RC structures has high degrees of variability during construction. Often in most of the project, RC structures are casted in situ. Compared to steel structures, where most of the parts has quality control at the manufacturing plant, the construction practise of the RC structure has greater degree of uncertaininty in its strength and its performance. Thus in larger project, generally RC works is handed to the professional construction contractors. Nonetheless, contractors often try to meet the minimum quality specified to maximize their profit margin.
Sometimes, quality may be compromised during construction to avoid delays. Such malpractices definitely results in low performing structure to start with.
The most common construction malpractices are:
- addition of undesired mixing water to increase workablity
- improper use of chemical admixtures
- premature striking of formwork resulting in mechanical stress induced in the such structure element [article on this coming soon]
- faulty formworks resulting in non-perfect shape
- use of aggregates grades other than specified in the mix design
Moreover, the entire construction work is validated by performing tests on few samples. Such sample tests, although adequate for payment procedure, will not represent 100% of the structure. In other words, statistical methods have margin for errors. And unfortunately, there is no other way around to test 100% of structure quality.
In conclusion, it can be said that construction malpractice is one of the reason which can induce the structures with some kind of inherent “genetic disorder” which in future results in some kind “cancer” in the infrastructure.
Portal on Deterioration of RC Structures 