The use of acoustic emission for the early detection of cracking in concrete structures

Acoustic emission testing of concrete structures shows great potential for monitoring and assessing their condition. The aim of this paper is to relate the AE obtained from reinforced concrete beams to the onset of cracking of these beams subjected to the four-point bending test. A pre-corroded test specimen was used where the cross-sectional area of the bar was reduced but, as they were cleaned before being cast into the concrete, the integrity of the concrete itself and the bond between the steel and the concrete were unaffected by the corrosion. This paper explores the capability of acoustic emission that can be used to obtain a warning of developing distress and the growth of internal microcracking at critical locations before the crack is visible on the surface. In addition, a comparison between visual observations of the cracking process and acoustic emission source location analysis indicates that areas of damage owing to cracking can be clearly identified by acoustic emission source location.