1、Designation: C1777 13Standard Test Method forRapid Determination of the Methylene Blue Value for FineAggregate or Mineral Filler Using a Colorimeter1This standard is issued under the fixed designation C1777; the number immediately following the designation indicates the year oforiginal adoption or,
2、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.1. Scope1.1 This test method provides a rapid test to determine theamount of methylene blue a
3、dsorbed by a specimen of fineaggregate or mineral filler and can be used both in thelaboratory and in the field.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety c
4、oncerns, 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:2C125 Terminology Relating to Concret
5、e and Concrete Ag-gregatesC702 Practice for Reducing Samples ofAggregate to TestingSizeD75 Practice for Sampling AggregatesE11 Specification for Woven Wire Test Sieve Cloth and TestSieves2.2 Other Standards:AASHTO T330 Standard Method of Test for the QualitativeDetection of Harmful Clays of the Smec
6、tite Group inAggregates Using Methylene Blue3EN 933-9 Tests for geometrical properties of aggregates.Part 9: Assessment of fines Methylene blue test43. Terminology3.1 Definitions:3.1.1 For definitions of terms used in this standard, refer toTerminology C125.3.2 Definitions of Terms Specific to This
7、Standard:3.2.1 mineral filler, na finely divided mineral product atleast 65 % of which passes the 75-m sieve.4. Summary of Test Method4.1 A specimen of fine aggregate or mineral filler is com-bined with a methylene blue solution of known concentrationand mixed for a prescribed period of time. The sp
8、ecimenadsorbs some of the methylene blue from solution. Theresulting mixture is filtered and a portion of the filtered solutionis diluted by a fixed amount.Acolorimeter is used to determinethe absorbance of the diluted solution, from which the concen-tration of methylene blue prior to dilution is ca
9、lculated. Thechange in concentration of methylene blue before and aftermixing with fine aggregate or mineral filler is converted to amethylene blue value and reported in units of mg/g.5. Significance and Use5.1 This test method is used to determine rapidly the amountof methylene blue adsorbed by a s
10、pecimen of fine aggregate ormineral filler. The result is reported as a methylene blue valuein units of mg of methylene blue adsorbed per g of fineaggregate or mineral filler. The methylene blue value is afunction of the amount and characteristics of clay mineralspresent in the test specimen. High m
11、ethylene blue valuesindicate increased potential for diminished fine aggregate ormineral filler performance in a cementitious mixture due to thepresence of clays.NOTE 1Results from this test method are not expected to be correlatedwith those obtained using AASHTO T 330 or EN 933-9. These three testm
12、ethods are likely to give very different numerical values even though theunits are the same. The AASHTO T 330 test is performed only on thefraction of an aggregate passing the 75 m sieve, the EN 933-9 test isperformed only on the fraction finer than 2 mm, and this test is performedon the fraction fi
13、ner than the 4.75 mm sieve. Therefore, when testing thesame fine aggregate source, the AASHTO test method would give thehighest methylene blue value because any clay present in the specimenwould be concentrated in the fraction finer than the 75 m sieve. TheAASHTO and EN test methods do not take into
14、 account the amount of1This test method is under the jurisdiction of ASTM Committee C09 onConcrete and Concrete Aggregates and is the direct responsibility of SubcommitteeC09.20 on Normal Weight Aggregates.Current edition approved Nov. 1, 2013. Published November 2013. DOI:10.1520/C1777-132For refer
15、enced 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 Summary page onthe ASTM website.3Available from American Association of State Highway and Transportatio
16、nOfficials (AASHTO), 444 N. Capitol St., NW, Suite 249, Washington, DC 20001,http:/www.transportation.org.4Available from European Committee for Standardization, Avenue Marnix 17,B-1000 Brussels, Belgium.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-29
17、59. United States1material passing the 75 m sieve or 2 mm sieve, respectively. Forexample, a fine aggregate with high methylene blue value measured by theAASHTO method but low percentage passing the 75 m sieve may haveless effect on concrete performance than a fine aggregate with lowmethylene blue v
18、alue measured by the AASHTO method but a highpercentage passing the 75 m sieve. In contrast, this test method expressesmethylene blue value based on the entire fine aggregate or mineral fillerspecimen.Additionally, theAASHTO and EN test methods use titration todetermine the amount of methylene blue
