Dynamic Testing Machines

Dynamic Testing

Used to relate laboratory mix design to actual field performance, asphalt dynamic tests measure a specimen’s recoverable strain and permanent deformation under reoccurring pressure. Unlike repeated load tests, dynamic tests apply a load over a range of frequencies, making it a more complicated measuring process. Test specimens are tested using three different loading frequencies (commonly 1, 4 and 16 Hz) at multiple temperatures. The applied load itself varies and is usually applied in a haversine wave.

Some primary variables that dynamic tests establish are:

• Flexural strength also called bending strength, is defined as a material’s ability to resist deformation under pressure. Measured in stress, this value represents the highest stress experienced within a material at its moment of rupture.
• Tensile strength is the maximum stress that a material can withstand while being stretched or pulled before breaking. Also called ultimate tensile strength, this number is equivalent to the resistance of a material to break under tension.
• Compressive strength determines the capacity a material has in withstanding loads working to reduce its size. This limit is established at the point that any given amount of deformation occurs.

Humboldt provides materials to perform the four-point bending test as well as a range of universal testing machines.

Four-Point Bending Beam Machine
The four-point bending test is able to provide values for the flexural stress and the flexural strength response of a material. Particularly suitable for brittle materials, it is one of the most widely used apparatuses to characterize fatigue and flexural stiffness of asphalt mixtures. Humboldt provides both large hydraulic and small stand-alone four-point machines, capable of performing fast and accurate flexural strength measurements.

Universal Testing Machines
The universal testing machine is more commonly used to test the tensile strength and compressive strength of materials. The term “universal” in its name reflects that it can perform a large variety of tests on a material. Both servo-pneumatic and servo-hydraulic options are available through Humboldt as well as a cDAC™ Controller.

If you have questions or need help selecting equipment, please call us at 1.800.544.7220 or use our Ask Humboldt form.