GENEQ > Essais sur Matériaux > Asphalte – Essais sur
| Appareil CoreLok pour la détermination de la densité brute |
| ASTM D6752 ASTM D6857 ASTM D7063 A fundamental density measurement. It does not require empirical calibrations. |
| An accurate method for Bulk Specific Gravity measurement |
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 operation. One Machine for All your
Gravity Measurements of Asphalt and Aggregate. |
| Features |
| • Measurements are not dependent on mix specific
calibrations • Works with different sample sizes and shapes • non-Nuclear • Fully automatic sealing process • Large vacuum chamber • Puncture resistant, easy to use polymer bags for lab and field sample testing • Meets local and national equipment standards and requirements • 110 Volt standard operation (220 volt optional) • Low maintenance • Measurements are not dependent on any inputs or empirical calibrations |
| Benefits |
| • Accurate specific gravity and air voids measurements • Excellent repeatability • Improved correlation between field, laboratory and nuclear gauge density results • No wax dipping, wrapping with film or trimming required • Samples remain dry and uncontaminated for further testing purposes • Complete sealing process in approximately 2 minutes • Minimal operator involvement • No license required |
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| 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 minutes. |