Extensometers for Simple Performance Testing of Asphalt – Model 3909
Designed for measuring axial displacements in the simple performance tests prescribed by NCHRP Report 465, and determining dynamic modulus of hot mix asphalt per AASHTO TP062.
These extensometers are typically mounted as two axial modules with independent outputs capable of measuring specimen deformations in two locations, but they can be mounted as a single unit or up to four on a sample. They quickly clip onto gauge points mounted per the test requirements.
Magnets at each end of the extensometer snap instantly in place on the steel gauge points glued to the test sample. The quick attachment is most advantageous when testing preconditioned samples that are heated or cooled, since the extensometers can be mounted before the sample changes temperature appreciably. For units intended to be used inside triaxial cells, extensometers are available with modules rotated 90°.
The standard Model 3909 has full scale measuring range of ±1.0 mm (0.040 inches). Gauge points are included with the extensometers and an optional gluing fixture is available. Two standard 3909 units can be converted to the Model 3910 with the purchase of optional gauge length adapters.
The Model 3909 extensometers are strain gaged devices, making them compatible with any electronics designed for strain gaged transducers. Most often they are connected to a test machine controller with electronics for a strain channel, and Epsilon will equip the extensometer with a compatible connector that is wired to plug directly into the controller. For systems lacking the required electronics, Epsilon can provide a variety of signal conditioning solutions that enable connecting to data acquisition systems or other equipment.