Nondestructive Testing of Advanced Concrete Structure during Lifetime

Table 2

Function parameters—.

	Days
Impact echo frequency [kHz]	2	3.7 kHz	0.0128 h^−1	5.9 kHz
	6	3.0 kHz	0.0164 h^−1	7.4 kHz
	28	3.4 kHz	0.0278 h^−1	8.4 kHz
Ultrasound velocity [mm⋅μs^−1]	2	1.7 mm⋅μs^−1	0.0128 h^−1	2.0 mm⋅μs^−1
	6	1.4 mm⋅μs^−1	0.0127 h^−1	2.5 mm⋅μs^−1
	28	1.0 mm⋅μs^−1	0.0105 h^−1	3.0 mm⋅μs^−1
Relative loss in weight (the first 48 h) [%]	2	2.9%	0.0446 h^−1	4.3%
	6	2.6%	0.0348 h^−1	5.0%
	28	2.1%	0.0275 h^−1	7.4%
Relative loss in weight (after 48 h) [%]	2	3.0%	0.0095 h^−1	2.8%
	6	2.7%	0.0090 h^−1	3.8%
	28	2.3%	0.0064 h^−1	6.5%