Model 4640 B Thin Layer Density Gauge

Product Code

Model 4640 B Thin Layer Density Gauge

Model 4640-B features patented technology to measure the density of thin asphalt and concrete layers from 2.5 to 10 cm thick (1 to 4 inches) without influence from underlying material. The 4640-B is specified by many state DOTs, government agencies and contractors as the best test method for determining the density of bituminous overlays.

Eliminates the need for nomographs and manual corrections: Variations in the density or composition of the base material do not affect the test results. No field calculations or charts are needed.

Operator selected depth of measurement: Enter the thickness of the overlay into the gauge memory and then accurately measure the overlay density (compaction) without influence from the underlying material.

Data storage is computer compatible: Store up to 750 readings by location and project number. Transfer stored readings to a printer or computer via RS232 interface. Additional site information can also be stored with each test.

The 4640-B meets or exceeds all applicable ASTM Standards.

Calibration: The Troxler 4640-B calibration process is unique. Your test results will improve and job penalties can be eliminated. For special materials, up to 11 field calibrations can be performed and stored.

User friendly: The operator will find the 4640-B very easy to use. It is a menu driven gauge, prompting the operator through the test procedure.

Mechanical Specifications

Case: Colored polycarbonate top shell withaluminum cast base

Operating Temp:        Ambient           : -10 to 70ºC (14 to 158ºF)

                                      Surface             : 175ºC (350ºF)

Storage Temperature: -55 to 85ºC (-70 to 185ºF)

Gauge Size (excluding handles): 472 x 231 x 158 mm (18.6 x 9.1 x 6.2 inches)

Gauge Height (including handles): 240 mm (9.5 inches)

Weight: 13.5 kg (29.7 pounds)

Shipping Weight: 40.8 kg (90 pounds) w/transport case

Radiological Specifications

Gamma Source                 : 8 ±1mCi Cesium - 137

Source Encapsulation      : Stainless Steel

Shielding                             : Tungsten and lead

Surface                                : Dose Rates 5 mrem/hour max. top and sides of gauge, 15 mrem/hour  max. bottom of gauge, gamma in shield position

Calibration Specifications

Accuracy of Density Standards    : ±0.3%

Calibration Range                           : 1600-2700 kg/m3   /  100-170 pcf density

Field Data Conversion:

4640-B contains a microprocessor providing direct reading in engineering units in pcf, kg/m 3 or g/cm3; no calculation is required.

Electrical Specifications

Stored Energy                  : 30 watt hours

Battery Recharge Time   : 14-16 hours (automatic shutoff)

Battery Recharge             : 110/220 V, 50-60 Hz or 12-14 VDC

Power Consumption (average) : 0.16 watt/hours

Readout (LCD) Liquid Crystal Display - 4 x 6 alpha numeric

Battery packs are fully protected against overcharge and overdischarge. Provided with RS232 interface. Capable of operation with D size batteries for emergency use.

Special Functions:

Automatic standard count comparison and storage. Determination of count time for selected precision. Field offsets of density. Field calibration for special asphalts. Calculator mode with storage. Self-test and service programs: Display, Keypad and Ram Test; GM Tube Test; Statistical Stability and Drift Test.

Standard Accessories:

Supplied with the Model 4640-B: air gap fixture, 1” magnesium block, AC battery charger, DC charger cord, transport case

Optional Accessories:

PN 021140 Radiation Sign Kit, PN 102866 Leak Test Kit,


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