Exp 10 Double Punch Test

Experiment No. 10:

Determination of the tensile strength of concrete by Double Punch Test. (Non-Standard Test)

Apparatus:Double Punch Test

  • Testing Machine
  • Testing Samples
  • Punches (2 in number, to be placed at the top and bottom of the sample) Double Punch Test

Test Specifications:

Double Punch Test

Size Of The Specimen

The specimen is a cylinder of 150mm diameter and 150mm height.

Procedure:

It is an indirect method in which we determine the tensile strength of concrete based on the theory of perfect plasticity. Double Punch Test

In this test a concrete cylinder is placed vertically between the loading platens of the machine and is compressed by two steel punches placed parallel to the top and bottom end surfaces. Double Punch Test

The sample splits across many vertical diametrical planes radiating from central axis.

Samples should be placed under wet conditions for 24 hours and later on in a curing tank for 28 days.

Calculation

10.4

The tensile strength can be computed as; Double Punch Test

Double Punch Test  where,   P = Crushing Load

Observations & Calculations:

Sr #

Maximum Applied Load

Diameter of Specimen

Length of specimen

Splitting Tensile Strength

Tons

N

mm

mm

Mpa

1

12.5

122625

150

150

2.97

2

12.75

125078

150

150

3.03

Avg

12.625

123851

150

150

3

Comments:

Double punch Test has been performed successfully and the Tensile Strength have been calculated which comes out to b 3MPa as an average value. The dimensions of the Specimens were 150 mm x 150 mm, we have not performed compression test on this sample so we cannot compare our values with those. Usually the Compressive to Tensile Strength ratio is 8 to 15. Taking  this concept we can estimate the Compressive Strength of Concrete to vary from 20 MPa to 37.5 MPa. Double Punch Test




Leave a Reply

Your email address will not be published.

*