Modeling of the pozzolanic reaction kinetics between lime and wastes of the sugar industry starting from the conductometric changes

In this paper the kinetics of the pozzolanic reaction between lime (calcium hydroxide) and sugar cane straw ash with 20 and 30% of clay burned at 800 and 1000 C is studied. A simple experimental technique where the conductivity is the experimental variable was used. A calibration curve was established for correlating the conductivity with the concentration of calcium hydroxide (CH). We elaborated a mathematical model that allows us to describe the process in kinetic - diffusive or kinetic regimen. The fitting of the model by computerized methods lets us determine the parameters that characterize the process: i.e. the diffusion coefficient and reaction rate constant. The pozzolanic activity is evaluated according to the obtained values of the reaction rate constant. The results show that sugar cane straw ash (SCSA) has a good pozzolanic activity comparable to that of the rice husk ask (RHA).