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Engineering Software
  Asphalt -> Asphalt/Aggregate Testing -> Specific Gravity/Density

  • CoreReader
  • CoreLok
  • Specific Gravity Water Station

  • Bulk specific gravity of laboratory compacted or field core specimens without a water bath, paraffin, parafilm, or any other sealers
  • Precise, accurate bulk density measurement, unaffected by surface or interconnected voids
  • No specimen volume estimations
  • 4 minute measurement time
  • 110 volt, 0.4 Amps
  • Small footprint (approx. 1 sq foot), less countertop needed


CoreReader Exempt from Licensing
Because of the extremely small amount of radioactive material in the Model 3660 CoreReader, the U.S. Nuclear Regulatory Commission has determined that the gauge is exempt from all NRC and Agreement State radioactive material regulations. This means that:

  • No radioactive material license required to possess or use the CoreReader
  • No special radiation safety training required
  • No leak testing of sealed sources required
  • No radiation monitoring required
  • No restrictions of any kind

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.


  • 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


  • Improved correlation between field, laboratory and nuclear gauge density results
  • Accurate specific gravity and air voids measurements
  • Excellent repeatability
  • 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

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.


  • Easy access weighing, no more bending under counters and strained backs
  • Only 36" wide x 18" deep x 67" tall, easy to move and store
  • Heavy duty 24" wide x 18" deep x 18" tall (5/16" wall) polyethylene tank
  • Heavy-duty casters, 1200 lb unit capacity
  • Easily adjustable shelving (adjustable in 1" increments)
  • Drain spigot for easy water changes (spigot attaches to standard water hose)
  • Over flow fitting with drain tube and overflow container
  • Storage shelf below tank
  • Heavy duty stainless steel shelves
  • Strong stainless steel uprights
  • Easy assembly
  • Water heater and circulator included