1、Designation: C1777 14C1777 15Standard 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 adopt
2、ion 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.1. Scope1.1 This test method provides a rapid test to determine the amount of methyle
3、ne blue adsorbed by a specimen of fine aggregateor mineral filler and can be used both in the laboratory and in the field.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 This standard does not purport to address all of
4、 the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C125 Terminology Relating
5、to Concrete and Concrete AggregatesC702 Practice for Reducing Samples of Aggregate to Testing SizeD75 Practice for Sampling AggregatesE11 Specification for Woven Wire Test Sieve Cloth and Test Sieves2.2 Other Standards:AASHTO T330 Standard Method of Test for the Qualitative Detection of Harmful Clay
6、s of the Smectite Group in AggregatesUsing 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 to Terminology C125.3.2 Definitions of Terms Sp
7、ecific to This Standard:3.2.1 mineral filler, na finely divided mineral product at least 65 % of which passes the 75-m sieve.4. Summary of Test Method4.1 Aspecimen of fine aggregate or mineral filler is combined with a methylene blue solution of known concentration and mixedfor a prescribed period o
8、f time. The specimen adsorbs some of the methylene blue from solution. The resulting mixture is filteredand a portion of the filtered solution is diluted by a fixed amount. A colorimeter is used to determine the absorbance of the dilutedsolution, from which the concentration of methylene blue prior
9、to dilution is calculated. The change in concentration of methyleneblue before and after mixing with fine aggregate or mineral filler is converted to a methylene blue value and reported in units ofmg/g.1 This test method is under the jurisdiction of ASTM Committee C09 on Concrete and Concrete Aggreg
10、ates and is the direct responsibility of Subcommittee C09.20 onNormal Weight Aggregates.Current edition approved Dec. 15, 2014Feb. 1, 2015. Published January 2015April 2015. Originally approved in 2013. Last previous edition approved in 20132014 asC1777-13.-14. DOI: 10.1520/C1777-14.10.1520/C1777-15
11、.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Available from American Association of State Highway and T
12、ransportation Officials (AASHTO), 444 N. Capitol St., NW, Suite 249, Washington, DC 20001,http:/www.transportation.org.4 Available from European Committee for Standardization, Avenue Marnix 17, B-1000 Brussels, Belgium.This document is not an ASTM standard and is intended only to provide the user of
13、 an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as pub
14、lished by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15. Significance and Use5.1 This test method is used to determine rapidly the amount of methylene blue adsorbed by a specimen of f
15、ine aggregate ormineral filler. The result is reported as a methylene blue value in units of mg of methylene blue adsorbed per g of fine aggregateor mineral filler. The methylene blue value is a function of the amount and characteristics of clay minerals present in the testspecimen. High methylene b
16、lue values indicate increased potential for diminished fine aggregate or mineral filler performance ina cementitious mixture due to the presence of clays.NOTE 1Results from this test method are not expected to be correlated with those obtained using AASHTO T 330 or EN 933-9. These three testmethods
17、are likely to give very different numerical values even though the units are the same. TheAASHTO T 330 test is performed only on the fractionof an aggregate passing the 75 m sieve, the EN 933-9 test is performed only on the fraction finer than 2 mm, and this test is performed on the fractionfiner th
18、an the 4.75 mm sieve. Therefore, when testing the same fine aggregate source, the AASHTO test method would give the highest methylene bluevalue because any clay present in the specimen would be concentrated in the fraction finer than the 75 m sieve. The AASHTO and EN test methodsdo not take into acc
19、ount the amount of material passing the 75 m sieve or 2 mm sieve, respectively. For example, a fine aggregate with high methyleneblue value measured by the AASHTO method but low percentage passing the 75 m sieve may have less effect on concrete performance than a fineaggregate with low methylene blu
