1、Designation: C185 15C185 15a American Association StateHighway and Transportation Officials StandardAASHTO No.: T137Standard Test Method forAir Content of Hydraulic Cement Mortar1This standard is issued under the fixed designation C185; the number immediately following the designation indicates the
2、year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S.
3、Department of Defense.1. Scope*1.1 This test method covers the determination of the air content of hydraulic cement mortar under the conditions hereinafterspecified.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.3 Value
4、s in SI shall be obtained by measurement in SI units or by appropriate conversion, using the Rules for Conversion andRounding in IEEE/ASTM SI 10, of measurements made in other units.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the r
5、esponsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.1.5 WarningFresh hydraulic cementitious mixtures are caustic and may cause chemical burns to skin and tissue uponprolonged exposure.22.
6、 Referenced Documents2.1 ASTM Standards:3C91 Specification for Masonry CementC109/C109M Test Method for Compressive Strength of Hydraulic Cement Mortars (Using 2-in. or 50-mm Cube Specimens)C150 Specification for Portland CementC183 Practice for Sampling and the Amount of Testing of Hydraulic Cement
7、C185 Test Method for Air Content of Hydraulic Cement MortarC230/C230M Specification for Flow Table for Use in Tests of Hydraulic CementC305 Practice for Mechanical Mixing of Hydraulic Cement Pastes and Mortars of Plastic ConsistencyC595 Specification for Blended Hydraulic CementsC778 Specification f
8、or SandC1005 Specification for Reference Masses and Devices for Determining Mass and Volume for Use in the Physical Testing ofHydraulic CementsC1157 Performance Specification for Hydraulic CementC1328 Specification for Plastic (Stucco) CementC1329 Specification for Mortar CementE438 Specification fo
9、r Glasses in Laboratory ApparatusE694 Specification for Laboratory Glass Volumetric ApparatusIEEE/ASTM SI 10 Standard for Use of the International System of Units (SI): The Modern Metric System3. Summary of Test Method3.1 Prepare a mortar with standard sand and the cement to be tested, using a water
10、 content sufficient to give a required flow.Compact the mortar into a measure of known volume and determine mass. Calculate the air content from the measured densityof the mortar, the known densities of the constituents, and the mixture proportions.1 This test method is under the jurisdiction of AST
11、M Committee C01 on Cement and is the direct responsibility of Subcommittee C01.21 on Air Entrainment.Current edition approved July 1, 2015Sept. 1, 2015. Published July 2015October 2015. Originally approved in 1944. Last previous edition approved in 20082015 asC185 08.C185 15. DOI: 10.1520/C0185-15.1
12、0.1520/C0185-15A.2 Refer to the section on Safety Precautions, “Manual of Cement Testing,” Annual Book of ASTM Standards, Vol 04.01.3 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume informa
13、tion, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depi
14、ct all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM Internation
15、al, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14. Significance and Use4.1 The purpose of this test method is to determine whether or not the hydraulic cement under test meets the air-entraining ornon-air-entraining requirements of the applicable hydraulic cem
16、ent specification for which the test is being made. The air contentof concrete is influenced by many factors other than the potential of the cement for air entrainment.5. Apparatus5.1 Flow Table, Flow Mold, and Caliper, shall conform to Specification C230/C230M.5.2 MeasureA cylindrical measure havin
17、g an inside diameter of 76 6 2 mm and a depth (approximately 88 mm) adjusted bystandardization with water to contain 400 6 1 mL at 23.0 6 2.0C (2.0C. Note 1). For the purposes of this test, the capacity ofthe measure in millilitres is the mass of the water content of the measure, in grams, divided b
18、y 0.9976, no correction in mass beingmade for the buoyant effect of air. The measure shall have a uniform wall thickness. The thickness of the wall and bottom shallnot be less than 2.9 mm. The total mass of the empty measure shall not be more than 900 g. The measure shall be made of a metalnot attac
19、ked by the cement mortar.NOTE 1Calibrate the 400 mL measure by filling with distilled water at 23.06 2.0C to a point where the meniscus extends appreciably above thetop of the measure, placing a clean piece of plate glass on the top of the measure, and allowing the excess water to be squeezed out. T
20、he absence of airbubbles as seen through the glass ensures that the measure is completely full. Care shall be taken that the excess water is wiped from the sides of thecontainer before weighing.5.3 VerificationVerify the volume of the 400 mL measure by filling with distilled water at 23.06 2.0C to a
21、 point where themeniscus extends appreciably above the top of the measure, placing a clean piece of plate glass on the top of the measure, andallowing the excess water to be squeezed out. The absence of air bubbles as seen through the glass ensures that the measure iscompletely full. Care shall be t
22、aken that the excess water is wiped from the sides of the container before weighing. Perform theverification at least every 2 years.5.4 Mixer, Bowl, and Paddle, shall conform to the apparatus section of Practice C305.5.5 StraightedgeA steel straightedge not less than 200 mm long and not less than 1.
