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 specifications. 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 deflection measurement system of the CRT-LH4PT-BB can be configured 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 specifications.

Standards

• EN 12697-24 Annex D
• EN 12697-26 Annex B
• AASHTO T321-03 (TP8)
• Chinese Standard

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 deflection measurement system
• Accepts various beam sizes: 380 to 660mm 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
• Supplied with certification of a UKAS accredited calibration
• Covered for noise reduction

Key Uses

• Mix design
• End product specification
• Assessment of new materials

cDAC – Advanced Data Acquisition System

• Measurement of up to 32 transducers
• Wave Types:
• Haversine
• Pulse
• Square
• Triangle
• Constant
• Ramped
• Rest Periods

Software

• User friendly, intuitive and reliable Windows™ software developed using LabVIEW™
• Specifically written to meet EN 12697-24 Annex D and EN 12697-26 Annex B
• The user interface can be translated into the user’s preferred language – please enquire
• One software package performs both fatigue and complex modulus testing
• Stored test data can be analysed and compared with other test data utilising a spreadsheet package
• Utilities are included for curve fitting of acquired data; testing of system’s inputs and outputs; phase correction and a transducer database for storing calibration factors

For more information visit: .uk/shop/asphalt-testing/large-hydraulic-four-point-bending-machine/