1、Designation: D 3880 90 (Reapproved 2004)e1Standard Test Method forAsbestos Strength Units1This standard is issued under the fixed designation D 3880; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A numb
2、er in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.e1NOTEAsbestos warning was moved from 8.1.1 to 1.7 in September 2004.1. Scope1.1 This test method gives a procedure for the evaluation ofthe strength-
3、giving properties of asbestos fibers used to rein-force asbestos-cement products.1.2 The purpose of this test method is to determine thenumber of strength units that may be assigned to the sampletested.1.3 Asbestos fiber possesses the ability to impart strength toan asbestos-cement product. Every fi
4、ber grade may be regardedas possessing a certain quantity of strength-giving units. Thequantity of fiber required in an asbestos-cement compositionvaries inversely with the number of strength units it possesses.For example, if an amount, designated by X, of a fiberpossessing 100 strength units produ
5、ces a product of a givenstrength, 2X would be required to produce a product ofequivalent strength from fiber possessing only 50 strengthunits.1.4 The following definition is the basis for the strength unittest: An asbestos fiber that gives the standard strength at thestandard density when used as 10
6、 % of the furnish is defined ashaving 100 strength units. Therefore, by knowing the percentfiber required in the mix to give standard strength at thestandard density, it is possible to calculate the strength units ofa sample of asbestos.1.5 This procedure is intended primarily for chrysotileasbestos
7、; it has not been verified whether or not it is applicableto other types.1.6 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.7 WarningBreathing of asbestos dust is hazardous.Asbestos and asbestos products present demonstrated
8、 healthrisks for users and for those with whom they come into contact.In addition to other precautions, when working with asbestos-cement products, minimize the dust that results. For informa-tion on the safe use of chrysoltile asbestos, refer to “Safe Useof Chrysotile Asbestos: A Manual on Preventi
9、ve and ControlMeasures.”21.8 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations pri
10、or to use. For specificprecautionary statements see 9.2.2, Note 6, and 1.7.2. Referenced Documents2.1 ASTM Standards:3C 150 Specification for Portland CementC 184 Test Method for Fineness of Hydraulic Cement bythe 150-m (No. 100) and 75-m (No. 200) SievesC 204 Test Method for Fineness of Portland Ce
11、ment by AirPermeability ApparatusC 430 Test Method for Fineness of Hydraulic Cement bythe 45-m (No. 325) SieveC 1120 Test Method for Wash Test of AsbestosC 1121 Test Method for Turner and Newall (T and N)Wet-Length Classification of AsbestosC 1162 Test Method for Loose Density of AsbestosD 1193 Spec
12、ification for Reagent WaterD 1655 Specification for Aviation Turbine FuelsD 2590 Test Method for Sampling Chrysotile AsbestosD 2946 Terminology Relating to Asbestos and Asbestos-Cement ProductsD 2589 Test Method for McNett Wet Classification ofAsbestos FiberD 3639 Test Method for Classification of A
13、sbestos Fibersby Quebec Standard TestD 3752 Test Method for Strength Imparted byAsbestos to aCementitious Matrix1This test method is under the jurisdiction of ASTM Committee C17 onFiber-Reinforced Cement Products and is the direct responsibility of C17.03 onAsbestos-Cement Sheet Products and Accesso
14、ries.Current edition approved June 1, 2004. Published August 2004. Originallyapproved in 1980. Last previous edition approved in 1999 as D 3880 90 (1999).2Available from The Asbestos Institute, http:/ referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at
15、 serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.E11 Specification for Wire-Cloth Sieves for Testin
16、g Pur-poses2.2 Other Standards:Quebec Asbestos Mining Association (QAMA) Standard,Designation for Chrysotile Asbestos Grades43. Terminology3.1 Definitions:3.1.1 point value, n in asbestos, an index of commercialvalue of asbestos fiber used in asbestos-cement products. Pointvalue = (SU-10)/1.39 where
17、 SU stands for strength units.3.1.2 strength unit, n in asbestos, unit of reinforcingpotential of asbestos fiber in asbestos-cement products. Anasbestos fiber that yields a flexural modulus of rupture of 27MPa at a product density of 1.6 g/cm3when used as 10 % ofthe furnish (dry ingredients) is defi
18、ned as having 100 strengthunits. Therefore, the number of strength units of a givenasbestos is equal to 1000/(% fiber required in the dry mix toyield 27 MPa at 1.6 g/cm3).3.1.3 Refer to Terminology D 2946 for other terms relatingto asbestos.4. Summary of Test Method4.1 This test method covers the fa
