ASTM C173 C173M-2014 Standard Test Method for Air Content of Freshly Mixed Concrete by the Volumetric Method《容量法测定新拌混凝土含气量的标准试验方法》.pdf

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1、Designation: C173/C173M 14Standard Test Method forAir Content of Freshly Mixed Concrete by the VolumetricMethod1This standard is issued under the fixed designation C173/C173M; the number immediately following the designation indicates the yearof original adoption or, in the case of revision, the yea

2、r of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope*1.1 This test method covers de

3、termination of the air contentof freshly mixed concrete containing any type of aggregate,whether it be dense, cellular, or lightweight.1.2 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The inch-pound unitsare shown in brackets. The values stated i

4、n each system maynot be exact equivalents; therefore, each system shall be usedindependently of the other. Combining values from the twosystems may result in non-conformance with the standard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It

5、 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 cementitious mixtures are caustic and may causechemical burns to skin and tissue upon prolonged expo

6、sure.2)2. Referenced Documents2.1 ASTM Standards:3C29/C29M Test Method for Bulk Density (“Unit Weight”)and Voids in AggregateC31/C31M Practice for Making and Curing Concrete TestSpecimens in the FieldC138/C138M Test Method for Density (Unit Weight), Yield,and Air Content (Gravimetric) of ConcreteC14

7、3/C143M Test Method for Slump of Hydraulic-CementConcreteC172 Practice for Sampling Freshly Mixed ConcreteC173/C173M Test Method forAir Content of Freshly MixedConcrete by the Volumetric MethodC231 Test Method for Air Content of Freshly Mixed Con-crete by the Pressure MethodC670 Practice for Prepari

8、ng Precision and Bias Statementsfor Test Methods for Construction MaterialsC1064/C1064M Test Method for Temperature of FreshlyMixed Hydraulic-Cement Concrete3. Significance and Use3.1 This test method covers the determination of the aircontent of freshly mixed concrete. It measures the air contained

9、in the mortar fraction of the concrete, but is not affected by airthat may be present inside porous aggregate particles.3.1.1 Therefore, this is the appropriate test to determine theair content of concretes containing lightweight aggregates,air-cooled slag, and highly porous or vesicular natural agg

10、re-gates.3.2 This test method requires the addition of sufficientisopropyl alcohol, when the meter is initially being filled withwater, so that after the first or subsequent rollings little or nofoam collects in the neck of the top section of the meter. Ifmore foam is present than that equivalent to

11、 2 % air above thewater level, the test is declared invalid and must be repeatedusing a larger quantity of alcohol. Addition of alcohol to dispelfoam any time after the initial filling of the meter to the zeromark is not permitted.3.3 The air content of hardened concrete may be eitherhigher or lower

12、 than that determined by this test method. Thisdepends upon the methods and amounts of consolidation effortapplied to the concrete from which the hardened concretespecimen is taken; uniformity and stability of the air bubbles inthe fresh and hardened concrete; accuracy of the microscopicexamination,

13、 if used; time of comparison; environmentalexposure; stage in the delivery, placement and consolidationprocesses at which the air content of the unhardened concreteis determined, that is, before or after the concrete goes througha pump; and other factors.1This test method is under the jurisdiction o

14、f ASTM Committee C09 onConcrete and Concrete Aggregatesand is the direct responsibility of SubcommitteeC09.60 on Testing Fresh Concrete.Current edition approved Jan. 1, 2014. Published February 2014. Originallyapproved in 1942. Last previous edition approved in 2012 as C173/C173M12.DOI: 10.1520/C017

15、3_C0173M-14.2Section on Safety Precautions, 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,

16、 refer to the standards Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14. Apparatus4.1 Air MeterAn air meter consisting of a me

17、asuring bowland a top section (Fig. 1) conforming to the followingrequirements:4.1.1 The measuring bowl and top sections shall be ofsufficient thickness and rigidity to withstand rough field use.The material shall not be attacked by high pH cement paste,deform when stored at high temperatures in clo

18、sed spaces, orbecome brittle or crack at low temperatures. A watertight sealmust be obtained when the top section is attached to themeasuring bowl.4.1.2 Measuring BowlThe measuring bowl shall have adiameter equal to 1 to 1.25 times the height and be constructedwith a flange at or near the top surfac

19、e. Measuring bowls shallnot have a capacity of less than 2.0 L 0.075 ft3.4.1.3 Top SectionThe top section shall have a capacity atleast 20 % larger than the measuring bowl and shall beequipped with a flexible gasket and a device to attach the topsection to the measuring bowl. The top section shall b