20、e value measured by the AASHTO method but a high percentage passing the 75 m sieve. In contrast, this test methodexpresses methylene blue value based on the entire fine aggregate or mineral filler specimen.Additionally, theAASHTO and EN test methods use titrationto determine the amount of methylene
21、blue of known concentration that is adsorbed by a specimen and require the operator to visually determine the endpoint of the test. In contrast, this test method uses a colorimeter to detect the change in concentration of methylene blue solution before and after beingmixed with the fine aggregate or
22、 mineral filler specimen.NOTE 2Recommendations for maximum methylene blue values for specific applications are not provided in this test method. Maximum methyleneblue values should be established based on successful performance of fine aggregate or mineral filler in the applications under considerat
23、ion.6. Interferences6.1 Methylene blue will degrade when exposed to light. Store in darkness. No appreciable degradation occurs during the timeit 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
24、 sieve conforming to E11.7.2 Mass Balance having a capacity of 50 g or more and capable 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 specimen at a wavelength of 610 6 1 nm at operating temperatur
25、es of atleast 0 to 50C. The colorimeter shall be able to read absorbance between zero and the absorbance associated with a 0.144 % massconcentration of methylene blue solution.7.5 Disposable items for each testtwo plastic 50-mL test tubes, one plastic 1-mL vial, one 3-mL syringe with Luer-Lokadapter
26、, one 0.2-m syringe filter, one colorimeter glass cuvette (or sample cell), one micropipette tip, and two transfer pipettes.7.6 Additional disposable items for confirming methylene blue starting concentrationplastic 50-mL test tube, colorimeterglass cuvette, micropipette tip, and transfer pipette.7.
27、7 Additional disposable items for standardizing the colorimeterplastic 50-mL test tube, colorimeter glass cuvette,micropipette tip, and transfer pipette.7.8 Drying ApparatusA ventilated oven capable of maintaining a uniform temperature of 110 6 5C. Other suitable dryingapparatuses shall be permitted
28、, such as an electric hot plate or heat lamp. The temperature of the specimen shall not exceed 150C.In cases where the fine aggregate or mineral filler itself is altered by temperature greater than 115C, use a ventilated,controlled-temperature oven at 110 6 5C.NOTE 3Drying by means other than a vent
29、ilated oven may be appropriate for field use.8. Reagents and Materials8.1 Purity of Reagentsreagent grade methylene blue shall be used in all tests.8.2 Purity of waterreferences to water shall be understood to mean distilled or deionized water.8.3 Methylene blue test solutiona 0.50 % mass concentrat
30、ion methylene blue solution based on mass of trihydrate methyleneblue in water.NOTE 4Methylene blue is available in both anhydrous and trihydrate form and can also be obtained in solution form. This test is based on the massof the trihydrate form.9. Sampling, Test Specimens, and Test Units9.1 Sample
31、 fine aggregate in accordance to Practice D75.9.2 Thoroughly mix the sample and reduce it as necessary using the applicable procedures in Practice C702.C1777 1529.3 If it appears necessary, dampen the material to avoid segregation or loss of fines during specimen preparation.9.4 Obtain at least 30 g
32、 of material passing the 4.75-mm sieve in the following manner:9.4.1 Separate the sample on the 4.75-mm sieve by means of a lateral and vertical motion of the sieve, accompanied by a jarringaction so as to keep the sample moving continuously over the surface of the sieve. Continue the sieving until
33、not more than 1 mass% of the residue passes the sieve during the 1-min sieving operation. Perform the sieving operation either by hand or by amechanical apparatus. When thoroughness of mechanical sieving is being determined, test by the hand method described aboveusing a single layer of material on
34、the sieve.9.4.2 Break down any lumps of material in the coarse fraction to pass the 4.75-mm sieve. Use a mortar and rubber-coveredpestle or any other means that will not fracture aggregate particles. Add this additional material passing the sieve to the separatedfine portion of the sample and mix th
35、oroughly.9.5 Dry the test specimen to constant mass by means of the selected source of heat, and cool to room temperature before testing.The sample is thoroughly dry when further heating causes, or would cause, less than 0.1 g additional loss in mass.9.6 Repeat the procedures in 9.4 and 9.5 to obtai
