BS 812-110-1990 Testing aggregates - Methods for determination of aggregate crushing value (ACV)《集料试验 集料破碎值(ACV)的测定方法》.pdf

1、BRITISH STANDARD BS 812-110: 1990 Testing aggregates Part 110: Methods for determination of aggregate crushing value (ACV)BS 812-110:1990 This British Standard, having been prepared under the directionof the Cement, Gypsum,Aggregates and QuarryProducts Standards PolicyCommittee, was publishedunder t

2、he authority ofthe Board of BSI and comes intoeffect on 29 June 1990 BSI 12-1998 The following BSI references relate to the work on this standard: Committee reference CAB/2 Draft for comment 85/13011 DC ISBN 0 580 18825 6 Committees responsible for this British Standard The preparation of this Briti

3、sh Standard was entrusted by the Cement, Gypsum, Aggregates and Quarry Products Standards Policy 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 Scient

4、ists Association of Lighweight Aggregate Manufacturers Brick Development Association British Aggregate Construction Materials Industries British Cement Association British Ceramic Research Ltd. British Civil Engineering Test Equipment Manufacturers Association British Geological Sciences British Pre

5、cast Concrete Federation Ltd. British Ready Mixed Concrete Association British Steel Industry Building Employers Confederation Calcium Silicate Brick Association Ltd. Chartered Institute of Building Concrete Society County Surveyors Society Department of tnhe Environment (Building Research Establish

6、ment) Department of the Environment (Property Services Agency) Department of Transport Department of Transport (Transport and Road Research Laboratory) Electricity Supply Industry in England and Wales Federation of Civil Engineering Contractors Institute of Concrete Technology Institution of Civil E

7、ngineers Institution of Highways and Transportation Institution of Structural Engineers Institution of Water and Environmental Management Mortar Producers Association Limited Sand and Gravel Association Limited Society of Chemical Industry Amendments issued since publication Amd. No. Date CommentsBS

8、 812-110:1990 BSI 12-1998 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 Definitions 1 3 Principle 1 4 Sampling 1 5 Apparatus 1 6 Preparation of test portions and specimens 2 7 Procedure 3 8 Calculation and expression of results 3 9 Precision 3 10 Test report 4 App

9、endix A Recommended method for determining the aggregate crushing value of other size fractions 5 Appendix B Details of the evaluation of precision data 6 Figure 1 Outline form of cylinder and plunger apparatus for the aggregate crushing value 1 Table 1 Principal dimensions of cylinder and plunger a

10、pparatus 2 Table 2 Guide to minimum mass of test portions required to obtain a suitable mass of material to determine the aggregate crushing value 2 Table 3 Particulars of test sieves for testing other size fractions of aggregates 5 Table 4 Precision values for the determination of aggregate crushin

11、g value 6 Publications referred to Inside back coverBS 812-110:1990 ii BSI 12-1998 Foreword This Part of BS 812 has been prepared under the direction of the Cement, Gypsum, Aggregate and Quarry Products Standards Policy Committee, and is a revision of clause 7 of BS 812-3:1975, which is withdrawn. I

12、t forms part of a general revision of the 1975 edition of BS812. As each of the tests, or collection of tests is revised, it will be issued as a separate Part or Section of this standard. The method described in this revision has not been changed technically from that given in BS 812-3:1975, but has

13、 been amended editorially to align it with other Parts in this series. It is intended that other British Standards should call up BS 812 test methods as the basis for compliance. Nevertheless it is not intended that all aggregates should be subjected to all the listed tests. Specifications in other

14、standards should call up only relevant test methods. Some of the tests in other Parts of BS812 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 to see whether more extensive testing is justified. Re

15、ference should be made to BS812-101:1984 for general guidance on testing aggregates, precision of test methods and variance arising from sampling errors. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their co

16、rrect 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, pages i and ii, pages1 to 6, an inside back cover and a back cover. This standard has been updated (see copy

17、right date) and may have had amendments incorporated. This will be indicated in the amendment table on theinside front cover.BS 812-110:1990 BSI 12-1998 1 1 Scope This Part of BS812 describes a method for the determination of the aggregate crushing value (ACV) which gives a relative measure of the r

18、esistance of an aggregate to crushing under a gradually applied compressive load. The method is applicable to aggregates passing a14.0mm test sieve and retained on a 10.0 mm test sieve. For other size fractions, a recommended method is described in appendix A. The method is not suitable for testing

