Значение и использование

5.1 The gradation of the soil is used for classification in accordance with Practice D2487.

5.2 The gradation (particle-size distribution) curve is used to calculate the coefficient of uniformity and the coefficient of curvature.

5.3 Selection and acceptance of fill materials are often based on gradation. For example, highway embankments, backfills, and earthen dams may have gradation requirements.

5.4 The gradation of the soil often controls the design and quality control of drainage filters, and groundwater drainage.

5.5 Selection of options for dynamic compaction and grouting is related to gradation of the soil.

5.6 The gradation of a soil is an indicator of engineering properties. Hydraulic conductivity, compressibility, and shear strength are related to the gradation of the soil. However, engineering behavior is dependent upon many factors (such as effective stress, stress history, mineral type, structure, plasticity, and geologic origins) and cannot be based solely upon gradation.

Note 1: The quality of the result produced by these test methods is dependent on the competence of the personnel performing it, and the suitability of the equipment and facilities used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent and objective testing/sampling/inspection/etc. Users of these test methods are cautioned that compliance with Practice D3740 does not in itself assure reliable results. Reliable results depend on many factors; Practice D3740 provides a means of evaluating some of those factors.

Область применения

1.1 Soils consist of particles with various shapes and sizes. This test method is used to separate particles into size ranges and to determine quantitatively the mass of particles in each range. These data are combined to determine the particle-size distribution (gradation). This test method uses a square opening sieve criterion in determining the gradation of soil between the 3-in. (75-mm) and No. 200 (75-µm) sieves.

1.2 The terms, soils and material, are used interchangeably throughout the standard.

1.3 In cases where the gradation of particles larger than 3 in. (75 mm) sieve is needed, Test Method D5519 may be used.

1.4 In cases where the gradation of particles smaller than No. 200 (75-µm) sieve is needed, Test Method D7928 may be used.

1.5 Typically, if the maximum particle size is equal to or less than 4.75 mm (No. 4 sieve), then single-set sieving is applicable. Furthermore, if the maximum particle size is greater than 4.75 mm (No. 4 sieve) and equal to or less than 9.5 mm (³/₈-in sieve), then either single-set sieving or composite sieving is applicable. Finally, if the maximum particle size is equal to or greater than 19.0 mm (³/₄-in sieve), composite sieving is applicable. For special conditions see 10.3.

1.6 Two test methods are provided in this standard. The methods differ in the significant digits recorded and the size of the specimen (mass) required. The method to be used may be specified by the requesting authority; otherwise Method A shall be performed.

1.6.1 Method A—The percentage (by mass) passing each sieve size is recorded to the nearest 1 %. This method must be used when performing composite sieving. For cases of disputes, Method A is the referee method.

1.6.2 Method B—The percentage (by mass) passing each sieve size is recorded to the nearest 0.1 %. This method is only applicable for single sieve-set sieving and when the maximum particle size is equal to or less than the No. 4 (4.75-mm) sieve.

1.7 This test method does not cover, in any detail, procurement of the sample. It is assumed that the sample is obtained using appropriate methods and is representative.

1.8 Sample Processing—Three procedures (moist, air dry, and oven dry) are provided to process the sample to obtain a specimen. The procedure selected will depend on the type of sample, the maximum particle-size in the sample, the range of particle sizes, the initial conditions of the material, the plasticity of the material, the efficiency, and the need for other testing on the sample. The procedure may be specified by the requesting authority; otherwise the guidance given in Section 10 shall be followed.

1.9 This test method typically requires two or three days to complete, depending on the type and size of the sample and soil type.

1.10 This test method is not applicable for the following soils:

1.10.1 Soils containing fibrous peat that will change in particle size during the drying, washing, or sieving procedure.

1.10.2 Soils containing extraneous matter, such as organic solvents, oil, asphalt, wood fragments, or similar items. Such extraneous matter can affect the washing and sieving procedures.

1.10.3 Materials that contain cementitious components, such as cement, fly ash, lime, or other stabilization admixtures.

1.11 This test method may not produce consistent test results within and between laboratories for the following soils and the precision statement does not apply to them.

1.11.1 Friable soils in which the sieving processes change the gradation of the soil. Typical examples of these soils are some residual soils, most weathered shales and some weakly cemented soils such as hardpan, caliche or coquina.

1.11.2 Soils that will not readily disperse such as glauconitic clays or some dried plastic clays.

1.11.3 To test these soils, this test method must be adapted, or altered, and these alterations documented. Depending on the design considerations, a specialized gradation-testing program could be performed. The alterations could require the washing and sieving procedures to be standardized such that each specimen would be processed in a similar manner.

1.12 Some materials that are not soils, but are made up of particles may be tested using this method. However, the applicable sections above should be used in applying this standard.

1.13 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026, unless superseded by this test method.

