Electrical Resistivity of Concrete

Title :
Pozzolanic behavior of bamboo leaf ash: Characterization and determination of the kinetic parameters

Authors :
Ernesto Villar-Cociñaa, Eduardo Valencia Moralesa, Sergio F. Santosb, Holmer Savastano Jr.b, Moisés Fríasc

Abstract :

The paper presents a characterization and study of the pozzolanic behavior between calcium hydroxide (CH) and bamboo leaf ash (BLAsh), which was obtained by calcining bamboo leaves at 600 °C for 2 h in a laboratory electric furnace. To evaluate the pozzolanic behavior the conductometric method was used, which is based on the measurement of the electrical conductivity in a BLAsh/CH solution with the reaction time. Later, the kinetic parameters are quantified by applying a kinetic-diffusive model. The kinetic parameters that characterize the process (in particular, the reaction rate constant and free energy of activation) were determined with relative accuracy in the fitting process of the model. The pozzolanic activity is quantitatively evaluated according to the values obtained of the kinetic parameters. Other experimental techniques, such as X-ray diffraction (XRD) and scanning electron microscopy (SEM), were also employed.

The results show that this kind of ash is formed by silica with a completely amorphous nature and a high pozzolanic activity. The correlation between the values of free energy of activation (ΔG#) and the reaction rate constants (K) are in correspondence with the theoretical studies about the rate processes reported in the literature."

Keywords :
Bamboo leaf ash, Kinetic-diffusive model, Material characterization, Pozzolanic activity

Source :
http://www.sciencedirect.com/science/article/pii/S0958946510001332