ISSN: 2277-9655 [Prabhakar* et al., 5(12): December, 2016] Impact Factor: 4.116 IC™ Value: 3.00 CODEN: IJESS7 http: // www.ijesrt.com © International Journal of Engineering Sciences & Research Technology [131] IJESRT INTERNATIONAL JOURNAL OF ENGINEERING SCIENCES & RESEARCH TECHNOLOGY ADVERSE EFFECT OF HOT WATER SPRINGS ON DURABILITY OF CONCRETE AND REMEDIAL MEASURES – A CASE STUDY Kachhal Prabhakar*, Dr RP Pathak, N. Sivakumar * Central Soil & Materials Research Station, Ministry of Water Resources, RD & GR, Olof Palme Marg, Hauz Khas, New Delhi – 110016 Central Soil & Materials Research Station, Ministry of Water Resources, RD & GR, Olof Palme Marg, Hauz Khas, New Delhi – 110016 Central Soil & Materials Research Station, Ministry of Water Resources, RD & GR, Olof Palme Marg, Hauz Khas, New Delhi – 110016 DOI: 10.5281/zenodo.192517 ABSTRACT Even with the perfect concrete mix design, it is possible that the durability/performance of concrete get adversely affected under certain hostile environment like lying of fresh concrete in hot water zone. 1500 MW Nathpa Jhakri HE Project is a major hydroelectric power project on river Satluj situated near Rampur Tehsil in Himachal Ptradesh comprises of construction of 60.5m high concrete dam, an underground desilting complex and powerhouse including 27.4Km long Head Race Tunnel. During excavation for HRT at Wadhal adit, hot water springs having a temperature ranging 57- 65 o centigrade were observed at several locations inside the Head Race Tunnel. This poses a great challenge in laying fresh concrete mix for lining work and special measures had to be taken in formulating concrete mix design for concrete lining work. CSMRS evaluated the water quality of the hot water at regular intervals. After assessing the quality of the hot water under reference, an attempt was made to classify the aggressiveness of water using JJ Basson and BJ Addis approach which quantify the aggressiveness due to temperature as corrosion indices like Leaching/Spalling/Overall corrosion indices to identify the class of concrete. Finally, remedial measures suggested to the project authorities for minimizing the adverse effects of hot water springs on the concrete lining inside HRT. This paper covers the above aspects in brief. INTRODUCTION Concrete can be made which will perform satisfactory when exposed to various atmospheric conditions like chmical attack; soils containing chemicals and polluted environments. There are some chemical environments in which the useful life of even the best concrete will be reduced. Understanding these environments would help us to prevent or reduce deterioration. While analyzing the above factors, it is seen that combination of higher temperature, and adverse water quality does not find much mention in the literature thus calling for additional care while suggesting remedial measures. The Nathpa Jhakri H.E. Project built across at the Sutlej river generates 1500 MW electricity. It consists of 60.5 m high concrete Dam and a 27.40 Km long Head Race Tunnel (HRT) terminating in a 301m deep surge shaft. The excavation of tunnel was carried out through seven adits viz. Nathpa, Sholding, Nugalsari, Wadhal, Manglasd, Rattanpur and Valve Chambers U/S. During excavation of HRT about 1 km down stream of Wadhal adit, sudden inflow of hot water having temp. 57-65 o C was encountered. CSMRS investigated the problem by collecting hot water samples from the HRT and analysing them at the project site. The present Paper focuses on the method published by JJ Basson and BJ Addis in their approach Paper “A Holistic Approach to Corrosion of Concrete in Aqueous Environments Using Indices of Aggressiveness” published in ACI materials journal, SP 131-2 which addresses the aggressiveness of water by developing a set of indices to quantify its impact to concrete. It also takes care of role of multiple parameters including temperature. Corrosion indices like Leaching Corrosion Index and Spalling Corrosion Index were calculated to classify the aggressivity of water and class of concrete. [2] Leaching corrosion of a concrete can result either from the direct dissolution of one or more of the components of the concrete into the water or by conversion of any of such components into more soluble forms as a result of