1、Designation: C563 17Standard Guide forApproximation of Optimum SO3in Hydraulic Cement1This standard is issued under the fixed designation C563; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in
2、parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This guide describes the determination of approximateoptimum SO3for maximum performance as a result of substi-tuting calcium sulfate for a porti
3、on of the cement.1.2 This guide refers to the sulfur trioxide (SO3) content ofthe cement only. Slag cements and occasionally other hydrauliccements can contain sulfide or other forms of sulfur. Thedetermination of SO3content by rapid methods may includethese other forms, and may therefore produce a
4、significanterror. If a significant error occurs, analyze the cement for SO3content using the reference test method of Test Methods C114for sulfur trioxide.1.3 Values stated as SI units are to be regarded as standard.1.4 This standard does not purport to address all of thesafety concerns, if any, ass
5、ociated 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:2C39/C39M Test Method for Compressive Strength of Cylin-d
6、rical Concrete SpecimensC78 Test Method for Flexural Strength of Concrete (UsingSimple Beam with Third-Point Loading)C109/C109M Test Method for Compressive Strength ofHydraulic Cement Mortars (Using 2-in. or 50-mm CubeSpecimens)C114 Test Methods for Chemical Analysis of HydraulicCementC150 Specifica
7、tion for Portland CementC192 Practice for Making and Curing Concrete Test Speci-mens in the LaboratoryC204 Test Methods for Fineness of Hydraulic Cement byAir-Permeability ApparatusC305 Practice for Mechanical Mixing of Hydraulic CementPastes and Mortars of Plastic ConsistencyC430 Test Method for Fi
8、neness of Hydraulic Cement by the45-m (No. 325) SieveC465 Specification for Processing Additions for Use in theManufacture of Hydraulic CementsC471M Test Methods for ChemicalAnalysis of Gypsum andGypsum Products (Metric)C595 Specification for Blended Hydraulic CementsC596 Test Method for Drying Shri
9、nkage of Mortar Contain-ing Hydraulic CementC1157 Performance Specification for Hydraulic CementC1437 Test Method for Flow of Hydraulic Cement MortarC1702 Test Method for Measurement of Heat of Hydrationof Hydraulic Cementitious Materials Using IsothermalConduction Calorimetry3. Significance and Use
10、3.1 The purpose of this guide is to estimate the SO3contentfor a hydraulic cement that gives maximum performance. Thevalue obtained is one way to establish an appropriate level ofsulfate in the manufacture of cements specified in Specifica-tions C150, C595, and C1157.3.2 The SO3content of a cement g
11、iving maximum perfor-mance is different at different ages, with different performancecriteria and with different materials such supplementary ce-mentitious materials and chemical admixtures. A manufacturercan choose the performance criteriato determine optimum SO3content. This optimum SO3content may
12、 be a compromisebetween different ages and different performance criteria.NOTE 1Typically, the optimum SO3content is higher the later the age.3.3 This guide indicates optimum SO3content for cement inmortar made and cured at a standard temperature of 23.0 62.0C (73.5 6 3.5F). The optimum SO3increases
13、 withincreasing temperature and may increase when water-reducingadmixtures are used.3.4 It should not be assumed that the optimum SO3esti-mated in this guide is the same SO3content for optimumperformance of a concrete prepared from the cement.3.5 The guide is applicable to cements specified in Speci
14、fi-cations C150, C595, and C1157.1This guide is under the jurisdiction of ASTM Committee C01 on Cement andis the direct responsibility of Subcommittee C01.28 on Sulfate ContentCurrent edition approved Feb. 1, 2017. Published March 2017. Originallyapproved in 1965. Last previous edition approved in 2
15、016 as C563 16. DOI:10.1520/C0563-17.2For referenced 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.*A Summary of Changes se
16、ction appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision
17、on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.14. Apparatus4.1 Use the apparatus as specified in Test Methods C109/C109M, C192, C596,orC1702.5. Materials5.1 Calcium SulfateUse
18、 calcium sulfate for addition to thecement that is either a high-grade natural gypsum having anSO3content of at least 46 %, or the calcium sulfate from thesource used for the intended plant production. Grind thecalcium sulfate to 100 % passing the 75-m (No. 200) sieve,and at least 800 m2/kg Blaine f
19、ineness (Test Method C204). Ifthe SO3content of the calcium sulfate is unknown, analyze itin accordance with Test Methods C471M.NOTE 2The calcium sulfate source can impact the optimum sulfateresult due in part to differences in form of the calcium sulfate (forexample, gypsum, calcium sulfate hemi-hy
