Determining Time Coefficient - Proceq DIGI-SCHMIDT 2000 ND Mode D'emploi

It is necessary to test samples of differing qualities and
/ or ages in order to prepare a new conversion curve for
the entire range of rebound values from R = 20 to R = 55.
• Using the pairs of values R
mathematical shape of the conversion curve, i.e. deter-
mine the parameters a, b and c of the x
EXCEL in the RGP function).
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.
Time coeff. Z =
f
R
m n.c.
R : Average rebound value R, measured on
m carb.
carbonate-impregnated concrete surface
R : Average rebound value R, measured on
m n.c.
non-carbonate-impregnated concrete
surface
24 Appendix
/ fckm, calculate the
m
2
function (e.g.
R
m carb.
⇒ R =
m n.c.
Z
f
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