23、5 mm nor more than 3.5 mm in thickness(Note 21).NOTE 1The trowel specified inTest Method C109/C109M and the straightedge specified inTest Method C185 may be used for this purpose, providingthey comply with the planeness indicated.5.6 Trowel, having a steel blade 100 to 150 mm in length, with straigh
24、t edges. The edges when placed on a plane surface shallnot depart from straightness by more than 1 mm (Note 21).5.7 Weights and Weighing Devices, shall conform to Specification C1005. Evaluate the weighing device for precision andaccuracy at a total load of 2 kg.5.8 Glass GraduatesGlass graduates of
25、 250 mL capacity, conforming to the requirements of Specifications E438 and E694.5.9 Tamper, conforming to the requirements of Test Method C109/C109M. The tamping face of the tamper shall be flat and atright angles to the length of the tamper.5.10 Tapping Stick, a piece of hard wood having a diamete
26、r of approximately 16 mm and a length of approximately 152 mm.5.11 SpoonA metal restaurant-type serving spoon not less than 230 mm in length and with a bowl approximately 100 mm inlength.6. Temperature and Humidity6.1 Maintain the temperature of the room and dry materials at 23.0 6 4.0C.6.2 Conditio
27、n the mixing water and the measure, if it is being calibrated at 23 6 2C.6.3 Maintain the relative humidity of the laboratory at not less than 50 %.7. Standard Sand7.1 Use sand conforming to the requirements of Specification C778 for 2030 sand.8. Sampling8.1 Sample the cement in accordance with Prac
28、tice C183.NOTE 2Polyvinyl chloride (PVC) sample containers, upon occasion, have been found to affect the air-entraining potential of a cement sample. Thesame problem might be experienced with containers made from other plastics.9. Procedure9.1 BatchProportion the standard mortar using 350 g cement t
29、o 1400 g 2030 standard sand and sufficient water to give a flowof 8712 6 712 % when determined in accordance with 9.3.C185 15a2NOTE 3Test Method C185 refers to hydraulic cements that comply under Specifications C150 and C595, and Performance Specification C1157.Masonry cements (see Specification C91
30、), mortar cements (see Specification C1329), and plastic cements (see Specification C1328) require different sand,mass, and flow. Refer to the applicable specification.9.2 Mixing of MortarMix the mortar in accordance with Practice C305.9.3 Flow DeterminationCarefully wipe dry the flow-table top and
31、place the flow mold at the center of it. Using the spoon,place a layer of mortar about 25 mm in thickness in the mold and tamp 20 times with the tamper. The tamping pressure shall bejust sufficient to ensure uniform filling of the mold. Overfill the top of the mold approximately 20 mm with mortar an
32、d tamp asspecified for the first layer. Then cut off the mortar to a plane surface, flush with the top of the mold, by drawing the straightedgewith a sawing motion across the top of the mold. Wipe the flow table top clean and dry, being especially careful to remove anywater from around the edge of t
33、he mold. Lift the mold away from the mortar 1 min after completing the mixing operation.Immediately drop the table 10 times in accordance with Specification C230/C230M. The flow is the resulting increase in averagediameter of the mortar mass, as determined with the calipers, measured on at least fou
34、r diameters at approximately equispacedintervals, expressed as a percentage of the original diameter. Make trial mortars with varying percentages of water until thespecified flow is obtained. Make each trial with fresh mortar.9.4 Mass per 400 mL of MortarWhen the quantity of mixing water has been fo
35、und that produces a flow of 8712 6 712 %,immediately determine the mass per 400 mL of mortar, using the mortar remaining in the mixing bowl after the flow has beendetermined. In the determination of the mass per 400 mL, do not use the portion of the mortar used in the flow determination. Usingthe sp
36、oon, place the mortar gently into the 400 mLmeasure in three equal layers.Tamp each layer 20 times around the inner surfaceof the measure. For the final layer of mortar, overfill the 400 mL measure approximately 20 mm. The position of the tamper shallbe that: the broad side of the tamper is parallel
