LTA zeolite as pozzolanic addition for hydraulic mortars: An effective, promising use

Further to a recent exploratory investigation on the possible use of cheap, commercially available, synthetic zeolites as pozzolanic addition to portland cement, the present study aims at characterizing a commercial zeolite Na-A-rich material, as possible component of hydraulic lime mortars. In order to evaluate the action played by the zeolite in developing hydraulicity and mechanical properties, three mortars with different lime-to-zeolite ratio were prepared and characterized in terms of compositional features and mechanical and physical properties. Thermogravimetric analysis was used as a tool to evaluate the pozzolanic activity of the zeolitic material utilized. The main results obtained are: (a) zeolite addition gives rise to a clear benefit on compressive strengths of the hardened mortars; (b) hardening is rapid, as more than 60% of the final compressive strengths is developed after only 7 days; (c) lime/zeolite ratio does not affect to a great extent both porosity and water absorption of the manufactured mortars; (d) mortars containing equal amounts of lime and zeolite show the best performances, either from a compositional point of view (absence of unreacted zeolite) or for mechanical and porosimetric properties. Performances are better than or comparable to those of an analogous, non-zeolitic, commercial mortar.