Large Hydraulic Four Point Bending Machine

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. This equipment is capable of testing over a wider frequency range (up to 60 Hz) than can be achieved with pneumatic loading systems.

The CRT-LH4PT-BB uses advanced servo-hydraulic 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 test frame is housed in a temperature controlled cabinet with fan-assisted air circulation and a temperature range of -20 to 30°C. The unique constant torque clamping and three-transducer defl ection measurement system of the CRT-LH4PT-BB can be confi gured to accept different beam sizes. This means that the ratio between beam dimensions and maximum aggregate size of test specimens will satisfy the requirements of the relevant European specifi cations.

KEY FEATURES
• Frequency range 0.1 to 60Hz
• High quality servo hydraulic four point bending machine
• Double acting fatigue rated hydraulic actuator with integral stroke transducer
• Utilises Star servo valve with ‘Sapphire Technology’
• Unique three transducer on-specimen defl ection measurement system
• Accepts various beam sizes: 380 to 600mm in length and 50 x 50mm to 100 x 100mm cross-section
• Temperature controlled cabinet range -20 to 30°C
• Sinusoidal controlled strain or controlled stress fatigue test modes
• Constant torque motorized specimen clamping to eliminate errors due to localised beam indentation
• User friendly software for determination of fatigue resistance and stiffness modulus
• The possibility to make frequency/temperature sweeps
• Covered for noise reduction

KEY USES
• Mix design
• End product specifi cation
• Assessment of new materials