《BS-812-101-1984.pdf》由会员分享,可在线阅读,更多相关《BS-812-101-1984.pdf(12页珍藏版)》请在三一文库上搜索。
1、BRITISH STANDARD BS 812-101:1984 Testing aggregates Part 101: Guide to sampling and testing aggregates UDC 625.07+691.22:620.1 BS 812-101:1984 This British Standard, having been prepared under the direction of the Cement, Gypsum, Aggregates and Quarry Products Standards Committee, was published unde
2、r the authority of the Board of BSI and comes into effect on 31 July 1984. BSI 11-1998 The following BSI references relate to the work on this standard: Committee reference CAB/2 Draft for comment 83/12686 ISBN 0 580 13878 X Committees responsible for this British Standard The preparation of this Br
3、itish Standard was entrusted by the Cement Gypsum Aggregates and Quarry Products Standards Committee (CAB/-) to Technical Committee CAB/2 upon which the following bodies were represented: Aggregate Concrete Block Association Association of Consulting Engineers Association of Consulting Scientists As
4、sociation of Lightweight Aggregate Manufacturers Brick Development Association British Aggregate Construction Materials Industries British Ceramic Research Association British Civil Engineering Test Equipment Manufacturers Association British Precast Concrete Federation Limited British Ready Mixed C
5、oncrete Association Calcium Silicate Brick Association Limited Cement and Concrete Association Cement Makers Federation Chartered Institute of Building Concrete Society County Surveyors Society Department of the Environment (Building Research Establishment) Department of the Environment (Property Se
6、rvices Agency) Department of the Environment (Transport and Road Research Laboratory) Department of Transport Electricity Supply Industry in England and Wales Federation of Civil Engineering Contractors Greater London Council Institute of Concrete Technology Institution of Civil Engineers Institutio
7、n of Highways and Transportation Institution of Public Health Engineers Institution of Structural Engineers Institution of Water Engineers and Scientists Mortar Producers Association Limited National Federation of Terrazzo-mosaic Specialists Natural Environment Research Council (Institute of Geologi
8、cal Science) Royal Institute of British Architects Sand and Gravel Association Limited Society of Chemical Industry Coopted member Amendments issued since publication Amd. No.Date of issueComments BS 812-101:1984 BSI 11-1998i Contents Page Committees responsibleInside front cover Forewordii 1Scope1
9、2Definitions1 3General2 4Significance of test results2 5Precision of test methods2 Table 1 Relationships4 Table 2 Characteristic test sieve4 Table 3 Sieve tests on coarse aggregate. % passing 10 mm5 Publications referred toInside back cover BS 812-101:1984 ii BSI 11-1998 Foreword This Part of this B
10、ritish Standard, prepared under the direction of the Cement, Gypsum, Aggregates and Quarry Products Standards Committee is a revision of clause 4 and appendix A of BS 812-1:1975, which are withdrawn by amendment. The remainder of the 1975 edition is being revised and as each of the tests, or collect
11、ion of related tests is revised it is intended to issue it as a separate Part or Section of this standard. It is intended that other British Standards should call up BS 812 test methods as the basis of compliance. Nevertheless, it is not intended that all aggregates should be subjected regularly to
12、all the listed tests. Specifications in other standards should call up only relevant test methods. Some of the tests in other Parts of this standard are of limited application, and advice on the use of simpler tests is given, for example when they can be used for a preliminary sorting of aggregates
13、to see whether more expensive testing is justified. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal ob
14、ligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 6, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table o
15、n the inside front cover. BS 812-101:1984 BSI 11-19981 1 Scope This Part of BS 812 gives general guidance on sampling and testing aggregates and procedures for assessing the precision of the tests described in other Parts of this standard. 2 Definitions For the purposes of this Part of BS 812 the de
16、finitions given in BS 812-102, together with the following apply. Other statistical terms have the meanings defined in BS 5532. 2.1 repeatability NOTEA lengthy discussion of this term is given in BS 5497. Briefly, repeatability is a measure of the within-laboratory variability of the results from a
17、test method. 2.1.1 repeatability r1) the value below which the absolute difference between two single test results obtained with the same method on identical test material under the same conditions (same operator, same apparatus, same laboratory and a short interval of time) may be expected to lie w
18、ith a probability of 95 % 2.1.2 repeatability r11) the value below which the absolute difference between two single test results obtained with the same method using different test portions of the same laboratory sample under the same conditions (same operator, same apparatus, same laboratory, and a
19、short interval of time) may be expected to lie with a probability of 95 % 2.2 reproducibility NOTEA lengthy discussion of this term is given in BS 5497. Briefly, reproducibility is a measure of the between-laboratory variability of the results of a test method. 2.2.1 reproducibility R1) the value be
