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1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS 7932:1998 Incorporatin
2、g Corrigendum No. 1 ICS 93.080.20 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Method for Determination of polished paver value (PPV) Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 14:54:58 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Th
3、is 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 September 1998 BSI 05-1999 The following BSI references relate to the work on this standard: Comm
4、ittee reference B/507 Draft for comment DD 155 ISBN 0 580 29593 1 BS 7932:1998Issue 2, May 1999 Amendments issued since publication Amd. No.DateText affected 10500 Corrigendum May 1999Indicated by a sideline Committees responsible for this British Standard The preparation of this British Standard wa
5、s entrusted to Technical Committee B/507, Paving units and kerbs, upon which the following bodies were represented: Brick Development Association British Cement Association British Ceramic Research Ltd. British Precast Concrete Federation Ltd. Cementitious Slag Makers Association County Surveyors So
6、ciety Department of Transport (Highways Agency) Institution of Civil Engineers Institution of Highways and Transportation Interlay, the Association of Block Paving Contractors Interpave, the Concrete Block Paving Association Landscape Institute Society of Chemical Industry Stone Federation The follo
7、wing bodies were also represented in the drafting of the standard, through subcommittees and panels: British Civil Engineering Test Equipment Manufacturers Association Institution of Structural Engineers National Federation of Clay Industries Ltd. National Paving and Kerb Association Licensed Copy:
8、London South Bank University, London South Bank University, Fri Dec 08 14:54:58 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Issue 1, May 1999BS 7932:1998 BSI 05-1999a Summary of pages The following table identifies the current issue of each page. Issue 1 indicates that a page has been introduced for
9、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). PageIssuePageIssue Front cover Inside front cover a b i ii 1 2 2 1 blank original original original 2 3 4 5 6 In
10、side back cover Back cover original original original original 2 original original Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 14:54:58 GMT+00:00 2006, Uncontrolled Copy, (c) BSI bblank Licensed Copy: London South Bank University, London South Bank Universit
11、y, Fri Dec 08 14:54:58 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7932:1998 BSI 1998i Contents Page Committees responsibleInside front cover Forewordii 1Scope1 2Normative references1 3Principle1 4Apparatus1 5Sampling and preparation of paver test specimens3 6Accelerated polishing procedure3 7Cali
12、bration of polishing procedure using a control stone tablet4 8Pendulum test5 9Calculation of polished paver value6 10Test report6 Annex A (normative) Sampling for test7 Figure 1 Flat-bed polishing machine2 Table 1 Grading requirements for corn emery3 Licensed Copy: London South Bank University, Lond
13、on South Bank University, Fri Dec 08 14:54:58 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii BSI 1998 BS 7932:1998 Foreword This British Standard has been prepared by Technical Committee B/507. It supersedes DD 155:1986 which is withdrawn. Annex A is normative. A British Standard does not purport to
14、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. Summary of pages This document comprises a front cover, an inside front cover, p
15、ages i and ii, pages 1 to 7 and a back cover. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 14:54:58 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BSI 19981 BS 7932:1998 1 Scope This British Standard describes a laboratory method for determining the polished pave
16、r value (PPV) of paving units using a flat-bed polishing machine in conjunction with pendulum test equipment. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this British Standard. For dated references, subse
17、quent amendments to, or revisions of any of these publications do not apply. For undated references, the latest edition of the publication referred to applies. BS 812-114:1989, Testing aggregates: Method for determination of the polished stone value. BS 903-A57:1997, Determination of indentation har
18、dness by means of pocket hardness meters (Identical with ISO 7619). IS0 3310, Test sieves Technical requirements and testing. 3 Principle The test methodology for determining the PPV consists of the application of an accelerated polishing regime using a flat-bed polisher, followed by measurement of
