Impact Products Digital Concrete Test Hammer CN652 User Manual
Page 24
8.4 Determining Time Coefficient
The age of the concrete and its carbonate penetration depth can significantly
increase the measured rebound values R.
It is possible to obtain accurate values for the effective strength by removing the
hard, carbonate-impregnated surface layer using a manual grinding machine
over a surface area of about Ø 120 mm and performing the measurement
on the non-carbonate-impregnated concrete.
The time coefficient, i.e. the measurement of the increased rebound values R,
can be ascertained by taking additional measurements on the carbonate-
impregnated surface.
R
m carb.
:
Average rebound value R, measured on carbonate-impregnated
concrete surface
R
m n.c.
:
Average rebound value R, measured on non-carbonate-
impregnated concrete surface
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