1.13.1 The procedures used to specify how data are collected/recorded and calculated in this standard are regarded as the industry standard. In addition, they are representative of the significant digits that generally should be retained. The procedures used do not consider material variation, purpose for obtaining the data, special purpose studies, or any considerations for the user's objectives; and it is common practice to increase or reduce significant digits of reported data to be commensurate with these considerations. It is beyond the scope of these test methods to consider significant digits used in analysis methods for engineering design.

1.14 Units—The dimensional values stated in either SI units or inch-pound units are to be regarded as standard, such as 200-mm or 8-in. diameter sieve. Except, the sieve designations are typically identified using the “alternative” system in accordance with Practice E11, such as 3 in. and No. 200, instead of the “standard” system of 75 mm and 75 µm, respectively. Only the SI units are used for mass determinations, calculations, and reported results. However, the use of balances or scales recording pounds of mass (lbm) shall not be regarded as nonconformance with this standard.

1.15 A summary of the symbols used in this test method is given in Annex A1.

1.16 This standard does not purport to address all of the safety concerns, if any, associated with its use. 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.

1.17 Table of Contents—All tables and figures appear at the end of this standard.

 

Section

Scope

1

 Method A

1.6.1

 Method B

1.6.2

 Sample Processing

1.8

 Units

1.14

Referenced Documents

2

 ASTM Standards

2.1

Terminology

3

 General

3.1

 Definitions

3.2

 Definitions of Terms Specific to This Standard

3.3

Summary of Test Method

4

Significance and Use

5

Apparatus

6

 Sieves

6.1

  Standard Sieve Set

6.1.1

  Washing Sieve, No. 200 (75-μm)

6.1.2

  Designated Separating Sieve

6.1.3

 Washing Sink with Spray Nozzle

6.2

 Mechanical Sieve Shaker

6.3

 Balances

6.4

 Drying Oven

6.5

 Sieving Containers

6.6

  Specimen Containers

6.6.1

  Collection/Transfer Device

6.6.2

  Cumulative Mass Container

6.6.3

 Sieve Brushes

6.7

 Miscellaneous Items

6.8

 Splitter or Riffle Box (optional)

6.9

 Quartering Accessories (optional)

6.10

 Mortar and Rubber-Covered Pestle (optional)

6.11

 Low Temperature Drying Oven (optional)

6.12

 Ultrasonic Water Bath (optional)

6.13

 Dispersion Shaker (optional)

6.14

Reagents

7

 Sodium Hexametaphosphate

7.1

  Dry Addition

7.1.1.1

  Solution

7.1.1.2

Preparation of Apparatus

8

 Verification of Sieves

8.1

  Verification Interval

8.1.1

 Verification of Mechanical Sieve Shaker and
 Standard Shaking Period

8.2

  Large Mechanical Sieve Shaker

8.2.1

  Verification Interval

8.2.2

  Hand Sieve Shaking Procedure

8.2.3

Sampling

9

 General

9.1

 Sample Sources

9.2

  Bulk Samples

9.2.1

  Jar and Small Bag Samples

9.2.2

  Intact Tube Samples

9.2.3

  Samples from Prior Testing

9.2.4

Specimen

10

 General

10.1

 Minimum Mass Requirement

10.2

 Selection of Sieving Procedure

10.3

  Single Sieve-Set Sieving

10.3.1

  Composite Sieving

10.3.2

 Specimen Procurement

10.4

  Moist Procedure

10.4.1

  Air-Dried Procedure

10.4.2

  Oven-Dried Procedure

10.4.3

  Discussion on Segregating Soils

10.4.4

 Specimen Procurement and Processing Requirements

10.5

  Moist Procedure, Single Sieve-Set Sieving

10.5.1

  Moist Procedure, Composite Sieving

10.5.2

   Coarse Portion Acceptable Loss (CP_L)

10.5.2.3

  Air-Dried Procedure, General

10.5.3

  Air-Dried Procedure, Single Sieve-Set Sieving

10.5.4

  Air-Dried Procedure, Composite Sieving

10.5.5

  Oven-Dried Procedure, General

10.5.6

  Oven-Dried Procedure, Single Sieve-Set Sieving

10.5.7

  Oven-Dried Procedure, Composite Sieving

10.5.8

Procedure (Sieving)

