The effect of relative humidity on the performance of lime-pozzolan mortars

Abstract

The development of strength in conservation mortars is of particular significance for new synthesized lime-based mixtures in terms of practical application, performance requirements and renovation cost of built monuments. In this work, the effect of relative humidity (RH%) on the strength characteristics of lime-natural pozzolan mortars was studied in three groups of specimens cured at different humidity conditions (45, 65 and 95 RH%). The development of compressive strength of the specimens was determined at preset time periods, from 7 days to 1 year. At the same time periods, the setting products and the microstructure of the mortars were monitored by thermal analysis (DTA/TG) and scanning electron microscopy (SEM/EDX). The results highlight the beneficial effect of elevated humidity on the strength of lime-pozzolan mortars and at the same time some issues related to the reliability and reproducibility of laboratory work in the field are addressed. © RILEM 2012.