Degradation of hydrated lime mortars subjected to freezing and thawing is common in historic building conservation. The pozzolanic additions, Argical M1000, diatomite (diatomaceous earth) and brick dust, were evaluated for their ability to improve performance for up to 720 days. Pozzolanic reactions influenced the pore structure evolution, mechanical performance, and chemical reactivity of the mortar matrix. Argical-lime mortars exhibited a sudden failure, while a gradual reduction in mechanical strength was observed for mortars containing brick dust. A slower rate of failure in diatomite mortars was attributed to pore refinement, which was associated with superior freeze thaw performance. This study has advanced the current state of the art regarding how pore structure affects lime mortars’ freeze and thaw resistance. Therefore it provides spesifications on how to optimise mortars for historic masonry. A key impact is the more effective use of lime mortars for conservation, thereby
protecting heritage structures from degredation.
Original languageEnglish
Article number131993
JournalConstruction and Building Materials
Early online date16 Jun 2023
Publication statusPublished - 29 Aug 2023

Bibliographical note

Data availability
The authors have permission to share data.

This research was carried out University of Bath within a doctoral studentship provided by Republic of Türkiye Ministry of National Education.

Funding Information:
The authors would like to thank the Republic of Turkiye Ministry of National Education for funding Tugce Busra Su's PhD project and this research. The authors would like to thank helpful conservations with Alison Henry, Historic England for helpful discussions. The authors appreciated Ahmet Akin's (Middle East Technical University Northern campus) help casting and freeze and thaw conditioning of mortar specimens. The support of the following colleagues at the University of Bath is also gratefully acknowledged; Vahiddin Alperen Baki and Pooja Anil Kumar Nair for help acquiring and interpreting calorimeter data, and Prof Frank Marken (Department of Chemistry) for his help with the Chapelle test.


  • Conservation
  • Hydrated lime mortars
  • Lime mortars
  • Pozzolan

ASJC Scopus subject areas

  • General Materials Science
  • Building and Construction
  • Civil and Structural Engineering


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