AASHTO T 100-2015 Standard Method of Test for Specific Gravity of Soils.pdf

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1、Standard Method of Test for Specific Gravity of Soils AASHTO Designation: T 100-15 ASTM Designation: D854-00 American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-1a T 100-1 AASHTO Standard Method of Test for Specific Gr

2、avity of Soils AASHTO Designation: T 100-15 ASTM Designation: D854-00 1. SCOPE 1.1. This method covers determination of the specific gravity of soils composed of particles smaller than the 4.75-mm (No. 4) sieve by means of a pycnometer. When the soil is composed of particles larger than the 4.75-mm

3、(No. 4) sieve, the method outlined in T 85 shall be followed. When the soil is composed of particles both larger and smaller than the 4.75-mm (No. 4) sieve, the sample shall be separated on the 4.75-mm (No. 4) sieve, the appropriate test method should be used on each portion, and a weighted average

4、should be calculated. 1.2. The values stated in SI units are to be regarded as the standard. 1.3. This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety concerns associated with its use. It is the responsibility of the us

5、er of this standard to consult and establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: M 92, Wire-Cloth Sieves for Testing Purposes M 231, Weighing Devices Used in the Testing of Mate

6、rials R 18, Establishing and Implementing a Quality Management System for Construction Materials Testing Laboratories R 61, Establishing Requirements for Equipment Calibrations, Standardizations, and Checks T 85, Specific Gravity and Absorption of Coarse Aggregate T 88, Particle Size Analysis of Soi

7、ls 2.2. ASTM Standards: C670, Standard Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials E1, Standard Specification for ASTM Liquid-in-Glass Thermometers E29, Standard Practice for Using Significant Digits in Test Data to Determine Conformance with Spec

8、ifications E77, Standard Test Method for Inspection and Verification of Thermometers E563, Standard Practice for Preparation and Use of an Ice-Point Bath as a Reference Temperature E644, Standard Test Methods for Testing Industrial Resistance Thermometers E1137, Standard Specification for Industrial

9、 Platinum Resistance Thermometers E2251, Standard Specification for Liquid-in-Glass ASTM Thermometers with Low-Hazard Precision Liquids 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1a T 100-2 AASHT

10、O 3. TERMINOLOGY 3.1. Definition: 3.1.1. specific gravityThe ratio of the mass of a unit volume of a material at a stated temperature to the mass of the same volume of gas-free distilled or deionized water at a stated temperature. 4. SIGNIFICANCE AND USE 4.1. The specific gravity of a soil is used i

11、n almost every equation expressing the phase relationship of air, water, and solids in a given volume of material. 4.2. The term “solid particles,” as used in geotechnical engineering, is typically assumed to mean naturally occurring mineral particles that are not soluble in water. Therefore, the sp

12、ecific gravity of materials containing extraneous matter (such as cement, lime, etc.), water-soluble matter (such as sodium chloride), and soils containing matter with a specific gravity of less than one, typically require special treatment or a qualified definition of specific gravity. 5. APPARATUS

13、 5.1. PycnometerEither a volumetric flask having a capacity of at least 100 mL or a stoppered bottle having a capacity of at least 50 mL (Note 1). A 500-mL flask is required for samples of clayey soils containing their natural moisture content (see Section 9.2). If a bottle is used, the stopper shal

14、l be of the same material as the bottle, and of such size and shape that it can be easily inserted to a fixed depth in the neck of the bottle. The stopper shall have a small hole through its center to permit the emission of air and surplus water. Note 1The use of either the volumetric flask or the s

15、toppered bottle is a matter of individual preference. However, the flask should be used when the sample is too large to fit into the stoppered bottle, based on the maximum grain size of the sample. 5.2. BalanceEither of the following, depending upon the type of pycnometer used. 5.2.1. A Class G1 bal

16、ance meeting the accuracy requirements of M 231 for use with the volumetric flask. 5.2.2. A Class B balance meeting the accuracy requirements of M 231 for use with the stoppered bottle. 5.3. OvenA thermostatically controlled drying oven capable of maintaining a temperature of 110 5C (230 9F). 5.4. A

17、pparatus for Removing Entrapped AirOne of the following devices shall be used: 5.4.1. VacuumCapable of subjecting the contents of the pycnometer to a partial vacuum of 13.33 kPa (100 mmHg) or less absolute pressure. Subjection of the contents to reduced air pressure may be done either by connecting

