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

Table 2

Comparison of compressive strength obtained by destructive and nondestructive tests.

Sample no.	No. of days of curing	Compressive strength by CTM (in N/mm^2)	Rebound hammer		Ultrasonic pulse velocity test	Compressive strength as per the SonReb method	Image analysis
		fck in N/mm^2	RN	fck in N/mm^2	Velocity (m/s)	fck in N/mm^2	fck in N/mm^2
1	7 days	20.444	21	14.5	4545.5	21.72	22.95
2	7 days	17.778	20	14.0	4622.5	21.27	16.90
3	7 days	19.555	20	14.0	4713.5	22.25	19.49514
4	7 days	19.111	21.5	16.5	4651.5	23.56	18.82616
5	7 days	18.889	23.5	18.5	4587	25.41	17.96898
6	7 days	19.555	24	19.5	4492	24.84	25.56
	Average	19.222		16.166		23.175	20.28
7	28 days	32.444	30.5	29.00	4833.5	39.36	27.26081
8	28 days	36.889	30.0	28.00	4792	37.81	32.54504
9	28 days	28.444	25.50	22.50	4870	32.20	26.6878
10	28 days	37.7778	24.00	19.50	4818	29.19	33.91921
11	28 days	39.111	27.00	24.00	4757	32.70	34.9321
12	28 days	31.111	27.50	25.00	4788	33.95	31.1603
	Average	34.298		24.40		34.20	31.08

f_ck = compressive strength of concrete in N/mm².