Bitumen Ductility Test

Bitumen Ductility Test   Aim To Determine the ductility of the given bitumen sample.

 Apparatus 1.

design to that shown in the figure and made of br ass. Mould  the mould similar in design The ends b and b being known as clips, and the parts a and a as sides of the mould. The dimensions of the assembled mould were: a. Total Length  75.0 ± 0.5mm b. Distance Between Clips- 30 ± 0.3mm c. Width at mouth of clip- 20 ± 0.2mm d. Width at minimum Cross-section- 10 ± 0.1mm e. Thickness ThroughoutThroughout- 10 ± 0.1mm

2.

W ater ater

Bath  the water bath maintained at the specified test temperature, varying

not more than 0.1°C from the specified temperature. The volume of water not less than 10 L, and the specimen immersed to a depth of not less than 10 cm and supported supported on a perforated shelf not less than 5 cm from the bottom of the bath. 3.

T esting esting

briquet te of bituminous bituminous material apart, any Machine for pulling the briquet

apparatus may be used which is so constructed that the specimen will be be continuously continuously immersed in water, while the two clips are pulled apart at a uniform speed, as specified, without undue vibration. 4.

T hermometer  A hermometer A

thermometer.

Procedure

1. The test was conducted at a temperature of 27 ± 0.5C and a rate of pull of 50 ± 2.5 mm/min. 2. The bituminous material was completely melted to a tem perature of 75 to 100C above the approximately softening point until it became thoroughly fluid. 3. The mould was assembled on a brass plat e. The surface of the plate and interior surfaces of the sides a and a of the mould was thoroughly coated with a thin layer of a mixture of glycerine and dextrin to prevent the ma terial under test from sticking. In filling the mould, care w as taken not to disarrange the parts and thus distort the briquette. In filling, the material was poured in a thin stream back and forth from end to end of the mould until the mould was more than level full. The mould containing the material was left to cool to room temperature for a period of 30 to 40 min and then it was placed in the water ba th maintained at the specified temperature of test for 30 min; then the excess bitumen was cut off with a hot straight edged putty knife or spatula to make the mould just level full. 4.

K eeping Specimen at

Standard T emperature  the brass plate and mould, with briquette

specimen, was placed in the water bath and kept at the specified temperature for a period of 85 to 95 min. Then the briquet te was remov ed from the plate, the side pieces were detached, and the briquette was immediately tested. 5.

T esting the

rings at each end of the clips were a ttached to the pins or hoo ks in the

testing machine and the two clips were pulled apart at a uniform speed as specified until the briquette ruptured. The distance was measured in centimetres through which the clips had been pulled to produce rupture. While the test was being made, the water in the tank of the testing machine covered the specimen both above and below it by at least 2.5 cm and was kept continuously at the specified temperature within ±0.5°C.

Observations

The bituminous material did not rupture even at a distance of 7 0 cm. a. The first thread ruptured at a distance of 96cm and b. The second thread did not rupture along the full length of the measuring instrument.

Result 

The ductility of the sample= 70cm+ (more than 70cm).

Inference The bitumen is grade 60/70.

Definitions The ductility of a bituminous material is measured by the distance to w hich it will elongate before breaking when two ends of a briquette specimen of the ma terial, of the form described in the apparatus, are pulled apart at a specified speed and at a spec ified temperature.