Study on the Influence of Closed-Cell Aluminum Foam on the Impact Performance of Concrete Pier after Equal Replacement with Stainless Steel Reinforcement

Table 10

Change of ultrasonic velocity of concrete.

Specimen	Height of drop hammer (m)	Average impact velocity (m/s)	Average sound velocity (km/s)		Reduction of the sound velocity (km/s)	Total reduction of the sound velocity (km/s)	Change rate of the sound velocity (%)	Specimen (%)
			Before impact	After impact
S1-16	2	0.72	4.323	4.305	0.018	−0.14	−0.895	−20.7
	4	1.10	4.305	4.256	0.049
	6	1.42	4.256	4.183	0.073
	8	1.67	4.183	4.016	0.167	−0.755
	10	1.84	4.016	3.739	0.277
	12	2.08	3.739	3.428	0.311
Z2-20	2	0.72	4.51	4.491	0.019	−0.152	−1	−22.17
	4	1.10	4.491	4.439	0.052
	6	1.42	4.439	4.358	0.081
	8	1.67	4.358	4.181	0.177	−0.848
	10	1.84	4.181	3.876	0.305
	12	2.08	3.876	3.51	0.366
S1-20	2	0.72	4.031	4.018	0.013	−0.102	−0.611	−15.16
	4	1.10	4.018	3.985	0.033
	6	1.42	3.985	3.929	0.056
	8	1.67	3.929	3.849	0.08	−0.509
	10	1.84	3.849	3.724	0.125
	12	2.08	3.724	3.42	0.304
Z2-25	2	0.72	4.179	4.164	0.015	−0.127	−0.733	−17.54
	4	1.10	4.164	4.119	0.045
	6	1.42	4.119	4.052	0.067
	8	1.67	4.052	3.967	0.085	−0.606
	10	1.84	3.967	3.824	0.143
	12	2.08	3.824	3.446	0.378