19、brication and flexuraltesting of asbestos-cement test specimens that contain asbestosfiber from the sample being evaluated. The calculation ofstrength units of the asbestos, based upon the flexural strength,density and composition of the test specimens, is also de-scribed.4.2 The specimen fabricatio
20、n process includes the followingsteps:4.2.1 Asbestos fiber preparation, including ball milling,fiberizing, and blending.4.2.2 Compounding, including dry mixing, the preparationof saturated water, and wet mixing.4.2.3 Test specimen formation, including the pressing ofasbestos-cement cakes in a semi-a
21、utomatic press.4.2.4 Specimen curing, including a stage in a humiditycabinet, autoclaving, air cooling, and saturating in a water bath.4.3 Specimen testing, including the determination of im-mersed mass, saturated mass, flexural strength, specimenthickness and width, and dry mass.4.4 Calculations, i
22、nvolving the determination of specimenvolume, modulus of rupture, density, modulus of ruptureadjusted for density, asbestos fiber content required to attainstandard strength, fiber ratio required, point value, and strengthunits.5. Significance and Use5.1 This test method facilitates the comparison o
23、f differenttypes and grades of chrysotile asbestos by the property mostpertinent to its use in asbestos-cement, namely, the strength orreinforcing value it imparts to the product.5.2 While similar comparative results could be obtained onany given production equipment, this method allows the testingo
24、f small samples, avoids costly interruptions in production fornumerous trial runs, and allows test values to be obtained by asingle standard method so that results can be compared amongdifferent locations.5.3 Strength Unit (SU) value of a fiber blend used inasbestos-cement products may be estimated
25、by taking theproportionate SU value of each component of the fiber blend.5.4 If the fiber blend is formulated with the aim to optimizeanother fiber property such as filterability, the SU calculationwill assure that the blend will not fall below an acceptablestrength level.5.5 This test method is res
26、tricted to grades of asbestos usedin asbestos-cement products. Very long (Group 3) fibers aredifficult to evaluate by this method because the test specimensproduced may not be sufficiently homogeneous. Similarly, veryshort (Group 7) grades may not be retained satisfactorily in themold during the pre
27、ssing of test specimens or may not providesufficient strength to meet the test requirements.NOTE 1The term Group 3 or 7 refers to the standard designation forchrysotile asbestos grades established by the Quebec Asbestos MiningAssociation, See 2.2.5.6 Because of certain differences between this metho
28、d andthe many variations in plant production procedure commonlyused in asbestos-cement manufacture, it is emphasized that thestrength values obtained by this standardized procedure willnot necessarily give exactly the same strength values asobtained at any one specific manufacturing plant.6. Apparat
29、us6.1 Ball Milling:6.1.1 Porcelain Ball Mill Jars,5meeting the followingspecifications:Capacity 11 000 cm3(671 in.3)External diameter 280 mm (11.02 in.)Internal diameter 230 mm (9.06 in.)Internal height 210 mm (8.27 in.)6.1.2 Porcelain Balls,6machine made, meeting the follow-ing specifications:Diame
30、ter 40 mm (1.575 in.)Mass (each) 74 to 75 g (0.163 to 0.165 lb)Specific activity 2.3 6 0.1 (The manufacturer specifies a nominalspecific gravity of 2.22.)Alternatively, handmade balls approaching these specifica-tions may be used.6.1.2.1 Discard balls when their diameter is 35 mm (1.38in.) or less.6
31、.1.3 Roll Table, to rotate the ball mill jars at 6.81 6 0.21rad/s (65 6 2 r/min). See Note 2.6.2 Fiberizing:4Available from Asbestos Institute, 1130 Sherbrooke St. West, Montreal, Q.C.,H3A2 M8.5Type KU5a ball mill jars, and machine-made balls, manufactured by StaatlichePorzellan Manufaktur, Berlin W
32、erk Seld, Selb/afr. Hartmannstrasse 13, GermanFederal Republic (West Germany), have been found suitable. These are distributedby Fish-Schurman, 70 Portman Road, New Rochelle, NY.6Manufactured by Ateliers de Lessines S.A., Division BOP, 55 rue de Wauthier1020, Bruxelles, Belgium.D 3880 90 (2004)e126.
33、2.1 Disintegrator,7B.O.P. (Ball, Opener, Penmen) TypeO, driven at 565 6 21 rad/s (5400 6 200 r/min) by asquirrel-cage induction motor rated at no less than 1.492 kW (2hp).6.2.2 Perforated Steel Discharge Plates, for the fiberizer.One each of the following opening diameters: 3, 5, 7 and 10mm, 6 3 %.
