SANS 5841-2008 Aggregate crushing value of coarse aggregates《粗骨料的骨料压碎值》.pdf

1、 Collection of SANS standards in electronic format (PDF) 1. Copyright This standard is available to staff members of companies that have subscribed to the complete collection of SANS standards in accordance with a formal copyright agreement. This document may reside on a CENTRAL FILE SERVER or INTRA

2、NET SYSTEM only. Unless specific permission has been granted, this document MAY NOT be sent or given to staff members from other companies or organizations. Doing so would constitute a VIOLATION of SABS copyright rules. 2. Indemnity The South African Bureau of Standards accepts no liability for any

3、damage whatsoever than may result from the use of this material or the information contain therein, irrespective of the cause and quantum thereof. ISBN 978-0-626-21535-4 SANS 5841:2008Edition 2.1Any reference to SABS SM 841 is deemedto be a reference to this standard(Government Notice No. 1373 of 8

4、November 2002)SOUTH AFRICAN NATIONAL STANDARD Aggregate crushing value of coarse aggregates Published by SABS Standards Division 1 Dr Lategan Road Groenkloof Private Bag X191 Pretoria 0001 Tel: +27 12 428 7911 Fax: +27 12 344 1568 www.sabs.co.za SABS SANS 5841:2008 Edition 2.1 Table of changes Chang

5、e No. Date Scope Amdt 1 2008 Amended to change the designation of SABS standards to SANS standards, update referenced standards, and change the sieve sizes and a note of reference. Foreword This South African standard was approved by National Committee SABS SC 59A, Construction standards Cement, lim

6、e and concrete, in accordance with procedures of the SABS Standards Division, in compliance with annex 3 of the WTO/TBT agreement. This document was published in October 2008. This document supersedes SABS SM 841:1994 (first revision). A vertical line in the margin shows where the text has seen tech

7、nically modified by amendment No.1. SANS 5841:2008 Edition 2.1 1 Aggregate crushing value of coarse aggregates 1 Scope and field of application This standard specifies a method for determining the aggregate crushing value (ACV) of an aggregate by crushing a prepared confined sample under a specific,

8、 gradually applied force and determining the percentage of the material crushed finer than a specified size in a dry or wet condition. NOTES 1 The aggregate crushing value (ACV) test is a rapid and repeatable test but it is only selective for aggregates that have an aggregate crushing value not exce

9、eding 30 %. 2 If the result of the aggregate tested in this manner has a percentage exceeding 30, the preferred test, described in SANS 5842, has to be followed. 3 The crushing strength of most aggregates used in concrete is far in excess of the compression strength usually obtained by the concrete

10、made with the aggregate. It is, however, desirable that attrition during handling and mixing not cause excessive fines and therefore this test serves as a useful guide to the general quality of the aggregate. 2 Normative references The following standards contain provisions which, through reference

11、in this text, constitute provisions of this standard. All standards are subject to revision and, since any reference to a standard is deemed to be a reference to the latest edition of that standard, parties to agreements based on this standard are encouraged to take steps to ensure the use of the mo

12、st recent editions of the standards indicated below. Information on currently valid national and international standards can be obtained from the SABS Standards Division. SANS 197, Preparation of test samples of aggregates. SANS 3310-1/ISO 3310-1, Test sieves Technical requirements and testing Part

13、1: Test sieves of metal wire cloth. Amdt 1 3 Apparatus 3.1 Metal, watertight, cylindrical measure, that is rigid enough to retain its form under rough usage, and that has the following internal dimensions: diameter : 115 mm; and depth : 180 mm. SANS 5841:2008 Edition 2.1 2 3.2 Crushing apparatus, th

14、at consists of steel, open-ended cylinders with plunger and base plate, each of the appropriate shape and dimensions given in figure 1. All the inner surfaces of the assembly (surfaces between the cylinder and base plate) in contact with the aggregate are machined. The opposite load-bearing faces of

15、 the plunger are parallel to within 0,1. NOTES 1 The inner surfaces of the assembly in contact with the aggregate are subject to severe abrasion and indentation during testing. To increase the service life of the apparatus, it is recommended that these surfaces be case-hardened (or otherwise treated

16、) to have a hardness of at least 400 HV 30. Amdt 1 2 For convenience, it is recommended that the base plate be recessed or that the base plate be provided with lugs to locate the cylinder centrally on the base plate. 3.3 Test sieves, of aperture sizes 11,2 mm, 8 mm, and 2,8 mm and that comply with t

17、he requirements of SANS 3310-1. Amdt 1 3.4 Metal tamping rod, straight, of nominal diameter 16 mm and of length 450 mm to 600 mm, and that has at least one hemispherical end. 3.5 Compression testing machine, of capacity approximately 500 kN and capable of applying a force of up to 400 kN at a unifor

18、m rate of 40 kN/min. 4 Preparation of test specimens 4.1 Specimens for the dry test 4.1.1 From the test sample (see SANS 197), take enough material to yield a test fraction of aggregate of approximately 3 kg that passes a 11,2 mm sieve and is retained on a 8 mm sieve. Amdt 1 4.1.2 Use a 8 mm sieve t

