EZ Asphalt’s ABCD Tester

Step 1

Prepare the molds by pouring the heated binder into the ring and letting it rest at room temperature for an hour prior to hooking up sensors in the cooling chamber. Step 2

Align sensors on the mold in the cooling chamber.

Step 3

The temperature in the chamber steadily decreases. Step 4

Sensors inside the ABCD ring measure and record temperatures and strains, sending the data to the software.

Step 5

When the strain is abruptly relieved, the ABCD cracking temperature is recorded.

The Asphalt Binder Cracking Device (ABCD), invented by Sang-Soo Kim, was developed alongside its low-temperature cracking potential test un der the National Cooperative Highway Research Program (NCHRP) Innovations Deserving Exploratory Analysis (IDEA) project 99. In 2011, the ABCD test method was ad opted as the American Association of State Highway and Transportation Officials (AAS HTO) TP 92 test method and then AASHTO T387 in 2019. Here’s how it works.

The laboratory device consists of round molds, cooling chamber, sensors and soft ware. Using proper safety protocol, a lab technician first pours a heated binder sam ple of 14.38 +/- 0.5 grams into a circular mold outside of a 2-inch diameter Invar ring. Invar is a steel alloy with a near-zero coefficient of thermal expansion (CTE).

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The filled molds should rest at room tem perature for an hour prior to testing. If the technician has overfilled the mold, trim the sample with a heated spatula.

She then places the ring with the specimen in the cooling chamber, lining up sensors that will collect data from the specimens.

As the temperature within the chamber steadily decreases, the binder specimen con tracts and compresses the ABCD ring. Sensors inside the ABCD ring measure and record the temperatures and strains throughout the test, feeding information to the “data acquisition” software on a computer desk top. The technician can monitor progress with the computer software real-time plots.

When the binder specimen cracks, the strain is abruptly relieved. The temperature recorded at the instant of that relief is the ABCD cracking temperature.

According to Alaska Department of Transportation Northern Region Materials Lab (NRML) Supervisor Heidi Schaefer, the test takes about one day to perform and was rela tively easy to perform.

For more information, contact Dr. SangSoo Kim at EZ Asphalt Technology at (740) 707-6817.

SHOW US HOW IT WORKS

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