19、of known concentration that isadsorbed by a specimen and require the operator to visually determine theend point of the test. In contrast, this test method uses a colorimeter todetect the change in concentration of methylene blue solution before andafter being mixed with the fine aggregate or minera
20、l filler specimen.NOTE 2Recommendations for maximum methylene blue values forspecific applications are not provided in this test method. Maximummethylene blue values should be established based on successful perfor-mance of fine aggregate or mineral filler in the applications underconsideration.6. I
21、nterferences6.1 Methylene blue will degrade when exposed to light.Store in darkness. No appreciable degradation occurs duringthe time it takes to complete the test method.6.2 Methylene blue will stain glassware and plastic ware.Therefore, do not reuse such apparatus.7. Apparatus7.1 4.75-mm sieve con
22、forming to E11.7.2 Mass Balance having a capacity of 50 g or more andcapable of measuring to the nearest 0.1 g or less.7.3 Micropipette capable of measuring to the nearest 1 L.7.4 Colorimeter capable of reading absorbance of a speci-men at a wavelength of 610 6 1 nm at operating temperaturesof at le
23、ast 0 to 50C. The colorimeter shall be able to readabsorbance between zero and the absorbance associated with a0.144 % mass concentration of methylene blue solution.7.5 Disposable items for each testtwo plastic 50-mL testtubes, one plastic 1-mL vial, one 3-mL syringe with Luer-Lokadapter, one 0.2-m
24、syringe filter, one colorimeter glass cuvette(or sample cell), one micropipette tip, and two transfer pipettes.7.6 Additional disposable items for confirming methyleneblue starting concentrationplastic 50-mL test tube, colorim-eter glass cuvette, micropipette tip, and transfer pipette.7.7 Additional
25、 disposable items for standardizing thecolorimeterplastic 50-mL test tube, colorimeter glasscuvette, micropipette tip, and transfer pipette.7.8 Drying ApparatusA ventilated oven capable of main-taining a uniform temperature of 110 6 5C. Other suitabledrying apparatuses shall be permitted, such as an
26、 electric hotplate or heat lamp. The temperature of the specimen shall notexceed 150C. In cases where the fine aggregate or mineralfiller itself is altered by temperature greater than 115C, use aventilated, controlled-temperature oven at 110 6 5C.NOTE 3Drying by means other than a ventilated oven ma
27、y beappropriate for field use.8. Reagents and Materials8.1 Purity of Reagentsreagent grade methylene blue shallbe used in all tests.8.2 Purity of waterreferences to water shall be understoodto mean distilled or deionized water.8.3 Methylene blue test solutiona 0.50 % mass concentra-tion methylene bl
28、ue solution based on mass of trihydratemethylene blue in water.NOTE 4Methylene blue is available in both anhydrous and trihydrateform and can also be obtained in solution form. This test is based on themass of the trihydrate form.9. Sampling, Test Specimens, and Test Units9.1 Sample fine aggregate i
29、n accordance to Practice D75.9.2 Thoroughly mix the sample and reduce it as necessaryusing the applicable procedures in Practice C702.9.3 If it appears necessary, dampen the material to avoidsegregation or loss of fines during specimen preparation.9.4 Obtain at least 30 g of material passing the 4.7
30、5-mmsieve in the following manner:9.4.1 Separate the sample on the 4.75-mm sieve by meansof a lateral and vertical motion of the sieve, accompanied by ajarring action so as to keep the sample moving continuouslyover the surface of the sieve. Continue the sieving until notmore than 1 mass % of the re
31、sidue passes the sieve during the1-min sieving operation. Perform the sieving operation eitherby hand or by a mechanical apparatus. When thoroughness ofmechanical sieving is being determined, test by the handmethod described above using a single layer of material on thesieve.9.4.2 Break down any lum
32、ps of material in the coarsefraction to pass the 4.75-mm sieve. Use a mortar and rubber-covered pestle or any other means that will not fractureaggregate particles. Add this additional material passing thesieve to the separated fine portion of the sample and mixthoroughly.9.5 Dry the test specimen t
33、o constant mass by means of theselected source of heat, and cool to room temperature beforetesting. The sample is thoroughly dry when further heatingcauses, or would cause, less than 0.1 g additional loss in mass.9.6 Repeat the procedures in 9.4 and 9.5 to obtain three testspecimens.10. Standardizat
34、ion10.1 Standardization of the colorimeter for the relationshipbetween absorbance and the methylene blue concentrationInsert a glass cuvette approximately 2/3 full with water into thecolorimeter and zero the instrument. Use the micropipette totransfer a 130 6 1 L aliquot of 0.50 % mass methylene blu
