CRONOSONIC Ultrasonic Pulse Velocity through Concrete

Methodologies

Ultrasonic Pulse Velocity

The method is based on the propagation speed of longitudinal ultra-sonic waves inside a reinforced concrete structure. The propagation speeds depends on the characteristics of the material such as elasticity, density, presence of gaps, micro-holes, etc… From the determination of the following parameters: reflection, refraction, transit time (T.O.F.) and mitigation of the vibration energy, it is possible to obtain information on:

    

• Homogeneity of the mix    
• Elasto-mechanical characteristic
• Entity, geometry and location of particular faults or internal defects, variations in time of the quality parameters of the concrete
• Ultra-sonic tests through which it is possible to evaluate the transit speed of the pulses (with known thickness and time) are particularly important.
  
   

The primary goal of the Ultra-sound survey is to record the time of fly (TOF, Time of Fly) and the following calculation of the speed. In order to calculate the propagation speed of longitudinal waves (P waves), the arrival of the first wave-train must be found out with accuracy. In order to perform this operation correctly, the instrument must be equipped with oscilloscope that allows to visualize the transit wave on the device display.

 

The ultra-sound tests can be carried out with: 

• Direct method
  
  

When the transmitting and receiving probes are positioned on the opposite sides of the element to test.

• Semi-direct method

When the E/R probes are positioned on adjacent surfaces, usually orthogonal, of the element to test

• Indirect method
  
  

When E/R probes are positioned in the same side of the structural element to test.