The neutralized concrete specimen were cored from a basement wall of an old apartment which was built in a warm area o.f Japan 38 years ago. The fresh air was fiowing in the room of the basernent as it was used very well, and outside of the wall was kept in touch with 80il. The diameter of specimen used for the uni-axial compression test wa8 Ia cm, and the height of them was 10 cm. Main results obtained are as follows :

( 1 ) The maximum depth of the neutralized part is 30mm from the surface of the room side, and the minimum depth is 2mm.

( 2 ) The dominant frequency f[Hz] which propagates in a concrete specimen changes with a distance Lmm] from the source of AE

f = 2.468 x lO⁶L^-0.527

( 3 ) AE event rate in the neutralized part is higher at the early load than that in the healthy part.

( 4 ) The amplitude of AE Iocated in the neutralized part is small, and the amplitude of AE Iocated at the boundary betveen the neutralized part and the healthy part is fairy well big.

( 5 ) The longitudinal wave velocity and the compression strength of specimen of room side is sFnaller than those of soil side.