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a A <br /> " . e <br /> Troxkr RoadreaderD13440 Application Brief <br /> Gauge Operation <br /> The Troxler Model 3440 gauge can measure the moisture content,density and percent <br /> compaction of soils,soil-stone aggregates,concrete,asphalt treated bases,asphalt surfacing <br /> and other materials that are similar in density and/or moisture content. This gauge otters two <br /> modes of operation:soil and asphalt. The direct transmission and backscatter testing positions <br /> can be used with each mode. <br /> Soil Mode is designed for measurements of soils,stone or other materials where both density <br /> and moisture content are desired. Direct transmission testing typicaUy offers better{recision <br /> and control of depth of measurement and is the preferred method. The Model 3440 gauge <br /> provides the Dry Density,Wet Density, Moisture, Percent Moisture and Percent Proctor when <br /> testing in the soil mode. <br /> Surface preparation for soil testing is critical to gauge performance and test results. The <br /> scraper plate accessory provided can be used to prepare rough surfaces by moving it back and <br /> forth across the test area. Small voids,cracks,or holes can be tilled with sand or native fines. <br /> This is most critical when testing in the backscatter position. <br /> Asphalt Mode is used on full depth,greater than 100 mm(4inch)asphalt. Typically,the source <br /> rod is in the backscatter positron,slightly above the asphalt, but direct transmission can be used <br /> if a hole can be drilled in the asphalt.The Model 3440 gauge provides the Wet Density, Percent <br /> Marshall and Percent Voidless values when testing in the asphalt mode. <br /> When performing density tests on coarse asphalt surfaces,or on open graded mixes,the <br /> surface voids may be filled with soft sand,cement powder or native fines. However,the asphalt <br /> surface should remain bare so that the gauge base makes contact with the surface. It is also <br /> important that the gauge sit flat on the asphalt surface and does not"rock". <br /> Offsets <br /> The Roadreader-Model 3440 gives the user the ability to input offsets to gauge readings to <br /> correct for non-standard conditions. In soil mode,the user may apply a correction factor to <br /> adjust for the presence of chemically bound hydrogen or neutron absorbers that may affect the <br /> moisture count. For example,mica is a mineral that usually contains considerable molecular <br /> hydrogen and wig cause the readings to indicate a higher moisture content than is actually <br /> present. In soil and asphalt mode a density correction factor may be used to correct for material <br /> composition or for material density outside of the calibration range. A trench offset may be used <br /> in either soil or asphalt mode when testing in a trench or near a large vertical object. Special <br /> Calibration is a function that allows the operator to temporarily"re-aUbrate"the gauge for <br /> measuring materials that do not fall within the range of a normal calibration. These functions <br /> are simple to access from the gauge's offset and special function menus,which walk the <br /> operator through the processes step by step. <br /> Keypad <br /> The Model 3440 gauge keypad is designed so the operator can easily access any of the <br /> gauge's many options. The control panel consists of 22 keys with the numeric keys also <br /> representing a second function,accessed by pressing the shift key. The result is a keypad with <br /> 32 direct options available. Full access to gauge functions is provided while Umiting the menus <br /> to be viewed or keys to be pressed. A"beep"verifies that the keystroke was received by the <br /> AB3440-0907 2 of 4 <br /> 13 <br />