1、Designation: C563 13C563 15Standard Test Method forApproximation of Optimum SO3 in Hydraulic Cement UsingCompressive Strength1This 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,
2、 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. Scope*Scope1.1 This test method describes the determination of approximate optimum SO3 for maximum compressive str
3、ength at 24 h, 3days, or 7 days by measuring the change in strength produced in hydraulic cement mortar as a result of substituting calcium sulfatefor a portion of the cement.1.2 This test method refers to the sulfur trioxide (SO3) content of the cement only. Slag cements and occasionally otherhydra
4、ulic cements can contain sulfide or other forms of sulfur. The determination of SO3 content by rapid methods may includethese other forms, and may therefore produce a significant error. If a significant error occurs, analyze the cement for SO3 contentusing the reference test method of Test Methods C
5、114 for 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 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 an
6、d determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C109/C109M Test Method for Compressive Strength of Hydraulic Cement Mortars (Using 2-in. or 50-mm Cube Specimens)C114 Test Methods for Chemical Analysis of Hydraulic CementC150 Specificatio
7、n for Portland CementC204 Test Methods for Fineness of Hydraulic Cement by Air-Permeability ApparatusC305 Practice for Mechanical Mixing of Hydraulic Cement Pastes and Mortars of Plastic ConsistencyC471M Test Methods for Chemical Analysis of Gypsum and Gypsum Products (Metric)C511 Specification for
8、Mixing Rooms, Moist Cabinets, Moist Rooms, and Water Storage Tanks Used in the Testing of HydraulicCements and ConcretesC595 Specification for Blended Hydraulic CementsC778 Specification for SandC1157 Performance Specification for Hydraulic CementC1437 Test Method for Flow of Hydraulic Cement Mortar
9、3. Significance and Use3.1 The purpose of this test method is to estimate the SO3 content for a hydraulic cement that gives maximum compressivestrength in mortar made and cured at 23 C. 23C. The value obtained is one way to establish an appropriate level of sulfate inthe manufacture of cements speci
10、fied in Specifications C150, C595 and C1157.3.2 The SO3 content of a cement giving maximum compressive strength is different at different ages of mortar; typically thisSO3 content is higher at 3 days than the 24-h, and often higher for 7 days than that for 3 days. A manufacturer can choose the ageof
11、 24-h, 3 days or 7 days for specimens at which to determine optimum SO3 content.1 This test method is under the jurisdiction of ASTM Committee C01 on Cement and is the direct responsibility of Subcommittee C01.28 on Sulfate ContentCurrent edition approved Jan. 1, 2013Sept. 1, 2015. Published Februar
12、y 2013October 2015. Originally approved in 1965. Last previous edition approved in 20072013 asC563C563 13.-07. DOI: 10.1520/C0563-13.10.1520/C0563-15.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Stand
13、ardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible
14、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 published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyrigh
15、t ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.3 This test method indicates optimum SO3 content for cement in mortar made and cured at a standard temperature of 23.0 62.0 C 2.0C (73.5 6 3.5 F). 3.5F). The optimum SO3 increases with increas
16、ing temperature and may increase whenwater-reducing admixtures are used.3.4 It should not be assumed that the optimum SO3 estimated in this test method is the same SO3 content for optimumperformance of a concrete prepared from the cement.3.5 The test method is applicable to cements specified in Spec
17、ifications C150, C595, and C1157.4. Apparatus4.1 Use the apparatus as specified in Test Method C109/C109M.5. Materials5.1 Calcium SulfateUse calcium sulfate for addition to the cement that is either a high-grade natural gypsum having an SO3content of at least 46 %, or the calcium sulfate from the so
18、urce used for the intended plant production. Grind the calcium sulfateto 100 % passing the 75-m (No. 200) sieve, and at least 800 m2/kg Blaine fineness (Test Method C204). If the SO3 content ofthe calcium sulfate is unknown, analyze it in accordance with Test Methods C471M.5.2 BlendedGraded Standard
19、 SandUse graded sand conforming to Specification C778.6. Test Specimens6.1 Make six specimens from each batch of mortar. Make two rounds of three mixtures of mortar as described in 6.3. Make bothrounds during the same day if possible. Make only complete rounds on any given day.6.2 Preparing Specimen
20、 MoldsPrepare molds in accordance with the section on Preparation of Specimen Molds of TestMethod C109/C109M.6.3 Proportioning, Consistency, and Mixing of MortarProportion the dry material for the standard mortar as one part ofcement to 2.75 parts graded sand by mass. Mix the following quantities of
21、 dry materials at one time for a 6-cube batch:Mixture No. 1 500 g cementMixture No. 1 500 g cement1375.0 g graded sand1375.0 g graded sandMixture No. 2 494.6 g cementMixture No. 2 494.6 g cement5.3 g calcium sulfate1375.0 g graded sand1375.0 g graded sandMixture No. 3 489.2 g cementMixture No. 3 489
22、.2 g cement10.6 g calcium sulfate10.6 g calcium sulfate1375.0 g graded sand1375.0 g graded sand6.3.1 Use an amount of mixing water to produce a flow of 110 6 5 using 25 drops of the table as determined in the sectionon Procedures in Test Method C1437 for all types of cement.6.3.2 Mix mechanically in
23、 accordance with the section on Procedure for Mixing Mortars of Practice C305, except as follows:6.3.2.1 Add the calcium sulfate to the water; then start the mixer and mix at slow speed (140 6 5 rpm) for 15 s; then stop themixer and add the cement to the water; then start the mixer and mix at slow s
24、peed (140 6 5 rpm) for 30 s.6.4 Molding of Test SpecimensMold specimens in accordance with the Procedure Section of Test Method C109/C109M.6.5 Storage of Test SpecimensImmediately upon completion of molding, place the test specimens in the moist closet or moistroom. Keep all test specimens, immediat