19、o sieve thoroughly all the aggregate that passes the 11,2 mm sieve. If loose dust adheres to the aggregate, remove it by brushing or by means of a jet of air. If adhering dust cannot be removed by these means, wash the aggregate on the 8 mm sieve in any suitable manner until all the adhering dust is

20、 removed. Amdt 1 4.1.3 Place the aggregate in shallow trays, dry it to constant mass at a temperature of 100 C to 110 C, and cool it to room temperature. 4.1.4 Fill the measure (see 3.1) to approximately one-third of its depth with the aggregate, and tamp with 25 light strokes of the tamping rod, us

21、ing the hemispherical end. Add a further similar quantity of aggregate and tamp as before. Finally fill the measure to overflowing, tamp as before, and strike off the excess material flush with the top of the measure, using the tamping rod as a straight-edge. 4.1.5 Determine, to the nearest 0,1 %, t

22、he mass of the aggregate contained in the measure (mass a). 4.1.6 Repeat the above to produce three test specimens. 4.2 Specimens for the wet test Use the procedure described in 4.1, but before sieving, soak the specimen for 24 h in potable water contained in a suitable vessel. SANS 5841:2008 Editio

23、n 2.1 3 5 Procedure 5.1 Dry test 5.1.1 Place the crushing cylinder on its base plate, and add a third of a test specimen at a time, and tamp each layer with 25 light strokes of the tamping rod, using the hemispherical end. Level the surface of the aggregate, and insert the plunger (taking care to en

24、sure that it does not jam in the cylinder) until it rests horizontally on the surface. 5.1.2 Place the assembly centrally on the bearing platen of the compression testing machine, and so apply force, at as uniform a rate as possible, that it reaches a value of 400 kN 5 kN in 10 min 15 s. Then releas

25、e the force. 5.1.3 Remove all the material from the crushing cylinder and sieve it on a 2,8 mm sieve until not more than 0,1 % of the total sample mass passes the sieve during further continuous sieving for 1 min. Determine, to the nearest 0,1 % of the total sample mass, the mass of the portion that

26、 passes through the sieve (mass b). Amdt 1 5.2 Wet test 5.2.1 After the 24 h soaking (see 4.2), take the specimen out of the water, and allow it to drain for approximately 5 min, and then surface-dry it by rolling it in a damp cloth. 5.2.2 Proceed as in 5.1.1 to 5.1.3, but, in the third step of the

27、test (see 5.1.3), dry the material taken from the cylinder to constant mass at a temperature of 100 C to 110 C before sieving it and determining the mass of the material that passes the sieve. 6 Expression of results 6.1 Calculate, to the nearest 0,1 %, the aggregate crushing value of each specimen,

28、 as relevant, as follows: 100bawhere b is the mass of the portion that passed through the sieve, in grams; and a is the mass of the aggregate contained in the measure, in grams. 6.2 Report, rounded-off to the first decimal place, the average aggregate crushing value for the dry and wet material sepa

29、rately. NOTES 1 If the calculated aggregate crushing value exceeds 30 %, the result is considered to be unreliable and the FACT value (see SANS 5842) should be determined instead. 2 The test described in 5.1 is the standard test, but if the available aggregate is not graded to pass the 11,2 mm sieve

30、 and to be retained on the 8 mm sieve, a non-standard test can be conducted, using the same procedure as described in clauses 4 and 5 on aggregate in any of the size ranges given in table 1. Amdt 1 3 It should be stated in the report that the results of the tests on the non-standard sizes will not b

31、e comparable with those obtained in the standard test: in general, the smaller size aggregates will produce lower values and the larger sizes higher values. SANS 5841:2008 Edition 2.1 4 Table 1 Aggregate sizes for non-standard test Dimensions in millimetres1 2 3 Nominal aperture sizes of test sieves

32、 For preparation of test specimens Passing Retained For separating fines (see 5.1.3) 26,5 19,0 9,5 6,7 19,0 13,2 6,7 4,75 4,75 3,35 1,70 1,18 For tests on aggregate sizes larger than the standard test size, use the apparatus listed in clause 3 and use the force as described in 5.1. For tests on the

33、smaller sizes of aggregate, use: a) crushing apparatus, of the same design but of internal diameter 77 mm, of internal depth 75 mm and with a plunger of diameter 75 mm; b) a measure that has an internal diameter of 60 mm and an internal depth of 90 mm; c) a tamping rod of nominal diameter 8 mm and o

34、f length approximately 300 mm; and d) a force that (at as uniform a rate as possible) reaches a value of 100 kN 2 kN in 10 min 15 s. SANS 5841:2008 Edition 2.1 5 Figure 1 Crushing apparatus SANS 5841:2008 Edition 2.1 6 Annex A (informative) Bibliography SABS 055, Methods of hardness testing of metallic materials. Amdt 1 SANS 5842, FACT value (10 % fines aggregate crushing value) of coarse aggregates. SABS