AASHTO T 267-1986 Standard Method of Test for Determination of Organic Content in Soils by Loss on Ignition《测定土壤有机物含量烧失量的标准测试方法》.pdf

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1、Standard Method of Test for Determination of Organic Content in Soils by Loss on Ignition AASHTO Designation: T 267-86 (2013) American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-1a T 267-1 AASHTO Standard Method of Tes

2、t for Determination of Organic Content in Soils by Loss on Ignition AASHTO Designation: T 267-86 (2013) 1. SCOPE 1.1. The Loss on Ignition method for the determination of organic content is most applicable to those materials identified as peats, organic mucks, and soils containing relatively undecay

3、ed or undecomposed vegetative matter or fresh plant materials such as wood, roots, or grass, or carbonaceous materials such as lignite, coal, etc. This method determines the quantitative oxidation of organic matter in these materials and gives a valid estimate of organic content. The Wet Combustion

4、method (T 194) is recommended when it is desired to determine the percentage of humus-like, easily oxidized organic material to provide information relating to the suitability of a soil for plant growth. 1.2. The following applies to all specified limits in this standard: For the purposes of determi

5、ning conformance with these specifications, an observed value or a calculated value shall be rounded off “to the nearest unit” in the last right-hand place of figures used in expressing the limiting value, in accordance with ASTM E29. 1.3. The values stated in SI units are to be regarded as the stan

6、dard. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: M 231, Weighing Devices Used in the Testing of Materials R 58, Dry Preparation of Disturbed Soil and Soil-Aggregate Samples for Test T 194, Determination of Organic Matter in Soils by Wet Combustion 2.2. ASTM Standard: E29, Standard Practice for U

7、sing Significant Digits in Test Data to Determine Conformance with Specifications 3. APPARATUS 3.1. OvenDrying oven capable of maintaining temperatures of 110 5C (230 9F). Gravity, instead of blower convection, may be necessary when drying lightweight material. 3.2. BalanceThe balance shall have suf

8、ficient capacity and conform to M 231, Class G 1. 3.3. Muffle FurnaceThe furnace shall be capable of maintaining a continuous temperature of 455 10C (833 18F) and have a combustion chamber capable of accommodating the designated container and sample. A pyrometer recorder shall indicate the temperatu

9、re while in use. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1a T 267-2 AASHTO 3.4. Crucibles or Evaporating DishesHigh silica, alundum, porcelain, or nickel crucibles of 30- to 50-mL capacity or

10、Coors porcelain evaporating dishes, approximately 100-mm top diameter. 3.5. DesiccatorA desiccator of sufficient size containing an effective desiccant. 3.6. ContainersSuitable rustproof metal, porcelain, glass, or plastic-coated containers. 3.7. Miscellaneous SuppliesAsbestos gloves, tongs, spatula

11、s, etc. 4. SAMPLE PREPARATION 4.1. A representative sample with a mass of at least 100 g shall be taken from the thoroughly mixed portion of the material passing the 2.00-mm (No. 10) sieve that has been obtained in accordance with R 58. 4.2. Place the sample in a container and dry in the oven at 110

12、 5C (230 9F) to constant mass. Remove the sample from the oven, place in the desiccator, and allow to cool. Note 1This sample can be allowed to remain in the oven until ready to proceed with the remainder of the test. 5. IGNITION PROCEDURE 5.1. Select a sample with a mass of approximately 10 to 40 g

13、, place into tared crucibles or porcelain evaporating dishes, and determine the mass to the nearest 0.01 g. Note 2Sample masses for lightweight materials such as peat may be less than 10 g but should be of sufficient amount to fill the crucible to at least three-quarter depth. A cover may initially

14、be required over the crucible during the initial phase of ignition to decrease the possibility of the sample being “blown out” from the container. 5.2. Place the crucible or dish containing the sample into the muffle furnace for 6 h at a temperature of 455 10C. Remove the sample from the furnace, pl

15、ace into the desiccator, and allow to cool. 5.3. Remove the cooled sample from the desiccator and determine the mass to the nearest 0.01 g. 6. CALCULATION 6.1. The organic content shall be expressed as a percentage of the mass of the oven-dried soil and shall be calculated as follows: percent organi

16、c matter 100ABAC= (1) where: A = mass of crucible or evaporating dish and oven-dried soil, before ignition; B = mass of crucible or evaporating dish and oven-dried soil, after ignition; and C = mass of crucible or evaporating dish, to the nearest 0.01 g. 6.2. Calculate the percentage of organic content to the nearest 0.1 percent. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.