ASTM C1875-2018 Standard Practice for Determination of Major and Minor Elements in Aqueous Pore Solutions of Cementitious Pastes by Inductively Coupled Plasma Optical Emission Spec.pdf

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1、Designation: C1875 18Standard Practice forDetermination of Major and Minor Elements in AqueousPore Solutions of Cementitious Pastes by InductivelyCoupled Plasma Optical Emission Spectroscopy (ICP-OES)1This standard is issued under the fixed designation C1875; the number immediately following the des

2、ignation indicates the 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.1. Scope1.1 This practice describes a pro

3、cedure for collection,sample preparation and analysis of aqueous pore solutionsobtained from cementitious materials at different hydrationtimes when analyzed by ICP-OES for the six most commonreadily soluble elements aluminum, calcium, potassium,silicon, sodium and sulfur.1.2 The values stated in SI

4、 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 concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety, health, an

5、d environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International

6、Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:C25 Test Methods for Chemical Analysis of Limestone,Quicklime, and Hydrated LimeC114 Test Methods for Chemical Analysis of HydraulicCemen

7、tC1738/C1738M Practice for High-Shear Mixing of Hydrau-lic Cement PastesD1129 Terminology Relating to WaterD1193 Specification for Reagent WaterD5673 Test Method for Elements in Water by InductivelyCoupled PlasmaMass SpectrometryD7111 Test Method for Determination of Trace Elements inMiddle Distilla

8、te Fuels by Inductively Coupled PlasmaAtomic Emission Spectrometry (ICP-AES)E1479 Practice for Describing and Specifying InductivelyCoupled Plasma Atomic Emission Spectrometers3. Terminology3.1 Definitions:3.1.1 Unless otherwise specified, for definitions of termsused in this practice refer to Termi

9、nology C1738/C1738M.4. Summary of Practice4.1 This document describes practice for determining theconcentration of multiple dissolved components in the poresolution of cementitious pastes as a function of time usinginductively coupled plasma optical emission spectroscopy(ICP-OES). A cementitious mat

10、erial is mixed with water at adesired water to solid ratio using a Practice D1129 certifiedconstant mixer. Aliquots of the mix are divided into centrifugetubes and stored in a water bath or environmental chamber atconstant temperature. The samples centrifuged at differenttimes. The extracted pore so

11、lution is filtered and diluted with a5 % nitric acid solvent. The prepared test solutions flow intothe plasma torch of the ICP instrument where it is vaporizedand ionized, producing characteristic atomic wavelength emis-sion spectra. The spectra are dispersed by a high resolutiongrating and the inte

12、nsities of the individual wavelengths aremeasured. Elemental concentrations are determined by relatingthe emission intensities at specific wavelengths for an unknownsample to analytical curves made from reference standards ofknown composition. The concentration of the elements in thesolutions can th

13、en be calculated. Internal standards compensatefor variations in test sample flow rates in the instrument.5. Significance and Use5.1 The chemical composition of the liquid in cementitiouspastes is an important indicator of the solid componentreactivity at early times, being influenced by the content

14、 andrate of reaction of readily soluble alkali components, lime, andother soluble phases. Monitoring the solution composition withtime can provide valuable diagnostic information about cement1This test method is under the jurisdiction of ASTM Committee C01 on Cementand is the direct responsibility o

15、f Subcommittee C01.23 on CompositionalAnalysis.Current edition approved July 1, 2018. Published August 2018. DOI: 10.1520/C1875-18Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance w

16、ith internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1quality and reactivity to supplement ot

17、her sources of charac-terization data. This practice is intended to aid in the interpre-tation of the concentrations of readily soluble components incement paste solutions, which may include portland cement,limestone, fly ash, ground granulated blast furnace slag, orother components. It provides gui

18、dance for measuring the timedependence of the concentrations of one or more components,on an elemental basis, including, but not limited to, aluminum,calcium, potassium, silicon, sodium, and sulfur.6. Apparatus6.1 SpectrometerSpectrometer-An inductively coupledplasma emission spectrometer of the sim

19、ultaneous or sequen-tial type including RF generator, torch, nebulizer, connectortube, spray chamber, recommended peristaltic pump and hostcomputer. Sample uptake is done by self-aspiration, or with aperistaltic pump.6.2 Mass Flow ControllersAmass-flow controller to regu-late the nebulizer gas may b

