Rebound Hammer Test Worksheet

ADVERTISEMENT

SD 409
Method of Test for Compressive Strength of Concrete
Using the Rebound Test Hammer
1.
Scope:
This test is for determining the approximate compressive strength of concrete in-
place.
2.
Apparatus:
2.1
Test hammer with carborundum stone.
3.
Procedure:
3.1
Calibration.
A.
The rebound test hammer is calibrated at the Central Laboratory.
Send the test hammer to the Central Laboratory when it is
malfunctioning or after approximately 2000 impacts.
3.2
Field Checks.
A.
Prior to using the test hammer for informational purposes, verify the
Central Lab calibration chart by performing the test procedure on
concrete with a similar mix design that has a known strength.
Compare the known strength to the test hammer result and consider
this information in any decisions that will be made based on the test
hammer results. Whenever possible, a more accurate field correction
factor (G) should be calculated according to 3.2(B) and applied to test
results.
B.
Field correction factor (G) calculation.
(1)
When possible, use a cylinder of the same mix design and age
of the in place concrete to be tested. If possible, perform the
calibration with the test hammer in the same orientation
(Horizontal, vertical up, or down) it will be used in the field. The
moisture condition on the surface of the cylinder should be
similar to what is going to be tested in the field.
(a)
If calibrating in the horizontal position, place the cylinder
in a compressive strength-testing machine and apply
10,000 to 15,000 pounds force (Enough to keep the
cylinder stationary).
(b)
If calibrating in the vertical down position, place the
cylinder on a firm surface and secure it from movement.
mso.mat 9-15

ADVERTISEMENT

00 votes

Related Articles

Related forms

Related Categories

Parent category: Business
Go
Page of 4