Ultrasonic pulse velocity test of concrete.

 Let us go through some of the queries related to the UPV test of concrete as follows.

1. What is the ultrasonic pulse velocity test of concrete?

The ultrasonic pulse velocity test or short UPV test is a non-destructive testing technique used over hardened concrete. In this test, the integrity, quality, & strength of the in-situ concrete structure is evaluated.

The ultrasonic pulse is passed from one surface of the concrete to the other surface & transit time is calculated. The transit time depends upon the density, uniformity, porosity, & elasticity of the tested concrete. 

With the rise in the ultrasonic pulse velocity, it is confirmed that the concrete is of good quality & slower velocity indicates poor concrete quality.

2. What are the factors that affect UPV test results? 

The different factors that affect the UPV test results are,

1. Dimension & shape of the concrete structure.

2. Moisture content of the concrete.

3. Temperature of the concrete.

4. Cracks, voids, & cavities within the concrete.

5. Percentage of reinforcement bars & their vicinity within the concrete.

6. Density of aggregates, type of aggregates, & their composition.

7. Acting stress over the concrete member.

8. Contact establishment between the concrete surface & transducer.

9. Placement method of two transducers & path length of the pulse.

3. What are the applications of the UPV test?

UPV test is conducted to 

1. Find the uniformity & homogeneity of the concrete.

2. Estimate the quality & strength of concrete.

3. Evaluate the density, compaction, & porosity of concrete.

4. Find the cracks & their depth, honeycombing, cavities, and fissures in concrete.

5. Calculate the dynamic Young's modulus of elasticity of concrete.

4. What are the different arrangments or placements of transducers in UPV testing?

The two transducers are arranged or placed over the concrete surface in 3 different methods.

1. Direct transmission method:

One transducer is placed over one concrete face & the other is placed exactly at the opposite end face of the concrete member.

2. Semi-direct transmission method:

Both transducers are placed over the adjacent face of the concrete member surface.

3. Indirect transmission method:

This is also known as the surface transmission method. Here, both transducers are placed over the same face of the concrete member.

5. What are the velocity criteria for the concrete quality grading in the UPV test?

The velocity criterion for the concrete quality grading is given in the table below.

Note: 

1. In case of doubtful quality, it may be necessary to do further tests.

2. If the difference between maximum & minimum apparent velocity < 0.5 km. /sec., then the concrete is considered as uniform quality.

3. If the difference is > 0.5km./sec., then the concrete is considered of doubtful quality.

6. What is the equipment or apparatus required to conduct the UPV test over the concrete?

The total set of apparatus used in the UPV test is called an ultrasonic pulse velocity meter ( tester). It consists of the following different units.

1. Electric pulse generator.

2. A pair of transducers.

a.) Transmitting transducer.  &  b.) Receiving transducer.

3. Standard calibration bar.

4.. Receiver amplifier.

5. Electronic timing device.

a.) Time measuring unit. &  b.) Time display unit.

7. What is the IS code for the UPV test on concrete?

The IS code for the ultrasonic pulse velocity test on concrete is IS 516: part-5 ( sec-1): 2018. 

The earlier IS code referred for the UPV test is IS 13311(PART-1)

To go through the field & laboratory tests conducted in civil engineering,  click here.

Thank you for going through this article❤. Have a good day 😄.

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