shows the heat evolution curve obtained by isothermal conduction calorimetry of the samples at 27 C for 24 h. It is important to mention here that mixing was carried out outside the instrument and the mixed pastes then introduced into the calorimeter. Time zero on the plots represents the time at which the sample was placed in the instrument, which was 2 min after the start of mixing in each case. The straight line in the beginning can be assigned to pre-induction stage which converged into peak without any induction period. This peak can be assigned to dissolution of alumino-silicate present in fly ash and precipitation of CSH (C = CaO, S=SiO2,H=H2O) gel [36]. As there was no major peak shift or change in peak behavior, the reaction mechanism was believed to be broadly similar in all samples. The change in peak intensity with the addition of red mud can be attributed to the high solubility of Al2O3, SiO2 and CaO due to increase in concentration of NaOH. It is interesting to note here that the maximum peak intensity was found in FARM10 samples which contain 10% red mud. With further increase in red mud, a decreasing trend of peak intensity was observed. This can be explained by taking into consideration the behavior of iron oxide, which is more soluble in acidic