AASHTO R 90-2018 Standard Practice for Sampling Aggregate Products.pdf

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1、Standard Practice for Sampling Aggregate Products AASHTO Designation: R 90-181Technical Section: 1c, Aggregates Release: Group 3 (August) American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-1c R 90-1 AASHTO Standard Pr

2、actice for Sampling Aggregate Products AASHTO Designation: R 90-181Technical Section: 1c, Aggregates Release: Group 3 (August) 1. SCOPE 1.1. This practice covers the procedures for obtaining representative samples of coarse, fine, or combinations of coarse and fine aggregate (CA and FA) products to

3、determine compliance with requirements of the specifications under which the aggregate is furnished. The method includes sampling from conveyor belts, transport units, roadways, and stockpiles. 1.2. This standard does not purport to address all of the safety concerns, if any, associated with its use

4、. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. REFERENCED STANDARDS 2.1. AASHTO Standards: M 323, Superpave Volumetric Mix Design T 11, Materials Finer Than 75-m (

5、No. 200) Sieve in Mineral Aggregates by Washing T 27, Sieve Analysis of Fine and Coarse Aggregates 2.2. ASTM Standard: D75/D75M, Standard Practice for Sampling Aggregates 3. SIGNIFICANCE AND USE 3.1. Sampling is a critical step in determining the quality of the material being evaluated. Care shall b

6、e exercised to ensure that samples are representative of the material being evaluated. 3.2. This practice is intended to provide standard requirements and procedures for sampling coarse, fine and combinations of coarse and fine aggregate products. The detailed requirements as to materials, interpret

7、ation of results, and precision and bias are described in specific test methods. 3.3. For sampling of potential aggregate sources and preliminary site investigation, refer to ASTM D75/D75M. 4. APPARATUS 4.1. Shovels or Scoops, or BothTools with which to gather the sample. 2018 by the American Associ

8、ation of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-1c R 90-2 AASHTO 4.2. Brooms, Brushes, and Scraping ToolsTools to assist in collecting the sample. 4.3. Sampling TubePlastic, aluminum, or similar tube whose diameter is at least

9、 three times the nominal maximum aggregate size; the end of the tube may be angled to assist in sampling. 4.4. Mechanical Sampling SystemsNormally, a permanently attached device that allows a sample container to pass perpendicularly through the entire stream of material or diverts the entire stream

10、of material into the container by manual, hydraulic, or pneumatic operation. 4.5. Belt TemplateA pair of templates, either joined to each other or separate, which are the shape and width of the aggregate stream belt. If the two templates are joined, enough space must be allowed between the templates

11、 to yield an increment of the required weight. 4.6. Sampling ContainersBags or other containers so constructed as to preclude loss or contamination of any part of the sample, or damage to the contents from mishandling during shipment. For moisture content samples, containers must prevent moisture lo

12、ss. 5. PROCEDURE 5.1. Sampling is as important as testing. The technician shall use every precaution to obtain samples that are representative of the material. Record the sampling time or location, or both. When samples will be used as part of a statistical quality control or acceptance program, det

13、ermine the time or location for sampling using a random sampling procedure. 5.1.1. Ensure sampling equipment and containers are clean and dry before sampling. 5.2. The field samples should meet or exceed the minimum mass in Table 1. The amounts specified in Table 1 will generally provide adequate ma

14、terial for routine grading and quality analysis (Note 1). Note 1Sample size is based upon the test(s) required. Generally, the field sample size should be such that, when split twice, it will provide a testing sample of proper size. For example, the sample size may be four times that shown in T 27,

15、or in T 11 if that mass is more appropriate. Table 1Recommended Sample Sizes Nominal Maximum Size Minimum Mass mm (in.) kg (lb) 90 (31/2) 175 (385) 75 (3) 150 (330) 63 (21/2) 125 (275) 50 (2) 100 (220) 37.5 (11/2) 75 (165) 25.0 (1) 50 (110) 19.0 (3/4) 25 (55) 12.5 (1/2) 15 (35) 9.5 (3/8) 10 (25) 4.7

16、5 (No. 4) 10 (25) 2.36 (No. 8) 10 (25) Note 2Nominal maximum size may be defined by aggregate type or usage; for example, as defined by M 323. 5.3. Sampling from Conveyor Belt Using a Sampling TemplateAvoid sampling at the beginning or end of the aggregate run due to the potential for segregation. B

17、e careful when sampling in the rain. Make sure to capture material that may stick to the belt or that the rain tends to wash away. 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-1c R 90-3 AASHTO 5.3

18、.1. Stop the belt. 5.3.2. Set the sampling template in place on the belt avoiding intrusion by adjacent material. 5.3.3. Remove the material from inside the template; include all of the material adhering to the belt. 5.3.4. Obtain equal increments when one increment is insufficient for the required

