AASHTO T 218-1986 Standard Method of Test for Sampling Hydrated Lime《熟石灰抽样》.pdf

1、Standard Method of Test for Sampling Hydrated Lime AASHTO Designation: T 218-86 (2013)1American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-3a T 218-1 AASHTO Standard Method of Test for Sampling Hydrated Lime AASHTO Des

2、ignation: T 218-86 (2013)11. SCOPE 1.1. This method covers the procedure for sampling hydrated lime from various conveyors, points of shipment, and while in various states of storage. 1.2. The values stated in SI units are to be regarded as the standard. 1.3. Refer to R 16 for regulatory information

3、 for chemicals. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standard: R 16, Regulatory Information for Chemicals Used in AASHTO Tests 3. APPARATUS 3.1. Apparatus shall consist of a 50-mm (2-in.) wide paint brush, 4-L (1-gal) buckets (or other container of approximately that capacity) with double seal fricti

4、on lids (or other sealing method), and suitable lengths of sampling tubes, such as 25 mm (1 in.) in diameter and 2.5 m (8 ft) in length, and 19 mm (3/4in.) in diameter and 1 m (3 ft) in length, with suitable diagonal cut on one end. 4. SAMPLING PROCEDURE FOR POWDERED LIME IN BULK 4.1. Being loaded o

5、r recently loaded into tank trucks, railway hopper cars, or box cars, take a representative 2-L (1/2-gal) portion of the powdered lime to be analyzed and place it in a 4-L (1-gal) bucket (see Note 1). Fit the bucket with a tight-fitting lid. Clean the lime from the groove before placing the lid; bru

6、shing with a 50-mm (2-in.) paint brush has been found to be satisfactory for this purpose. Note 1These sample buckets shall be only half filled with sample material so that subsequent mixing may take place within the bucket itself. Half filling the container will allow sufficient space to permit pro

7、per agitation during subsequent mixing operations. The sample bucket shall be dry and clean so as to prevent sample contamination. 4.1.1. Tank trucks or railroad cars being loaded with material shall be sampled during the loading operation by inserting the bucket into the flowing stream of material

8、if conditions permit (see Note 2). The sampler should exercise due discretion in taking samples during the loading operation so that the total sample obtained is representative of the material. If material is being loaded from one or more bins or silos or from silo and plant production or various co

9、mbinations, the composite sample contained in the bucket shall be representative of the composite material. Insofar as the possibility of poor mixing may exist, the sampler may at his or her discretion take separate 2016 by the American Association of State Highway and Transportation Officials.All r

10、ights reserved. Duplication is a violation of applicable law.TS-3a T 218-2 AASHTO samples of individual portions of material being loaded. This is particularly advisable where, to effect a complete load, material is being loaded from more than one plant source. Note 2If conveyors are being loaded in

11、 the rain, make every effort to ensure the material contained in the sample bucket is typical of the material being shipped. In cases of suspected moisture difficulty, it is always advisable to rod the load with the long sampling tubes. 4.1.2. Trucks shall be rodded in three separate places from the

12、 top through the openings provided. Rod the center of the load and the two ends, rodding the material vertically or diagonally so as to obtain a composite 2-L (1/2-gal) portion of material that will be representative insofar as possible of the material. 4.1.3. If loading has been completed rather re

13、cently and weather conditions permit, “scoop” samples may be taken from the top of the loaded material and, depending upon the plant source of the material, the sampler may consider this sample to be representative. If the load is composed of one or more portions from more than one plant source, a “

14、scoop” sample may be taken from the top of each portion during the loading operation and these samples may either be combined or submitted separately for analysis. 4.1.4. Added precautions are necessary in sampling railway hopper cars. The sampler should request assistance from plant personnel in at

15、tempting to sample material in hopper cars. From the standpoint of safety, it is advisable that two people lift the heavy steel doors on as many openings as the sample requires be opened to allow for proper sampling. Should the level of material in the hopper car be too low to obtain a “scoop” sampl

16、e with a minimum of hazard, the material should be rodded in as many places as the sampler feels necessary, or the option of sampling from the loading spout with the assistance of plant personnel may be employed. Rodding the entire load in the prescribed fashion is the preferred method to be employe

17、d, but the sampler shall have the option of using any of the other methods described for such conditions should he or she believe the situation warrants employing such optional sampling procedures. With the exceptions noted, the details and principles suggested for the sampling of tank trucks while

18、being loaded, or recently loaded, also apply in the case of railway hopper cars under like conditions. 4.2. In Storage Awaiting ShipmentThis procedure applies to material loaded and left standing awaiting shipment in what might be considered a modification of bin storage. These loads in so-called “t

19、ruck storage” should be sampled by rodding the material with the long 2.5-m (8-ft) sampling tube. The sampler shall decide if the trucks have been loaded recently enough to permit “scoop” sampling or if sufficient time has elapsed since loading to make it advisable to rod the material so as to obtai

20、n a representative “through” sample of the material. The sampler shall base all decisions concerning the optional forms of sampling on what he or she considers will yield a representative sample of the material being shipped within the practicalities of the situation at hand. 4.3. At Job SiteA repre