19、the PPV using pendulum test equipment. Measurements obtained are calibrated against readings taken from a reference stone tablet in order to maintain a constant point of comparison. The method is similar to that used for establishing a polished stone value (PSV) of aggregate particles as described i
20、n BS 812-114, except that an additional correction factor is applied to take into account the flat surface of paver units. 4 Apparatus 4.1 Straight-edge. 4.2 Feeler gauge. 4.3 Pendulum test equipment, conforming to BS 812-114:1989, 5.2. 4.4 Flat-bed polishing machine (see Figure 1) consisting of the
21、 following: a) a machined, flat circular cast iron or steel grinding lap not less than 600 mm in diameter, which can be rotated in a horizontal plane at a speed of (29 1) r/min; b) a smoothsurfaced styrene butadiene rubber annulus of 600 mm maximum external diameter, approximately 320 mm internal di
22、ameter and 8 mm thickness, attached to the upper surface of the grinding lap with a solvent-free adhesive. The rubber annulus shall have an initial hardness of (693) IRHD in accordance with BS 903-A57. It shall be covered by a certificate of conformity from the manufacturer which includes the date o
23、f manufacture. It shall be stored in the dark at a temperature in the range 5 8C to 25 8C and shall be conditioned by bringing to a temperature of (302) 8C throughout its mass before attaching to the grinding plate. After attachment, the grinding plate and annulus shall be kept in the dark at a temp
24、erature in the range (205) 8C. The annulus shall not be used after three years from the date of manufacture; NOTEIf glue is used to attach the annulus to the grinding plate, care should be taken to ensure it does not affect the hardness of the rubber. c) two adjustable metal holders capable of loose
25、ly holding in place cut sections of pavers with dimensions conforming to 5.2.1 and control stone tablets of the same plan dimensions; d) a means of locating, two cut paver specimens (or control stone tablets with tray) within the two holders according to the following configuration: with the centre
26、points of their outer edges (2501) mm from the centre of the lap; positioned diametrically opposite to each other; with their long sides lying in the direction of rotation of the lap. The specimens shall be free to move in a vertical plane but be restrained from moving in the horizontal plane; e) me
27、ans to ensure that the required load can be applied evenly to each test specimen and can move in a vertical direction; f) weights which permit uniform loading of the test specimen against the surface of the rubber annulus and which, including test specimen, tray (if used) and adjustable weight, will
28、 provide a contact stress of (2 27610) N/m2over the area of the final prepared contact surface. This stress corresponds to a total mass of 1.15 kg for an area of 92 mm 3 54 mm; g) separate mechanisms to feed corn emery and emery flour and a means to feed water. Licensed Copy: London South Bank Unive
29、rsity, London South Bank University, Fri Dec 08 14:54:58 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 2 BSI 1998 BS 7932:1998 1. Sample holder 2. Sample 3. Adjustable mass 4. Water supply 5. Emery hoppers with calibrated conveyors 6. Polishing lap 7. Rubber annulus Figure 1 Flat-bed polishing machine
30、4.5 Polishing media, consisting of the following: a) fresh natural corn emery, of a grading that conforms with Table 1. b) Fresh air-floated or water-washed emery flour, which passes a 50 mm test sieve. All polishing media shall be used only once. Licensed Copy: London South Bank University, London
31、South Bank University, Fri Dec 08 14:54:58 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BSI 19983 BS 7932:1998 Table 1 Grading requirements for corn emery Nominal width of sieve aperture Total passing mm% 60098 to 100 50070 to 100 42530 to 90 3550 to 30 3000 to 5 5 Sampling and preparation of paver te
32、st specimens 5.1 Sampling 5.1.1 Obtain a representative sample of ten paving units in accordance with the sampling technique described in annex A. Inspect the paving units and assess their surface quality using the straight-edge and feeler gauge in accordance with 5.1.3 and 5.1.4. Alternatively the
33、surface can be assessed using a depth gauge. 5.1.2 Select three paving units which, after cutting to produce a sample of nominal size 92 mm 3 54 mm, are representative of the batch in terms of texture and surface finish but show no undue cracks or other blemishes. To ensure that a plane-surface can
34、be presented to the polishing action, they shall have no transverse or longitudinal warp and if possible, no formed or natural surface features such as ridges or plateaux or incised grooves. 5.1.3 If the surface of the units contains grooves, channels or other similar flaws exceeding 0.5 mm deep and
