Economical impact:
In India, the cost of corrosion due to rebar corrosion problem alone was estimated as Rs.10000 crores being spent annually by the building and construction industries. Since most of the bridges are located along the sea coast or across the river, in which chloride ingress leads to the major failure of concrete structures. By periodically monitoring the condition of the important structures we can able to assess the service life of the structures. Thereby the integrity of the structures gets restored and suitable remedial measures can be taken to enhance the durability of the structures. Thus the structures are put under safe condition and thus avoiding the unnecessary wastage of economy. Many of the important bridges like thane creek bridge, Pamban bridge, Narmada river bridge, Gujarat, Koodankulam nuclear reactors, NFCL, Hyderabad are some of the important structures which are assessed embedded corrosion monitoring sensors.
Technological Impact:
In the annual production of steel rebars, a substantial portion of more than 10 million tons of steel rods are used as reinforcements in RCC structures. Due to rebar corrosion problems, often more than the cost of construction is being spent on repair of bridge structures in ports and industrial areas. Especially for some RCC structures repairs are to be carried out within 2 or 3 years of construction. In the years to come, if rebar corrosion problem continues, nearly 10 to 15% of cost of annual construction will be spent towards repair and renovation. Marine concrete infrastructures suffer severe deterioration. Additional protective measures like coatings to steel rebars, coatings to concrete surface, application of high performance concrete may be undertaken in the initial stage itself in order to enhance the durability. Chloride induced corrosion of reinforcing steel is recognized as a primary factor, contributing to the deterioration of concrete infrastructures. The chloride scavengers developed is highly useful in reducing the critical chloride level at the steel concrete interface so that initiation of corrosion of rebars is avoided. The high performance concrete formulation developed based on binary and ternary cement is highly useful to enhance the durability of concrete structures.
Societal Impact:
In India, about 1400 bridges especially in the coastal regions are said to be in distress. It was estimated that within 10 to 20 years, the durability of concrete structures exposed to marine condition is affected even though they have been designed for a minimum life of 60 years providing a trouble free life of only about 1/5th of the designed life. To increase the trouble free life of the structures, effective additional protective measures must be undertaken at the initial stage itself.
The NDT techniques developed for corrosion monitoring identify the corrosion hot spot areas. Repair and rehabilitation of such areas at the right time is highly useful to avoid propagation of corrosion process and catastrophic failures of highway bridges.
The smart corrosion monitoring sensors developed provide useful information regarding the corrosion condition of rebars and concrete. It is possible to predict the residual life of structures from the condition survey parameters.
The rapid setting concrete formulations developed using chemical admixtures is highly useful for repair and rehabilitation of concrete structures.