20、low which the absolute difference between two single test results obtained with the same method on identical test material under different conditions (different operators, different apparatus, different laboratories and/or different time) may be expected to lie with probability of 95 % 2.2.2 reprodu
21、cibility R11) the value below which the absolute difference between two single test results obtained with the same method using different test portions of the same laboratory sample under different conditions (different operators, different apparatus, different laboratories and/or different time) ma
22、y be expected to lie with a probability of 95 % 2.2.3 reproducibility R21) the value below which the absolute difference between two single test results obtained with the same method using different laboratory samples from the same batch under different conditions (different operators, different app
23、aratus, different laboratories and/or different time) may be expected to lie with a probability of 95 % 2.3 single test result the value obtained by applying a standard test method fully, once NOTEA single test result may be a value derived from tests on a number of specimens, or the mean value of a
24、 number of observations, or the result of a calculation from a set of observations, as specified by the standard test method. The standard test method may require one or more test portions to be tested to obtain a single test result. 2.4 sampling error the error in a single test result arising from
25、known and acceptable deficiencies in both the sampling and sample reduction operations in obtaining a laboratory sample from a batch 2.5 sample reduction error the error in a single test result arising from known and acceptable deficiencies of the sample reduction operation in obtaining the test por
26、tion or test portions from a laboratory sample 2.6 variance a measure of dispersion based on the mean squared deviation from the arithmetic mean 1) According to the above definitions, r1 and R1 make allowance for sample reduction errors whereas r and R do not. In addition R2 makes allowances for sam
27、pling errors. With many aggregate tests it is not possible to carry out repeat tests on identical material so that r1, R1 and R2 are the measures of variability which will be of use in practice. BS 812-101:1984 2 BSI 11-1998 3 General Attention is drawn to the aim of sampling by the principal method
28、 given in Part 102 of this standard, i.e. to obtain a sample representative of the average quality. For other purposes it may be necessary to use a modified procedure. Special sampling procedures, for example to allow for the determination of the presence and quantity of occasional contaminants, are
29、 given in other Parts, when appropriate. Particular emphasis is placed on the need for proper reporting, and each test method requires a report including a certificate of sampling, (see BS 812-102). The test(s) have to be done in accordance with the relevant Part(s) and the reports have to affirm th
30、is. If any departure from specified sampling or test procedures is found to be necessary this has to be made clear on the report together with reasons and, if possible, an estimate of the effects. The report should also include details of any special processing of the sample, other than that require
31、d by the test methods, carried out in the laboratory, e.g. crushing to provide larger quantities of smaller sizes, or the separation of constituent sizes from a graded or blended aggregate. Each report should include all the information specified in the report clause in the appropriate Part includin
32、g precision estimates. Because the precision of testing has important consequences, the estimates of repeatability and reproducibility given have been established using the full procedures and recommendations of BS 5497 modified only as necessary to take account of the special nature of aggregates o
33、r the particular test methods (see clause 5). Aggregates may contain, or during handling, processing or testing may generate particles or fumes that could be injurious to health. It is essential that, in addition to ensuring that test equipment is properly guarded, appropriate precautions are taken
34、such as by the use of goggles, dust masks, dust containing and extracting facilities, or fume cupboards. 4 Significance of test results The applicability of test results depends on several factors and their interactions, e.g. the methods used for sampling and sample reduction, the number of samples
35、taken, the precision of the test method, the extent to which a test simulates reality. All these are capable of producing important effects often as great as real variations in the materials. Some tests described in BS 812 are not accurate measures of well defined properties but are included as usef
36、ul preliminary tests. This is to encourage a reduction in the mis-application of expensive and time consuming, but more accurate, methods which are not always justified. Information on the use of such preliminary tests is given in the appropriate Parts of the standard. Many of the tests described in
37、 BS 812 give a measure of the comparative behaviour of materials under the specified test regime. It is not necessarily implied that the results give a realistic indication of the behaviour of the material in practice. Guidance on the interpretation of test results is given in the appropriate Parts.
