Comparison of Compressive Strength of M30 Grade Concrete with Destructive and Nondestructive Procedures Using Digital Image Processing as a Technique

Table 3

Comparative difference between destructive and nondestructive tests.

No. of curing days	Destructive test	Nondestructive tests
		Rebound hammer		SonReb method		Image analysis
			% diff		% diff		% diff
7 days	19.222	16.166	−15.89%	23.175	+20.56%	20.28	+0.055%
28 days	34.298	24.40	−28.85%	34.20	−0.0028%	31.08	−9.382%

% diff indicates the percentage difference between average compressive strength of destructive and particular nondestructive tests.