Bending Machines #4533264

Bending tests are widely used for measuring the stiffness modulus and assessing the fatigue resistance of asphaltic paving materials. Four point bending tests are included in CEN, AASHTO and Chinese test specifi cations. The specimen is a prismatic beam which is subjected to sinusoidal loading in either the controlled strain or controlled stress modes. The CRT-SA4PT-BB uses advanced servo pneumatic technology and a high-speed digital data acquisition and control system together with user-friendly software. During testing both graphical and tabular data are displayed on screen and test data is stored to disc in Microsoft Excel compatible format. The clamps are at 118.5mm centres (the distance between the outer clamps is 335.6mm (14 inches) according to AASHTO specifi cations2 but the height and width of the beam can be varied.2 Tests on beams containing aggregates greater than 20mm are not strictly in accordance with annex D of EN 12697-24 which states that this non-compliance should be explicitly mentioned in the test report.

Bending tests are widely used for measuring the stiffness modulus and assessing the fatigue resistance of asphaltic paving materials. The two-point bending test on trapezoidal specimens is, arguably, the most repeatable and reproducible bending test method detailed in the relevant EN12697 standards. In this test the specimen is mounted as a vertical cantilever. The base is fi xed and the top is moved sinusoidally with a constant displacement amplitude. The trapezoidal shape ensures that the maximum values of bending stress and strain occur away from the ends of the specimen where there are likely to be stress concentrations. With the Cooper Technology equipment, two trapezoidal specimens are tested simultaneously and stiffness modulus can be determined at a range of frequencies and temperatures. In the fatigue test the specimens are subjected to a constant strain amplitude at a selected frequency and temperature until the stiffness modulus decreases to a user-selected target level (normally 50 percent of its initial value).

KEY FEATURESRigid test frame housed within temperature cabinetTemperature cabinet with fan assisted air circulation and glazed viewing doorTemperature cabinet range -20 to 30CMachine designed to test two specimens simultaneouslyFrequency range from 0.1 to 35HzPrecise manual setting of strain amplitudeAccurate pre-test displacement transducer adjustment using software feedbackTwo high-precision 2.5kN fatigue rated piezoelectric force transducersHigh-speed control and acquisition system for interfacing to host computerUser-friendly software for fatigue and stiffness modulus testsSoftware for automatically carrying out frequency sweeps

KEY USESMixture designEnd product specifi cationAssessment of new materials

Bending tests are widely used for measuring the stiffness modulus and assessing the fatigue resistance of asphaltic paving materials. Four point bending tests are included in CEN, AASHTO and Chinese test specifi cations. The specimen is a prismatic beam which is subjected to sinusoidal loading in either the controlled strain or controlled stress modes.

The CRT-SA4PT-BB uses advanced servo pneumatic technology and a high-speed digital data acquisition and control system together with user-friendly software. During testing both graphical and tabular data are displayed on screen and test data is stored to disc in Microsoft Excel compatible format. The clamps are at 118.5mm centres (the distance between the outer clamps is 335.6mm (14 inches) according to AASHTO specifi cations2 but the height and width of the beam can be varied.2 Tests on beams containing aggregates greater than 20mm are not strictly in accordance with annex D of EN 12697-24 which states that this non-compliance should be explicitly mentioned in the test report.

KEY FEATURESFrequency range 0.1 to 30HzLow cost pneumatic stand alone four point bending machineUtilises a low-friction actuator and high performance ceramic spool servo-valveOn-specimen measurement system removes errors due to frame fl exureAccepts AASHTO beam sizesSinusoidal controlled strain or controlled stress fatigue test modesConstant torque motorized specimen clamping to eliminate errors due to localised beam indentationSelf-contained loading systemUser friendly software for determination of fatigue resistance and stiffness modulusConstant torque motorized specimen clamping removes errors due to localised beam indentation

KEY USESMix designEnd product specifi cationAssessment of new materials