Hot-Lime Mortars: A Current Perspective

AbstractAnalytical and documentary evidence indicates that hot-lime mortars were used in traditional construction. These are defined as mortars manufactured by mixing quicklime and sand, rather than the current and more commonly adopted method of combining previously slaked lime with sand. Hot-lime mortars are again being used and are perceived to have advantages over cold- manufactured mortars. Little is understood, however, regarding the physical and chemical performance of hot-lime mortars. This paper highlights current views on the subject and considers why hot-mixed mortars appear to offer better performance than alternative lime mortars. The potential for altered hydraulic properties, bond characteristics between the lime/aggregate interface, pore-structure development, and micro-structure performance are assessed, although it is stressed that this is only a preliminary investigation aimed at stimulating debate and further research. Additional informationNotes on contributorsAlan ForsterBiographyAlan M. Forster BSc (Hons), PhD, SPAB Lethaby ScholarDr Alan Forster qualified as a building surveyor and gained his PhD from Heriot-Watt University in 2002 for his work on the hydraulicity and water-vapour permeability of lime-based mortars. He was awarded a travelling scholarship with the Society for the Protection of Ancient Buildings (SPAB) in 2001. Alan Forster has published several papers on lime science, technology, and specification, and contributed to various science projects. He worked as a surveyor for the Royal Commission on the Ancient and Historic Monuments for Scotland (RCAHMS) and is currently employed by the Scottish Lime Centre Trust as a building surveyor/training manager. He is a member of the RICS building conservation working group (Scotland).