B air meter and auxiliary equipmentconforming to Test Method C231/C231M.5.2 Vibrating HammerA vibrating compaction hammerconforming to Practice C1435/C1435M.5.3 Ta

20、mping PlateA circular steel plate attached to a steelshaft, which is inserted into the vibrating hammer chuck. Theplate diameter shall be 6 to 13 mm 14 to12 in. less than theinside diameter of the measuring bowl. The mass of the plateand shaft assembly shall be 8 to 12 kg 18 to 26 lb (see Fig.1).5.4

21、 MalletA mallet conforming to Test Method C231/C231M.5.5 Strike-Off PlateA strike-off plate conforming to TestMethod C231/C231M.5.6 Sieve37.5-mm (112-in.) with at least 0.2 m22 ft2ofsieving area.5.7 ScoopA size large enough so each amount of concreteobtained from the sampling receptacle is represent

22、ative andsmall enough so it is not spilled during placement in themeasuring bowl.5.8 StopwatchA stopwatch capable of measuring elapsedtime to the nearest second.5.9 BalanceA balance or scale accurate to 50 g 0.1 lb orto within 0.3 % of the test load, whichever is greater, at anypoint within the rang

23、e of use. The range of use shall beconsidered to extend from the mass of the measure empty tothe mass of the measure plus its contents at 2600 kg/m3160lb/ft3.5.10 SyringeA syringe capable of injecting water into onepetcock on the cover assembly.6. Standardization of Apparatus6.1 Standardize the appa

24、ratus and maintain standardizationrecords in accordance with the procedure prescribed in AnnexA1 of Test Method C231/C231M for a Type B meter.7. Determination of Aggregate Correction Factor7.1 Determine the aggregate correction factor on a com-bined sample of fine and coarse aggregate as directed in

25、 TestMethod C231/C231M.NOTE 2The aggregate correction factor will vary with differentaggregates. It can be determined only by test. The test can be made easily.Ordinarily the factor will remain reasonably constant for given aggregates,but an occasional check test is recommended.8. Preparation of Con

26、crete Test Sample8.1 Obtain the sample of freshly mixed concrete in accor-dance with applicable procedures of Practice C172/C172M.8.2 Use concrete that does not appear to have undergonesegregation.NOTE 3Concrete with stiff to very dry consistency is highly suscep-tible to segregation during handling

27、, transporting, and preparing samplesfor testing.8.3 If the concrete contains coarse aggregate particles thatwould be retained on a 50-mm (2-in.) sieve, wet-sieve asufficient amount of the representative sample over a 37.5-mm(112-in.) sieve, as described in Practice C172/C172M, to yieldsufficient ma

28、terial to completely fill the measuring bowl.Weigh and record the mass of the sample before and afterwet-sieving. Make no attempt to wipe adhering mortar fromcoarse aggregate particles retained on the sieve.8.4 Remix the concrete passing through the sieve with ashovel until it appears uniform and pr

29、oceed with testing.9. Procedure9.1 PlacementDampen the interior of the measuring bowl.Weigh the dampened bowl. Record the mass of the bowl andplace it on a supporting surface that will not deform during thetest procedure. The entire surface of the bottom of the bowlshall remain in contact with the s

30、upporting surface during thetest procedure with the sides of the bowl plumb to within 5degrees of vertical. Using the scoop described in 5.7, place theconcrete in the measuring bowl in two layers of approximatelyequal volume. While placing the concrete in the bowl, movethe scoop around the perimeter

31、 of the bowl opening to ensurean even distribution of the concrete with minimal segregation.9.2 ConsolidationPlace the vibrating hammer with tamp-ing plate onto the first layer of concrete. Start the vibratinghammer and allow the concrete to consolidate under thetamping plate. Observe the concrete i

32、n the annular spacebetween the outer edge of the tamping plate and the inside wallof the measuring bowl. As the concrete consolidates, mortarshould move into the annular space between the outer edge ofthe tamping plate and the inside wall of the measuring bowl.Observe the mortar until it forms a rin

33、g around the totalperimeter of the tamping plate. Stop the vibrating hammerwhen the mortar ring forms completely around the tampingplate. Return mortar that remains on the tamping plate to themeasuring bowl before placing the second layer. Place thesecond layer and repeat the process to consolidate