19、testing. 5.3.5. Combine the increments to form a single sample. 5.4. Sampling from Conveyor Belt DischargeAvoid sampling from the beginning or end of an aggregate run due to the potential for segregation. To collect a representative sample the sampling device must pass through the full stream of mat

20、erial as it runs off the conveyor belt. A manually, semi-automatic, or automatically operated sampling device may be used to collect the sample. 5.4.1. Pass a sampling device, at a constant speed and perpendicular to the flow of material, through the full stream once in each direction without overfi

21、lling; include all material that may adhere to the sampling device when emptying into the container, or divert the full stream of material into container. 5.4.2. Obtain multiple equal increments when one increment is insufficient for the required testing. 5.4.3. Combine the increments to form a sing

22、le sample. 5.5. Sampling from Transport Units: 5.5.1. Visually divide the unit into four quadrants. 5.5.2. Identify one sampling location in each quadrant. 5.5.3. Remove approximately 0.3 m (1 ft) of material from the sampling area. Obtain an increment from the exposed surface. Repeat in each of the

23、 remaining quadrants. 5.5.4. Combine the increments to form a single sample. 5.6. Sampling from RoadwayBerm or Windrow: 5.6.1. Do not take the sample or any increment from the beginning or end of the windrow or berm. 5.6.2. Remove the top one third of the windrow or berm before taking an increment.

24、5.6.3. Obtain a minimum of three approximately equal increments from random locations along the windrow or berm. 5.6.3.1. Fully insert the shovel into the location, exclude the underlying material, roll back the shovel, and lift the material slowly out of the pile to avoid material rolling off the s

25、hovel. 5.6.4. Combine the increments to form one single sample. 5.7. Sampling from RoadwayIn Place: 5.7.1. Obtain representative sample after spreading and before compacting. 5.7.2. Insert the shovel to the full depth of the material, exclude the underlying material, roll back the shovel, and lift t

26、he material slowly to avoid material rolling off the shovel. Repeat as necessary. 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-1c R 90-4 AASHTO 5.8. Sampling from Stockpile for Coarse Aggregate an

27、d Mixtures of Coarse and Fine Aggregate Products: 5.8.1. Sampling from a Flat Surface Created by a Loader: 5.8.1.1. Direct the loader operator to enter the stockpile with the bucket at least 0.3 m (1 ft) above ground level without contaminating the stockpile. 5.8.1.2. Discard the first bucketful. 5.

28、8.1.3. Have the loader re-enter the stockpile, obtain a full loader bucket of the material, and tilt the bucket back and up. 5.8.1.4. Form a small sampling pile at the base of the stockpile by gently rolling the material out of the bucket with the bucket just high enough to permit free flow of the m

29、aterial. Repeat as necessary. 5.8.1.5. Create a flat surface by having the loader back drag the small pile. 5.8.1.6. Obtain increments from at least three randomly selected locations on the flat surface at least 1 ft (300 mm) from the edge. 5.8.1.7. Fully insert the shovel, exclude the underlying ma

30、terial, roll back the shovel, and lift the material slowly out of the pile to avoid material rolling off the shovel. 5.8.1.8. Combine the increments to form a sample. 5.8.2. Sampling from a Horizontal Surface on the Stockpile Face: 5.8.2.1. Create horizontal surfaces with vertical faces in the top,

31、middle, and bottom third of the stockpile with a shovel, or with a loader if one is available. 5.8.2.2. Shove a flat board against the vertical face behind sampling location to prevent sloughing. Discard sloughed material to create the horizontal surface. 5.8.2.3. Obtain sample from the horizontal s

32、urface as close as possible to the intersection of the horizontal and vertical faces. 5.8.2.4. Obtain at least one increment of equal size from each of the top, middle, and bottom thirds of the pile. 5.8.2.5. Combine the increments to form a single sample. 5.9. Sampling from a Stockpile for Fine Agg

33、regate (Alternate Tube Method): 5.9.1. Remove the outer layer of material. 5.9.2. Using a sampling tube, obtain increments of equal size from a minimum of five random locations on the pile. 5.9.3. Combine the increments to form a single sample. 2018 by the American Association of State Highway and T

34、ransportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-1c R 90-5 AASHTO 6. SHIPPING SAMPLES 6.1. Use bags or containers to transport aggregate samples. Make sure the bags and containers are clean and undamaged to avoid contamination or loss of sample. 6.2. Labe

35、l each sample with unique identification labels that contain the following information: 6.2.1. Date and time the sample was obtained; 6.2.2. Sampling location; 6.2.3. Quantity of material represented by the sample, if applicable; 6.2.4. Material type; and 6.2.5. Supplier. 7. KEYWORDS 7.1. Coarse aggregate; fine aggregate; samples. 1Formerly T 2. First published as a practice in 2018. 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.