Hello Friends, This is Mukesh from Learning Technology. I will tell you in today’s post, Test to Determine the Stripping Value of Road Aggregate by Dynamic Immersion Method in very easy way.
Contents
Object of Experiment
Determine the Stripping Value of Road Aggregate
Theory and Scope
Determination of Stripping Value by static immersion method requires more than 24 hours for its completion. The dynamic immersion test speeds up the stripping action. The sample is agitated mechanically. Stone screenings for use in seal coats or open-graded mixtures are usually subjected to this test. The test is applied to the aggregate fraction passing through 10 mm sieve and retained on the 2.36 mm sieve.
Equipments
Film Stripping Device
Water Bath
Balance
IS Sieves
Riffle box
Measuring cylinder
Tray
Spatula
Miscellaneous items such as containers for the heating and mixing of materials etc.
Description of Equipments
The film stripping device consists of a circular disc which rotates in a vertical plane at a rate of approximately 100 RPM by an electric motor. It is provided with 4 glass bottles of approximately 400 cc capacity clamped to the holders positioned equidistant on the disc at an angle of 90 degree to each other with their mouths towards the centre of the disc. The machine with a time switch is mounted over a firm base.
Thermostatically controlled water bath capable of maintaining a temperature of 60 degree Celsius
Riffle box with 10 mm openings for collecting the representative sample.
Balance to weigh 200 grams with an accuracy of 0.1 gram.
IS sieves of 10 mm and 2.36 mm
READ MORE
- Determination of Efficiency of a Centrifugal Pump
- Calibration of V-Notch Experiment
- Aggregate Impact Value Test as per IS 2386 (Part-IV) 1993
- Aggregate Crushing Value Test
- Water Content of Soil by Oven Drying Method
- Specific Gravity of Cement by Specific Gravity Bottle
- Sp. Gravity & Water Absorption Of Coarse Aggregate
- Sp. Gravity & Water Absorption of Fine Aggregates
Procedure
1. Preparation of Sample: By means of a riffle box quarter out sufficient aggregate fraction passing 10 mm and retained on the 2.36 mm sieves to yield test samples. Prepare four test specimens as follows:
(a) Unscrew the clamps and clean the holders.
(b) Clean the bottles thoroughly.
(c) Weigh 60 grams of representative test sample and place it in a suitable container. Coat the sample with the binder of type and quantity to be used in construction.
(d) Transfer the sample to the cleaned bottle.
2. Cure all the four coated specimens for 15 hours at 60 degree Celsius.
3. Remove the specimens and cool them to room temperature of about 25 degrees Celsius.
4. Add 175 ml of the distilled water in each bottle and screw on the cap to the bottle with the rubber gasket in between the bottle top and the cap.
5. Place the bottles in the holders of the stripping device and clamp the bottles; ensure that each bottle protected by the cushion.
6. Start the machine and agitate the mixture for 15 minutes.
7. Stop the machine and allow the disc to come to rest; remove the bottles holders.
8. Estimate by visual observation the percentage stripped.
Observations and Calculations
The mean value of at least three visually estimated values, being rounded off to the nearest 5 percent.
|
Sample in Bottle |
I | II | III |
IV |
|
Area of aggregate uncoated by immersion in water, percent |
||||
|
Average stripping value, percent |
||||
Stripping value of aggregate with the given binder = ………. percent
Precautions
1. Wear safety glasses and / or face shields, heat-resistant gloves with close-fitting cuffs.
2. There shall be no smoking or the presence of other ignition sources in close proximity of test set-up.
3. It should be ensured that the bottles are tightly clamped against cushion so as to prevent breakage.
4. When not in use keep the bottles clean.
Discussions
Both the tests are qualitative and provide a subjective evaluation of the stripping; to the best, they can be considered just capable of discriminating between poor and good performers in regard to stripping. However, the results must still be tied to field performance. The results of the stripping test given an indication regarding the susceptibility of aggregate to the action of water, or moisture. The more the stripping value, the poorer are the aggregate from point of view of adhesion. IRC has specified the maximum stripping value of 25 percent for aggregate to be used in bituminous road construction.
