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<br />a~~ Designation: D 4643 - 00 <br />Standard Test Method for <br />Determination of Water (Moisture) Content of Soil by the <br />Microwave Oven Heating' <br />Thu wadaN u issued macs the faed desigoatiw D 4601; the smmba immediately fdlasviag the desigaa0® iadieues the year of <br />original W apri® or, m We case of rtviaioa the year of last tevisim. A sntmber m pvmthua iadicsres the year of last teappmvd. A <br />mpusoipt epsilon (eJ iadicatu m editorial change sintx We last sevuiw or rcappmvsl <br />Ihia arondard hoe bem approved fw urc by agenciu of the Deparnaat of Defense. <br />1. Slope <br />I.1 This test method outlines procedures for determining the <br />water (moisture) content of soils by incrementally drying soil <br />in a microwave oven. <br />l.2 This test method can be used as a substitute for Test <br />Method D 2216 when more zapid results are desired to expe- <br />dite other phases of testing and slightly less atxtaate results aze <br />acceptable. <br />1.3 Wh® questions of accuracy between this test method <br />and Test Method D 2216 arise, Test Method D 2216 shall be <br />the referee method. <br />1.4 This test method is applicable for most soil types. For <br />some soils, such es those containing significant amolmts of <br />halloysite, mica, montmorillotrite, gypsum or other hydrated <br />materials, highly organic soils, or soils in which the pore water <br />contains dissolved solids (such as salt is the case of marine <br />deposits), this test method tray not yield reliable water coment <br />values. <br />1.5 The values stated in SI units are to be regarded es the <br />standard. <br />1.6 Thrs standard does not purport to address a(! of the <br />safety concerns, ij any, associated with its use. It is the <br />responsibility of the Yser of this standard to establish apprtr <br />prtate safety and health practices and determine the applica- <br />bility ojregulatory limitations prior to use. See Section 7. <br />2. Referenced Documents <br />2.1 ASTM Standanis: <br />D 653 Terminology Relating to Soil, Rock, and Contained <br />Fluids2 <br />D 221b Test Method forLaboratory Determination of Water <br />(Moisture) Content of Soil and Rock' <br />D 3740 Practice for Minimum Requimments for Agencies <br />Engaged in the Testing and/or Inspection of Soil and Rock <br />as Used is Engineering Design and Construction <br />D 4753 Specification for Evaluating, Selecting, and Speci- <br />fying Balances and Scales for Use in Testing Soil, Rock, <br />' 17ris test method u Dade 0e juri5ditti® ofASmM Cnmmiom D-18 on Soil <br />and flack and u the direct rcspuusibility of suhcammame DISne w Special and <br />CemsWtEOO Control rem. <br />Qmem editim approved Feb. 10, 2000. Poblisbed Apta 2000. Originaay <br />published u D060J - 97. Last prrviam edition D0643 - 9J. <br />t Anwal Book °I ASIA! Sandardr. WI 00.08. <br />and Related Construction Materials= <br />3. Terminology <br />3.1 Definitions.• <br />3.1.1 All definitions ate in accordance with Temninology <br />D 653. <br />32 Definitions ojTerms Specific to This Stmdard• <br />32.1 microwave heating--a process by which heat is in- <br />duced within a material due m the interaction between tiipolaz <br />molecules of the material and ao alternating, high frequrncy <br />electric field. Microwaves are electromagnetic waves with 1 <br />mm to 1 m wavelengths, <br />3.2.2 water (moisture) content-the ratio, expressed as a <br />percentage, of the ttlass of'~are" or "free" water in a given <br />mass of soil to tbe mass of the slid particles. <br />d. Smnmtrry of Teat Method <br />4.l A moist soil specim® is placed in a suitable container <br />and its mass is determined. It is tom placed in a microwave <br />oven, subjected to an interval of drying, and removed from the <br />oven and its new mass is determined. This procedure is <br />repeated until the mass becomes nearly constant <br />42 The differelmce between the mass of tha moist specimen <br />and the dried specimen is used as the mass of water originally <br />contained in the specimen. The water coatem is determined by <br />dividing the mass of water by the dry mass of soil, multiplied <br />by 100. For a given soil and sample size, the time to achieve a <br />constant dry mass can be noted and used as a minimum drying <br />time for subsequent tests using the same size specimen of ate <br />same soil. <br />5. Slgnifictmce and Use <br />5.1 The water wntent of a soil is used throughout geotech- <br />nical engineering practice onto in the laboratory and in the <br />field. The use of Test Method D 2216 for water content <br />determination can be time containing and there are occasions <br />when a more expediem method is desirable. The use of a <br />microwave oven is one such method. <br />52 The principal objection to the use of the microwave <br />oven for wetetcontent determinadoa has been the possibility <br />of overheating the soil, thereby yielding a water comeat higher <br />than would be determined by Test Method D 2216. While not <br />eliminating this possibility, the incremental drying procedtne <br />•A Summary of Chmaes section appur0 a 0e eml o[ this modad. <br />CoPYr4M O ASTY, 1W nil Narnor Orlr•. Waal GoiYneaecbn. PA 191163958, ttaa.s slats <br />