In flexible pavement construction, bitumen binders are used. It is important that bituminous material forms ductile thin film around the aggregates, Which serves as a binder. The binder material not of sufficient ductility renders pervious pavement surface and leads to development of cracks.
Therefore it is important to carry out the ductility tests on bituminous material. Ductility is defined as distance in cms to which a standard briquette of bitumen can be stretched before the thread breaks. The briquette is stretched at a rate of 50mm/minute ±25mm per minute at a temperature of 27ºC ± 0.5ºC.Specifications :
The apparatus consists of a water bath with a thermostatic heater, and a circulating pump to maintain uniform water temperature. One half of the briquette moulds is fixed on a fixed plate in the water bath, the other half of the briquette mould is fixed to a carrier which slides over a rotating threaded shaft with a clutch.
The motor and gears to rotate the shaft are housed in a cabinet fixed above the other end of the bath. A pointer fixed to the carrier moves over a scale graduated from 0-110 cm x 1mm fixed on the bath with “0” (zero) of the scale towards the fixed plate side. The rotating shaft has 2 speeds of travel for the bracket, 5cm/min and 1 cm/min., selected by a clutch. Water bath inside is aluminium, it is an insulated water bath. Water bath is provided with a drain. A heater with thermostatic control is fixed inside the water bath. Control switches for motor, stirrer, heater and indicator lamps are fixed at a convenient place on the water bath, complete with three briquette moulds and one base plate, all made of brass. Operates on 230 volts A.C. single phase.
* Supplied with Digital Temp indicator cum Controller
* Also with Cooling Arrangement