The ductility of a given bitumen sample is measured
The suitability of the bitumen for use in road construction is measured.
Ductility of bitumen is the distance by which it extends in cm before breaking when kept in standard briquettes under standard conditions.
The standard temperature of 25oC must be maintained. The 100 mm x 100 mm cross-section in the mold is prepared at a specified temperature, the excess bitumen is removed and the chips are hooked after zeroing the pointer.
The sample is pulled at 50 mm per minute until rupture. The distance to the breaking point in cm is the ductility value that depends on the temperature, briquette size, traction rate.
Ductility values can vary from 5 to 100 cm. A minimum value of 5 cm is required for bitumen grade 45 and above.
All equipment, including bitumen briquette and brass plate, is air-cooled.
A hot knife is used to cut excess bitumen and the surface is also leveled with the help of a hot knife.
The whole set is now kept in a bath maintained at 27 oC for about 85 to 95 minutes.
The mold side has been removed, the clamps hooked on the machine and the pointer set to zero or the initial reading noted.
The clips are now separated horizontally at a rate of 50 mm per minute and the distance to the point where the line breaks are observed. This distance in cms gives the bitumen ductility value.
The ductility of the bitumen can vary from 5 to more than 100 for different degrees of bitumen, but, for satisfactory performance, it should not be less than 50.
The ductility of the bitumen depends on the casting temperature, briquette dimensions, test temperature, tensile rate, etc.
For many decades, different ductility methods, including the ductility test of bitumen pdf references, have proven to be a reliable indicator of the rheological characteristics of bitumen and bituminous binders at medium temperatures.
The basic principle of the test is that a bitumen sample is prepared in special molds between two clips. The sample is then separated horizontally at a uniform speed and at a specified temperature in a long water bath.
Ductility is used as a performance-based specification criterion for bitumen in product specification standards.