35、esolution to a 50-mL test tube. Dilute the aliquot with water sothat the net mass of the diluted solution is 45.0 6 0.1 g. Placea cap on the test tube and gently shake the diluted solution for5 6 1 s. Using a new transfer pipette, fill a glass colorimetercuvette approximately 2/3 full with the dilut
36、ed solution. Wipethe cuvette with a clean towel if necessary to remove anymarks. Insert the cuvette with the diluted methylene bluesolution into the colorimeter and measure the absorbance.Rotate the cuvette within the meter a quarter revolution andtake another measurement. Repeat until four measurem
37、ents areC1777 132made. Calculate the average of the four values, and record asAstdto the nearest 0.01A. Perform this standardization for eachcolorimeter at least once every 6 months or whenever the lightsource or batteries are replaced (if applicable). Use a freshly-made 0.5 % mass methylene blue te
38、st solution for standardiza-tion of the colorimeter.10.2 Determination of actual initial methylene blueconcentrationBefore testing the fine aggregate or mineralfiller, determine the actual initial concentration of methyleneblue test solution that will be used. Insert a cuvette approxi-mately 2/3 fil
39、led with water into the colorimeter and zero theinstrument. Use the micropipette to transfer a 130 6 1Laliquot of the methylene blue solution to a 50-mL test tube.Dilute the aliquot with water so that the net mass of the dilutedsolution is 45.0 6 0.1 g. Cap the test tube and gently shake thediluted
40、solution for 5 6 1 s. Follow the procedure in 10.1 toobtain four values of absorbance of the diluted test solution.Calculate the average of the four values, and record as Ai.Determine the actual initial concentration of the test solution,Ci, prior to dilution, using the following equation:Ci5 0.50 %
41、! 3AiAstd(1)Repeat the process with two more aliquots. Calculate theaverage of the three values and record this as the average initialconcentration of methylene blue in the test solution to thenearest 0.01 %. Perform this determination of actual initialconcentration each day or whenever a new source
42、 or batch ofmethylene blue test solution is used.NOTE 510.2 is conducted to ensure the methylene blue solution to beused in the test is at the correct initial concentration.10.3 Adjustment of initial concentration of methylene bluesolutionIf the actual initial concentration is below 0.48 %,discard a
43、nd prepare a new test solution. If the actual initialconcentration is greater than 0.50 %, add sufficient water toadjust to 0.50 %.11. Procedure11.1 Test specimensWeigh 20.0 6 0.1 g of dry fineaggregate or mineral filler as obtained in Section 9 and recordthe actual mass of the specimen. Place 30.0
44、6 0.1gofmethylene blue test solution into a 50-mL test tube. Add theweighed aggregate to the methylene blue solution, ensuring allfines are incorporated.11.2 MixingCap the test tube and shake the mixture byhand for 60 6 1 s and allow to rest for 180 6 5 s. Shake themixture again for 60 6 1 s to comp
45、lete the mixing process.11.3 FiltrationRemove the plunger from the 3-mL-syringe and attach the 0.2-m syringe filter. Using a transferpipette, add approximately 2 mLof the specimen mixture to thesyringe and replace the plunger. Push the plunger slowly until0.5 to 1 mL of the filtered solution is coll
46、ected in a new 1-mLvial.11.4 DilutionUsing the micropipette, transfer 130 6 1Lof the filtered solution into a new 50-mL test tube. Dilute thefiltered solution with water until the net mass is 45.0 6 0.1 g.Cap the 50-mL test tube and gently shake the diluted solutionfor 5 6 1 s. Using a new transfer
47、pipette, fill a glass colorimetercuvette approximately 2/3 full with the diluted solution.11.5 Colorimeter zero adjustmentPlace a cuvette filledapproximately 2/3 with water into the colorimeter and zero theinstrument.11.6 Absorbance measurementRemove the cuvette filledwith water and replace with the
48、 cuvette filled with the dilutedsolution. Measure and record the absorbance to the nearest 0.01A. Rotate the cuvette within the colorimeter a quarter revolu-tion and take another measurement. Repeat a total of four timesand calculate the average of the four values; record as Af.11.7 Calculation of u
49、ndiluted final methylene blueconcentrationUsing the average value of Affrom 11.6,calculate the final methylene blue concentration, beforedilution, to the nearest 0.01 % using the following equation:Cf5 0.50 %! 3AfAstd(2)11.8 Replicate testingRepeat steps 11.1 through 11.7 ontwo additional specimens.12. Calculation of Methylene Blue Value12.1 For each determination of the final concentration ofmethylene blue solution, determine the methylene blue value(MBV) in units of mg/g by using the following equation:MBV 5Ci2 Cf!MMB!MFM31000 (3)where
