Influence of Aggressivity of Water on the Long Term Sustainability of Hydro Power Structures – A Review
To fulfil country’s irrigation and power requirements various large capacity dams have been constructed on major rivers in last 50 years. The long term sustainability of these structures is largely dependent on hydro-environment and the capacity of these structures to resist weathering action, chemical attack, abrasion, or any other process of deterioration. The concrete deterioration is directly influenced by various geographical, climatic and ecological conditions. The chemical reactions between cement and water enable the setting and hardening of cement, resulting in a binding medium for the aggregates and development of strength. Quality of water plays an important role in the production of concrete. There are some chemical environments under which the useful life of even the best concrete will be affected adversely. The aggressiveness of water is dependent on the pH value, the total dissolved salts, the degree of hardness, soluble chlorides, sulphates, carbonation, temperature and alkalinity etc. Understanding these conditions permit measures to be taken to prevent or reduce deterioration.Some case studies related to some peculiar problems encountered during the pre and post construction investigations with special reference to deterioration of concrete due to highly acidic water quality faced at Kopili H.E. Project, Lower Kopili HE Project and Myntdu HE project, all the projects located in North Eastern part of India are presented in this review. A brief discussion on the findings of filed observations made in recent past by the CSMRS over the environmental aspects of water quality and its detrimental effects already caused on structures has also been done. Few remedial measures for the upgradation of catchment area to control the acidification of rivers are also discussed here.