20、e used as recommended by theinstrument manufacturer.6.3 BalanceTop loading or analytical, with automatic tare,with capacity of at least 500 g and a sensitivity of at least 0.1g to weigh paste mix components.6.4 CentrifugeUse a centrifuge capable of accommodat-ing two or more 50 mL centrifuge tubes a

21、t rotational speeds upto 5000 min-1.6.5 TimerCalibrated timer for use of tracking blendingand reaction times.7. Reagents and Materials7.1 Ordinary laboratory apparatus are not listed, but areassumed to be present.7.2 Purity of ReagentsAt a minimum, reagent grade orbetter chemicals shall be used in a

22、ll tests.7.3 Purity of WaterReferences to water shall be under-stood to mean deionized water. Tap water may be used only toprepare cement paste mixes if desired. If tap water is used formixing the composition of the water itself must be separatelymeasured as a test sample as described in Section 11.

23、7.4 ArgonHigh purity grade (99.99 %).7.5 Calibration StandardsSingle-element or multi-element calibration reference solutions that combine appropri-ate volumes of the stock solutions or weighed reagent-gradechemicals in acid-rinsed volumetric flasks. Dilute to thevolume of the flask usinga5%(v/v) ni

24、tric acid solution. Priorto preparing the multi-element solutions, analyze each stocksolution separately to check for strong spectral interference andthe presence of impurities. Take care when preparing themulti-element solutions to verify that the components arecompatible and stable (i.e., that the

25、y do not interact to causeprecipitation) and that none of the elements present willcontribute to mutual spectral interference. Calibration refer-ence solutions must be verified initially using a quality controlsample and monitored periodically for stability. Mixed calibra-tion standards will vary, d

26、epending on the number of elementsbeing determined.7.6 Calibration Blank Solution5 % (v/v) HNO3.7.7 Nitric Acid5 % (v v).7.8 Check StandardsQuality control certified NIST trace-able samples that are stable and representative of the samplesof interest. These check standard samples represent groundtru

27、th samples and are used to check that the measurementprocess is in control.7.9 Internal StandardsInternal standards are used to cor-rect for instrument drift and physical interferences. Refer toinstrument operating manual for suggested internal standards.Add internal standards to blanks, samples, an

28、d standards in alike manner.7.10 Membrane FilterNylon 25 mm diameter, 0.2 m.7.11 Syringe and NeedleCapacity of at least 2 mL.7.12 Centrifuge TubesClean plastic centrifuge tubes theappropriate size for centrifuge.7.13 GlasswareVolumetric flasks complying with the re-quirements of ISO 1042, made of bo

29、rosilicate glass complyingwith the requirements of ISO 3585. Glassware should becleaned before each use by soaking in nitric acid and thenrinsing thoroughly with deionized water.7.14 PipetteCalibrated volumetric pipettes and pipettetips, for dispensing.8. Hazards8.1 The toxicity or carcinogenicity o

30、f each reagent used inthis practice has not been precisely defined; however, eachchemical should be treated as a potential health hazard.Adequate precautions should be taken to minimize exposure ofpersonnel to chemicals used in this practice.8.2 Gases under high pressure are used in this practice. U

31、seonly apparatus rated for handling the high gas pressures thatoccur in this practice.9.1 Powder HomogenizationA uniform distribution ofpowder components is essential to ensure representative sam-pling during the mixing process, especially for blended powdercomponents such as portland cement and fly

32、 ash. Powdersshould therefore be homogenized for 30 minutes with aplanetary mixer or similar device.10. Sample Preparation and Collection10.1 High Shear Mixing:10.1.1 Blend the solid and liquid components to make apaste according the standard practice described in PracticeD1129.10.1.2 Set a timer to

33、 mark the end of mixing. The time onthis timer will serve as the total reaction time for the remainderof the procedure.10.1.3 Stir the paste with the spatula for no more than 15 sensure homogeneity.10.1.4 Transfer (25 6 1) g of the paste into each of twelvecentrifuge tubes with secured lids in the m

34、inimum amount oftime possible, preferably less than 2 min.C1875 18210.1.5 Place the twelve centrifuge sample tubes upright insample holders and place them in the temperature controldevice (water bath or environmental chamber).10.2 Liquid Solution Extraction:10.2.1 Refer to manufacturers manual for i