38、 Precision estimates of the test procedures are given in the appropriate Parts of the standard. Their application to the setting of compliance limits, data screening, and monitoring of laboratories is discussed in clause 5. 5 Precision of test methods 5.1 General. This clause describes how the preci
39、sion estimates given in other Parts of this British Standard may be used, and gives a method, involving tests on duplicate laboratory samples, which may be used to measure the variability arising from sampling errors. 5.2 Symbols. The symbols used in this clause are as follows: Na number of batches;
40、 a, bsingle test results obtained on the same laboratory sample; A, Blaboratory samples from the same batch; Dthe difference between two single test results obtained on the same laboratory sample; Mthe mean value of two single test results obtained on the same laboratory sample; overall mean of data
41、; VSvariance arising from sampling errors; VSrvariance arising from sample reduction errors; VLvariance arising from between-laboratory differences; Vr, Vr1repeatability variances; VR, VR1, VR2reproducibility variances; x BS 812-101:1984 BSI 11-19983 5.3 Relationships. Table 1 shows the relationship
42、s between repeatability and reproducibility and their variances, and also how the sampling, sample reduction and laboratory variances contribute to the repeatability and reproducibility variances. 5.4 Uses of repeatability 5.4.1 General. Pairs of single test results obtained under appropriate repeat
43、ability conditions from the same laboratory sample are required. If the intention is to consider the results of the tests without a contribution from sample reduction error, steps should be taken to ensure that sample reduction error does not contribute to differences between pairs of results. In th
44、is case the differences would be compared with r. This is possibly only when the test portion is not changed by the test method and thus can be used again for the second test. Alternatively, if the intention is to consider results that include sample reduction errors, each test portion should be obt
45、ained from its laboratory sample by a separate sample reduction operation. In this case the differences would be compared with r1. 5.4.2 Data screening. This procedure will be appropriate when the tests can be repeated in a reasonable time and at a reasonble cost. A pair of single test results shoul
46、d be rejected and the tests repeated if the difference between them exceeds r or r1. 5.4.3 Laboratory monitoring. When the same test is carried out regularly in a laboratory it is recommended that pairs of single test results should be obtained and the differences compared with r or r1 to check the
47、standard of testing in the laboratory. 20 or more pairs of test results are sufficient to allow a reliable assessment to be made. 5.5 Uses of reproducibility 5.5.1 Laboratory comparisons. If it is required to carry out a comparison of two laboratories assuming no sampling errors, the laboratories sh
48、ould use test portions obtained from the same laboratory sample, and the difference between the two single test results should be compared with R1. When two laboratories apply the same test method to different laboratory samples of the same batch of material, the difference between their two single
49、test results should be compared with R2. If the differences is greater than R2, the following should be investigated. a) The test procedures, including sample reduction, and the apparatus used in both laboratories should be examined thoroughly to eliminate errors, and the tests repeated on the same laboratory samples. b) The sampling procedure should be reviewed and the tests repeated using new bulk samples. c) Where the aggregate presents sampling problems (as in the case of aggregate prone to severe segregation and sampled from heaps), the value of R2 should be recal
链接地址:https://www.31doc.com/p-3736369.html