20、eequipped with a transparent scale, graduated in increments notgreater than 0.5 % from 0 at the top to 9 %, or more, of thevolume of the measuring bowl. Graduations shall be accurateto 60.1 % by volume of the measuring bowl. The upper end ofthe neck shall have a watertight cap that will maintain awa

21、tertight seal when the meter is inverted and rolled.4.2 FunnelA funnel with a spout of a size permitting it tobe inserted through the neck of the top section and long enoughto extend to a point just above the bottom of the top section.The discharge end of the spout shall be so constructed thatwhen w

22、ater is added to the container there will be a minimumdisturbance of the concrete.4.3 Tamping RodA round, smooth, straight steel, high-density polyethylene, or other plastic rod of equal or greaterabrasion resistance with a 16 mm 58 in. 6 2mm116 in.diameter. The length of the tamping rod shall be at

23、 least 100mm 4 in. greater than the depth of the measuring bowl inwhich rodding is being performed, but not greater than 600 mm24 in. in overall length (Note 1). The rod shall have thetamping end or both ends rounded to a hemispherical tip of thesame diameter as the rod.NOTE 1A rod length of 400 mm

24、16 in. to 600 mm 24 in. meets theFIG. 1 Apparatus for Measuring Air Content of Fresh Concreteby Volumetric Method (a) Brass MeterFIG. 1 Apparatus for Measuring Air Content of Fresh Concreteby Volumetric Method (b) Aluminum Meter (continued)C173/C173M 142requirements of the following: Practice C31/C3

25、1M, Test Method C138/C138M, Test Method C143/C143M, Test Method C173/C173M, and TestMethod C231.4.4 Strike-off BarA flat, straight steel bar at least 3 by 20by 300 mm 18 by34 by 12 in. or a flat, straight high-densitypolyethylene bar, or other plastic of equal or greater abrasionresistance, at least

26、 6 by 20 by 300 mm 14 by34 by 12 in.4.5 Calibrated CupA metal or plastic cup either having acapacity of or being graduated in increments equal to 1.00 60.04 % of the volume of the measuring bowl of the air meter.The calibrated cup is only to be used to add water when theconcrete air content exceeds

27、9 % or the calibrated range of themeter.4.6 Measuring Vessel for Isopropyl AlcoholA vessel witha minimum capacity of at least 500 mL 1 pt with graduationsnot larger than 100 mL 4 oz for measuring a quantity ofisopropyl alcohol.4.7 SyringeA rubber syringe having a capacity of at least50 mL 2 oz.4.8 P

28、ouring Vessel for WaterAcontainer of approximately1 L 1 qt capacity.4.9 Scoopof a size large enough so each amount ofconcrete obtained from the sampling receptacle is representa-tive and small enough so it is not spilled during placement inthe measuring bowl.4.10 Isopropyl AlcoholUse 70 % by volume

29、isopropylalcohol (approximately 65 % by weight) (Note 2). Otherfoam-dispersing agents are permitted if tests demonstrate thatthe use of the agent does not change the indicated air content,in the amounts being used, by more than 0.1 % or if correctionfactors are developed similar to those in Table 1.

30、 When otherdispersing agents are used, a copy of the records documentingthe testing or calculations shall be available in the laboratory.NOTE 2Seventy percent isopropyl alcohol is commonly available asrubbing alcohol. More concentrated grades can be diluted with water tothe required concentration.4.

31、11 MalletA mallet (with a rubber or rawhide head) witha mass of approximately 600 6 200 g 1.25 6 0.5 lb.5. Calibration5.1 Calibrate the meter and calibrated cup initially andannually or whenever there is reason to suspect damage ordeformation of the meter or calibrated cup.5.2 Determine the volume o

32、f the measuring bowl with anaccuracy of at least 0.1 % by determining the mass of waterrequired to fill it at room temperature and dividing it by thedensity of the water at the same temperature. Follow thecalibration procedure outlined in Test Method C29/C29M.5.3 Determine the accuracy of the gradua

33、tions on the neckof the top section of the air meter by filling the assembledmeasuring bowl and top section with water to the level of themark for highest air content graduation.5.3.1 Add water in increments of 1.0 % of the volume of themeasuring bowl to check accuracy throughout the graduatedrange

34、of air content. The error at any point throughout thegraduated range shall not exceed 0.1 % of air.FIG. 1 Apparatus for Measuring Air Content of Fresh Concreteby Volumetric Method (c) High Density Plastic Meter (continued)TABLE 1 Correction for the Effect of Isopropyl Alcohol onC173/C173M Air Meter

