PSI - Issue 60

704 Harikrishna S et al. / Procedia Structural Integrity 60 (2024) 700–708 Harikrishna S / Structural Integrity Procedia 00 (2019) 000–000 dismantled along with bonding agent to have further assessment. Later the brick linings over middle wall were dismantled.

Detailed visual inspection was carried out along with conventional hammer sounding survey to map the distress locations (delamination/ spalling) . The following observations were noticed. • The condition of the concrete is observed to be bad at middle portion of the wall. The thickness of centre wall has been reduced considerably & reinforcement rods in exposed condition. • Hammer sounding method indicated distress in several patches of the wall surfaces. At such locations, concrete materials are observed to breaking & falling off indicating loss of strength of concrete. Concrete in distress locations were found friable. It seems that sulphur contact has altered the concrete into a semi gelatinous material. The concrete layer over reinforcement rods could be removed easily with a hammer. • Yellow patches were noticed inside the surface of concrete wall after loose concrete was chipped off. Thus, sulphur attack was confirmed on RCC wall. • Concrete appeared dark in colour at middle & bottom portion of the pit (portions that remains immersed in sulphur) • Since the strength of concrete was lost, the integrity of wall was compromised. Reinforcement rods at distress locations were also found heavily corroded & absent due to loss of entire material. Other locations, reinforcement rods appeared blackish. Scaling & material loss is noticed on reinforcement rods.

Fig. 7. Condition of middle partition wall -North side

Fig. 8. Condition of middle partition wall -South side