34、Holes must be on an equilateral triangular pitchwith wire edges pointing outward.6.2.3 Cardboard Drum, approximately 410 mm (16 in.) indiameter by 400 mm (15 in.) in height with removable ringclamp on top, and canvas dust cover (transition piece) to serveas a receiver for the fiberizer discharge. Ot
35、her arrangements forreceiving the fiberizer discharge that are satisfactory withrespect to relief of static pressure generated by the fiberizerrotor and with respect to the prevention of sample losses andcontamination are acceptable. The free area of cloth while inoperating position must be within t
36、he limits from 1300 to 4500cm2, and the cloth must be square weave, unbleached cottonduck weighing 0.41 6 0.02 kg/m2(12 oz/yd2), or a cloth ofequivalent permeability.6.3 Blending:6.3.1 Polyethylene Jar with Cover,8meeting the followingspecifications:Inside diameter 311 mm (12.25 in.)Outside diameter
37、 327 mm (12.875 in.) (wall thickness 8 mm (0.3 in.)Inside height 311 mm (12.25 in.)Other containers, such as stainless steel blenders, withsimilar internal dimensions may be used.6.3.1.1 The jar may be fitted with a circumferential rubbertension band 100 mm (3.94 in.) wide by 3 mm (0.125 in.) thickt
38、o retain the cover. This band may be rolled down, turtleneckfashion, when the cover must be opened. Alternatively, thecover may be retained by mechanical clamps. In that case, theuse of a gasket to seal the cover may be necessary.6.3.1.2 The jar must be fitted with tires around the outerdiameter to
39、allow it to roll on a roll table in a horizontal attitudeand to allow any clamps or projections to clear the rolls.6.3.2 Roll-Table, to rotate the blending jar at a speed of 5.876 0.21 rad/s (56 6 2 r/min). See Note 2.6.3.3 Rolling Sheet,1m2(1 yd2) or larger, made of rubber,plastic, or some other fl
40、exible elastomer.6.4 Dry Mixing:6.4.1 Polyethylene Jar with Cover,8meeting the followingspecifications:Inside diameter 248 mm (9.75 in.)Outside diameter 257 mm (10.125 in.)Inside height 273 mm (10.75 in.)Capacity 13 200 cm3Other containers, such as stainless steel mixers, with similarinternal dimens
41、ions may be used.6.4.1.1 The jar must be fitted with a rubber band asdescribed in 6.3.1.1.6.4.1.2 The exterior of the jar must be fitted with tires asdescribed in 6.3.1.2.6.4.1.3 The interior of the jar must be fitted with threemixing vanes located 2.09 rad (120) apart, along the fulllength of the j
42、ar and projecting 38.1 mm (1.5 in.) from theinside wall. The vanes may be fastened to the wall by smoothhead rivets or an adhesive. The corners of the vanes at the jaropening should be rounded to a radius of 12.7 mm (0.5 in.).The vanes may be fabricated from aluminum or any othercorrosion-resistant
43、sheet metal 1 mm (0.04 in.) thick.6.4.2 Roll-Table, to rotate the blending jar at a speed of 8.176 0.21 rad/s (78 6 2 r/min).7Those supplied by Canadian Laboratory Supplied Limited, Box 2090 Stn. St.Laurent, Montreal 307, P. Q., Canada, are suitable. Specify dimensions required,request a design simi
44、lar to Catalog No. J3028, and refer to Canlab Quotation No.2713 (1969).8Containers supplied by Canadian Laboratory Supplies Limited, Box 2090, Stn.St. Laurent, Montreal 307, P. Q., Canada, (Catalog No. J3028-14), are suitable.These must be fitted with suitable vanes.FIG. 1 Wet-Mixer AssemblyD 3880 9
45、0 (2004)e13NOTE 2If a judicious choice of drive roll diameter and speed ischosen for the roll table, together with suitable tire dimensions forcontainers mentioned in 6.1.1, 6.3.1 and 6.4.1, it is possible to use thesame roll table for the three containers. For example, if the drive roll hasa diamet
46、er of 125 mm (4.93 in.) and a speed of 17.3 rad/s (165 r/min), thenthe appropriate speed would be obtained for each container if tires wereadjusted to bring the effective outer diameters to 311 mm (12.25 in.) forthe ball mill jars, 361 mm (14.21 in.) for the blending jars, and 259 mm(10.2 in.) for t
47、he dry-mixing jars.6.5 Wet Mixing:6.5.1 Wet Mixer, as described in Fig. 1, Fig. 2, Fig. 3 andFig. 4 and mounted on the press. The drive motor must be ableto maintain a speed of 62.83 6 2.62 rad/s (600 6 25 r/min)under load.6.5.1.1 The Sunbeam Mix Mastert motor suggested in Fig.1 may be replaced for
48、heavier duty by another motor, such asthe Bodine motor9with one shaft at motor speed and anothershaft driven through a right-angle gear with a speed reductionof 6:1 or 10:1. This motor may be operated with a rheostatspeed control, but more satisfactory performance is achievedby means of an autotrans
49、former.6.5.1.2 The Bodine motor has an additional advantage. If astrobe card is mounted on the higher speed shaft while theimpeller is mounted on the other shaft, then the strobe card(consisting of two black and two white alternating segments)will rotate at 377 rad/s (3600 r/min) when the impeller is at62.8 rad/s (600 r/min), and the strobe card will appearstationary when illuminated with standard fluorescent lampsoperating on 60 Hz alternating current. For the 10:1 speedreduction motors, mount the strobe card on the impeller
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