Bitumen Extraction Test

Bitumen Extraction Test is used to determine the percentage of bitumen content present in the asphaltic pavement by cold solvent extraction.

The properties of flexible pavement such as durability, compatibility, and resistance from defects bleeding, raveling, and aging of flexible pavement are majorly dependent on the percentage of bitumen used with the aggregate to lay the pavement.

Aim of the Test

To determine the binder content (bitumen) in the asphalt mix by cold solvent extraction method.

Code References

1. IRC: SP 11 –1988 (Appendix – 5)
2. ASTM D 2172

Apparatus Required

1. Centrifuge
2. Balance of capacity 500 grams and sensitivity 0.01grams.
3. Thermostatically controlled oven with capacity up to 2500 C.
4. Beaker for collecting extracted material.

Procedure of Test

1. Take exactly 500 grams of the representative sample and place it in the bowl of the extraction apparatus (W1).
2. Add benzene to the sample until it is completely submerged.
3. Dry and weigh the filter paper and place it over the bowl of the extraction apparatus containing the sample (B).
4. Clamp the cover of the bowl tightly.
5. Place a beaker under the drain pipe to collect the extract.
6. Sufficient time (not more than an hour) is allowed for the solvent to disintegrate the sample before running the centrifuge.
7. Run the centrifuge slowly and then gradually increase the speed to a maximum of 3600 rpm.
8. Maintain the same speed till the solvent ceases to flow from the drain pipe.
9. Run the centrifuge until the bitumen and benzene are drained out completely.
10. Stop the machine, remove the cover and add 200ml of benzene to the material in the extraction bowl and the extraction is done in the same process as described above.
11. Repeat the same process not less than three times till the extraction is clear and not darker than a light straw color.
12. Collect the material from the bowl of the extraction machine along with the filter paper and dry it to constant weight in the oven at a temperature of 1050 C to 1100 C and cool to room temperature.
13. Weigh the material (W2) and the filter paper (D) separately to an accuracy of 0.01grams.

Calculation and Observation

Sl No	Observation	Sample 1	Sample 2	Sample 3
1	Weight of mix taken before extraction (W1)
2	Weight of filter paper before extraction (B)
3	Weight of mix after extraction (W2)
4	Weight of filter paper after extraction (D)
5	Weight of filler collected in filter paper (B-D) =W3

The formula to calculate the percentage of binder content is given by-

Report

The average percentage of Binder content in the given Bitumen Mix = _______%

The result obtained shall be reported as the percentage of binder content in the mix to the nearest second decimal.

Thank You

Bump Integrator Test

After construction of New Road, there will be one test to know the frequency of bumps on the newly constructed Road. 

Bump Integrator also known as Roughometer or Automatic Road Unevenness Recorder gives quantitative integrated evaluation of surface irregularities on an digital counter I LCD screen. It comprises of a single wheeled trailer, with a pneumatic tyre mounted on a chassis, on which an integrating device is fitted.

Automatic Road Unevenness Recorder / Bump Integrator

• An Indigenous device developed by CRRI
• It comprises of a standard pneumatic wheel mounted within a rectangular frame with single leaf spring on either side.
• Spring dashpots mounted on the leaf spring provide damping for the suspension
• Integrating unit, mounted on one side of the frame integrates the unevenness in cm.
• For the measurement It is towed by a jeep at a constant speed of 32 kmph under standard tyre pressure of 2.1 kg/cm2 along the designated wheel path
• Bumps in cm and corresponding road length in terms of wheel revolution pulses are displayed / recorded on a panel board

Vehicle Mounted Bump Integrator With GPS (ROMDAS Bump Integrator)

• It is a Vehicle Mounted Bump Integrator System
• This Vehicle Mounted Bump Integrator consists of an integrating unit which is mounted in the dicky on the rear axle of a car/jeep.
• Integrating unit, mounted on the dicky integrates the unevenness in cm or pulses.
• For the measurement vehicle is run at a constant speed of 32 kmph
• Bumps in cm or pulses and corresponding road length in meters are recorded on a computer based data acquisition system.

The unevenness of road is calculated in either one of the above mentioned method. 

Unevenness index is a measure of unevenness which is the cumulative measure of vertical undulations of the pavement surface recorded per unit horizontal length of the road.

Roughometer is a high speed device used for measuring pavement surface roughness. It is a portable type equipment and consists of a small accelerometer (sensor) device installed at the rear axle of survey vehicle, a distance measuring instrument, interface module and a controller. The pavement roughness measurements using this equipment are required to be done preferably at a speed in between 40 to 60 km/hr, in order to obtain most reliable and accurate data. The output is in the units of International Roughness Index (IRI).

 

    A Typical view of Roughometer Control Panel with GPS

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