1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS 812 : Part 2 : 1995 In
2、corporating Amendments Nos. 1 and 2 Corrected and reprinted, March 1999 Correction Page 3 In 5.4.4 2nd para., the second word “apparent” should be deleted. ICS 91.100.15 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Testing aggregates Part 2. Methods of determination of dens
3、ityBS 812 : Part 2 : 1995 Issue 3, February 1999 This British Standard, having been prepared under the direction of the Sector Board for Building and Civil Engineering, was published under the authority of the Standards Board and comes into effect on 15 August 1995 BSI 02-1999 First published August
4、 1975 Second edition August 1995 Third edition February 1999 The following BSI references relate to the work on this standard: Committee reference B/502 Draft for comment 94/106633 DC ISBN 0 580 24257 9 Amendments issued since publication Amd. No. Date Text affected 9195 September 1996 Indicated by
5、a sideline in the margin 10379 February 1999 Indicated by a sideline Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee B/502, Aggregates, upon which the following bodies were represented: Aggregate Concrete Block Associatio
6、n Association of Consulting Engineers Association of Lightweight Aggregate Manufacturers British Aggregate Construction Materials Industries British Cement Association British Civil Engineering Test Equipment Manufacturers Association British Geological Sciences British Iron and Steel Producers Asso
7、ciation British Precast Concrete Federation Ltd. British Ready Mixed Concrete Association County Surveyors Society Department of the Environment Department of the Environment (Building Research Establishment) Department of Transport Department of Transport (Transport Research Laboratory) Electricity
8、 Association Institute of Concrete Technology Institution of Civil Engineers Institution of Highways and Transportation Institution of Structural Engineers Local Authority Organizations Sand and Gravel Association Limited Society of Chemical Industry The following bodies were also represented in the
9、 drafting of this standard, through subcommittees and panels: Department of Trade and Industry (National Measurement Accreditation Service) Department of Transport (Highways Agency)Issue 3, February 1999 BS 812 : Part 2 : 1995 BSI 02-1999 a Summary of pages The following table identifies the current
10、 issue of each page. Issue 1 indicates that a page has been introduced for the first time by amendment. Subsequent issue numbers indicate an updated page. Vertical sidelining on replacement pages indicates the most recent changes (amendment, addition, deletion). Page Issue Page Issue Front cover Ins
11、ide front cover a b i ii 1 2 3 3 3 3 blank original 2 original original 4 4t o9 10 11 12 13 14 Inside back cover Back cover original 3 original original 2 original original 3b blankBS 812 : Part 2 : 1995 i Contents Page Committees responsible Inside front cover Foreword ii Methods 1 Scope 1 2 Refere
12、nces 1 3 Reporting 1 4 Significance of results 1 5 Determination of particle densities and water absorption 1 6 Determination of bulk density, voids and bulking 8 Annex A (informative) Repeatability and reproducibility of test results 13 Tables 1 Details of containers to be used for the bulk density
13、 tests 9 A.1 Estimates of repeatability and reproducibility 14 Figures 1 Section of a pyknometer made from a preserving jar 4 2 Estimation of free-running condition of fine aggregate 6 3 Filler compaction apparatus 11ii BSI 02-1999 BS 812 : Part 2 : 1995 Issue 2, February 1999 | | Foreword This Part
14、 of BS 812 has been prepared by Technical Committee B/502. This edition introduces technical changes but does not reflect a full review or revision of the standard. Work on testing procedures for aggregates is being carried out in Europe under the auspices of CEN/TC 154, Aggregates. The methods desc
15、ribed in this Part of BS 812 are included in the programme of work of CEN/TC 154 and will be superseded by European Standards which will be published in due course. This standard supersedes BS 812 : Part 2 : 1975, which is withdrawn. In this edition, for health and safety reasons, the use of toluene
16、 has been replaced by the use of kerosene in the method for the determination of bulk density of filler. The tests described in this Part are now based on particle density rather than relative density and, because the determination of moisture content of aggregates, formerly included in this Part, i
17、s now covered by BS 812 : Part 109, the title of the 1975 edition, Methods for determination of physical properties is no longer appropriate and has been amended to reflect the revised content. The opportunity has also been taken to update references to other Parts of BS 812 that have been published
18、 following the 1975 revision of this Part. BS 812 comprises the following Parts: Part 100 General requirements for apparatus and calibration Part 101 Guide to sampling and testing aggregates Part 102 Methods for sampling Part 103 Methods for determination of particle size distribution Part 104 Metho
19、d for qualitative and quantitative petrographic examination of aggregates Part 105 Methods for determination of particle shape Part 106 Method for determination of shell content in coarse aggregate Part 109 Methods for determination of moisture content Part 111 Methods for determination of ten per c
