Effects of natural zeolite addition on the properties of lime putty-based rendering mortars

Abstract

The application of locally available component materials (lime putty and zeolitic rock as pozzolanic admixture) in two types of rendering mortars (designed for inner and outer render layer), was assessed through TG/DTA, XRD and MIP analysis and by testing the compressive strength, dynamic modulus of elasticity, water transport behavior and open porosity of mortars cured under two different regimes.Higher levels of lime replacement with fine natural zeolite (40% and 50% by mass), for both render layers,led to 1.5 to 2.5 times higher values of compressive strength when cured in humid conditions. The changes in zeolite content led to different pore size distributions of mortars and influenced their water transport behavior and open porosity. Overall, mortars with 40% and 20% of zeolite addition for the inner and outer layer (by mass), respectively, showed the best agreement of properties, when cured in humid conditions.