How to Determine the PG of Asphalt Binder

Pour asphalt binder into a bucket.

Stick the tip of a meat thermometer into the asphalt binder, and observe the temperature reading. The binder must be at 77 degrees Fahrenheit, which is average room temperature. If the reading is above or below 77 degrees, allow the asphalt binder to set until it reaches 77 degrees. Otherwise, a higher or lower temperature will skew the results.

Adhere a chunk of polymer clay to the top of the 20-gauge needle or wire, and measure it on a small scale. In total, the needle and clay must weigh 100 grams.

Place the tip of the needle or wire at the surface of the asphalt binder, and allow it to penetrate for five seconds.

Withdraw the needle or wire from the asphalt binder, and use a tape measure to determine the penetration depth. The binder will adhere to the needle or wire, so measure the asphalt-covered portion of the needle.

Calculate the PG of the asphalt binder using a calculator. Every 0.1 millimeter equals one point, so 1 millimeter equals 10 points. A penetration depth of 10.1 millimeters is equal to a PG rating of 110.