18、the pycnometer directly to an aspirator or vacuum pump, or by use of a bell jar; or 5.4.2. Heat SourceA hot plate, Bunsen burner, or similar apparatus capable of bringing the contents of the pycnometer to a gentle boil for a minimum of 10 min. 5.5. ThermometerThe thermometer shall be one of the foll

19、owing: 5.5.1. A liquid-in-glass partial immersion thermometer of suitable range with subdivisions and maximum scale error of 0.5C (1.0F) that conforms to the requirements of ASTM E1. Calibrate 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplica

20、tion is a violation of applicable law.TS-1a T 100-3 AASHTO the thermometer in accordance with one of the methods in ASTM E77 or verify its original calibration at the ice point (Notes 2 and 3). Note 2ASTM E563 provides instructions on the preparation and use of an ice-point bath as a reference tempe

21、rature. Note 3If the thermometer does not read 0.0 0.5C (32.0 1.0F) at the ice point, then the thermometer should be recalibrated. 5.5.2. A liquid-in-glass partial immersion thermometer of suitable range with subdivisions and maximum scale error of 0.5C (1.0F) that conforms to the requirements of AS

22、TM E2251. Calibrate the thermometer in accordance with one of the methods in ASTM E77 or verify its original calibration at the ice point (Notes 2 and 3). 5.5.3. A platinum resistance thermometer (PRT) with a probe that conforms to the requirements of ASTM E1137. The PRT shall have a 3- or 4-wire co

23、nnection configuration and the overall sheath length shall be at least 50 mm (2 in.) greater than the immersion depth. Calibrate the PRT system (probe and readout) in accordance with E644 or verify its original calibration at the ice point (Notes 2 and 3). Corrections shall be applied to ensure accu

24、rate measurements within 0.5C (1.0F). 5.5.4. A metal-sheathed thermistor with a sensor substantially similar in construction to the PRT probe described in Section 5.5.3. Calibrate the thermistor system (sensor and readout) in accordance with ASTM E644 or verify its original calibration at the ice po

25、int (Notes 2 and 3). Corrections shall be applied to ensure accurate measurements within 0.5C (1.0F). 5.6. WaterDistilled or deionized. 5.7. For Samples of Clayey Soils Containing Natural MoistureThe following additional equipment is required for samples containing natural moisture: 5.7.1. Dispersin

26、g EquipmentAs specified in T 88. 6. CALIBRATIONS, STANDARDIZATIONS, AND CHECKS 6.1. Unless otherwise specified, follow the requirements and intervals for equipment calibrations, standardizations, and checks in R 18. 6.2. Follow the procedures for performing equipment calibrations, standardizations,

27、and checks found in R 61. 7. GENERAL REQUIREMENTS FOR WEIGHING 7.1. When the volumetric flask is used in the specific gravity determination, determine all masses to the nearest 0.01 g. When the stoppered bottle is used in the specific gravity determination, determine all masses to the nearest 0.001

28、g. 8. STANDARDIZATION OF PYCNOMETER 8.1. Select a clean, dry pycnometer and record its mass. Fill the pycnometer with distilled or deionized water at room temperature (Note 4). Determine and record the mass of the pycnometer and water, Wa. Insert the thermometer into the water and determine its temp

29、erature T, to the nearest whole degree. Note 4Kerosene is a better wetting agent than water for most soils and may be used in place of distilled or deionized water for oven-dried samples. If kerosene is used in place of water, a 2015 by the American Association of State Highway and Transportation Of

30、ficials.All rights reserved. Duplication is a violation of applicable law.TS-1a T 100-4 AASHTO temperature correction factor based on the relative density of kerosene should be used in place of Table 1. 8.2. A table of values of mass Washall be prepared for a series of temperatures that are likely t

31、o prevail when the mass Wbof the pycnometer, sample, and water is determined at the end of testing (Note 5). These values of Washall be calculated as follows: ( )xa if fiDW WW WD= +(1) where: Wa= mass of pycnometer and water at temperature Tx, g; Wi= mass of pycnometer and water at temperature Ti, g

32、; Wf= mass of empty pycnometer, g; Di= relative density of water at temperature Ti; Dx= relative density of water at temperature Tx; Ti= observed temperature of water, C; and Tx= any other desired temperature, C. Note 5This method provides a procedure that is most convenient for laboratories making

33、many determinations with the same pycnometer. It is equally applicable to a single determination. Bringing the pycnometer and contents to some designated temperature when masses Waand Wbare taken requires considerable time. It is much more convenient to prepare a table of masses Wafor various temper

