1、Standard Method of Test for One-Point Method for Determining Maximum Dry Density and Optimum Moisture AASHTO Designation: T 272-16 Release: Group 3 (August 2016) American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-1b T
2、 272-1 AASHTO Standard Method of Test for One-Point Method for Determining Maximum Dry Density and Optimum Moisture AASHTO Designation: T 272-16 Release: Group 3 (August 2016) 1. SCOPE 1.1. This method is for the rapid determination of the maximum dry density and optimum moisture content of a soil s
3、ample using a one-point determination and an individual moisture/density curve or a family of curves. 1.2. The following applies to all specified limits in this standard: For the purposes of determining conformance with these specifications, an observed value or a calculated value shall be rounded o
4、ff “to the nearest unit” in the last right-hand place of figures used in expressing the limiting value, in accordance with the rounding-off method of ASTM E 29. 1.3. The values stated in SI units are to be regarded as the standard. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: R 75, Developing a Fa
5、mily of Curves T 99, Moisture-Density Relations of Soils Using a 2.5-kg (5.5-lb) Rammer and a 305-mm (12-in.) Drop T 180, Moisture-Density Relations of Soils Using a 4.54-kg (10-lb) Rammer and a 457-mm (18-in.) Drop T 217, Determination of Moisture in Soils by Means of a Calcium Carbide Gas Pressure
6、 Moisture Tester T 255, Total Evaporable Moisture Content of Aggregate by Drying T 265, Laboratory Determination of Moisture Content of Soils 2.2. ASTM Standard: E29, Standard Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications 3. SIGNIFICANCE AND USE 3.1.
7、 The method described herein corresponds to the methods in either T 99 or T 180 and must be chosen accordingly; for example, when moisture-density relationships as determined by Method C of T 99 are used to form the family of curves, then Method C described in T 99 must be used for the one-point det
8、ermination. 2016 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-1b T 272-2 AASHTO 3.2. A family of curves is a group of typical soil moisture-density relationships determined using T 99 or T 180, which r
9、eveal certain similarities and trends characteristic of the soil type and source. Soils sampled from one source will have many different moisture-density curves, but if a group of these curves are plotted together, certain relationships usually become apparent. In general, it will be found that high
10、er unit mass soils assume steeper slopes with maximum dry densities at lower optimum moisture contents, while the lower unit mass soils assume flatter, more gently sloped curves with higher optimum moisture contents. 4. METHOD SELECTION 4.1. See T 99 or T 180. 4.2. One-point determinations are made
11、by compacting soil using T 99 or T 180 and one of the procedural methods described therein: Method AA 101.6-mm (4-in.) mold; soil material passing a 4.75-mm (No. 4) sieve. Method BA 152.4-mm (6-in.) mold; soil material passing a 4.75-mm (No. 4) sieve. Method CA 101.6-mm (4-in.) mold; soil material p
12、assing a 19.0-mm (3/4in.) sieve. Method DA 152.4-mm (6-in.) mold; soil material passing a 19.0-mm (3/4in.) sieve. 4.3. The method used to compact the sample shall be the same method and procedure used to develop the moisture/density curve or family of curves used for the reference curve(s). 5. APPAR
13、ATUS 5.1. See T 99 or T 180 for the selected method. 6. SAMPLE 6.1. Refer to T 99 or T 180. 6.1.1. Follow the initial drying step in Sample section of T 99 or T 180 or; 6.1.2. Sieve sample over the appropriate sieve. 7. PROCEDURE 7.1. The representative sample needs to be between 80 to 100 percent o
14、f the optimum moisture. Adjust the moisture content, if necessary. The maximum density determination will be more accurate the closer the moisture content is to the optimum moisture content. 7.2. Compact the prepared soil using the selected procedural method. 7.3. Determine the wet density of the co
15、mpacted sample according to T 99 or T 180. 7.4. Determine the moisture content using one of the following methods: T 217, T 255, or T 265. 2016 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-1b T 272-3 A
16、ASHTO 7.5. Determine the dry density using the wet density determined in Section 7.3 and moisture content determined in Section 7.4 according to the Calculation section in T 99 or T 180. 8. MAXIMUM DENSITY AND OPTIMUM MOISTURE CONTENT DETERMINATION 8.1. An individual moisture/density curve as determ
17、ined by T 99 or T 180 or a family of curves as developed by R 75 may be used for the reference curve(s). 8.2. Individual Moisture/Density Curve: 8.2.1. Moisture content must be within 80 to 100 percent of optimum moisture of the reference curve. Compact another specimen, using the same material, at
18、an adjusted moisture content if the one-point does not fall in the 80 to 100 percent of optimum moisture range. 8.2.2. Plot the one-point moisture content as the abscissa and the corresponding dry density (unit mass) of the soil as ordinate to define the one-point on the reference curve. 8.2.3. Use
19、the maximum dry density and optimum moisture content defined by the curve when the one-point falls on the curve or within 2.0 lbs/ft3of the curve at the one-point moisture content (Figure 1). 8.2.4. Perform a full moisture/density relationship if the one-point determination cannot meet these require
20、ments. Figure 1Determining Maximum Dry Density and Optimum Moisture Content Using Individual Moisture/Density Curve 2016 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-1b T 272-4 AASHTO 8.3. Family of Cu
21、rves: 8.3.1. Plot the one-point moisture content as the abscissa and the corresponding dry density (unit mass) of the soil as ordinate to define the one-point on the reference family of curves. 8.3.2. If the one-point falls on one of the curves in the family of curves, use the maximum dry density an
22、d optimum moisture content defined by that curve. 8.3.3. Draw a new curve through the plotted one-point parallel and in character with the nearest existing curve in the family of curves when the one-point falls within the family but not on a curve. 8.3.4. Determine the maximum dry density and optimu
23、m moisture content as defined by the new curve. The moisture content must be within 80 to 100 percent of the determined optimum moisture content (Figure 2). 8.3.5. Perform a full moisture/density relationship if the one-point determination does not fall within the family or cannot meet the 80 to 100
24、 percent range. Figure 2Determining Maximum Dry Density and Optimum Moisture Content Using Family of Curves 9. REPORT 9.1. The report shall include the following: 2016 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applic
25、able law.TS-1b T 272-5 AASHTO 9.1.1. The method used (Method A, B, C, or D). 9.1.2. The optimum moisture content as a percentage to the nearest whole number. 9.1.3. The maximum dry density to the nearest 0.5 kg/m3(1.0 lb/ft3). 10. KEYWORDS 10.1. Individual moisture/density curve; maximum dry density; one-point determination; optimum moisture content. 2016 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.