20、drate, or anhydrous calciumsulfate). Temperatures in cement finish mills during production can reachlevels to partially or completely change the form of calcium sulfate incement.5.2 CementMake cements of different sulfate levels at asingle production site. Make the cements so that the amount ofcalci
21、um sulfate added, and the subsequent dilution effects, arethe only difference in constituent materials.5.2.1 Grind samples to a fineness within 13 m/kg of theother samples when tested in accordance with Test MethodC204. Since calcium sulfate sources are typically softer thanclinker, an adjustment of
22、 10 m2/kg for every 1 % calciumsulfate addition is permitted, as shown in equation Eq 1.FA,X5 FM,X210SO3,X2 SO3,median!SO3,CS 100(1)where:SO3,CS= percentage of SO3in the calcium sulfate,SO3,median=SO3percentage of the sample with the medianSO3of the samples tested,SO3,X=SO3percentage of cement sampl
23、e X,FM,X= measured fineness of cement sample X, andFA,X= adjusted fineness of cement sample X.NOTE 3Differences in the mill conditions between samples ofdifferent sulfate levels should be minimized. For this reason samples arenormally taken during the same production campaign. Strategies shouldbe em
24、ployed to minimize the differences in fineness of the clinker whentaking samples, such as targeting a specific sieve size range and adjustingaround that target within reasonable tolerances. Since calcium sulfate issofter, and thus easier to grind than clinker, increases in calcium sulfatecontent wil
25、l elevate the fineness of the cement without a change in thegrinding energy or the fineness of the clinker.NOTE 4As an example, consider the case of one cement sample withan SO3content of 2.7 % and a fineness of 380 m2/kg, which is the samplewith the median SO3content, and another sample with an SO3
26、content of3.7 % and a fineness of 405 m2/kg. The second sample has a 1.0% higherSO3content, or 2.2 % more calcium sulfate addition, assuming thecalcium sulfate was 45 % SO3. The adjusted cement fineness of the secondsample would be reduced by 22 m2/kg (10 2.2) to 383 m2/kg by usingEquation Eq 1 as s
27、hown in Eq 2. This value of 383 m2/kg is within13 m2/kg of the fineness of 380 m2/kg, and thus is acceptable for testing.FA,X5 405 2103.7 2 2.7!451005 383 m2kg (2)5.2.2 Determine the percentage of the following analytes byTest Method C114 for each cement tested: silicon dioxide(SiO2), aluminum oxide
28、 (Al2O3), ferric oxide (Fe2O3), calciumoxide (CaO), magnesium oxide (MgO), sulfur trioxide (SO3),loss on ignition, insoluble residue, sodium oxide (Na2O), andpotassium oxide (K2O). Calculate the potential percentages ofthe following compounds for portland cements according toSpecification C150: tric
29、alcium silicate, dicalcium silicate, tri-calcium aluminate and tetracalcium aluminoferrite. Whenapplicable, report the amount of limestone and SpecificationC465 inorganic processing additions according to SpecificationC150. Determine the fineness of each cement tested accordingto Test Methods C204 a
30、nd C430.NOTE 5The amount of material retained on the 45-m sieve has beenused as an indication of the clinker fineness. When high efficiencyseparators are used, the amount retained on a 20-m sieve has also beenused as an indicator of clinker fineness.6. Procedure6.1 Sulfate Levels to TestTest at leas
31、t five different sulfatelevels.6.1.1 SO3contents are to be at least 0.20 % different unlessmore than five different SO3contents are being tested. Themaximum and minimum SO3content of the blended samplesmust differ by at least 2.0 % SO3content.NOTE 6The same mixture design and materials shall be used
32、 whencomparing different SO3contents. Use one or more of the following testmethods to evaluate the performance:6.1.1.1 When adding calcium sulfate it is considered as partof the mass of cement for proportioning.6.1.1.2 Use the following equation to calculate the total SO3in the blended sample of cem
33、ent and calcium sulfate:SO3-Total5Mcalcium sulfateMcalciumsulfate1Mcememnt3SO3-calcium sulfate1McementMcalciumsulfate1Mcement3SO3-cement(3)where:Mcalcium sulfate= the mass of the calcium sulfate,Mcement= the mass of the cement,SO3-cement sulfate= the percent by mass of SO3in the calciumsulfate, andS
34、O3-cement= the percent by mass of the SO3in thecement.NOTE 7More sulfate levels may be tested to help improve theprecision of the interpretation of the results. Extremely high and lowsulfate levels can give results that deviate from the typical peak behaviorwhich may need to be treated as outliers w
