With the ductility machines of the DDA 3 series the afore mentioned procedures can be performed automatically. Exept for recovery tests, 3 tests can be performed simultaneously.

The drive is microprocessor controlled and uses a stepping motor and a feed rod. Both are located outside the tempering bath and therefore are not affected by corroding influences of the bath liquid.

The tempering bath itself is double-walled with an outer water circulation system. The tractor cradle is made of stainless steel as well as the bath walls.

If extremely thin threads are measured, the built-in circulation pump for the inner bath can be switched off.

A very even and exact temperature can be obtained in the bath by the connection of a good coolant circulator and due to several temperature probes plus the transparent bath cover.

Traction speed, elongation and pauses can be pre-set on the control unit. During the whole test run the tensile force on each line is permanently measured. The maximum tensile force may be up to 300 Newton's per line. With the DDA 3 a minimum tensile force margin can be set.

When a bitumen briquette ruptures and the tensile falls below this setting, the pertinent elongation will be stored and the machine will be stopped automatically after all three briquettes have broken.

There is a special program for recovery tests of polymer-modified bitumen. The bitumen briquette will be expanded to a pre-set elongation, then the tractor (after a pause) returns to a position where no more stress is in the material, equivalent to the cut-up state of the specimen.

If due to any recovery of the material a tension should occur, the tractor will move until there is a stress-free condition again.

The control unit is equipped with two RS232 interface. This allows to connect a serial printer and a PC to record all test parameters, the final values on each test line as well as peaks with their pertinent elongation. Further, the DDA 3 has analog output sockets so that force/elongation curves can be drawn.

The ductility meters are also available as DD 3 in a basic version without force measurement. These models have a digital indication of the elongation only.

DDACon Software
A program for recording, saving and graphic presentation of DDA values.

Replacing analog line recorder or serial data-printer, allows to control the DDA by PC, the data-transfer to MS EXCEL® or LIMS and simplifies the download of firmware-upgrades.

The sample status of up to 3 samples will be displayed simultaneously, indicating the traction distance or for Recovery-tests the percentage of relief and the total energy.

Significant points like the local minimum, maximum, turn-points of in- & decreasing flanks and tangent-points can be determined automatically and displayed as diagram or chart.

The numerical display of force or distance for a single point on the curve is possible, too.

Individual diagram areas can be increased, curves can be hidden or indicated numerically.

Since every sample will be saved under an individual filename, it is possible to compare 3 samples of different tests with each other.

The evaluated data can be exported as ASCII-files. They include information like the sample name, file name, user ID, date & time, duration, program, speed, temperature at start & end, status and distance & force.
Printing of numerical or graphic evaluations, including relevant point like maxima and fracture are possible on a usual printer.

Ductilometer Test Equipment

to be composed of:

- Automatic Force-Ductilometer - DDA 3
- Circulator for external & internal heating & cooling
- Hose-Set for circulator