Experimental Study on the Impact Resistance of Closed-Cell Aluminum Foam Protective Materials to RC Piers under Lateral Impact

Table 8

Changes in the ultrasonic velocities of the concrete piers.

Group	Specimen no.	Impact velocity (m)	Average sound velocity (km/s)		Reduction of sound velocity (km/s)	Total reduction of sound velocity (km/s)	Change rate of sound velocity (%)
			Before impact	After impact
A	Z1	0.76	4.179	4.174	0.005	0.696	16.65
		1.14	4.161	4.146	0.015
		2.43	3.658	3.483	0.175
	Z2	0.76	4.04	4.032	0.008	0.365	9.03
		1.14	4.018	4.001	0.017
		2.43	3.777	3.675	0.102
	Z3	0.76	4.1	4.084	0.016	0.853	20.80
		1.14	4.054	4.012	0.042
		2.43	3.457	3.247	0.21
B	Z4	0.76	4.333	4.327	0.006	0.69	15.9
		1.14	4.316	4.307	0.009
		2.43	3.826	3.643	0.183
	Z5	0.76	4.102	4.096	0.006	0.351	8.57
		1.14	4.087	4.076	0.011
		2.43	3.851	3.751	0.1
	Z6	0.76	4.131	4.118	0.013	0.821	19.84
		1.14	4.092	4.062	0.03
		2.43	3.414	3.310	0.204