The Smeaton Project: Factors Affecting the Properties of Lime-Based Mortars

Abstract

The Smeaton Project is a joint research program involving ICCROM, English Heritage, and Bournemouth University. It was established for the purpose of characterizing the chemical and physical properties of lime-based mortars intended for the repair and conservation of historic buildings. In Phase I of the program, the authors used a variety of test procedures to evaluate the effect of set additives, specifically brick dust and cements, on the performance of lime:sand mortars. The principal objective of this initial phase was to confirm various trends in the behavior of lime-based mortars observed in the field and to refine test procedures. The results of Phase I are presented though the authors caution that these are only preliminary and further testing is needed. Preliminary findings suggest that the addition of brick dust significantly alters the properties of lime mortars and that low fired brick dusts seem to have the most positive effect on the strength and durability of lime:sand:brick dust mixtures. The addition of small quantities of cement to lime:sand:mortars seemed to have a negative effect on the strength and durability of the mortars.