Ductility Testing Apparatus
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 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 mount at a temperature of 25C ± 0.50C
The apparatus consists of a water bath with a the 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 Stainless Steel, 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 two briquette moulds and one base plate, all made of brass. Operates on 230 volts A.C. single phase.