1、Designation: C 1451 05Standard Practice forDetermining Uniformity of Ingredients of Concrete From aSingle Source1This standard is issued under the fixed designation C 1451; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year o
2、f 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. Scope1.1 This practice covers a procedure for determining theuniformity of properties of concrete materials from a singlesou
3、rce. It includes recommendations on sampling, testing,analysis of data, and reporting.1.2 The values stated in SI units are to be regarded as thestandard.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 t
4、his 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:2C 109/C 109M Test Method for Compressive Strength ofHydraulic Cement Mortars (Using 2-in. or 50-mm CubeSpecimens)C 125
5、 Terminology Relating to Concrete and ConcreteAggregatesC 219 Terminology Relating to Hydraulic CementC 294 Descriptive Nomenclature for Constituents of Con-crete AggregatesC 494/C 494M Specification for Chemical Admixtures forConcreteC 638 Descriptive Nomenclature of Constituents of Aggre-gates for
6、 Radiation Shielding ConcreteC 917 Test Method for Evaluation of Cement StrengthUniformity from a Single SourceD75 Practice for Sampling AggregatesD 3665 Practice for Random Sampling of ConstructionMaterials2.2 Other DocumentMNL 7 (STP 150) Manual on Presentation of Data andControl Chart Analysis, 6
7、th edition3. Terminology3.1 DefinitionsFor definitions of terms relating to thispractice refer to Terminology C 125, Terminology C 219,Descriptive Nomenclature C 294, and Descriptive Nomencla-ture C 638.3.2 Definitions of Terms Specific to This Standard:3.2.1 lot, na user-defined quantity, typically
8、 representingany amount of material for which uniformity information is tobe calculated.3.2.1.1 DiscussionThe minimum lot size is generally theamount of material in a single conveyance, such as a truckload, a rail-car load, or a barge load. At the other extreme, a lotmight be defined by a user as th
9、e total amount of material usedin a single construction or by a supplier as the amount ofmaterial produced over a given interval of time.3.2.2 sampling unit, namount of material from which agrab sample is taken.3.2.2.1 DiscussionGenerally a lot is subdivided into sam-pling units, and then sampling u
10、nits are chosen at random fortaking of grab samples. The size of the sampling unit isuser-defined, depending on the purposes of the evaluation. Theterm sub lot is sometimes used to define this concept.4. Significance and Use4.1 This practice provides a systematic procedure for sam-pling and determin
11、ing the uniformity of user-selected proper-ties of ingredients of concrete. Results derived from applica-tion of the practice are generally intended for information onlyand are not requirements of any existing ASTM specificationon concrete or concrete materials. A concrete materials speci-fication m
12、ay make reference to this practice as a means ofobtaining uniformity information, but needs to define theproperties to be measured and the lot size and sample unit to beused. The practice is applicable to both producers of concretematerials and to consumers of concrete materials, althoughdetails of
13、application of the practice may vary, depending onthe intended purpose of the user of the practice.4.2 The procedure is applicable to any property of anyconcrete ingredient that can be described quantitatively, and forwhich conventional parametric statistics are applicable. The1This practice is unde
14、r the jurisdiction of ASTM Committee C09 on Concreteand ConcreteAggregates and is the direct responsibility of Subcommittee C09.94 onEvaluation of Data.Current edition approved Nov. 1, 2005. Published November 2005. Originallyapproved in 1999. Last previous edition approved in 1999 as C 1451 99.2For
15、 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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700
16、, West Conshohocken, PA 19428-2959, United States.procedure is based on grab samples, which will tend to showthe maximum amount of variation in the selected materialproperty. The procedure was developed for application tomaterials from a single source, but it can be applied to amaterials delivery st
17、ream from more than one source, depend-ing on the purposes of the user of the practice. Calculations arecorrected for testing error, therefore giving an estimate of theuniformity of the selected material property. The uniformity ofthe selected material property provides the user with oneindicator of
18、 the source variation of the concrete ingredient.4.3 Although variability in properties of concrete materialscan be a significant cause of variability in concrete properties,this practice does not purport to give information on thisrelationship. This practice does give information on uniformityof in
19、gredients from which the user can, along with supplemen-tary information or correlative testing of concrete properties,develop quantitative estimates of the effects.5. Sampling5.1 The sampling plan underlying the analysis of uniformityis critical to the interpretation of results. The sampling plan w