35、nstructionson safe and optimal operation of centrifuge.10.2.2 Set centrifuge parameters to 5000 rpm for approxi-mately 1 min, and load one centrifuge tube filled with (25 6 1)g of solid to serve as a counterweight.10.2.3 Within the first 10 min on the timer, select one of thesamples and place it int

36、o the centrifuge opposite the preloadedcounterweight. Begin centrifuging. Record the time indicatedon the timer when the centrifuge started.10.2.4 Immediately after the centrifuge comes to a completestop, remove sample centrifuge tube.10.2.5 Using a needle tip syringe, extract pore solution fromsamp

37、le without disturbing solid material in tube.10.2.6 Invert syringe and cautiously remove needle tip andadd a 0.20 m nylon membrane filter at the syringe opening.10.2.7 Transfer pore solution from syringe through filterinto a clean empty plastic sample container. Label and notecentrifugation time rec

38、orded in 10.2.3.10.2.8 Repeat 10.2.2 through 10.2.7 at different desiredtimes, based on the running time being kept on the timer set in10.1.2.NOTE 1Many cement pastes will begin to harden after three hours, orperhaps even sooner, making extraction of the liquid by a centrifugedifficult or impossible

39、.11. Preparation of Test Solutions and Standards11.1 Preparation of Test Sample:11.1.1 Transfer appropriate amount of a filtered sample intoa volumetric flask then dilute to volume with 5 % HNO3.Repeat for each filtered pore solution from 10.2.NOTE 2Appropriately dilute samples to within the calibra

40、tion range ofeach chosen element.11.2 Preparation of Calibration Standard:11.2.1 BlankPrepare a blank solution by adding sameconcentration of diluted acids as used in the sample dissolution(usually 5 % nitric acid).11.2.2 Calibration Standardsrepare known concentrationsof single-element or multi- el

41、ement calibration reference solu-tions by combining appropriate volumes of the stock solutionsin acid-rinsed volumetric flasks. Add sufficient 5 % nitric acidto dilute to volume. Take care when preparing the multi-element solutions to verify that the components are compatibleand stable (they do not

42、interact to cause precipitation) and thatnone of the elements present exhibit mutual spectral interfer-ence. Calibration reference solutions must be verified initiallyusing a quality control sample and monitored periodically forstability.11.3 Preparation of Check Standard:11.3.1 Prepare the same way

43、 as the calibration standards11.2.2 specifically using NIST traceable certified referencesolutions.12. Interfaces12.1 Refer to ICP-OES operating manual for instructions onminimizing and checking for interferences.13. Preparation of ICP-OES Apparatus13.1 Prepare and operate the spectrometer in accord

44、ancewith the manufacturers instructions. The present practiceassumes that good operating procedures are followed. Designdifferences between spectrometers make it impractical tospecify the required steps in detail.13.2 Peristaltic PumpIf a peristaltic pump is used, inspectthe pump tubing and replace

45、it, if necessary, before startingeach day. Verify the solution uptake rate and adjust it to thedesired rate.13.3 ICP Excitation SourceInitiate the plasma source atleast 30 min before performing an analysis. During this warmup period, nebulize either water or a dilute (5 %) acid solution.NOTE 3Some i

46、nstrument manufacturers recommend even longerwarm-up periods to minimize changes in the slopes of calibration curves.13.4 Wavelength ProfilingPerform any wavelength profil-ing that is specified in the normal operation of the instrument.13.5 Operating ParametersAssign the appropriate oper-ating param

47、eters to the instrument task file so that the desiredelements can be determined. Parameters to be included areelement, wavelength(s), background correction points(optional), inter-element correction factors, and integrationtime. Multiple integrations (typically three) are required foreach measuremen

48、t. A typical measurement time is 10 s.14. Calibration and Standardization14.1 Allow the ICP-OES instrument to warm up for at least30 min. Operate the spectrometer according to the operationmanual for the instrument.14.2 Calibrate the instrument for the elements chosen over asuitable concentration ra

49、nge by atomizing the calibration blankand mixed calibration standard solutions, including any inter-nal standards, and recording their concentrations and signalintensities. A minimum of six standards and a blank should beused for calibration with one of the standards. The computersoftware will establish the slope, intercept and correlationcoefficients for each element. Use manufacture suggestedwavelengths each element. The calibration correlation coeffi-cient shall be equal to or greater than 0.990. It is recommendedthat the calibration blank and stand