Evolution of mechanical properties and drying shrinkage in lime-based and lime cement-based mortars with pure limestone aggregate

In order to understand the behavior of the natural hydraulic lime, pure lime and lime cement-based mortars as a repair mortar it is necessary to investigate their mechanical-properties. In this paper, the specimens were made with limestone aggregate as the restorers prepared the restoration works. The mechanical-strength as well as the evolution of Young's modulus and the drying shrinkage were monitored. The study was performed under curing conditions which lead to the development of a suitable mortar strength within the first 28 days without having to wait for longer curing periods. The study revealed that NHL5 (1:1.75) mortar exhibits, for 28 days in a 70 +/- 5% RH chamber, better results from the point of view of strength and shrinkage. A NHL5 (1:1.75) mortar could be a good candidate to be used like a repair mortar due to its good response to the movements of the stones in the buildings and its higher strengths. However the shrinkage in a lime cement-based mortar as well as a pure lime-based mortar is high enough as to cause a decrease in their strength. This information is very useful for the design of repair mortars. (C) 2015 Elsevier Ltd. All rights reserved.