Tests on Emulsion

Coating ability and Water Resistance

Code: This test is done as per IS: 8887:2004.

Procedure:

• i) Carry out the test at 24 t 5.5°C.
• ii) Weigh 460 g of the air dried/graded limestone aggregates in the mixing pan.
• i) Weigh 4 g of CaC03 dust in the mixing pan and mix with the 460 g of aggregate for approximately 1 min by means of a mixing blade to obtain uniform film of dust on the aggregate particles. The total weight of aggregate shall be 460 g.
• iv) Pipette 9.3 ml of water to the aggregate and CaCO, dust mixture into the mixing pan and mix thoroughly to obtain uniform wetting.
• iv) Weigh 35 g of bitumen emulsion into the aggregate in the pan and mix vigorously with the mixing blade for 5 min by a back and forth motion in an elliptical path of the mixing blade of spoon. At the end of the mixing period, tilt the pan and permit any excess emulsion not on the aggregate to drain from the pan.
• iv) Remove approximately one half of the mixture from the pan and place it on absorbent paper and evaluate the coating.
• iv) Immediately spray the mixture remaining in the pan with tap water from the constant head water spraying apparatus to cover the mixture. The distance from the spray head to the sample shall be (305 ± 75 mm). Then carefully pour off the water. Continue spraying and pouring off the water until the overflow water runs clear. Carefully drain off the water on the pan. Scoop the mixture from the mixing pan on to absorbent paper for evaluation of coating retention in the washing test.
• iv) Evaluate the mixture immediately by visual estimation as to the total aggregates surface area that is coated with bitumen.
• iv) Report the evaluation by visual estimation of the coating of the aggregate surface area by bitumen after the mixture has been surface air dried in the laboratory at room temperature. A fan may be used for drying if desired.

Uses:

It is used for to determine the Coating ability and water resistance of emulsion.