35、Reading70 % Isopropyl Alcohol UsedPints FluidOuncesLitres Correction, %A# 2.0 # 32 # 1.0 0.0B3.0 48 1.5 0.254.0 64 2.0 0.505.0 80 2.5 0.75ASubtract from final meter reading.BCorrections are applied only when 1.25 L 2.5 pt or more of isopropyl alcohol isused. The values given are for air meters that

36、have a measuring bowl volume of2.1 L0.075 ft3 and a top section that is 1.2 times the volume of the meauring bowl.C173/C173M 1435.4 Determine the volume of the calibrated cup using waterat 21.1 C 70 F by the method outlined in 5.2.Aquick checkcan be made by adding one or more calibrated cups of wate

37、r tothe assembled apparatus and observing the increase in theheight of the water column after filling to a given level.6. Sampling6.1 Obtain the sample of freshly mixed concrete in accor-dance with Practice C172. If the concrete contains coarseaggregate particles that would be retained on a 37.5-mm1

38、12-in. sieve, wet sieve a representative sample over a 25-mm1-in. sieve to yield somewhat more than enough material tofill the measuring bowl. The wet sieving procedure is describedin Practice C172.6.2 The concrete used to fill the measuring bowl shall nothave been previously used in the performance

39、 of any other testor practice, other than wet sieving in accordance with PracticeC172 or the temperature test in accordance with Test MethodC1064/C1064M.7. Procedure7.1 Rodding and TappingWet the inside of the measuringbowl and dry it to a damp but not shiny appearance. Using thescoop described in 4

40、.9, fill the measuring bowl with freshlymixed concrete in two layers of approximately equal volume.While placing the concrete in the measuring bowl, move thescoop around the perimeter of the measuring bowl opening toensure an even distribution of the concrete with minimalsegregation. Rod each layer

41、25 times uniformly over the crosssection with the rounded end of the rod. Rod the bottom layerthroughout its depth. In rodding this layer, use care not todamage the bottom of the measuring bowl. For the upper layer,allow the rod to penetrate through the layer being rodded andinto the layer below app

42、roximately 25 mm 1 in. After eachlayer is rodded, tap the sides of the measuring bowl 10 to 15times with the mallet to close any voids left by the tamping rodand to release any large bubbles of air that may have beentrapped. After tapping the final layer, a slight excess ofconcrete, 3 mm 18 in. or l

43、ess, above the rim is acceptable.Add or remove a representative sample of concrete if necessaryto obtain the required amount of concrete.7.2 Striking OffAfter rodding and tapping of the secondlayer, strike off the excess concrete with the strike-off bar untilthe surface is flush with the top of the

44、measuring bowl. Wipethe flange of the measuring bowl clean.7.3 Adding Water and AlcoholWet the inside of the topsection of the meter, including the gasket. Attach the topsection to the measuring bowl and insert the funnel. Add atleast 0.5 L 1 pt of water followed by the selected amount(Note 3) of is

45、opropyl alcohol. Record the amount of isopropylalcohol added. Continue adding water at least until it appears inthe graduated neck of the top section (Note 4). Remove thefunnel. Adjust the liquid level until the bottom of the meniscusis level with the zero mark on the graduated neck. A rubbersyringe

46、 is useful for this purpose. Attach and tighten thewatertight cap.NOTE 3The amount of isopropyl alcohol necessary to obtain a stablereading, and a minimum amount of foam immediately above the watercolumn, will depend upon a number of factors. Many concretes made withless than 300 kg/m3500 lb/yd3 of

47、cement and air contents less than 4 %may require less than 0.2 L 0.5 pt of alcohol. Some high-cement mixesmade with silica fume that have air contents of 6 % or more may requiremore than 1.4 L 3 pt of alcohol. The amount required will vary with theconcrete air content, the amount and type of air-ent

48、raining admixture, thecement content and cement alkali content, and perhaps other factors.Generally, the amount of alcohol necessary can be established for givenmixture proportions and should not change greatly during the course of ajob.NOTE 4When, if ever, it is necessary to use more than 2.0 L 4 o

49、r 4.5pt of isopropyl alcohol, it may be necessary to restrict the amount ofwater added initially to avoid overfilling the meter. However, it isdesirable to add at least some water initially to aid in mixing the alcoholand limit the contact of the concentrated alcohol with the top surface of theconcrete.7.4 Displacing the Volume of Air in the Concrete SpecimenUsing These Procedures:7.4.1 Free the Concrete from the Measuring BowlQuicklyinvert the meter, shake the measuring bowl horizontally, andretu