Materials Testing Bending Beam Testing

CRT-SA4PT-BB Stand Alone Four Point Bending Beam 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.

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 specifications² 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 Uses
Mix design
End product specification
Assessment of new materials

Standards
EN 12697-24 Annex D
EN 12697-26 Annex B
AASHTO T321-03 (TP08)

Key Features
Frequency range 0.1 to 30Hz (1)
Low cost pneumatic stand alone four point bending machine
Utilises a low-friction actuator and high performance ceramic spool servo-valve
On-specimen measurement system removes errors due to freame flexure
Accepts AASHTO beam sizes
Sinusoidal controlled strain or controlled stress fatigue test modes
Constant torque motorized specimen clamping to eliminate errors due to localised beam indentation
Self-contained loading system
User friendlysoftware for determination of fatigue resistance and stiffness modulus
Constant torque motorized specimen clamping removes errors due to localised beam indentation

CRT-LH4PT 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 60Hz) 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 30ºC. 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 the beam dimensions and maximum aggregate size of test specimens will satisfy the
requirements of the relevant European specifications.

Key Uses
Mix design
End product specification
Assessment of new materials

Standards
EN 12697-24 Annex D
EN 12697-26 Annex B
AASHTO T321-03 (TP8)

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 tranducer
Utilises Star servo valve with 'Sapphire Technology'
Unique three transducer on-specimen deflection measurement system
Accepts various beam sizes: 380 to 600mm in length and 50x50mm to 100x100mm cross-section
Temperature controlled cabinet range -20 to 30ºC
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

CRT-2PT Two Point Trapezoidal Bending Beam Machine
Bending tests are widely used for measuring the stiffness modulus ans 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 revelant EN 12697 standards. In this test,
the specimen is mounted as a vertical cantilever. The base is fixed and the top is moved sinusoidally with
a constant displacement amplitude. The trapezodal specimens are tested simultaneously and stiffness
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 Uses
Mixture design
End product specification
Assessment of new materials

Standards
EN 12697-24 Annex A
EN 12697-26 Annex A
NF-P-98-260-2

Key Features
Rigid test frame housed within temperature cabinet
Temperature cabinet with fan assisted air circulation and glazed viewing door
Temperature cabinet range -20 to 30ºC
Machine designed to test two specimens simultaneously
Frequency range from 0.1 to 35Hz
Precise manual setting of strain amplitude
Accurate pre-test displacement transducer adjustment using software feedback
Two high-precision ±2.5kN fatigue rated piezoelectric force transducers
High-speed control and acquisition system for interfacing to host computer
User-friendly software for fatigue and stiffness modulus tests
Software for automatically carrying out frequency sweeps