The Digital Absolute Pressure Manometer meets the requirements of ASTM D2041/AASHTO T209 to measure specific gravity and density of asphalt mixtures, often called the Rice Test. The gauge is also useful for other applications to measure and display air pressure (vacuum) in a range from 0 to 1000mm of mercury (Hg) with resolution to 0.01mm Hg.

Factory calibrated prior shipping, undergo a multi-point calibration at 25, 30 and 35mm Hg. SANAS Calibration available on request (separate).

Can be operated with a 9-volt alkaline battery for approximately 80 hours of continuous use or powered by a 115V/60Hz electrical supply using the AC adapter provided.

The gauge display is factory set to shut off after approximately 18 minutes to conserve battery life.



The Manometer is a very sensitive and accurate instrument designed for use with only dry, non corrosive gases. Mishandling or abuse can compromise operation and performance. Do not allow the gauge to come in contact with any liquid.


Specific Gravity of Asphalt

Several AASHTO and ASTM standards govern the measurement of the specific gravity of asphalt, also known as theoretical maximum specific gravity, or simply the Rice Test. Test methods AASHTO T 209 and ASTM D2041 determine theoretical maximum specific gravity and density values used to calculate air voids in the compacted mix and establish targets for compaction during laydown.

Percent Air Voids in Asphalt

The test results also allow calculation of bitumen absorption by mineral aggregates. If the percent air voids are too low, rutting and shoving of the pavement can happen. If the percentage of air voids is too high, the pavement can be subject to moisture damage, exhibit decreased strength, and have a shorter fatigue life when compared to pavements with correct air void percentages.

These standards define density as “the mass of a cubic meter of the material at 25°C in SI units,” and specific gravity as “the ratio of a given mass of material at 25°C to the mass of an equal volume of water at the same temperature.” Many state DOTs also have state-specific test procedures, in addition to the ASTM and AASHTO standards. This blog post will explore the basics of what to know about the specific gravity of asphalt, what equipment is needed, and how it gets the job done with the Rice Test.

What is the Asphalt Rice Test?

The Asphalt Rice Test is a routine test performed by asphalt producers, state departments of transportation, and testing labs. Reliable results from this test method depend on competent personnel, and the selection of quality equipment can have a direct impact on test results. Choosing equipment that minimizes human input variables will increase the accuracy and repeatability of this test, as well as increase lab efficiency.


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