19、aggregates with an aggregate crushing value higher than30, and in such cases the method for ten per cent fines value described in BS 812-111 is applicable. NOTEThe titles of the publications referred to in this standard are listed on the inside back cover. 2 Definitions For the purposes of this Part

20、 of BS 812 the definitions given in BS 812-100, BS 812-101 and BS812-102 apply. 3 Principle A test specimen is compacted in a standardized manner into a steel cylinder fitted with a freely moving plunger. The specimen is then subjected to a standard loading regime applied through the plunger. This a

21、ction crushes the aggregate to a degree which is dependent on the crushing resistance of the material. This degree is assessed by a sieving test on the crushed specimen and is taken as a measure of the aggregate crushing value (ACV). 4 Sampling The sample used for the test (the laboratory sample) sh

22、all be taken in accordance with the procedure described in clause 5 of BS 812-102:1989. 5 Apparatus NOTEAll apparatus should comply with the general requirements of BS 812-100. 5.1 A steel cylinder, open-ended, of nominal 150 mm internal diameter with plunger and baseplate of the general form and di

23、mensions shown in Figure 1 and given in Table 1. The surfaces in contact with the aggregate shall be machined and case hardened, or otherwise treated, so as to have a hardness value of not less than 650 HV, in accordance with BS 427, and shall be maintained in a smooth condition. Figure 1 Outline fo

24、rm of cylinder and plunger apparatus for the aggregate crushing valueBS 812-110:1990 2 BSI 12-1998 Table 1 Principal dimensions of cylinder and plunger apparatus 5.2 A tamping rod, made out of straight iron or steel bar of circular cross section, 16 1 mm diameter and600 5 mm long, with both ends hem

25、ispherical. 5.3 A balance, of at least 3 kg capacity, readable and accurate to 1 g. 5.4 Test sieves, with square-hole perforated plate, of sizes14.0 mm and 10.0 mm and a woven wire2.36mm test sieve.The test sieves shall comply with BS 410. 5.5 A well-ventilated oven, thermostatically controlled at a

26、 temperature of 105 5 C. 5.6 A compression testing machine, capable of applying any force up to 400 kN and which can be operated to give a uniform rate of loading so that this force is reached in 10 min (see 7.2). The machine shall comply with the requirements of BS1610 for a grade 1 or a grade 2 ma

27、chine.The machine may be used with or without a spherical seating. NOTEAlthough the maximum force applied to this test is400kN it may be more convenient to use a compression testing machine capable of applying any force up to 500 kN as is required for the ten per cent fines test described in BS 812-

28、111. 5.7 A cylindrical metal measure, for measuring the test samples, of sufficient rigidity to retain its form under rough usage and having an internal diameter of 115 1 mm and an internal depth of 180 1 mm 5.8 A rubber mallet. 5.9 A metal tray, of known mass large enough to contain3kg of aggregate

29、. 5.10 A brush, with stiff bristles. 6 Preparation of test portions and specimens 6.1 Reduce the laboratory sample using the procedures described in clause 6 of BS 812-102:1989 to produce a test portion of sufficient mass to produce three test specimens of 14 mm to 10mm size fraction. NOTEA single t

30、est specimen is that quantity of material required to fill the cylinder (see 7.1 and Table 2). Table 2 Guide to minimum mass of test portions required to obtain a suitable mass of material to determine the aggregate crushing value 6.2 Thoroughly sieve the entire surface dry test portion on the 14 mm

31、 and 10 mm test sieves to remove the oversize and undersize fractions. Divide the resulting 14 mm to 10 mm fraction to produce three test specimens each of mass such that the depth of the material in the cylinder is approximately 100 mm after tamping as described in7.1 (see note 1). Component Dimens

32、ions (see Figure 1) Nominal 150 mm internal diameter of cylinder Nominal 75 mm internal diameter of cylinder (see appendix A) mm mm Cylinder Internal diameter, A 154 0.5 78.0 0.5 Internal depth, B 125 to 140 70.0 to 85.0 Minimum wall thickness, C 16.0 8.0 Plunger Diameter of piston, D 152 0.5 76.0 0

33、.5 Diameter of stem, E 45.0 to D Overall length of piston plus stem, F 100 to 115 60.0 to 80.0 Minimum depth of piston, G not less than 25.0 not less than 19.0 Diameter of hole, H 20.0 0.1 10.0 0.1 Baseplate Minimum thickness, I 10 10 Length of each side of square, J 200 to 230 110 to 115 Grading of