35、 2 mm wide, and which prevent a plane-surfaced test specimen being cut, the unit may be tested on the reverse surface providing that it contains the same material throughout. This shall be noted in the test report. 5.1.4 If the surface of the unit contains formed ridges or domes or plateaux greater
36、than 0.5 mm high, these shall be carefully removed by grinding. This surface pretreatment shall be noted in the test report. 5.1.5 If three suitable paving units cannot be obtained, a further ten paving units shall be sampled. If these do not conform with the requirements, testing shall proceed on t
37、he three most acceptable paving units. The noted surface characteristics shall be stated in the test report. 5.2 Preparation of paver test specimens 5.2.1 Cut the pavers to a size of (92.0 3.0) mm 3 (54.03.0) mm 3 actual thickness. The specimens shall have a bevel of 2 mm to 3 mm at an angle of appr
38、oximately 45 8 along the leading edge of each specimen, to enable the emery polishing agents to access the contact area between the specimens and the rubber annulus more readily. The bevel may comprise the natural chamfer of the unit or may be specifically ground. 5.2.2 Calculate the applied load on
39、 each specimen necessary to give a contact stress of (2 27610) N/m2over the area of the final prepared contact surface. NOTE 1 The contact area excludes prepared bevels and chamfers on the pavers themselves. NOTE 2 The mass of the specimen is considered to be part of the calculated load. 6 Accelerat
40、ed polishing procedure WARNING The application of emery polishing agents during the course of the operations described in this clause can generate particles that could be injurious to health. It is essential to ensure that appropriate precautions are taken, e.g. the use of dust masks and/or dust ext
41、racting facilities. It is also essential to ensure that the equipment is electrically safe in wet test conditions. Carry out accelerated polishing using the flat-bed polishing machine (see 4.4) at (205) 8C according to the following procedure. a) Place the test surfaces of two specimens face down in
42、 the metal holders (see 4.4c) on the rubber annulus (see 4.4b) at positions diametrically opposite each other. Apply the appropriate loads calculated in accordance with 5.2.2. Set the machine in motion at a rate of (29 1) r/min. b) Feed corn emery of the specified grading (see Table 1) onto the surf
43、ace of the rubber annulus at a rate of (202) g/min, spread evenly over the surface immediately in front of each of the test specimens, for (70010) revolutions. Simultaneously feed water onto the surface at a rate just sufficient to carry the corn emery under the test specimens without being washed a
44、way. NOTEA water-feed rate of 6 ml/min has been found satisfactory. c) Within 30 min of completing 700 revolutions, remove the specimens from the machine and remove all traces of corn emery under running water using a stiff bristled brush. Remove any corn emery from the surface of the rubber and sub
45、stitute fine emery flour of the specified grading (see 4.5) as the polishing agent. Apply the flour at a rate of (20.2) g/min spread evenly over the surface in front of each of the test specimens with water applied simultaneously at a rate sufficient to maintain a wet paste under the specimens. Poli
46、sh the specimens for a further (70010) revolutions. NOTEA water-feed rate in the range (1.0 to 3.0) ml/min has been found satisfactory to maintain a creamy paste. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 14:54:58 GMT+00:00 2006, Uncontrolled Copy, (c) BSI
47、 4 BSI 1998 BS 7932:1998 1) Information on availability can be obtained from BSI Information Centre, British Standards House, 389 Chiswick High Rd, London W4 4AL. d) Remove the specimens from the machine within 30 min of the completion of the polishing process and thoroughly wash in running water to
48、 remove all trace of the emery flour. Remove any emery flour which has packed into cracks on the paver surface by scrubbing with a stiff bristled brush. e) Repeat items a) to d) for two further test specimens, one of which may be a control stone specimen. f) After washing the specimens store face do
49、wnwards under water at a temperature of (202) 8C for at least 2 h to ensure that the specimens are within the temperature tolerance. It is essential not to allow the specimens to dry out before the pendulum test. 7 Calibration of polishing procedure using a control stone tablet 7.1 General 7.1.1 To maintain a constant standard of comparison, control stone tablets shall be polished at a rate of one tablet for each three specimens tested if only one determination is to be made, or a minimum rate of one tablet for each nine specimens if testin
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