SPECIAL ISSUE - Future Cements 49 The Indian Concrete Journal July 2014 TECHNICAL PAPER The Indian Concrete Journal, July 2014, Vol. 88, Issue 7, pp. 49-68 Pozzolanic industrial waste based geopolymer concretes with low carbon footprint N.P. Rajamane, M.C. Nataraja and R. Jeyalakshmi Geopolymers are novel binders with unique and desirable chemical, mechanical and eco-friendly properties. Geo- polymeric Source Materials can be industrial by-products such as fly ash (FA) and ground granulated blast furnace slag (GGBS). This paper presents a general overview of geopolymeric cement concrete (GPC) Technology; the data from the extensive works carried out at CSIR-SERC, SJCE, and SRMU is utilised to present various aspects of GPC which has high potential to become eco-friendly alternate to conventional Portland cement based concretes, specifically in some application areas. The GPCs can be self curing, with compressive strengths ranging from 20 to 75 MPa. Data on GPCs with reference to stress-strain curves, bond strengths, corrosion and sulphate resistances, thermal conductivity and ex- pansion coefficients, electrical and acid resistances, ultrasonic pulse velocity, flexural and shear behaviour etc. indicate that the GPCs can be designed to possess satisfactory structural and durability performances related characteristics with low carbon footprint. Keywords: Geopolymer; y ash; blast furnace slag; sodium silicate; sodium hydroxide; carbon footprint. INTRODUCTION Considering the limited reserve potentiality of petroleum & natural gas, eco-conservation restriction on hydel project and geo-political perception of nuclear power, coal will continue to occupy centre-stage of Indias energy scenario. Indian coal can offer a fuel source to domestic energy market for the next century & beyond. Based on estimates, the consumption of coal is projected to rise by nearly 40 percent over the next five years and almost to double by 2020. An estimated 90-95 per cent of the thermal energy requirement in cement manufacturing is met by coal in India where 80% of mining itself is in coal [88]. About 80% of the coal in India is consumed in the power sector [89]. In addition, other industries like steel, cement, fertilizers, chemicals, paper and thousands of medium and small-scale industries are also dependent on coal for their process and energy requirements. India is expected to have a coal production of 447 million tonnes by the end of the 11th Five Year Plan and 633 million tons by end of the 12th Five Year Plan [90]. The coal reserves of India up to the depth of 1200 m have been estimated by the Geological Survey of India at 247.85 billion tonnes as on January 1, 2005 of which 92 billion tonnes are proven. In order to meet the growing energy demand of the country, coal-based thermal power generation would play a dominant role in the future as well, since coal reserves in India are expected to last