Ali Allahverdi - Department of Chemical Engineering, Iran University of Science and Technology
Ebrahim Najafi Kani
Reza Karkeabadi
Shima Sabbaghian Rad

In this research work, autogenous and drying shrinkage of alkali-activated pumice-type natural pozzolan were studied by changing parameters of chemical composition, i.e. SiO2/Na2O molar ratio of activator and total molar ratios of Na2O/Al2O3, and H2O/Al2O3. It can be concluded from the results that SiO2/Na2O molar ratio has a significant effect on shrinkage amount so that it increases by increasing the amount of SiO2/Na2O molar ratio up to 0.75 for the systems with Na2O/Al2O3 molar ratios of 0.77 and 0.92 and after that any increase in SiO2/Na2O molar ratio of activator causes a decrease in total shrinkage. However, for the systems with Na2O/Al2O3 molar ratios of 1.08 and 1.23, total shrinkage increase continuously by increasing in SiO2/Na2O molar ratio of activator. Also, for all the studied systems, autogenous and drying shrinkage increase as the H2O/Al2O3 molar ratio increases.

Alkali-activation, Autogenous Shrinkage, Chemical Composition, Drying shrinkage, Natural Pozzolan