The method is valid provided the crack is not filled with water. Detection of Defects with Ultrasonic Test on Concrete When ultrasonic pulse travelling through concrete meets a concrete-air interface, there is a negligible transmission of energy across this interface so that any air filled crack or void lying directly between the transducers will obstruct the direct beam of ultrasonic when the void has a projected area larger than the area of transducer faces.
Procedure for Ultrasonic Pulse Velocity i Preparing for use: The pulse time for the bar is engraved on it. Estimating the depth of cracks An estimate of the depth of a crack visible at the surface can be obtained by the transit times across the crack for two different arrangements of the transducers placed on the surface.
A reference bar is provided to check the instrument zero. Apply a smear of grease to the transducer faces before placing it on the opposite ends of the bar. The internal battery, An external battery or The A.
This ultrasonic test is done as per IS: Apply couplant to the surfaces of the transducers and press it hard onto the surface of the material.
The mean value of the display readings should be taken when the units digit hunts between two values. An equation may be derived by assuming that the plane of the crack is perpendicular to the concrete surface and that the concrete in the vicinity of the crack is of reasonably uniform quality.
It is advisable to prevent the two transducer leads from coming into close contact with each other when the transit time measurements are being taken. It is important that the distance X be measured accurately and that very good coupling is developed between the transducers and the concrete surface.
If this is not done, the receiver lead might pick-up unwanted signals from the transmitter lead and this would result in an incorrect display of the transit time.
One suitable arrangement is one in which the transmitting and receiving transducers are placed on opposite sides of the crack and distant from it. The first pulse to arrive at the receiving transducer will have been directed around the periphery of the defect and the time will be longer than in similar concrete with no defect.
Two values of X are chosen, one being twice that of the other, and the transmit times corresponding to these are measured.
High UPV values, high rebound number Not corrosion prone Medium range UPV values, low rebound numbers Surface delamination, low quality of surface concrete, corrosion prone 3 Low UPV, high rebound numbers Not corrosion prone, however to be confirmed by chemical tests, carbonation, pH 4 Low UPV, low rebound numbers Corrosion prone, requires chemical and electrochemical tests.Evaluation of residual mechanical properties of steel fiber-reinforced reactive powder concrete after exposure to high temperature using nondestructive testing Schematic heating time plot Fig.
2: RF test setup Fig. 3: UPV test setup UPV and RF test procedure The UPV and RF measurements were taken for samples at room. Ultrasonic testing of concrete or ultrasonic pulse velocity test on concrete is a non-destructive test to assess the homogeneity and integrity of.
Presence of reinforcement steel; Table 1 shows the guidelines for qualitative assessment of concrete based on UPV test results.
The results indicated that the addition of steel fiber increases the compressive strength at all tested heating levels with a maximum percentage increase of (%) at temperature level (°C) in spite of that they have the same behavior but the residual compressive strength decreases with the addition of steel fiber for the tested heating.
damage in steel fiber reinforced cementitious composite panels A. Prakash1, S.
M. Srinivasan2, (UPV) measurement on a square grid spacing of 20 mm is carried out.
Internal compressive waves are most frequently used for ultrasonic testing. Steel fiber reinforced cementitious composite and concrete are heterogeneous. Request PDF on ResearchGate | Estimating properties of reactive powder concrete containing hybrid fibers using UPV | In this research, the application of ultrasonic pulse velocity (UPV) test as a.
ULTRASONIC PULSE VELOCITY INVESTIGATION OF STEEL FIBER REINFORCED SELF-COMPACTED CONCRETE By Belayhun .Download