REBOUND HAMMER
Rebound hammer test is done to find out the compressive strength of concrete by using rebound hammer as per IS: 13311 (Part 2) – 1992. The underlying principle of the rebound hammer test is
The rebound of an elastic mass depends on the hardness of the surface against which its mass strikes. When the plunger of the rebound hammer is pressed against the surface of the concrete, the pring-controlled mass rebounds and the extent of such a rebound depends upon the surface hardness of the concrete. The surface hardness and therefore the rebound is taken to be related to the compressive strength of the concrete. The rebound value is read from a graduated scale and is designated as the rebound number or rebound index. The compressive strength can be read directly from the graph provided on the body of the hammer.
Procedure to determine strength of hardened concrete by rebound hammer.
i) Before commencement of a test, the rebound hammer should be tested against the test anvil, to get reliable results, for which the manufacturer of the rebound hammer indicates the range of readings on the anvil suitable for different types of rebound hammer.
ii) Apply light pressure on the plunger – it will release it from the locked position and allow it to extend to the ready position for the test.
iii) Press the plunger against the surface of the concrete, keeping the instrument perpendicular to the test surface. Apply a gradual increase in pressure until the hammer impacts. (Do not touch the button while depressing the plunger. Press the button after impact, in case it is not convenient to note the rebound reading in that position.)
iv) Take the average of about 15 readings.
Interpretation of Results
The rebound reading on the indicator scale has been calibrated by the manufacturer of the rebound hammer for horizontal impact, that is, on a vertical surface, to indicate the compressive strength. When used in any other position, appropriate correction as given by the manufacturer is to be taken into account.
You can have the complete details of Non destructive Test by rebound hammer test here
If you have a query, you can ask a question here.
dear sir
is it enough if we just do the rebound hammer test on the slab?
why my client still want to do the coring test on the slab?
the problem on the slab is just the surface cracks.
can u please provide the facts that doing the rebound hammer test is just enough than doing the coring test.
dear sir kindly send me the details regarding the values that indicates hard structure which are obtained from rebonnd hammer
and also a clear picture of rebound hammer showing all the readings on it
Please tell me what’s the importance in feilds in this experiment and disadvantage & advantages.
hi pease sir let me know about correct
ion factor of rebound hammer test how many factors apply against angle
what is frictional error% please send me information about factors
against angles and also zero angle
I really want to know, is it accepted if the concrete strength is to be 29.5 kN/mm2?
how can I get the rebound hammer test results verified through the calibrated graph?i don’t know how to use the calibrated graph..can u explain it to me…thanxx..
Please give the detailed information about Rebound Hammer test..Please also explain its graph deeply..I will be very oblige to u.
Average Rebound Number is 22 for concrete. What will be the equivalent compressive strength of concrete in N/mm2 and Kg/cm2.
1.is it recomended to do a rebound hammer test on 10cm thick floor slab which is casted on 25cm thick
hard core?
2.Would you let me know that what kind of surface is ready to carry out the rebound hammer test
and please tell me other procedures
Dear sir
what happened if rebound hammer test done on rough surface of concrete?
I need to know the answers given for these 30 questions.
How do I get the standards?
Dear Sir , Can I need me the the Calculation for Concrete Hammer Tests
Sir,
Please tell me about hammer test reding means, like as 26 is safe on M-20 grade concrete or not.
is that same result for rebound hammer and test cube result
Is it show cube strength
Dear Sir,
Can you please send the table for calculation of rebond hammer test
lot of thanks
SIR,
Please send the procedure on how to use rebound hammer, calculation procedures with example, and BS specifications on various concrete strength.
I will be most greatful.
THANKS
SIR,
Please send the procedure on how to calculate the rebound hammer result obtained at site to get the concrete strength result. and BS specifications on various concrete strength.
THANKS IN ADVANCE