What Is Bitumen Ductility? How Does the Bitumen Ductility Test Machine Work?

The purpose of establishing the bitumen ductility test standard is to measure the ductility or stretchability of bituminous materials and determine the elongation of the specimen before rupture. The ends of a molded specimen are stretched at a specified temperature and at a fixed speed until the specimen breaks.

This test must be performed at 25±0.5°C and with a speed of 5±0.25 cm/min. For other temperatures, the speed must be specified.

Equipment and Accuracy

The bitumen ductility tester has a precision of 1 mm and is available in two models:

1. A version with insulated heater and a powerful automatic refrigerator (for heating and cooling).
2. A version with only a heater (for heating only).

For purchasing information, contact the sales team on the “Contact Us” page.

Safety Guidelines for the Bitumen Ductility Tester

1. Place the device on a level lab bench. You can level it using the adjustable feet.
2. Connect the power cable directly to a reliable wall outlet. Do not use a weak or non-standard power strip. At startup, each tank can draw up to 10 amps, so ensure proper wiring and connections.
3. Maintain a minimum 20 cm clearance between the device and walls to allow proper ventilation of electronic parts.
4. Do not place objects on the device.
5. Be careful when cleaning to avoid impact or damage.
6. If there’s any malfunction, do not service it yourself. Unauthorized servicing voids the warranty.
7. Do not tamper with or remove warranty seals, unless directed by support under specific conditions.
8. All devices have a unique serial and customer ID. Use this when contacting support.
9. For accuracy, use a calibrated ASTM thermometer verified by a certified lab.
10. Prevent liquid or foreign objects from entering the device’s moving arm.
11. For cooling, use high-purity ethanol in the refrigeration chamber.
12. Fill the water bath with distilled or regular water (not well or tank water to avoid mineral deposits).
13. To prevent heater damage, fill the paraffin or silicone oil exactly to the marked line.

Calibration of the Bitumen Ductility Tester

Glass thermometers must have a traceable temperature calibration report from a certified lab. Calibration should be done every six months.

Key Definitions

• Ductility: The distance between two ends of a bitumen specimen stretched under controlled temperature and speed until it breaks.
• Pure Bitumen: Fluid or semi-fluid bitumen used in asphalt production; penetration at 25°C under 100g load for 5s is between 50–500.
• Tar Bitumen: A black or brown viscous material derived from destructive distillation (e.g., coal, shale, wood).
• Water Bath: Must maintain test temperature, fully immerse the specimen, and be capable of heating.
• Specific Gravity Additives: Substances like methanol, sodium chloride, or ethylene glycol prevent specimens from floating or touching the bottom.

Accessories:

• C63 thermometer
• Anti-adhesive (glycerin + dextrin/talc or mineral oil)
• Scraping tools
• 300-micron (№50) sieve

Preparing the Device for Testing

1. Mount the mold on a brass plate, coat internal walls with anti-adhesive.
2. Pour in the thoroughly mixed bitumen without shifting or deforming the mold.
3. Leave at room temp for 30±5 minutes to cool, then immerse in a 25°C bath for 35±5 minutes.
4. Remove, level the surface using a scraper.

Reporting Ductility Test Results

• Report a single valid test as the ductility value.
• If a valid test isn’t obtained, state that ductility could not be measured.
• If rupture occurs due to machine length limitation, report as e.g., 150+ cm.

Cleaning the Device

• Change bath fluid regularly to avoid damage.
• Always clean molds with solvents like acetone before a new test.

Ductility Test Report Should Include:

1. Reference to the national standard
2. Date of sample receipt
3. Date of test
4. Product information (manufacturer, location, etc.)
5. Production date
6. Test location
7. Any deviations from the standard
8. Name, surname, and signature of tester
9. Name, surname, and signature of verifier

Precision and Error Range

The acceptable range for ductility at 25°C is shown in the accompanying figure (not included here). There’s insufficient data for 15.6°C. In a study involving 13 labs testing one bitumen type with an average ductility of 45 cm, the inter-lab precision (D2S) was found to be 23 cm.

Technical Tips

• If the device doesn’t power on: Check the fuse under the power cable (15A glass fuse).
• If the bath doesn’t heat:
• 1. Check if the emergency button is disengaged and that the Set Point is at least 50°C above the desired temperature.
• 2. Ensure the Start button is pressed.
• 3. If still not working, it may require opening the seal (only by support staff).
• If the specimen floats or touches the bath floor, the test is invalid. Adjust water density using appropriate additives.
• If tearing occurs at clamps, the test is invalid.
• For disagreements, perform 3 repetitions and average valid results.

Summary of Ductility Test Procedure

1. Pressing Start stops the circulator to eliminate bath turbulence.
2. The pre-cooled bitumen sample in brass molds is stretched at 5 cm/min.
3. Displacement (ductility) is displayed live on a 7” screen.
4. Although ductility is reported in cm, Parsian Technology’s Full model measures with millimeter accuracy.
5. Test ends when the sample breaks from the center or reaches the device’s length limit.
6. If breakage occurs at the clamps, repeat the test.
7. On rupture, press Stop to record and optionally print results.

This translation was provided by ChatGPT.

source: تست کشش قیر