Non-Destructive Test

Non-Destructive Tests

**OUR PLAN**

AIM

**Thinking**

Rebound

Hammer Test

Ultrasonic Pulse Velocity Test

Resonant Frequency Test

Step 1

Step2

Determine the uniformity of blocks by

Rebound Hammer Test

Step 3

Determine compressive strength of blocks by UPV test

Group 10

Zhongkai Hu

Sisi Du

Dan Wang

Hao Chen

Yaodong Li

Zheng Wang

What is Rebound Hammer Test?

Principles

Advantages

1.Check

Uniformity

2.Determine the time for removal of formwork

3.

Time saving

, easy to record data

4.Economical

Limitation

1. Sensitive to Local Variarion

2. The angle between the hammer and the suface

3. Moisture Content

4. Temperature

Data and Calculation

What is Ultrasonic Pulse Velosity Test

The test procedure is measuring the time taken for an ultrasonic pulse to travel though a known length of concrete, from the results we can therefore calculate the Velocity by using formula

V=L/T.

The

velocity

of the longitudinal ultrasonic pulse is related to the

elastic properties of the concrete

and

compressive strength

Limitation

1.Constituent materials

2. Moisture Condition

Data and Calculation

What is Resonant Frequency Test?

principle

Resonant frequency

Dynamic Elastic Modulus

Compressive Strength

Limitations

Laboratory test on

prepared specimens

Therefore, we cannot ues this method for real structure

Data from Experiment

Estimate the likely

deformation

if a vertical compressive load of

1.5MN

is applied uniformly to the top face of each of blocks

Deformation

Young's Modulus

E

is unknown, solve for

E

?

Find E by NDT

Ultrasonic Pulse Velocity Test

Velocity

Dynamic elastic Modulus

Poisson's Ratio

Resonant Frequency Test

Dynamic elastic Modulus

Resonant

Frequency

Length

Density

HOWEVER..

Resonant frequency test can only be used for

prepared

specimens

As a result....

Elastic Modulus

Compressive

Strength

Find

k

from resonant frequency test

Determine Dynamic elastic Modulus

For Mix 1:

From the Data, n=

4609

Hz, l=

0.5

m, ρ=

2407.

4kg/m^3.

Ed=4*(

4609

Hz) 2(

0.5

m)^ 2 (

2407.4

kg/m^3)=

51140.11

Mpa

Determine Static Elastic Modulus

The ratio of static to dynamic modulus is normally between

0.8

and

0.85

Es=

0.83

Ed

Determine the Compressive Strength

During the lab, we crushed the cubes and got compressive strength

(Resonant frequency test)

Determine K accoding to lab records

k

=4.97

MIX A

MIX B

Calculate deformation

separately

1. Determine the Velocity

2.Compressive Strength

As the ultrasonic pulse velocity can be correlated empirically with strength, the further measurement for block B,C can be used to determine the compressive strength from the graph above.

Step 4

Calculations

Compressive Strength of each Mix

UPV TEST

Elastic Modulus

Deformation of each Mix

Total Deformation

Sum up

**Thanks for listening !**

Questions?

**TEAM 10**

1. contacting surface

2.direct set-up

3. Calibration