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1、BRITISH STANDARD BS 812-111: 1990 Testing aggregates Part 111: Methods for determination of ten per cent fines value (TFV) BS 812-111:1990 This British Standard, having been prepared under the direction of the Cement, Gypsum, Aggregates and Quarry Products Standards Policy Committee, was published u
2、nder the authority of the Board of BSI and comes into effect 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 84/13012 DC ISBN 0 580 18826 4 Committees responsible for this British Standard The preparation of th
3、is British 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 Consultin
4、g Scientists 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 Bri
5、tish Precast 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 the Environment (Building Research Es
6、tablishment) 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
7、Civil Engineers 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.DateComme
8、nts BS 812-111:1990 BSI 12-1998i Contents Page Commitees responsibleInside front cover Forewordii 1Scope1 2Definitions1 3Principle1 4Sampling1 5Apparatus1 6Preparation of test portions and specimens3 7Procedure3 8Calculations and expression of results4 9Precision4 10Test report4 Appendix A Recommend
9、ed method for determining the ten per cent fines value for other size fractions of aggregate5 Appendix B Details of the evaluation of precision data6 Figure 1 Outline form of cylinder and plunger apparatus for the ten per cent fines test2 Table 1 Principal dimensions of cylinder and plunger apparatu
10、s2 Table 2 Guide to minimum mass of test portions required to obtain a suitable mass of material to determine the ten per cent fines value3 Table 3 Particulars of test sieves for testing other size fractions of aggregates5 Table 4 Precision values for the determination of ten per cent fines value us
11、ing materials in the dry condition6 Table 5 Precision values for the determination of ten per cent fines value using materials in the soaked condition6 Publications referred toInside back cover BS 812-111:1990 ii BSI 12-1998 Foreword This Part of BS 812 has been prepared under the direction of the C
12、ement, Gypsum, Aggregate and Quarry Products Standards Policy Committee, and is a revision of clause 8 of BS 812-3:1975, which is withdrawn. It forms part of a general revision of the 1975 edition of BS 812. As each of the tests, or collection of tests is revised, it will be issued as a separate Par
13、t or Section of this standard. The methods described in this revision have not been changed technically from that given in BS 812-3:1975, but the opportunity has been taken to include a procedure for determining the ten per cent fines value of aggregates in a soaked condition. This has been done bec
14、ause some aggregates have a significantly reduced resistance to crushing when tested in this condition. With such aggregates, tests on soaked samples give a more reliable indication of their performance in practice. It is intended that other British Standards should call up BS 812 test methods as th
15、e basis for compliance. Nevertheless it is not intended that all aggregates should be subjected to all the listed tests. Specifications in other standards should call up only relevant tests. Reference should be made to BS 812-101:1984 for general guidance on testing aggregates, precision of test met
16、hods 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 correct application. Compliance with a British Standard does not of itself confer immunity from legal obliga
17、tions. 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 on th
18、e inside front cover. BS 812-111:1990 BSI 12-19981 1 Scope This Part of BS 812 describes methods for the determination of the ten per cent fines value (TFV) of aggregates which give a relative measure of the resistance of an aggregate to crushing under a gradually applied compressive load. Two proce
19、dures are described, one in which the aggregate is tested in a dry condition and the other in a soaked condition. The methods are applicable to both weak and strong aggregates passing a 14.0 mm test sieve and retained on a 10.0 mm test sieve. For other size fractions, a recommended method is describ
20、ed in appendix A. 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 of BS 812 the definitions given in BS 812-100, BS 812-101 and BS 812-102 apply. 3 Principle A test specimen is compacted in a standardize
21、d manner into a steel cylinder fitted with a freely moving plunger. The specimen is then subjected to a load applied through the plunger. This action crushes the aggregate to a degree which is dependent on the crushing resistance of the material. The degree of crushing is assessed by a sieving test
22、on the crushed specimen. The procedure is repeated with various loads to determine the maximum force which generates a given sieve analysis. This force is taken as the ten per cent fines value (TFV). 4 Sampling The sample used for the test (the laboratory sample) shall be taken in accordance with cl
23、ause 5 of BS 812-102:1989. 5 Apparatus NOTEAll apparatus should comply with the general requirements of BS 812-100. 5.1 General 5.1.1 A steel cylinder, open-ended of nominal 150 mm internal diameter with plunger and baseplate, of the general form and dimensions shown in Figure 1 and given in Table 1
24、. 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. 5.1.2 A tamping rod, made out of straight iron or steel bar of cir
25、cular cross section, 16 1 mm diameter and 600 5 mm long, with both ends hemispherical. 5.1.3 A balance, of at least 3 kg capacity readable to 1 g. 5.1.4 Test sieves, with square-hole perforated plate of sizes 14.0 mm and 10.0 mm and a woven wire 2.36 mm test sieve. The test sieves shall comply with
26、BS 410. 5.1.5 A compression testing machine, capable of applying any force up to 500 kN and which can be operated to give a uniform rate of loading so that this force is reached in 10 min (see 7.1.2). The machine shall comply with the requirements of BS 1610 for a grade 1 or grade 2 machine. The mac
27、hine may be used with or without a spherical seating. 5.1.6 A cylindrical metal measure, for measuring the sample, 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. 5.1.7 A well-ventilated oven, thermostatically
28、 controlled at a temperature of 105 5 C. 5.1.8 A rubber mallet. 5.1.9 A metal tray, of known mass large enough to contain 3 kg of aggregate. 5.1.10 A brush, with stiff bristles. 5.2 Additional apparatus for testing aggregate in a soaked condition 5.2.1 Drying cloths or absorbent paper, for the surfa
29、ce drying of the aggregate after it has been soaked in water, e.g. two hand-towels of a size not less than 750 mm 450 mm or rolls of absorbent paper of suitable size and absorbency. 5.2.2 One or more wire-mesh baskets, having apertures not larger than 6.5 mm or a perforated container of convenient s
30、ize with hangers for lifting purposes. 5.2.3 A stout watertight container, in which the basket(s) may be immersed 5.2.4 A supply of clean water, of drinking quality. BS 812-111:1990 2 BSI 12-1998 Table 1 Principal dimensions of cylinder and plunger apparatus Figure 1 Outline form of cylinder and plu
31、nger apparatus for ten per cent fines test ComponentDimensions (see Figure 1)Nominal 150 mm internal diameter of cylinder Nominal 75 mm internal diameter of cylinder (see appendix A) Cylindermmmm Internal diameter, A154 0.578.0 0.5 Internal depth, B125 to 14070.0 to 85.0 Minimum wall thickness, C16.