34、 the aggregate Minimum mass of the test portion a mm kg All-in aggregate 40 max. size 60 All-in aggregate 20 max. size 45 Graded aggregate 40 to 5 40 Graded aggregate 20 to 5 25 Graded aggregate 14 to 5 15 a For normal density aggregates.BS 812-110:1990 BSI 12-1998 3 NOTE 1The appropriate quantity o

35、f aggregate may be found conveniently by filling the cylindrical measure in three layers of approximately equal depth. Tamp each layer 25 times, from a height of approximately 50 mm above the surface of the aggregate, with the rounded end of the tamping rod. Level off using the tamping rod as a stra

36、ightedge. NOTE 2 Mechanical sieving should only be used for aggregates which do not degrade under this action. 6.3 Dry the test specimens by heating at a temperature of 105 5 C for a period of not more than 4 h. Cool to room temperature and record the mass of material comprising the test specimens b

37、efore testing. 7 Procedure 7.1 Place the cylinder of the test apparatus in position on the baseplate and add the test specimen in three layers of approximately equal depth, each layer being subjected to 25 strokes from the tamping rod distributed evenly over the surface of the layer and dropping fro

38、m a height approximately 50 mm above the surface of the aggregate. Carefully level the surface of the aggregate and insert the plunger so that it rests horizontally on this surface. Take care to ensure that the plunger does not jam in the cylinder. 7.2 Place the apparatus, with the test specimen pre

39、pared as described in 6.3 and plunger in position, between the platens of the testing machine and load it at as uniform a rate as possible (see note) so that the required force of 400 kN is reached in10min 30s. NOTEWhen, during the early stages of the test, there is a significant deformation, it may

40、 not be possible to maintain the required loading rate and variations in the loading rate may occur especially at the beginning of the test. These variations should be kept to a minimum with the principal object of completing the test in the overall time of 10 min 30 s. 7.3 Release the load and remo

41、ve the crushed material by holding the cylinder over a clean tray of known mass and hammering on the outside of the cylinder with the rubber mallet until the particles are sufficiently disturbed to enable the mass of the specimen to fall freely on to the tray. NOTEIf this fails to remove the compact

42、ed aggregate other methods may be used but take care not to cause further crushing of the particles. Transfer any particles adhering to the inside of the cylinder, to the baseplate and the underside of the plunger, to the tray by means of a stiff bristle brush. Weigh the tray and the aggregate and d

43、etermine the mass of aggregate used (M 1 ) to the nearest gram. 7.4 Sieve the whole of the test specimen on the tray on the 2.36mm test sieve until no further significant amount passes during a further period of1min. Weigh and record the masses of the fractions passing and retained on the sieve to t

44、he nearest gram (M 2and M 3respectively). If the total mass of the two individual fractions (M 2plus M 3 ) differs from the initial mass (M 1 ) by more than 10g, discard the result and repeat the complete procedure using a new test specimen. NOTE 1In all of the procedures described in 7.3 and 7.4 ta

45、ke care to avoid loss of fines and overloading the sieves. NOTE 2Mechanical sieving should only be used for aggregates which do not degrade under its action. 7.5 Repeat the whole procedure described in 7.1 to7.4 with a second test specimen. 8 Calculation and expression of results 8.1 Calculate the a

46、ggregate crushing value (ACV) expressed as a percentage to the first decimal place, of the mass of fines formed to the total mass of the test specimen from the following equation: where 8.2 Calculate the mean of the two results to the nearest whole number. Report the mean as the aggregate crushing v

47、alue, unless the individual results differ by more than 0.07 times the mean value. In this case repeat the test on two further specimens, calculate the median of the four results to the nearest whole number, and report the median as the aggregate crushing value. NOTEThe median of four results is cal

48、culated by excluding the highest and the lowest result and calculating the mean of the two middle results. 9 Precision 9.1 A precision experiment was carried out involving 14 laboratories. Details of the experiment and the precision data are given in appendix B. 9.2 Uses of precision data are descri

49、bed in clause 5 of BS 812-101:1984. M 1 is the mass of the test specimen (ing); M 2 is the mass of the material passing the2.36 mm test sieve (in g). ACV M 2 M 1 -100 =BS 812-110:1990 4 BSI 12-1998 10 Test report The report shall affirm that the aggregate crushing value was determined in accordance with this Part of BS 812 and whether or not a certificate of sampling is available. If available, a copy of the certificate of sampling shall be provided. The test report shall contain the following additional information: a)