NDT for condition assessment of IDCT RC walls and repair measures for long term durability

This paper presents the condition assessment of reinforced concrete (RC) walls of induced draft cooling tower (IDCT) structure. The main focus is on the assessment of quality, integrity and long term durability of RC walls, with reference to rebar corrosion. Details of non-destructive testing (NDT) carried out to evaluate the prevailing condition of the IDCT structure are presented. Test results revealed that the RC wall, which is intended to be an enclosure/curtain wall to arrest the splashing of sea water fed to the IDCT, is found to be of poor quality and could not arrest the seepage/dampness from inner face to outer face of the wall. To arrive at an effective repair measure to arrest the seepage/dampness in RC walls, porous concrete panels are cast to simulate the poor quality of in-situ concrete of IDCT walls and also to explore and evaluate the effectiveness of different repair schemes. The best repair scheme for improving water tightness is established by conducting selected durability tests on the cores extracted from the repaired porous slab panels. As a pilot study, the identified repair methodology is implemented on the selected wall panels of IDCT structure and its efficacy for water tightness/impermeability is confirmed through visual observation and IRT image scanning.