Case 3

Cause of Defects

Thermal Movement

Thermal condition difference on the different times of the day may have caused periodical expansion and contraction of the various concrete structure. This periodical expansion and contraction results in crack lines forming and they widen and lengthen with time.

Uneven earth settlement

All new constructions will experience settlement due to exertion of loads on the freshly compacted soil for the initial 5-10 years of its life. Even settlement will not threathen the structure’s integrity whereas uneven settlement will give signs of structural deterioration via cracking.

Precast components

The scupper drain could be a precast component and is cast in factory and brought on site and finished with the cast in-situ concrete roof. The jointing could have been done poorly due to poor workmanship during casting. This may lead to concrete cracking.

Insufficient curing of concrete

For example, if the curing of concrete is not done properly and there is excessive rapid evaporation of water from the surface of the concrete will lead to excessive plastic shrinkage cracks on the surface.

In addition early thermal contractions may also induce in formation of micro-cracks. It is formed when the concrete dissipates heat of hydration and adjacent structures posed external restrain on the concrete resulting in the formation of cracks upon contraction.