Table 3. Types and application of The Schmidt hammer.

Type	Test material	Hammering energy(kgf·m)	Measurement range(MPa)
N type	Normal concrete	0.225	15-60
NR type	Normal concrete	0.225	15-60
L type	Lightweight concrete	0.075	10-60
LR type	Lightweight concrete	0.075	10-60
M type	Mass concrete	3.00	60-100
P type	Low strength concrete	0.090	5-15