20、ent fines values (TFV) Part 112 Methods for determination of aggregate impact value (AIV) Part 113 Method for determination of aggregate abrasion value (AVV) Part 114 Method for determination of the polished-stone value Part 117 Method for determination of water-soluble chloride salts Part 118 Metho
21、ds for determination of sulphate content Part 119 Method for determination of acid-soluble material in fine aggregate Part 120 Method for testing and classifying drying shrinkage of aggregates in concrete Part 121 Method for determination of soundness Part 124 Method for determination of frost-heave
22、 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 obligations.1 BS 812 : Part 2 : 1995 Methods 1 Scope
23、This Part of BS 812 describes methods for the determination of the particle density, water absorption, bulk density, voids and bulking of aggregates and of the particle density, bulk density and voids of filler. Some of the tests are intended for use in obtaining assurance that material complies wit
24、h British Standard or other requirements, for research, production control or assessment of variation. However, other methods are not intended for assurance testing and their suitability for other purposes is defined. NOTE. The density terms used are defined in clause 2 of BS 812 : Part 100 : 1990.
25、2 References 2.1 Normative references This Part of BS 812 incorporates, by dated or undated reference, provisions from other publications. These normative references are made at the appropriate places in the text and the cited publications are listed on the inside back cover. For dated references, o
26、nly the edition cited applies; any subsequent amendments to or revisions of the cited publication apply to this Part of BS 812 only when incorporated in the reference by amendment or revision. For undated references, the latest edition of the cited publication applies, together with any amendments.
27、2.2 Informative references This Part of BS 812 refers to other publications that provide information or guidance. Editions of these publications current at the time of issue of this standard are listed on the inside back cover, but reference should be made to the latest editions. 3 Reporting 3.1 Gen
28、eral The report shall affirm that the tests were done in accordance with this standard. Any departure from the specified test procedure shall be described with reasons for the departure and, if possible, estimates of its effect on the test results. The report shall also include details of any specia
29、l processing of the sample, other than that required by the test methods, carried out in the laboratory, e.g. crushing to provide larger quantities of smaller sizes or the separation of constituents from an as-dug gravel. 3.2 Certificate of sampling The report shall affirm that a certificate of samp
30、ling was received with the sample and shall declare all the information given on the certificate. If a certificate was not received this shall be stated in the report. 4 Significance of results The distribution of the results of any test on any material stems from a number of contributing factors. I
31、n assessing the significance of the results the repeatability and reproducibility of the test should be recognized. Estimates of these are given in annex A and should be used in assessing test results. 5 Determination of particle densities and water absorption 5.1 General Three main methods are desc
32、ribed for aggregates, a wire basket method for aggregates larger than 10 mm, a gas jar method for aggregates between 40 mm and 5 mm and a pyknometer or gas jar method for aggregates 10 mm nominal size and smaller. A buoyancy method using a bucket, as described in BS 1881, is allowed as an alternativ
33、e for aggregates between 40 mm and 5 mm nominal size. The method for filler is by use of a density bottle. As with any porous material the value obtained for the particle density of an aggregate depends on the details of the method of test. Furthermore, different sizes of the same aggregate often ha
34、ve different values of particle density and absorption. Therefore, when comparing different aggregates it is essential that the test be made on samples sensibly of the same grading. The wire basket method for aggregates larger than 10 mm is not suitable for testing friable aggregates which may break
35、 down during the test, and therefore the gas jar method for aggregates between 40 mm and 5 mm should be used for such material. 5.2 Sampling The sample for these tests shall be taken in accordance with BS 812 : Part 102. 5.3 Method for aggregates all larger than 10 mm 5.3.1 Apparatus NOTE. All appar
36、atus described should conform to the general requirements of BS 812 : Part 100. 5.3.1.1 Balance, of capacity not less than 3 kg, accurate to 0. 5 g, and of such a type and size as to permit the basket containing the sample to be suspended from the beam and weighed in water. 5.3.1.2 Well ventilated o
37、ven, thermostatically controlled to maintain a temperature of 105 C 5 C.2 BS 812 : Part 2 : 1995 5.3.1.3 Wire mesh basket, having apertures not larger than 6.5 mm, or a perforated container of convenient size, preferably chromium plated and polished, with wire hangers (not thicker than 1 mm) suspend
38、ing it from the balance. 5.3.1.4 Stout watertight container, in which the basket may be freely suspended. 5.3.1.5 Two dry soft absorbent cloths, each no less than 750 mm3 450 mm. 5.3.1.6 Shallow tray, of area not less than 0.065 m 2 . 5.3.1.7 Airtight container, of similar capacity to the basket. 5.