34、atures likely to prevail when masses Wb(see Section 10.3) are taken. It is important that masses Waand Wbbe based on water at the same temperature. Values for the relative density of water at temperatures from 18 to 30C are given in Table 1. Table 1Relative Density of Water and Correction Factor K f

35、or Various Temperatures Temperatures, C Relative Density of Water Correction Factor K 18 0.9986244 1.0004 19 0.9984347 1.0002 20 0.9982343 1.0000 21 0.9980233 0.9998 22 0.9978019 0.9996 23 0.9975702 0.9993 24 0.9973286 0.9991 25 0.9970770 0.9989 26 0.9968156 0.9986 27 0.9965451 0.9983 28 0.9962652 0

36、.9980 29 0.9959761 0.9977 30 0.9956780 0.9974 9. SAMPLE 9.1. The soil to be used in the specific gravity test may contain its natural moisture or be oven-dried. The mass of the test sample on an oven-dry basis shall be at least 25 g when the volumetric flask is to be used, and at least 10 g when the

37、 stoppered bottle is to be used. When the specific gravity value is to be used in calculations in connection with the hydrometer portion of T 88, it is intended that the specific gravity test be made on that portion of the soil that passes the 2.00-mm (No. 10) sieve. 2015 by the American Association

38、 of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1a T 100-5 AASHTO 9.2. Samples Containing Natural MoistureWhen the sample contains its natural moisture, determine the mass of the oven-dried soil, Wo, at the end of the test by evapor

39、ating the water in an oven maintained at 110 5C (230 9F) (Note 6). Disperse samples of clay soils containing their natural moisture content in distilled or deionized water using the dispersing equipment specified in T 88 (Note 7) before placing in a 500-mL flask. 9.3. Oven-Dried SamplesDry the sampl

40、e for at least 12 h, or to constant mass, in an oven maintained at 110 5C (230 9F) (Note 6). Cool the sample to room temperature, record its mass, and transfer it to the pycnometer. Alternatively, the sample may be transferred to the pycnometer and then weighed. Add distilled or deionized water into

41、 the pycnometer in an amount that will provide complete sample coverage. Soak the sample for at least 12 h. Note 6Drying of certain soils at 110C may bring about a change in composition. In such cases, drying may be done in reduced air pressure and at a lower temperature. Note 7The minimum volume of

42、 slurry that can be prepared by the dispersing equipment specified in T 88 is such that a 500-mL flask is needed as the pycnometer. 10. PROCEDURE 10.1. Add distilled or deionized water to the previously prepared sample (see Section 9) to a maximum level of about three-fourths full in the volumetric

43、flask, or about one-half full in the stoppered bottle (Note 8). 10.2. Remove entrapped air by one of the following methods: (1) subject the contents to a partial vacuum of 13.33 kPa (100 mmHg) or less absolute pressure by use of an aspirator or vacuum pump, (2) subject the contents to a partial vacu

44、um of 13.33 kPa (100 mm Hg) or less absolute pressure by use of a bell jar, or (3) boil gently for at least 10 min, while occasionally rolling the pycnometer to assist in the removal of the air. Some soils boil violently when subjected to reduced air pressure. It will be necessary in those cases to

45、reduce the air pressure at a slower rate or to use a larger flask (Note 9). Cool samples that have been subjected to boiling to room temperature. Note 8If the vacuum method of air removal is used, the required amount of distilled or deionized water may be added in layers, with each layer being subje

46、cted to the vacuum until the sample ceases to release air. Note 9When using a partial vacuum, agitate the flask gently at intervals during the evacuation process. Samples containing natural moisture with high plasticity may require 6 to 8 h to remove air; samples with low plasticity may require 4 to

47、 6 h to remove air. Oven-dried samples may require 2 to 4 h to remove air. 10.3. Fill the pycnometer with distilled or deionized water to its standardized capacity. Clean and dry the outside of the pycnometer with a clean, dry cloth. Determine the mass of the pycnometer and contents Wb, and the temp

48、erature in degrees Celsius, Tx, of the contents as described in Section 8, after the added water and existing water have reached the same temperature. 11. CALCULATION AND REPORT 11.1. Calculate the specific gravity of the soil, based on water at a temperature Tx, as follows: ( )/x o o abS W W WW= +(

49、2) where: Sx= specific gravity of soil based on water at temperature Tx; Tx= temperature of the contents of the pycnometer when mass Wbwas determined, C; Wo= mass of sample of oven-dried soil, g; 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1a T 100-6 AASHTO Wa= mass of pycnometer filled with water at temperature Tx(Note 10), g; and Wb= mass of pycnometer filled with water