# Elastic Recovery | Force Ductility

The ductility of bitumen refers to their ability to deform without breaking. This ability is mainly studied when bitumens are modified by elastomeric polymers. A specimen of binder, of defined shape and size, is stretched at a constant speed over a length “L” and under specified conditions of temperature. During the Elastic Recovery test, the bitumen yarn thus obtained is cut in the middle to obtain two half-threads whose shrinkage will be measured. This retraction distance is called “Elastic Recovery” and is expressed as the percentage of the initial elongation “L”.

The Force-Ductility test consists in measuring the elongation resistance of the bituminous binders in real-time and in calculating the cohesion energy, by the way of load cells measuring the force in Newton (N) during an elongation of 1333% (400 mm).

The brand new Numeric Ductilometer EVO 1500 – 4-ways was developed and manufactured by VIALAB, incorporating the latest generation of mechanical and electronic components, to meet users’ needs for precision, robustness and productivity in compliance with current standards.