32、08.0 Plunger Diameter of piston, D152 0.576.0 0.5 Diameter of stem, E 95 to # D 45.0 to # D Overall length of piston plus stem, F100 to 11560.0 to 80.0 Minimum depth of piston, Gnot less than 25.0not less than 19.0 Diameter of hole, H20.0 0.110.0 0.1 Baseplate Minimum thickness, I1010 Length of each
33、 side of square, J200 to 230110 to 115 BS 812-111:1990 BSI 12-19983 6 Preparation of test portions and specimens 6.1 Test portions 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 o
34、f 14 mm to 10 mm size fraction. NOTEA single test specimen is that quantity of material required to fill the cylinder (see 7.1.1 and Table 2). Table 2 Guide to minimum mass of test portions required to obtain a suitable mass of material to determine the ten per cent fine value 6.2 Test specimens in
35、a dry condition 6.2.1 Thoroughly sieve the entire surface dry test portion on the 14 mm 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
36、is approximately 100 mm after tamping as described in 7.1 (see note 1). NOTE 1The appropriate quantity of 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 surf
37、ace of the aggregate, with the rounded end of the tamping rod. Level off using the tamping rod as a straightedge. NOTE 2Mechanical sieving should only be used for aggregates which do not degrade under its action. 6.2.2 Dry the test specimens by heating at a temperature of 105 5 C for a period of not
38、 more than 4 h. Cool to room temperature before testing. Record the mass of material comprising the test specimens. 6.3 Test specimens in a soaked condition 6.3.1 Prepare the test specimens using the procedure described in 6.2 except that the test portion is tested in the as-received condition and n
39、ot as oven-dried material. Place each test specimen (see note) in the wire basket and immerse it in the water in the container with a cover of at least 50 mm of water above the top of the basket. Immediately after immersion remove the entrapped air from the specimen by lifting the basket 25 mm above
40、 the base of the container and allowing it to drop 25 times at a rate of about once a second. Keep the basket and aggregate completely immersed during the operation and for a subsequent period of between 24 2h and maintain the water temperature at 20 5 C. NOTEThe appropriate quantity of aggregate to
41、 use may be found as described in 6.2. 6.3.2 After soaking, remove the specimen of aggregate from the basket and blot the free water from the surface with the absorbent cloths. Carry out the test procedure immediately after this operation. 7 Procedure 7.1 Aggregates in dry condition 7.1.1 Place the
42、cylinder of the test apparatus in position on the baseplate and add the test specimen in thirds, each third being subjected to 25 strokes from the tamping rod distributed evenly over the surface of the layer and dropping from a height approximately 50 mm above the surface of the aggregate. NOTEThe p
43、articles of some aggregates may break down when tamped in this way. If this occurs it should be reported. 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. 7.1.2 Place
44、the apparatus, with the test specimen and plunger in position, between the platens of the testing machine. Apply force at as uniform a rate as possible (see note 1) so as to cause a total penetration of the plunger in 10 min 30 s of approximately: a) 15 mm for rounded or partially rounded aggregates
45、, e.g. uncrushed gravels; b) 20 mm for normal crushed aggregates; c) 24 mm for vesicular (honeycombed) aggregates e.g. some slags. NOTE 1When, during the early stages of the test, there is a significant deformation, it may not be possible to maintain the required loading rate and variations in the l
46、oading 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 mins 30 s. NOTE 2These figures may be varied according to the extent of the rounding or honeycombing. NOTE 3When an a
47、ggregate impact value (AIV) as determined by the procedure given in BS 812-112 is available, the force required (in kW) for the first ten per cent fines test can be estimated by means of the following equation more conveniently than by the use of the dial gauge. Grading of the aggregateMinimum mass
48、of the test portiona mmkg All-in aggregate 40 max. size60 All-in aggregate 20 max. size45 Graded aggregate 40 to 540 Graded aggregate 20 to 525 Graded aggregate 14 to 515 a For normal density aggregates Required force 4 000 AIV = BS 812-111:1990 4 BSI 12-1998 This value of force will nearly always g
49、ive a percentage of fines within the required range of 7.5 % to 12.5%. 7.1.3 Record the maximum force (f) applied to produce the required penetration. Release the force and remove 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 compacted aggregate other methods shoul