36、n three test specimens.10. Standardization10.1 Standardization of the colorimeter for the relationship between absorbance and the methylene blue concentrationInserta glass cuvette approximately 2/3 full with water into the colorimeter and zero the instrument. Use the micropipette to transfer a130 6
37、1 L aliquot of 0.50 % mass methylene blue solution to a 50-mL test tube. Dilute the aliquot with water so that the net massof the diluted solution is 45.0 6 0.1 g. Place a cap on the test tube and gently shake the diluted solution for 5 6 1 s. Using a newtransfer pipette, fill a glass colorimeter cu
38、vette approximately 2/3 full with the diluted solution. Wipe the cuvette with a clean towelif necessary to remove any marks. Insert the cuvette with the diluted methylene blue solution into the colorimeter and measure theabsorbance. Rotate the cuvette within the meter a quarter revolution and take a
39、nother measurement. Repeat until fourmeasurements are made. Calculate the average of the four values, and record as Astd to the nearest 0.01 A. Perform thisstandardization for each colorimeter at least once every 6 months or whenever the light source or batteries are replaced (ifapplicable). Use a f
40、reshly-made 0.5 % mass methylene blue test solution for standardization of the colorimeter.10.2 Determination of actual initial methylene blue concentrationBefore testing the fine aggregate or mineral filler, determinethe actual initial concentration of methylene blue test solution that will be used
41、. Insert a cuvette approximately 2/3 filled with waterinto the colorimeter and zero the instrument. Use the micropipette to transfer a 130 6 1 L aliquot of the methylene blue solutionto a 50-mL test tube. Dilute the aliquot with water so that the net mass of the diluted solution is 45.0 6 0.1 g. Cap
42、 the test tubeand gently shake the diluted solution for 5 6 1 s. Follow the procedure in 10.1 to obtain four values of absorbance of the dilutedtest solution. Calculate the average of the four values, and record as Ai. Determine the actual initial concentration of the testsolution, Ci, prior to dilu
43、tion, using the following equation:Ci 50.50 %!3 AiAstd(1)Repeat the process with two more aliquots. Calculate the average of the three values and record this as the average initialconcentration of methylene blue in the test solution to the nearest 0.01 %. Perform this determination of actual initial
44、 concentrationeach day or whenever a new source or batch of methylene blue test solution is used.NOTE 510.2 is conducted to ensure the methylene blue solution to be used in the test is at the correct initial concentration.10.3 Adjustment of initial concentration of methylene blue solutionIf the actu
45、al initial concentration is below 0.48 %, discardand prepare a new test solution. If the actual initial concentration is greater than 0.50 %, add sufficient water to adjust to 0.50 %.11. Procedure11.1 Test specimensSpecimensWeigh 20.0 6 0.1 g of dry fine aggregate or mineral filler as obtained in Se
46、ction 99 andrecord the actual mass of the specimen. Place Tare a 50-ml test tube, weigh 30.0 6 0.1 g of methylene blue test solution directlyinto a 50-mL test tube. the test tube, and record the actual mass of solution. Add the weighed aggregate to the methylene bluesolution, ensuring all fines are
47、incorporated.11.2 MixingCap the test tube and shake the mixture by hand for 60 6 1 s and allow to rest for 180 6 5 s. Shake the mixtureagain for 60 6 1 s to complete the mixing process.11.3 FiltrationRemove the plunger from the 3-mL-syringe and attach the 0.2-m syringe filter. Using a transfer pipet
48、te, addapproximately 2 mL of the specimen mixture to the syringe and replace the plunger. Push the plunger slowly until 0.5 to 1 mLof the filtered solution is collected in a new 1-mL vial.11.4 DilutionUsing the micropipette, transfer 13061 Lof the filtered solution into a new 50-mLtest tube. Dilute
49、the filteredsolution with water until the net mass is 45.0 6 0.1 g. Cap the 50-mL test tube and gently shake the diluted solution for 5 6 1s. Using a new transfer pipette, fill a glass colorimeter cuvette approximately 2/3 full with the diluted solution.C1777 15311.5 Colorimeter zero adjustmentPlace a cuvette filled approximately 2/3 with water into the colorimeter and zero theinstrument.11.6 Absorbance measurementRemove the cuvette filled with water and replace with the cuvette filled with the dilutedsolution. Measure and record the abs
