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SURVEYDurham Geo
2175 West Park Court |
There are three ways to measure the air content of fresh concrete specimens: the pressure method, the volumetric method, and the free-air method.
The Press-Ur-Meter is made from corrosion resistant aluminum alloy with a heavy duty pump and built in pressure gauge. The base has a volume of 0.25 cubic feet (7000 cubic cm) and can also be used for unit weight measurements. Instructions include a chart for using the meter to determine the specific gravity of aggregates. Wood and plastic cases are available. Applicable Standards: ASTM C 231 AASHTO T-152
A direct reading sight gauge is built-in to the instrument. The base has a volume of 130 in3 (2.13 dm3) and the sight tube reads 0-10%. The Roll-a-Meter can be used as a pycnometer to determine the specific gravity of cement, sand or gravel as well as the percent free-water in damp sand and gravel. The Roll-a-Meter is available in bronze or aluminum and is supplied in a wood case with straight edge, tamping rod, syringe, baffle-bottom funnel and instructions. Applicable Standards: ASTM C 173 AASHTO T-196
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Pressure
Type "B" Meter: This
device measures the air content of fresh concrete based on the pressure-to-volume
relationship of Boyles Law. Pressure is applied to the sample to compress
the entrained air in the pores. The Press-Ur-Meter uses the change in
known volume of air to determine the air content of the mix. Readings
are not affected by changes in barometric pressure. This method is faster
to use than the volumetric method. 
Volumetric
Air Meter: This
device measures air entrainment by the "Volumetric Method." Air is removed
from a known volume of concrete by agitation in an excess of water. It
may be used with any type of aggregate including light weight and porous
material. The test is not affected by atmospheric pressure and the specific
gravity of the material need not be known. 
Air
Indicator Kit: This kit provides a quick and easy method to check
air content. A sample is placed in the vial and alcohol is added to
free the air. The change in level of the alcohol in the vial stem indicates
the air content. The test takes about 3 minutes to perform and is therefore
ideal for field use at either a pour site or batch plant. It may also
be used to determine whether more thorough testing may be needed. The
open end of the vial has a reinforced lip and extra graduation marks
are included on the stem. The kit includes a vial with stopper/cup,
squeeze bottle for alcohol, brush and instructions in a plastic case.
Applicable Standard: AASHTO T-199