Sint Jacobskerk (Saint James Church) in Leuven, Belgium. Lime mortar use in many masonry structures has proved durable for hundreds of years. Photo: Koenraad Van Balen.

This cement repair has caused damage to the brick units, while leaving the repair mortar itself unharmed and even more unsightly. Photo: John Fidler, © English Heritage.

The stages of the lime cycle indicated in red, with the fundamental properties that have been the focus of research projects indicated in blue. Drawing: Beril Bicer-Simsir.

The evolution of prisms into platelets as putty ages: a) fresh lime putty; b) putty aged two months, with corrosion on the prism side [arrow] as platelets begin to form; c) putty aged six months; d) putty aged two years. Photo: Carlos Navarro-Rodriguez.

FESEM photomicrographs of a) oven dried slaked lime putty showing agglomeration of platelike Ca(OH)₂ nanocrystals, and b) commercial dry hydrated lime also displaying extensive agglomeration. In both a) and b), randomly oriented and crystallographically oriented aggregates are present. Details of representative oriented aggregate of Ca(OH)₂ nanoparticles attached by the (0001) planes are seen in c) and randomly oriented aggregates in freeze-dried slaked lime particles are seen in d). Photo: Carlos Navarro-Rodriguez.

The nopal cactus (Opuntia ficus indica). The water extract of the nopal cactus is a common ingredient of plasters in the Southwestern United States. It is added to the slaking water to make slaked lime putty, or to the water to make the putty with hydrated lime. Photo: Eric Hansen.

Detail of Sint Jacobskerk (Saint James Church) in Leuven, Belgium. The deformability of the masonry wall without cracking is due to the use of a weak lime mortar. Photo: Koenraad Van Balen.