20、illvary, depending on the details of concrete materials supply anduser-defined purpose of the evaluation. The sampling planshould, at a minimum, address the lot size and samplingfrequency, location and procedure of sampling from samplingunit, and handling of samples. All sampling is to be performedb
21、y personnel specifically trained for this purpose.5.2 The first step in determining the sampling plan is todefine the objective and scope of the evaluation. This requiresconsiderable experience and knowledge of details involvedwith the particular production under evaluation. The objectiveand scope o
22、f the evaluation may vary between users andproducers of materials. It may also range from determining theuniformity of materials during a relatively small productionperiod to covering a very long production period. If there is noprior knowledge of the uniformity of a material property, or ifit is su
23、spected that the material might show considerablevariation, a relatively intense sampling plan might be designedinitially. If the prior knowledge indicates that the materialproperty is relatively stable, then a less intense sampling planmight be designed.5.3 The second step is to define the size of
24、the lot and thesize of the sampling unit (see 3.2). Typically a lot is dividedinto a number of sampling units; then sampling units areselected at random for the taking of grab samples. Typically,the number of sampling units is larger than the number actuallysampled, although for small lot sizes, the
25、 number of samplingunits may equal the number of samples being taken.5.4 Take random grab samples from a point in the storageand handling process of the material that will accurately reflectthe uniformity of the material as it will be used in concrete.Practice D 3665 provides general guidance. Addit
26、ional guid-ance for specific materials is listed in 5.4.1-5.4.4. Identifysamples by the date on which the material was shipped orreceived, its source, and designated type and applicable speci-fications.5.4.1 Sample cement in accordance with Test MethodC 917.5.4.2 Sample fine and coarse aggregates in
27、 accordance withPractice D75.5.4.3 Sample chemical admixtures in accordance withSpecification C 494/C 494M.5.4.4 Sample pozzolan or ground granulated blast-furnaceslag in accordance with Test Method C 917.5.5 The required sampling frequency depends on how thedata are being used and the nature of the
28、 material beingevaluated. The sampling plan used should be described in thereport (Section 8).6. Procedure6.1 GeneralTest all samples in accordance with the ap-propriate ASTM Test Method for the particular property beingmeasured. Choose a property and method that has goodprecision so that the materi
29、al uniformity is not masked by thetesting error. It is also advisable to select a method that doesnot incur significant cost and is conducted frequently so theoperators are proficient with the procedure. Variation within asingle source is estimated by first calculating total variationfrom test data
30、on grab samples, and then correcting this bysubtracting variation inherent in the test method (testing error).Best results are obtained if all tests are conducted in the samelaboratory, but guidance is provided if it is necessary to usedata from more than one laboratory.6.2 Total VariationTest all s
31、amples in accordance with theappropriate ASTM Standard Test Method for the particular testproperty being measured. Choose a property and method thathas good precision so that the material uniformity is notmasked by the testing error. It is also advisable to select amethod that does not incur signifi
32、cant cost and is conductedfrequently so the operators are proficient with the procedure.Calculate the total variation among the samples, as directed in7.1.2.6.3 Testing ErrorTesting error is composed of compo-nents due to within-laboratory variation and between-laboratory variation. If results are o
33、btained from only onelaboratory, then between-laboratory variation makes no contri-bution. If data are obtained from more than one laboratory, it ispreferable to keep data from each one separate during dataanalysis, pooling estimates of variation at the end of theanalysis.6.3.1 To estimate within-la
34、boratory testing error, duplicatetests made from a single sample are required. Samples must betested in duplicate on different days until at least ten sampleshave been tested in duplicate. The rate of duplicate testsinitially should be at least once in five samples and not lessfrequently than once p
35、er month. Calculate the testing errorstandard deviation and the coefficient of variation, as outlinedin 7.1.3. If the testing error exceeds the single laboratoryprecision (1s or 1s%) reported in the precision statement for theapplicable test method, but is less than 1.5 times this value,continue dup
36、licate tests at this same rate. When the testingerror is equal to or less than the testing error reported in theprecision statement, reduce the frequency of duplicate testing.If the testing error exceeds 1.5 times the testing error reportedin the precision statement, the data are of unacceptableprec
37、ision, and the laboratory procedure and equipment shouldbe thoroughly examined. Use the results of duplicate tests,C1451052indicating acceptable precision to estimate the within-laboratory testing error for all other types of similar materialstested in that laboratory during the same period of time.
