The CoreLok® is a system for sealing asphalt
samples so that the sample densities may be measured by water
displacement method. Samples are automatically sealed in specially
designed puncture resistant polymer bags. Densities measured with
the Corelok system are highly reproducible and accurate. The results
are not dependent on material type or sample shape. The GravitySuite
PC software package calculates and manages your data for ease of
Measurements are not dependent on mix specific calibrations
Works with different sample sizes and shapes
Fully automatic sealing process
Large vacuum chamber
Puncture resistant, easy to use polymer bags for lab and field
Meets local and national equipment standards and requirements
110 Volt standard operation (220 volt optional)
Measurements are not dependent on any inputs or empirical
Improved correlation between field, laboratory and nuclear gauge
Accurate specific gravity and air voids measurements
No wax dipping, wrapping with film or trimming required
Samples remain dry and uncontaminated for further testing
Complete sealing process in approximately 2 minutes
Minimal operator involvement
No license required
Bulk Specific Gravity of Compacted samples
Specific gravity (density) is the single most specified parameter in the
construction industry. For open graded mixes (i.e. SMA and OGFC) and absorptive
mixtures of asphalt, the Saturated Surface Dry (SSD) method is inaccurate.
Water infiltration in and out of the sample produces a lower than actual
measurement for sample volume, higher calculated density and a lower estimate
of air voids. The CoreLok system automatically seals these samples in specially
designed polymer bag and allows for measurement of accurate water displacement
test. The present sealing methods, Wax and films, are labor intensive and the
results are extremely operator dependent.
Maximum Specific Gravity (Gmm)
This method may be used as an alternative to the conventional "Rice Test" for
the determination of maximum specific gravity of loose asphalt mixtures. The
CoreLok test can be completed in seven minutes with minimal exposure to water,
eliminating the need for a lengthy "Dry Back" method.
This procedure requires that a sample of dry asphalt mixture is placed inside
the vacuum bags and sealed within the CoreLok vacuum chamber. The bags are then
cut open under water and a submerged weight is determined. The weight in air
and the submerged weight can be used to calculate the maximum specific gravity
of the asphalt mixture.
Apparent Specific Gravity, Absorption and Bulk Specific Gravity of Aggregates
Oven dry aggregates are used in this test to determine the specific gravity and
absorption of fine or coarse aggregates in less than 20 minutes. This test is
highly accurate and repeatable.
In this test, a density measurement is obtained by fully saturating the sample
with CoreLok and another density is measured under an unsaturated condition.
These two densities can be used with already known equations to calculate
apparent specific gravity, absorption and bulk specific gravity. The AggSpecTM
PC software allows for simple entry and calculation of these parameters.
Porosity of Compacted Asphalt samples
Porosity is the measure of the percentage of water permeable voids in a
compacted sample. Porosity gives an accurate estimate of sample permeability.
You can now determine the interconnectivity of voids within your sample and
determine your mix performance during design or after lay down. Two different
mixes with 7% air voids can have different permeability performance on the
field, depending on the interconnectivity of voids. However, these same mixes
will never have the same porosity. For open graded mixes Porosity is a more
meaningful measure of performance than % air voids. GravitySuite software
included with CoreLok provides automatic calculation of porosity based on a
sealed and unsealed density of your sample.
Percent Asphalt Calculation
Use the CoreLok to get an
accurate measure of percent asphalt. The measurements using the
CoreLok, involves the determination of gravity of combined
aggregate, only available with the CoreLok unit, and maximum gravity
of your mixture. These two critical measurements of your mixture can
be used with the standard Superpave™ equations to accurately
calculate the %AC in your mixture. This method is unique and very
accurate for determination of %AC for difficult aggregates with
significant variability and breakdown in the NCAT ignition furnace.
The CoreLok method is simple and can be completed in less than 20