37、 to the radius and is perpendicular to the inner surface of the measure. Each layeris tamped in one complete revolution (rotation) with only sufficient pressure to adequately fill the measure and eliminate voidswithin the mortar.After the measure has been filled and tamped in the above prescribed ma
38、nner, tap the sides of the measure lightlywith the side of the tapping stick, one each at five different points at approximately equal spacing around the outside of the measure,in order to preclude entrapment of extraneous air (Note 54). No obvious space shall be left between the mortar and the inne
39、r surfaceof the measure as a result of the tamping operation. Then cut the mortar off to a plane surface, flush with the top of the measure,by drawing the straightedge with a sawing motion across the top of the measure, making two passes over the entire surface, thesecond pass being made at right an
40、gles to the first. If, in the striking-off operation, loose sand grains cause the straightedge to rideabove the top surface of the measure, these grains shall be removed, and the operation repeated. Complete the entire operation offilling and striking off the measure within 112 min. Wipe off all mor
41、tar and water adhering to the outside of the measure. Determinethe mass of the measure and its contents. Subtract the mass of the container, and record the mass of the mortar in grams.NOTE 4This operation may be facilitated by placing the measure on a steady flat-surfaced support of lesser diameter
42、than the measure while fillingand wiping.10. Calculation10.1 Calculate the air content of the mortar from the following formula which is based on the batch proportions given in 9.1,taking the specific gravity of portland cement as 3.15 and of 2030 standard sand as 2.65. When the hydraulic cement is
43、other thanportland, the appropriate value for its specific gravity shall be substituted for the value of 3.15 and the formula rederivedaccordingly:Air content,volume%51002W182.71P!/200014P!# (1)where:W = mass of 400 mL of mortar, g, andP = percentage of mixing water, based on mass of cement used.NOT
44、E 5This formula is derived as follows:Air content,volume%510012Wa/Wc!# (2)where:Wa = actual mass per unit of volume as determined by this test method.= W/400 g/mL, where W is the mass in grams of the specified 400 mL of mortar (9.4),Wc = theoretical mass per unit of volume, calculated on an air-free
45、 basis as follows and using the values for quantities ofmaterials and specific gravities as given in 9.1 and 10.1,= 3501140013503P 30.013503.15114002.6513503P 30.011= 510.01P!1.82710.01P! , andC185 15a3P = percentage of mixing water, based on mass of cement.Substituting for Wa and Wc we have:Air con
46、tent,volume%5100 S12 W400 31.82710.01P510.01P DAir content,volume%51002W4 3 1.82710.01P!510.01P!Air content,volume%510022.5W 182.71P!5000110P!Air content,volume%51002W 182.71P!200014P!10.2 Make only one determination of air content on a batch.NOTE 6Difficulty has occasionally been experienced with t
47、his test method by some persons. These difficulties usually have taken the form of valuesfor air content that are abnormally high and that may be greater than the specified maxima in specifications for hydraulic cement. The air-entrainingpotential of the sand may be reduced by washing in the laborat
48、ory with potable water by decantation until a clear, colorless supernatant liquid is obtained.In case of dispute, such freshly washed sand shall be used.11. Report11.1 When this test method is used for specific action in compliance testing, report the value for the air content to the nearest1 %.12.
49、Precision and Bias12.1 The single-operator, within-laboratory, standard deviation has been found to be 0.56 % air content throughout the rangeof 8 to 19 % air. Therefore, results of two properly conducted tests by the same operator on similar batches should not differ bymore than 1.6 % air.12.2 The multilaboratory standard deviation has been found to be 1.0 % air content throughout the range from 8 to 19 % air.Therefore, results of two different laboratories on similar batches should not differ from each other by more than 2.8 %