25、ely after molding, in the molds on the base plates in the moist closet or moist room for20 to 24 h with their upper surfaces exposed to the moist air but protected from dripping water. If the specimens are removed fromthe molds before 24 h, keep them on the shelves of the moist closet or moist room
26、until they are 24-h old and then immerse thespecimens, except those for the 24-h test, in saturated lime water in storage tanks constructed of noncorroding materials until theage chosen for the test. Keep the storage water clean by changing as required.7. Temperature and Humidity7.1 The temperature
27、and humidity of the moist cabinet or moist room shall be as specified in Specification C511.7.2 The temperature and humidity of the mixing room shall be as specified in Test Method C109/C109M.C563 1528. Procedure8.1 Test the specimens at the age of 24 6 14 h, 3 days 6 1 h, 1 h, or 7 days 6 3 h, from
28、 the time the cement and water madecontact during mixing, immediately after removal from storage in accordance with Test Method C109/C109M. If more than onespecimen at a time is removed from storage, keep these specimens covered with a damp cloth until time of testing. Note andobserve precautions re
29、garding testing and retesting given in the applicable sections of Test Method C109/C109M.9. Calculation9.1 Calculate and record the strength of specimens as described in the section on Calculation in Test Method C109/C109M.9.1.1 Calculate the indicated optimum SO3 content as follows:G 5a/a 2b!# c1d1
30、c/2where:G = optimum percent SO3,a = average strength both rounds of Mixture No. 2 minus Mixture No. 1,b = average strength both rounds of Mixture No. 3 minus Mixture No. 2,c = (percent SO3 in calcium sulfate)/100, andd = percent SO3 in test cement.10. Retest10.1 Regard the results obtained as suspe
31、ct and repeat the test under any of the following conditions:10.1.1 If a and b both are positive and the ratio a/b is less than 2.00,10.1.2 If a and b both are negative and the ratio a/b is greater than 0.500, or10.1.3 If a is negative and b is positive.11. Report11.1 If repeat tests confirm that th
32、e ratio of a/b departs from the limiting values as stated above, report the SO3 content of thecement as “above optimum” or “below optimum” as the data may indicate, but without stating the numerical value of optimumSO3.11.2 If the test data indicate that the cement is “below optimum” but do not perm
33、it a computation of the percentage of SO3required for optimum, an additional series of tests involving greater substitutions of gypsum for part of the cement should yieldresults that will permit an acceptable calculation of the percentage of SO3 required for optimum. If the test data indicate that t
34、hecement is “above optimum” but do not permit a computation of the percentage of SO3 required for optimum, in order to establishthe required percentage of SO3 for optimum, it is necessary to make tests of a new sample of similar cement but having an originalSO3 content lower than that of the origina
35、l cement.11.3 Report the age of the test specimens.12. Precision and Bias12.1 PrecisionThe coefficient of variation of strength values for this test method, using 6 cubes per batch, is very similar tothat for Test Method C109/C109M compression cubes tested at later ages. Refer to Test Method C109/C1
36、09M for suitable values.No data currently exist for the precision of the estimate for optimum sulfate content.12.2 BiasSince there is no accepted reference material suitable for determining optimum SO3, bias has not been determined.13. Keywords13.1 blended hydraulic cement; calcium sulfate; cement;
37、compressive strength; gypsum; hydraulic cement; optimum sulfatecontent (of cement); portland cement; strength (of cement); sulfate content (of cement)C563 153APPENDIX(Nonmandatory Information)X1. DISCUSSION OF THE TERM “OPTIMUM”X1.1 The scope statement notes that this test method determines the opti
38、mum SO3 content in cements in mortar at a particulartemperature and age. Usually, but not always, the SO3 content that produces the highest 24-h strength at 23 C 23C also producesapproximately the lowest expansion in water and the lowest contraction in air at that temperature.X1.2 The “optimum” dete
39、rmined by this test is approximate. The “optimum” SO3 content will vary with changes in mortarproportions; between cement paste, mortars and concrete; will vary with the source of SO3; with the age of test; with the use ofchemical admixtures; and with the use of supplementary cementitious materials.
40、 Thus, the term “optimum SO3” refers to anapproximate value.X1.3 The age for determining the optimum is typically chosen by the manufacturer based on experience with local concretematerials.X1.4 For convenience, the method uses the compressive strength of specimens at three different SO3 contents fo
41、r the cement. Ifthe strength results are plotted against SO3 content, the three points are assumed to give a curve in the shape of a parabola, andthe calculation used assumes this shape. If more points are used with smaller SO3 content increments, the shape of the curve isseen to be that of a “sawto
42、oth,” with a decreasing slope up to the apex at maximum strength, followed by a precipitous fall instrength immediately after the apex. The apex represents the actual optimum SO3 content, and is typically higher than thatcalculated using three points. Therefore, this affords a small “cushion” when t
43、argeting the calculated optimum SO3 (determinedusing three points) during manufacture to allow for variation in the process.SUMMARY OF CHANGESCommittee C01 has identified the location of selected changes to this test method since the last issue,C563 07, which may impact the use of this test method.
44、(Approved January 1, 2013)(1) In Section 3.1 the following statement was removed: “In Specifications C150 and C595 it is used to justify exceeding theprescriptive limits for SO3.”(2) Section 12.1 was revised to reflect lack of precision data.ASTM International takes no position respecting the validi
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