38、6.3.2 When two or more laboratories are used to evaluatethe uniformity of a source, then additional tests of a standardsample or exchanged portions of the same sample may benecessary to determine differences in testing that are likely tobe obtained in the different laboratories. When two laboratorie
39、sexchange portions of the sample and run single tests, resultsfrom the laboratories shall not differ by more than the multi-laboratory precision (D2S value) of the average of the twolaboratories. If a larger number of samples are exchanged, thenthe difference between laboratories exceed the D2S no m
40、orethan 5 % of the time.6.3.3 Calculate the testing error from duplicate tests con-ducted in each laboratory as outlined in 7.1.3.6.4 Single-Source VariationCalculate single-source varia-tion according to 7.1.4.7. Calculation7.1 The calculations shall include the following (Note 1):NOTE 1Values for
41、averages and standard deviations can be calculatedby other methods that are available in MNL 7 (STP 150). Electroniccalculators and spreadsheets are available for obtaining these statisticsdirectly.7.1.1 Average Measurement:x 5x11 x21 . 1 xnn(1)where:x = average measurement,x1,x2, . xn= individual m
42、easurements, andn = number of individual tests.7.1.2 Standard Deviation:st5x1 x!21 x2 x!21 . 1 xn x!2n 1!(2)where:st= standard deviation in units of measurement.7.1.3 Testing Error:7.1.3.1 The standard deviation for testing error is calculatedas follows (See Table 1):se5(d22k(3)where:se= standard de
43、viation for testing error estimated fromtests of duplicate measurements made in a singlelaboratory from the sample,d = difference between duplicate determinations, andk = number of sets of duplicate determinations.7.1.3.2 The coefficient of variation for testing error iscalculated as follows,ve5sexd
44、(4)where:ve= coefficient of variation for testing error estimated fromtests of duplicate measurements made in a singlelaboratory from the sample, andxd= average measurement from duplicate tests.7.1.4 Single-Source Variation:7.1.4.1 Variation of material from a single source expressedin terms of stan
45、dard deviation, corrected for testing error, iscalculated as follows:sc5 =st2 se2(5)where:sc= standard deviation corrected for testing error,st= standard deviation for all tests included in the calcu-lation, andse= standard deviation for testing error estimated fromtests of duplicate measurements ma
46、de in a singlelaboratory from the sample.7.1.4.2 When data are collected from two laboratories,calculate the pooled single-source standard deviation as fol-lows:sc5n11!sc121 n21!sc22n11 n22(6)where:sc= pooled estimate of single-source standarddeviationsc1and sc2= standard deviation corrected for tes
47、ting errorfrom lab 1 and lab 2, respectively, andn1and n2= number of tests in lab 1 and lab 2, respec-tively.7.1.4.3 Single-source variation expressed as coefficient ofvariation, corrected for testing error, is calculated as follows:vc5scx(7)8. Report8.1 Sufficient information shall be provided to i
48、dentify thematerial sampled including the following:8.1.1 Name of manufacturer and location,8.1.2 Classification or type of material,TABLE 1 Example Illustrating Calculation of Testing ErrorDate Samp. No. Test “a,”MPaTest “b,”MPaAverage,MPad201/06 3 43.9 45.7 44.8 2.9701/16 6 43.1 41.5 42.3 2.5201/3
49、0 9 41.7 42.2 42.0 0.2302/05 12 41.5 43.0 42.2 2.1002/13 15 38.6 37.4 38.0 1.5402/21 18 37.9 38.1 38.0 0.0403/04 21 43.6 43.3 43.4 0.0803/14 24 40.8 41.4 41.1 0.3903/19 27 43.4 41.7 42.6 2.9703/27 30 43.8 44.2 44.0 0.17k = 10 Average, xd= 41.9(d213.0Testing Standard Deviation, se0.81Testing Coefficient of Variation, ve1.9 %C14510538.1.3 Location of sampling,8.1.4 Laboratory designation,8.1.5 Period of time represented by the report, and8.1.6 Description of sampling frequency.8.2 For ongoing programs, the minimum period covered bythe report shal
