Early Age Concrete Strength Monitoring Using Power Spectral Density and Wavelet Packet Analysis

Figure 6

STFT time-frequency diagram, (a) day 1, (b) day 5, (c) day 9, (d) day 13, (e) day 19, (f) day 25, and (g) day 28.

(a)

(b)

(c)

(d)

(e)

(f)

(g)