ULTRASONIC PULSE VELOCITY TEST
Hello friends, Welcome to our blog post. In today's post I will share amazing information about the: "ULTRASONIC PULSE VELOCITY TEST".
So, Read these : ULTRASONIC PULSE VELOCITY TEST, post completely. After reading these today's post, you will understand the UPV Test on concrete.
So guys, don't forget to like & share these today's post. Also Follow our page, for such more new amazing ideas and posts.
Without wasting more time, Let's start with these post
The Ultrasonic pulse velocity test (UPV) is an example of a non-destructive test for concrete.
The tests performed on hardened concrete are Non-destructive testing (NDT) and Destructive testing.
Concrete is the most oldest as well as more used for the construction material in the world. Hence, Concrete testing is used to determine the stability, strength, durability, and condition of structures.
NDT test of concrete is a way of analysing concrete structures without causing any damage to the structures.
These test helps to ensure the structural quality as well as its condition.
The strength of the concrete may get affected due to various reasons which mainly includes hardness, density, curing circumstances, ingredient quality, Workability and w/c ratio, etc.
Ultra sonic Pulse Velocity (UPV Test) :
The most efficient as well as the most fast method of testing concrete by using the ultrasonic pulse velocity tests.
The Quality of concrete can be determined by using the results of UPV tests.
These results shows that the period of travel of ultrasonic pulse waves.
For these a 50–55 kHz range must be maintained for the ultrasonic pulse wave’s frequency.
Here, the pulses are generated by the UPV tester’s pulse generator, as well as they are allowed to travel through the hard concrete surface.
By inspecting the traversing distance and the duration, the pulse velocity can be easily determined.
As a result, the Higher velocity indicates that the density and elastic modulus of the concrete are higher.
In old concrete structures, cracks as well as defects are detected using UPV tests.
If there is variations in pulse velocity values, this shows that there is an indications of broken as well as the degraded concrete.
The concrete’s density and wave velocity are related with eachother.
Therefore, this test has a more importance for determining the quality of concrete.
IS code for (UPV Test)
IS-13311 (Part 1) : 1992 (Reaffirmed- May 2013) “Non-Destructive Testing of Concrete - Methods of Test (Ultrasonic Pulse Velocity)”.
Ultrasonic Pulse Velocity tester :
The UPV Tester is the name of the type of equipment which we used for the measurement of the Ultrasonic pulse velocity.
Here are the following list of the accessories are included in UPV tester :
- Electrical Pulse generator,
- Pair of Transducers or Probes,
- Amplifier,
- Electronic timing device.
Principles of Ultrasonic Pulse Velocity test :
The electrical pulse generator generates pulses that are sent through the UPV tester’s transducer.
Then, after that through the concrete surfaces, the pulse generates many reflections.
By Using the below given formula, the pulse velocity is calculated :
Pulse velocity (V) = L/T
where,
L is the traverse distance,
T is the time for the receiver to receive the pulse.
The geometry of the material is unrelated to the UPV test. As the Better concrete strength is associated with higher velocity and vice versa.
Objective of UPV tests
The main objectives of the ultrasonic pulse velocity test or UPV tests are listed below :-
- Know about the homogeneity of concrete.
- To inspect as well as to determine the presence of cracks, voids and imperfections.
- Also, To calculate the elastic modulus of concrete.
- Also to find the quality of concrete by comparing with the standard requirements.
- Atlast, To determine the age of concrete.
Factors affecting Ultrasonic pulse velocity test are given below :
As we know that, The UPV test detects cracks present on concrete structures and which can helps to assists in structure development.
However, a number of factors influence how pulse velocity is measured. As a result, cannot generally be approximated from the pulse velocity.
Here are the factors mentioned that affects the UPV test :
- Presence of reinforcement,
- Water content,
- Mix proportion,
- Temperature of concrete,
- Age of Concrete,
- Stress level of concrete.
Methodology of UPV tests are explained below :
For the UPV tests, Piezoelectric as well as the magneto strictive types of transducers are suitable.
The range of frequency for the UPV test requires should be between 20 & 150 kHz. The electronic timing device monitors time with an accuracy of 0.1 microseconds.
In these test, The transducer transmits the waves which travel through the concrete surface.
After that the receiver transducer detects the electric signals that are generated once the pulse waves are transformed to them.
These traversal length is displayed as ( L). The electronic timing device calculates, what time will be required for signals to arrive.
And the Time is denoted by (T).
These Electronic timing device measures the receiving time of the signals. The time is denoted as (T).
Below are the two most important methods of performing UPV tests are :
- Direct Method of UPV Testing
- Indirect Method of UPV Testing.
Pulse velocity (v) = L/T
1. Direct method
In these Direct method of UPV test, The maximum energy is transmitted at right angles to the face of the transmitter.
As a result, to achieve the accurate results, the receiving transducer must be placed on the side of the transmitting transducer.
This is referred to as the direct approach or cross probing.
2. Indirect method :
In these Indirect method of UPV test, due to some reasons, the opposite side of the structure may be inaccessible.
While performing the test, The receiving and transmitting transducers are installed on the same face of the concrete members.
This test is less effective than the direct method of testing. The test results are mostly varies by the surface concrete, having different properties from the structural components’ core concrete.
Result interpretation of UPV testing :
The density and elastic modulus of concrete are correlated with the UPV.
The concrete strngth mainly depends on the components, mixing processes, placement techniques, compaction of concrete and curing methods, casting temperature, etc.
The main reasons which causing internal cracks and pockets in concrete are due to lack of compaction as well as the segregation ofconcrete.
Lower pulse velocity values indicates that presence of the defects in concrete surface. However, the laboratory tests might have confirmed a well-designed concrete.
The range of pulse velocity by using the direct method is as shown below :
- Above 4.5 means concrete is in Excellent condition,
- 3.5 to 4.5 indicates concrete is Good condition,
- 3.0 to 3.5 is an indication of concrete is in Medium condition,
- Below 3.0 value is an indication that concrete condition was Doubtful.
Conclusion of UPV test :
The final result of the compressive strength from UPV is not the sole criterion which may be used to determine concrete strength.
The strength is confirmed by comparing it to a compressive strength estimate derived from the same ingredient mix as well as with the same conditions.
The results of the UPV test and site tests conducted using similar ingredients may be correlated.
When compared to actual UPV intensities, the numbers may change by about 20%.
0 Comments