11

 General

11.1

 Mass Measurements

11.2

 Sieve Overloading

11.3

 Single Sieve-Set Sieving

11.4

  Specimen Mass

11.4.1

  Specimen Dispersion

11.4.2

   Soaking without a Dispersant

11.4.2.1

   Soaking with a Dispersant

11.4.2.2

   Using an Ultrasonic Water Bath

11.4.2.3

  Washing Specimen

11.4.3

   General Precautions

11.4.3.1

   Transfer Specimen

11.4.3.2

   Washing

11.4.3.3

   Transfer Washed Specimen

11.4.3.4

  Dry Sieving

11.4.4

   Sieve Set

11.4.4.1

   Mechanical Shaking

11.4.4.2

  Cumulative Material/Mass Retained

11.4.5

   First Sieve

11.4.5.1

   Remaining Sieves

11.4.5.2

 Composite Sieving, Single Separation

11.5

  Coarser Portion

11.5.1

   Dispersing and Washing

11.5.1.1

   Dry Sieving Coarser Portion

11.5.1.3

  Subspecimen from Finer Portion

11.5.2

   Dispersing and Washing Subspecimen

11.5.2.1

   Dry Sieving Subspecimen

11.5.2.2

 Composite Sieving, Double Separation

11.6

  Separating 1^st Subspecimen

11.6.1

  Dispersing and Washing 2^nd Coarser Portion

11.6.2

  Dry Sieving 2^nd Coarser Portion

11.6.3

  2^nd Subspecimen

11.6.4

   Dispersing and Washing 2^nd Subspecimen

11.6.4.1

   Dry Sieving 2^nd Subspecimen

11.6.4.2

Calculations

12

 General

12.1

 Sieve Overloading

12.2

 Single Sieve-Set Sieving, Percent Passing

12.3

 Composite Sieving, Mass of Specimen

12.4

 Composite Sieving, Single Separation

12.5

  Composite Sieving, Coarser Portion (CP)

12.5.1

   CP, Percent Passing

12.5.1.1

   CP, Composite Sieving Correction
    Factor (CSCF)

12.5.1.2

   CP, Acceptable Loss During Washing
    and Sieving

12.5.1.3

   Composite Sieving, Subspecimen (finer
    portion)

12.5.2

   Percent Passing, Specimen (combined
    coarser and finer portions)

12.5.2.1

   Subspecimen, Acceptable Fractional
    Percent Retained

12.5.2.2

   Percent Passing, Acceptance Criterion

12.5.2.3

   Finer Portion, Percent Passing (optional)

12.5.3

 Composite Sieving, Double Separation

12.6

  1^st Coarser Portion

12.6.1

  1^st Subspecimen

12.6.2

   Percent Passing, 2^nd Coarser Portion

12.6.2.1

   2^nd Coarser Portion, Composite Sieving
    Correction Factor (2^ndCSCF)

12.6.2.2

   2^nd Coarser Portion, Acceptable Loss on
    Sieving and Washing

12.6.2.3

   2^nd Coarser Portion, Acceptable Fractional
    Percent Retained

12.6.2.4

   Percent Passing, Acceptance Criterion

12.6.2.5

  2^nd Subspecimen

12.6.3

   Percent Passing, 2^nd Subspecimen

12.6.3.1

   2^nd Subspecimen, Acceptable Fractional
     Percent Retained

12.6.3.2

   Percent Passing, Acceptance Criterion

12.6.3.3

  1^st Finer Portion, Percent Passing (optional)

12.6.4

   2^nd Finer Portion, Composite Sieving
    Correction Factor (optional)

12.6.4.1

   2^nd Finer Portion, Percent Passing for
    2^nd Subspecimen (optional)

12.6.4.2

Report: Test Data Sheet(s)/Form(s)

13

Precision and Bias

14

 Precision

14.1

  Precision Data Analysis

14.1.1

  Calculation of Precision

14.1.2

   Acceptance Criterion

14.1.2.4

  Triplicate Test Precision Data (TTPD)

14.1.3

   TTPD-Method A Repeatability

14.1.3.1

   TTPD-Method A Reproducibility

14.1.3.2

   TTPD-Method B Repeatability

14.1.3.3

   TTPD-Method B Reproducibility

14.1.3.4

  Single Test Precision Data (STPD)

14.1.4

   STPD-Method A Reproducibility

14.1.4.1

   STPD-Method B Reproducibility

14.1.4.2

  Soils Type

14.1.5

  Discussion on Precision

14.1.6

 Bias

14.2

Keywords

15

ANNEXES

 

Symbols

Annex A1

Sample to Specimen Splitting/Reduction Methods

Annex A2

 General

A2.1

  Mechanical Splitting

A2.1.1

  Quartering

A2.1.2

  Miniature Stockpile Sampling

A2.1.3

 Sample Processing Recommendation Based
  on Soil Type

A2.2

  Clean Gravel (GW, GP) and Clean Sand
   (SW, SP)

A2.2.1

  Gravel with Fines (GM, GC, GC-GM,
   GW-GM, GP-GM, GP-GC)

A2.2.2

  Sand with Silt Fines (SW-SM, SP-SM,
   SM)

A2.2.3

  Sand with Clay and Silt Fines or Clay
   Fines (SW-SC, SP-SC, SC, SC-SM)

A2.2.4

  Silts with Sand or Gravel, or Both (ML,
   MH)

A2.2.5

  Organic Soils with Sand or Gravel, or
   Both (OL, OH)

A2.2.6

APPENDIXES

 

Example Test Data Sheets/Forms

Appendix X1

 General

X1.1

Precision: Example Calculations

Appendix X2

 General

X2.1

TABLES and FIGURES

 

1.18 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.