35、hen using a mathematical fittingprocedure.6.2 The same mixture design and materials shall be usedwhen comparing different SO3contents. Use one or more of thefollowing test methods to evaluate the performance:6.2.1 Mortar compressive strengthDetermine mortar com-pressive strength at each sulfate leve
36、l at the age of 24 614 h,3 days 6 1 h, or 7 days 6 3 h in accordance with Test MethodC109/C109M except as follows:6.2.1.1 When mixing in accordance with the “Procedure forMixing Mortars” section of Practice C305, add the calciumsulfate to the water, unless the calcium sulfate addition hasbeen previo
37、usly ground and mixed with the cement; then startthe mixer and mix at slow speed (140 6 5 rpm) for 15 s; thenC563 172stop the mixer and add the cement to the water; then start themixer and mix at slow speed (140 6 5 rpm) for 30 s.6.2.1.2 Use the amount of mixing water to produce a flow of110 6 5 for
38、 one of the mixtures using 25 drops of the table asdetermined in the section on Procedures inTest Method C1437.Use that same amount of water (constant w/cm) for eachmixture with different sulfate levels.NOTE 8The mixture with the median sulfate level or lowest sulfatelevel is often used to determine
39、 the water content.6.2.2 Heat of hydrationDetermine heat of hydration ateach sulfate level at the age of 24 614 h, 3 days 6 1h,or7 days 6 3 h in accordance with Test Method C1702 except asfollows:6.2.2.1 Add the calcium sulfate to the water, unless thecalcium sulfate addition has been previously gro
40、und and mixedwith the cement;6.2.2.2 Additions of other materials typically used inconcrete, such as supplementary cementitious materials andchemical admixtures, can be used.6.2.2.3 Mortars are allowed to be used in addition to pastes.When testing with mortars use the same sand content for eachdiffe
41、rent mixture.6.2.2.4 Testing at temperatures besides 23C is allowed. Usethe same temperature for each different mixture.6.2.3 Concrete StrengthPrepare all material according toPractice C192 except as follows:6.2.3.1 Add the calcium sulfate to the water, unless thecalcium sulfate addition has been pr
42、eviously ground and mixedwith the cement.6.2.3.2 When applicable, determine compressive strengthaccording to Test Method C39/C39M. When applicable, deter-mine flexural strength according to Test Method C78.6.2.3.3 Testing at concrete and curing temperatures otherthan specified is allowed. Use the sa
43、me material temperature(all mixtures within 10C range) and the same curing tempera-ture (all curing temperatures within 4C range) for each of thedifferent mixtures6.2.4 Drying Shrinkage of MortarPrepare all materialaccording to Practice C596 except as follows:6.2.4.1 When mixing in accordance with t
44、he section onProcedure for Mixing Mortars of Practice C305, add thecalcium sulfate to the water, unless the calcium sulfate additionhas been previously ground and mixed with the cement; thenstart the mixer and mix at slow speed (140 6 5 rpm) for 15 s;then stop the mixer and add the cement to the wat
45、er; then startthe mixer and mix at slow speed (140 6 5 rpm) for 30 s.6.2.4.2 Instead of using the amount of mixing water suffi-cient to produce a flow of 110 6 5, use the amount of mixingwater to produce a flow of 110 6 5 for one of the mixturesusing 25 drops of the table as determined in the sectio
46、n onProcedures in Test Method C1437. Use that same amount ofwater (constant w/cm) for each mixture with different sulfatelevels.NOTE 9The mixture with the median sulfate level or lowest sulfatelevel is often used to determine the water content.7. Interpretation of Results7.1 Approximate the SO3conte
47、nt which gives the maximumperformance by one of the following methods:NOTE 10See the appendix for an example of how this interpretationis done for each method described below. Depending on which method ischosen the results may differ.7.1.1 Visual FitPlot the performance level versus SO3content and i
48、nterpolate the sulfate level at the peak.7.1.2 Least Squares Parabolic Fit.7.1.2.1 Determine the equation of a least squares fit accord-ing to follow equation:Performance Level 5 aSO3!21bSO31cwhere a, b, and c are fitting coefficients.NOTE 11Spreadsheet and graphing programs have the capability toca
49、lculate the least squares parabolic fit.7.1.2.2 Approximate the optimum SO3by calculating vertexof the parabolic least squares fit from the following equation:Optimum SO3approximation = 2 b2 a!where a and b are coefficients of the parabolic least squaresfit.7.1.3 Asymmetric FitIn cases where the performance levelversus SO3is skewed to the right or left of the peak a fit usingan asymmetric distribution function may provide a better fitthan parabolic fit.NOTE 12Mathematical and statistics software programs are useful indoing such fits.NOTE
