1、Designation: C 563 07Standard Test Method forApproximation of Optimum SO3in Hydraulic Cement UsingCompressive Strength1This standard is issued under the fixed designation C 563; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the y
2、ear of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method describes the determination of approxi-mate optimum SO3for maximum compressive strength at 2
3、4 h,3 days, or 7 days by measuring the change in strength producedin hydraulic cement mortar as a result of substituting calciumsulfate for a portion of the cement.1.2 This test method refers to the sulfur trioxide (SO3)content of the cement only. Slag cements and occasionallyother hydraulic cements
4、 can contain sulfide or other forms ofsulfur. The determination of SO3content by rapid methods mayinclude these other forms, and may therefore produce asignificant error. If a significant error occurs, analyze thecement for SO3content using the reference test method of TestMethods C114for sulfur tri
5、oxide.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, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the ap
6、plica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C 109/C 109M Test Method for Compressive Strength ofHydraulic Cement Mortars(Using 2-in. or 50-mm CubeSpecimens)C114 Test Methods for Chemical Analysis of HydraulicCementC 150 Specification for Portland Ce
7、mentC 204 Test Methods for Fineness of Hydraulic Cement byAir-Permeability ApparatusC 305 Practice for Mechanical Mixing of Hydraulic CementPastes and Mortars of Plastic ConsistencyC 471M Test Methods for Chemical Analysis of Gypsumand Gypsum Products MetricC511 Specification for Mixing Rooms, Moist
8、 Cabinets,Moist Rooms, and Water Storage Tanks Used in theTesting of Hydraulic Cements and ConcretesC 595 Specification for Blended Hydraulic CementsC 778 Specification for Standard SandC 1157 Performance Specification for Hydraulic CementC 1437 Test Method for Flow of Hydraulic Cement Mortar3. Sign
9、ificance and Use3.1 The purpose of this test method is to estimate the SO3content for a hydraulic cement that gives maximum compres-sive strength in mortar made and cured at 23 C. The valueobtained is used to establish an appropriate level of sulfate inthe manufacture of cements specified in Specifi
10、cations C 150,C 595 and C 1157. In Specifications C 150 and C 595 it is usedto justify exceeding the prescriptive limits for SO3.3.2 The SO3content of a cement giving maximum compres-sive strength is different at different ages of mortar; typicallythis SO3content is higher at 3 days than the 24-h, a
11、nd oftenhigher for 7 days than that for 3 days. A manufacturer canchoose the age of 24-h, 3 days or 7 days for specimens at whichto determine optimum SO3content.3.3 This test method indicates optimum SO3content forcement in mortar made and cured at a standard temperature of23.0 6 2.0 C (73.5 6 3.5 F
12、). The optimum SO3increaseswith increasing temperature and may increase when water-reducing admixtures are used.3.4 It should not be assumed that the optimum SO3estimated in this test method is the same SO3content foroptimum performance of a concrete prepared from the cement.3.5 The test method is a
13、pplicable to cements specified inSpecifications C 150, C 595, and C 1157.4. Apparatus4.1 Use the apparatus as specified in Test Method C 109/C 109M.5. Materials5.1 Calcium SulfateUse calcium sulfate for addition tothe cement that is either a high-grade natural gypsum having anSO3content of at least
14、46 %, or the calcium sulfate from thesource used for the intended plant production. Grind the1This test method is under the jurisdiction of ASTM Committee C01 on Cementand is the direct responsibility of Subcommittee C01.28 on Sulfate ContentCurrent edition approved April 1, 2007. Published May 2007
15、. Originallyapproved in 1965. Last previous edition approved in 2004 as C 563-04.2For 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
16、 onthe ASTM website.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.calcium sulfate to 100 % passing the 75-m (No. 200) sieve,and at least 800 m2/kg Blaine fineness (T
17、est Method C 204). Ifthe SO3content of the calcium sulfate is unknown, analyze itin accordance with Test Methods C 471M.5.2 Blended Standard SandUse graded sand conformingto Specification C 778.6. Test Specimens6.1 Make six specimens from each batch of mortar. Maketwo rounds of three mixtures of mor
18、tar as described in 6.3.Make both rounds during the same day if possible. Make onlycomplete rounds on any given day.6.2 Preparing Specimen MoldsPrepare molds in accor-dance with the section on Preparation of Specimen Molds ofTest Method C 109/C 109M.6.3 Proportioning, Consistency, and Mixing of Mort
19、arProportion the dry material for the standard mortar as one partof cement to 2.75 parts graded sand by mass. Mix the followingquantities of dry materials at one time for a 6-cube batch:Mixture No. 1 500 g cement1375.0 g graded sandMixture No. 2 494.6 g cement5.3 g calcium sulfate1375.0 g graded san
20、dMixture No. 3 489.2 g cement10.6 g calcium sulfate1375.0 g graded sand6.3.1 Use an amount of mixing water to produce a flow of110 6 5 using 25 drops of the table as determined in thesection on Procedures in Test Method C 1437 for all types ofcement.6.3.2 Mix mechanically in accordance with the sect
21、ion onProcedure for Mixing Mortars of Practice C 305, except asfollows:6.3.2.1 Add the calcium sulfate to the water; then start themixer and mix at slow speed (140 6 5 rpm) for 15 s; then stopthe mixer and add the cement to the water; then start the mixerand mix at slow speed (140 6 5 rpm) for 30 s.
