Pore structure and mechanical properties of cement–lime mortars

Abstract

Studies focusing on materials used in Cultural Heritage conservation projects are becoming increasingly important. In this paper, the pore structure and mechanical properties of lime–cement mortars are evaluated in order to analyze their potential use, because this kind of mortar could reduce the disadvantages presented by both lime-based mortars and cement-based mortars. The microstructure of these blended mortars is studied taking into account porosity, pore size distribution and surface fractal dimension. Compressive and flexural strengths are discussed as a function of several parameters: curing time, binder composition and B/Ag (Binder/aggregate) ratio. The mechanical strength versus the deformation of the material is also evaluated, by analysis of Young's modulus, as well as the elastic and plastic zones. Unlike cement-based mortars, blended mortars with a high percentage of lime present a large plastic zone, which could be useful in the service-life of these mortars as a result of their ability to absorb strains caused by wall movements.