21、sentative 2-L (1/2-gal) portion of material should be taken by rodding the material in the rail car or tank truck (before unloading; see Note 3) in at least three positions: the center and on both ends. Use the long 2.5-m (8-ft) sampling tube. Note 3The material in rail cars should be sampled by rod

22、ding the material before unloading, thus preventing the possibility of material contamination after unloading and possibility of obtaining an otherwise unrepresentative composite sample. Due to varying conditions of storage, and the possibility of sample contamination due to moisture, exposure to ai

23、r, etc., scoop samples are not recommended. 4.4. At Loading Spouts Feeding from Plant Production, from Bin Storage, or at Bagger Outlet Spouts Being Supplied by Either Plant Production or Bin StorageMake sure that a reasonable quantity of material has moved through the feed system so the possibility

24、 of contamination by material of long standing will be minimized. The 2-L (1/2-gal) sample should be taken from loaded bags rather than from the bagger outlet spout because sampling from the latter often tends to be 2016 by the American Association of State Highway and Transportation Officials.All r

25、ights reserved. Duplication is a violation of applicable law.TS-3a T 218-3 AASHTO nonrepresentative due to the presence of nonfresh or contaminated material in the outlet itself, and the usual spillage that occurs in attempting to sample at the bagger outlet spout does not add to overall plant clean

26、liness. (See Note 4.) Note 4Samplers shall keep in mind that no plant equipment shall be operated by sampling personnel. In general, it should be the responsibility of the plant personnel to operate all equipment and make the sample available in the sampler. Reasonable and safe sampling facilities s

27、hall be arranged for by the producer and furnished when possible, provided such arrangements meet with the principles involved in obtaining a truly representative sample of the material shipped. 4.5. From Loaded Silos or Storage BinsThere is usually a considerable lack of mixing in the material cont

28、ained in bulk hydrate storage bins. Stratification and flow patterns tend to occur, and experience in attempting to correlate silo samples with samples obtained from rodded trucks loaded from such silos indicates poor correlation. Wherever possible, avoid taking silo or bin storage samples and conce

29、ntrate the sampling on individual loads or shipments rather than taking composite samples of larger reservoirs that, due to poor mixing or other conditions prevalent, may contain portions of potentially unsatisfactory material that a composite sample might indicate to be satisfactory. (See Notes 5 a

30、nd 6.) Note 5Screw conveyors being supplied by either plant production or bin storage are dangerous sources for sampling material, and no attempt should be made to obtain material at such locations. Note 6Cumulative samples obtained by rodding should be thoroughly blended, after the container is tig

31、htly sealed, by repeatedly inverting and agitating the container. 5. SAMPLING PROCEDURE FOR BAGGED HYDRATED LIME 5.1. From Warehouse Stock Consigned for ShipmentIf necessary, request that plant personnel make the material available to the sampler. Take care not to sample among bagged material that i

32、s stacked dangerously high. If necessary, the sampler should ask plant personnel to make available the sacks that he or she desires to sample. Choice of sacks should be made on the basis of obtaining a representative sample of the lot being shipped. If the entire lot consigned for an individual truc

33、k or group of trucks is from several different warehouse lots, the sampler may at his or her discretion take samples from the separate lots that comprise the whole. The sampler should use the short sampling rod and, through the sack loading spout, take sufficient diagonal roddings to ensure a repres

34、entative portion from each sack, but not a sufficient quantity to materially reduce the poundage being supplied in any individual sack. For this reason and for the obvious reason of attempting to obtain a representative sample, it is suggested that at least four to six sacks from each lot be inspect

35、ed and sampled. These sampled lots may be combined to form one sample representing the individual truck, or they may be submitted for analysis separately. Generally speaking, at least six sacks should be sampled to represent each truck being shipped from consigned, previously produced, and stored wa

36、rehouse stock, to obtain the 2-L (1/2-gal) sample. 5.2. From Bag LoadsIf the truck is partially loaded, the sampler may choose sacks at his or her discretion to effect a representative sample and may also sample floor stock consigned for the partially loaded truck so as to obtain a representative sa

37、mple. The sampler may combine sampling from a partially loaded truck with material being produced by obtaining a sample at the bagger however, due to the usual spillage and interruption of plant activities, this bagger sampling option is not recommended. Rather than sampling at the bagger, it would

38、be preferable to sample the bags being loaded on the truck or the loaded bags at various stages of the loading operation. The matter of which bags to sample should be at the discretion of the sampler; however, the sacks chosen for sampling should be selected from various points in the load so as to

39、effect a representative sample. In sampling from loaded trucks and rail cars, the short sampling rod should be used to obtain a total of a 2-L (1/2-gal) sample from at least six sacks of material. Insert the sampling rod through the loading valve and take several through samples diagonally from each

40、 sack, taking care not to puncture the bottom or sides of the sack with the sharp sampling tube. (See Note 6.) 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3a T 218-4 AASHTO 6. PRECISION 6.1. Becau

41、se this method of sampling produces no numerical values, determination of the precision and accuracy is not applicable. 7. KEYWORDS 7.1. Hydrated lime; lime; sampling. 1Minor editorial revisions have been made at the discretion of the authors responsible for standards on hydraulic cement and lime (technical section 3a). 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.