The NU14 is a servo-pneumatic machine for testing asphaltic paving materials. Maximum loading capacity is normally up to 14kN with an air supply of 7 bar. The actuators are double acting which means that both compressive and tensile forces can be applied. This gives a high degree of control over the load waveform and enables loads to be cycled between tension and compression at high frequencies for tests such as bending beam fatigue.

This machine is a development of the NAT which was conceived by K E Cooper and Professor S F Brown at the University of Nottingham. The use of a high precision pneumatic servo valve in conjunction with a specially conceived low friction actuator, and sophisticated data acquisition gives performance that is equal to many servo hydraulic systems.

Allied to state of the art Windows software, this system digitally generates the waveforms applied by the actuator so that materials are tested under conditions that are simulative of those applied by static or moving vehicles. The actuator is double acting which means that both compressive and tensile forces can be applied. This gives a very high degree of control over the load waveform and enables loads to be cycled between tension and compression at high frequencies. Most international test standards are available in software, and, if necessary, users can use the LabView software platform to develop their own test routines.

FEATURES

The CRT-NU14 can be used for:
� Mix design
� End product specification
� The assessment of new materials
� Failure investigation
�Pavement assessment

SYSTEM ELEMENTS



CRT-NU14. Universal servo-pneumatic asphalt testing system comprising:
Rigid stainless steel test frame with adjustable height cross-head
Pneumatic actuator with low friction seal and pneumatic servo-valve and integral displacement transducer (14kN maximum static load at 7bar - up to 19kN at10bar)
Load transducer (�20kN capacity)

Acquisition and control system comprising:
� Signal conditioning for load transducer, 2 thermocouples and 2 displacement transducers (optional additional displacement transducer channels)
�Servo-amplifier for PID control of servo-valve
�Power supplies
� Multifunction high speed, 16bit analogue to digital, 16bit digital to analogue and digital input-output card for closed loop computer control of system (National Instruments)
� Pneumatic fittings including filter, regulator and tubing
� All signal and power cables
� Thermocouples
� Basic operational and diagnostic software
� Instruction manual

TECHNICAL SPECIFICATIONS




See also:
NAT Asphalt Testing System
Universal Servo-Hydraulic Test System
Four point beam fatigue test
Hamburg Wheel tracker
Wheel tracker EN12697-22 Large device CRT-WTENLD
Roller Compactor