Kaneda, S, Kubo, H, Nakano, Y, Kubo, G, Sakai, T, Estimation of Compressive Strength of High Strength Concrete by Means of Mechanical Impedance Measurement, Japanese Society for Non-destructive ...

Although concrete has good compression strength, the tensile strength is quite poor. Around the late 1800s, someone thought to fortify spans of concrete with steel reinforcing bars, better known ...