34、the secondlayer. Return mortar that remains on the tamping plate to themeasuring bowl. If the top of the concrete is below the top ofthe measuring bowl after returning the mortar that remains onthe tamping plate, add concrete and repeat the process toC1849/C1849M 172consolidate the added concrete. B

35、efore strike off, return mortarthat remains on the tamping plate to the measuring bowl. If arock or rock pocket prevents the mortar ring from forming atone location, even though it has formed in all other locations,stop the vibrating hammer and add the next layer of concrete orfinish the top surface

36、 as described in 9.3. If a significant portionof the mortar ring does not form after 20 s, stop the vibratinghammer and add the next layer of concrete or finish the topsurface as described in 9.3.9.3 Strike-OffAfter consolidation, strike-off the top sur-face of the concrete and finish it using the s

37、trike-off plate sothat the measure is level full. A small quantity of concrete maybe added or removed to correct a deficiency. Strike off themeasure by pressing the strike-off plate on the top surface ofthe measure to cover about two thirds of the surface andwithdraw the plate with a sawing motion t

38、o finish only the areaoriginally covered. Then return the plate to the top of themeasure to cover the same two thirds of the surface and strikeoff the other one third of the surface by advancing it with avertical pressure and a sawing motion until it slides completelyoff the measure. Repeat as neces

39、sary to produce a surface thatis even with the rim of the bowl. Removal of 3 mm 18 in.FIG. 1 Example of Tamping Plate and Shaft AssemblyC1849/C1849M 173during strike off is optimal. If the consistency of the concreteis such that a smooth surface cannot be attained with thestrike-off plate, use the v

40、ibrating hammer and tamping plate tostrike-off and finish the top surface of the concrete. With thehammer in operation and the tamping plate in contact with therim of the measuring bowl, move the tamping plate back andforth across the top of the measuring bowl to force excessmaterial beyond the rim.

41、 Continue working the surface until itis smooth and level with the top of the measuring bowl. (SeeNote 4.) Avoid tearing the surface of the concrete. If necessary,complete strike-off with the strike-off plate as detailed above toproduce a flat finish.NOTE 4The use of the tamping or strike-off plate

42、on cast aluminum orother relatively soft metal measuring bowl rims may cause rapid wear ofthe rim and require frequent maintenance, standardization, and ultimately,replacement.9.4 Preparation for TestThoroughly clean the flange orrim of the measuring bowl and the cover assembly so that whenthe cover

43、 is clamped in place a pressure-tight seal will beobtained. Remove any concrete remaining on the outside of themeasuring bowl and determine and record the mass of themeasuring bowl full of compacted concrete to the nearest 0.05kg 0.1 lb. Assemble the apparatus. Close the main air valvebetween the ai

44、r chamber and the measuring bowl and openboth petcocks on the cover. Using the syringe, inject waterthrough one petcock until water emerges from the oppositepetcock. Jar the meter gently until air is no longer expelledfrom the petcocks.9.5 TestClose the air bleeder valve on the air chamber andpump a

45、ir into the air chamber until the gauge hand is on theinitial pressure line. Allow a few seconds for the compressedair to cool. Stabilize the gauge hand at the initial pressure lineby pumping or bleeding-off air as necessary, tapping the gaugelightly by hand. Close both petcocks. Open the main air v

46、alvebetween the air chamber and the measuring bowl. Whilemaintaining the main air valve in an open position, tap thesides of the measuring bowl smartly with the mallet. (See Note5.) Observe the apparent air content on the dial of the pressuregauge for 2 minutes or longer until the reading stops chan

47、ging.(See Note 6.) Tap the sides of the measuring bowl and observethe pressure gauge until the reading stops changing. Lightly tapthe pressure gauge by hand to stabilize the gauge hand andrecord the reading. Close the main air valve. Failure to closethe main air valve before releasing the pressure f

48、rom either thecontainer or the air chamber will result in water being drawninto the air chamber, thus introducing error into subsequentmeasurements. In the event water enters the air chamber, itmust be bled from the air chamber through the air bleeder valvefollowed by several strokes of the pump to

49、blow out the lasttraces of water. Release the pressure from the measuring bowlby opening both petcocks before removing the cover.NOTE 5The main air valve on most Type B meters is a spring loadedvalve that is designed to close automatically when the lever is notdepressed. In order to keep the main air valve open on this type of airmeter, the operator must keep the lever depressed with one hand whiletapping the sides of the bowl and gauge with the other hand.NOTE 6The apparent air content reading may continue to rise until theno-slump mixture f