39、3.1.8 10 mm BS test sieve (see 5. 4 of BS 812 : Section 103.1 : 1985). 5.3.1.9 Supply of water, free from any impurity (e.g. dissolved air) that would significantly affect its density. If distilled or deionized water is not available in sufficient quantity, tap water which has been freshly boiled an
40、d cooled to room temperature may be used. This water shall be used throughout the test. 5.3.2 Sample for test A sample of not less than 2 kg of aggregate shall be tested. Aggregates which have been artificially heated shall not normally be used; if such material is used, the fact shall be stated in
41、the report. Two tests shall be made. The sample for test shall be thoroughly washed on the test sieve to remove finer particles and drained. 5.3.3 Test procedure Place the prepared test sample in the wire basket and immerse it in the water (5.3.1.9)a ta temperature of 20 C 5 C with a cover of at lea
42、st 50 mm of water above the top of the basket. Immediately after immersion remove the entrapped air from the sample by lifting the basket containing it 25 mm above the base of the tank and allowing it to drop 25 times at a rate of about one per second. The basket and aggregate shall remain completel
43、y immersed during this operation and for a period of 24 h 0.5 h. Again jolt the basket and sample and weigh them in water at a temperature of 20 C 5 C. If it is necessary for them to be transferred to a different tank for weighing, jolt them 25 times as described above in the new tank before weighin
44、g (mass B). Then remove the basket and aggregate from the water and allow them to drain for a few minutes, after which gently empty the aggregate from the basket on to one of the dry cloths, and return the empty basket to the water, jolt it 25 times and weigh it in water (mass C). With the cloth, ge
45、ntly surface-dry the aggregate placed on the dry cloth, transferring it to a second dry cloth when the first will remove no further moisture. Then spread it out not more than one stone deep on the second cloth, and leave it exposed to the atmosphere away from direct sunlight or any other source of h
46、eat until all visible films of water are removed, but the aggregate still has a damp appearance. Weigh the aggregate (mass A) . If the apparent particle density only is required the operations described in this paragraph may be omitted. Place the aggregate in the oven in the shallow tray at a temper
47、ature of 105 C 5 C and maintain it at this temperature for 24 h 0.5 h. Then remove it from the oven, cool it in the airtight container, and weigh it (mass D). If the particle density on a saturated and surface-dried basis only is required, the operations described in this paragraph may be omitted. 5
48、.3.4 Calculations The particle density on an oven-dried basis (in Mg/m 3 ) is calculated from the formula: D A2 (B2 C) The particle density on a saturated and surface-dried basis (in Mg/m 3 ) is calculated from the formula: A A2 (B2 C) The apparent particle density (in Mg/m 3 )i s calculated from th
49、e formula: D D2 (B2 C) The water absorption (as % of dry mass) is calculated from the formula: 100 ( A2 D ) D where A is the mass of the saturated surface-dry aggregate in air (in g); B is the apparent mass in water of the basket containing the sample of saturated aggregate (in g); C is the apparent mass in water of the empty basket (in g); D is the mass of the oven-dried aggregate in air (in g). BSI 02-1999 3 Issue 4, February 1999 BS 812 : Part 2 : 1995 5.3.5 Reporting of results The mean result shall be reported for each form of particle density determined, the