22、6.4 Molding of Test SpecimensMold specimens in accor-dance with the Procedure Section of Test Method C 109/C 109M.6.5 Storage of Test SpecimensImmediately upon comple-tion of molding, place the test specimens in the moist closet ormoist room. Keep all test specimens, immediately after mold-ing, in t
23、he molds on the base plates in the moist closet or moistroom for 20 to 24 h with their upper surfaces exposed to themoist air but protected from dripping water. If the specimensare removed from the molds before 24 h, keep them on theshelves of the moist closet or moist room until they are 24-hold an
24、d then immerse the specimens, except those for the 24-htest, in saturated lime water in storage tanks constructed ofnoncorroding materials until the age chosen for the test. Keepthe storage water clean by changing as required.7. Temperature and Humidity7.1 The temperature and humidity of the moist c
25、abinet ormoist room shall be as specified in Specification C511.7.2 The temperature and humidity of the mixing room shallbe as specified in Test Method C 109/C 109M.8. Procedure8.1 Test the specimens at the age of 24 614 h, 3 days 6 1h, or 7 days 6 3 h, from the time the cement and water madecontact
26、 during mixing, immediately after removal from storagein accordance with Test Method C 109/C 109M. If more thanone specimen at a time is removed from storage, keep thesespecimens covered with a damp cloth until time of testing.Note and observe precautions regarding testing and retestinggiven in the
27、applicable sections of Test Method C 109/C 109M.9. Calculation9.1 Calculate and record the strength of specimens asdescribed in the section on Calculation in Test Method C 109/C 109M.9.1.1 Calculate the indicated optimum SO3content as fol-lows:G 5 a/a 2 b!# c 1 d 1 c/2where:G = optimum percent SO3,a
28、 = average strength both rounds of Mixture No. 2 minusMixture No. 1,b = average strength both rounds of Mixture No. 3 minusMixture No. 2,c = (percent SO3in calcium sulfate)/100, andd = percent SO3in test cement.10. Retest10.1 Regard the results obtained as suspect and repeat thetest under any of the
29、 following conditions:10.1.1 If a and b both are positive and the ratio a/b is lessthan 2.00,10.1.2 If a and b both are negative and the ratio a/b isgreater than 0.500, or10.1.3 If a is negative and b is positive.11. Report11.1 If repeat tests confirm that the ratio of a/b departs fromthe limiting v
30、alues as stated above, report the SO3content ofthe cement as “above optimum” or “below optimum” as thedata may indicate, but without stating the numerical value ofoptimum SO3.11.2 If the test data indicate that the cement is “belowoptimum” but do not permit a computation of the percentage ofSO3requi
31、red for optimum, an additional series of testsinvolving greater substitutions of gypsum for part of thecement should yield results that will permit an acceptablecalculation of the percentage of SO3required for optimum. Ifthe test data indicate that the cement is “above optimum” butdo not permit a co
32、mputation of the percentage of SO3requiredfor optimum, in order to establish the required percentage ofSO3for optimum, it is necessary to make tests of a new sampleof similar cement but having an original SO3content lowerthan that of the original cement.11.3 Report the age of the test specimens.12.
33、Precision and Bias12.1 PrecisionThe coefficient of variation for this testmethod, using 6 cubes per batch, is very similar to that for TestC563072Method C 109/C 109M compression cubes tested at later ages.Refer to Test Method C 109/C 109M for suitable values.12.2 BiasSince there is no accepted refer
34、ence materialsuitable for determining optimum SO3, bias has not beendetermined.13. Keywords13.1 blended hydraulic cement; calcium sulfate; cement;compressive strength; gypsum; hydraulic cement; optimumsulfate content (of cement); portland cement; strength (ofcement); sulfate content (of cement)APPEN
35、DIX(Nonmandatory Information)X1. DISCUSSION OF THE TERM “OPTIMUM”X1.1 The scope statement notes that this test methoddetermines the optimum SO3content in cements in mortar at aparticular temperature and age. Usually, but not always, theSO3content that produces the highest 24-h strength at 23 Calso p
36、roduces approximately the lowest expansion in water andthe lowest contraction in air at that temperature.X1.2 The “optimum” determined by this test is approxi-mate. The “optimum” SO3content will vary with changes inmortar proportions; between cement paste, mortars and con-crete; will vary with the s
37、ource of SO3; with the age of test;with the use of chemical admixtures; and with the use ofsupplementary cementitious materials. Thus, the term “opti-mum SO3” refers to an approximate value.X1.3 The age for determining the optimum is typicallychosen by the manufacturer based on experience with local
38、concrete materials.X1.4 For convenience, the method uses the compressivestrength of specimens at three different SO3contents for thecement. If the strength results are plotted against SO3content,the three points are assumed to give a curve in the shape of aparabola, and the calculation used assumes
39、this shape. If morepoints are used with smaller SO3content increments, the shapeof the curve is seen to be that of a “sawtooth,” with adecreasing slope up to the apex at maximum strength, followedby a precipitous fall in strength immediately after the apex. Theapex represents the actual optimum SO3c
40、ontent, and istypically higher than that calculated using three points. There-fore, this affords a small “cushion” when targeting the calcu-lated optimum SO3(determined using three points) duringmanufacture to allow for variation in the process.SUMMARY OF CHANGESCommittee C01 has identified the loca
41、tion of selected changes to this test method since the last issue,C 563 04, which may impact the use of this test method. (Approved April 1, 2007)(1) Changed the titled to add the word “Approximate” andremove “24-h.”(2) Added 3- and 7-day testing options.(3) Added an appendix to provide a home for e
42、xplanatoryinformation, and moved appropriate text into the appendix.(4) Changed 6.5 to match Test Method C 109/C 109M provi-sions for storage, and made the corresponding change toSection 8.ASTM International takes no position respecting the validity of any patent rights asserted in connection with a
43、ny item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technica
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45、at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor
46、 Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).C563073
