Microstructure aspects related to durable lime mortars

Author(s): Maria Stefanidou
Paper category: Proceedings
Book title: Proceedings of the International Conference on Sustainable Materials Systems and Structures (SMSS2019) Durability, Monitoring and Repair of Structures
Editor(s): Ana Baričević, Marija Jelčić Rukavina, Domagoj Damjanović, Maurizio Guadagnini
ISBN: 978-2-35158-217-6
e-ISBN: 978-2-35158-218-3
Publisher: RILEM Publications SARL
Publication year: 2019
Pages: 637-643
Total Pages: 848
Language: English

Abstract: The durability of old lime-based mortars was for many years a research subject and many techniques have been employed in order to understand the influence of the microstructure on macro properties that those mortars present. Under a wide range of magnification, important information can be revealed and enlighten their behavior. Particularly for the “soft” nature of lime mortars, information concerning the proportion of empty spaces (porosity) in relation to solid material, their shape, geometry and position as well as the composition of the crystal matrix and the aggregate characteristics has a detrimental role to the remarkable durability that old lime mortars present. The binder- aggregate transition zone was recorded strong in some cases while in others a loose bond was recorded. The proportion of aggregates in relation to the binder, the maximum size used, and their gradation seems to affect the volume stability and the form of discontinuities.
Microstructure analysis performed in historic mortars reveals that the most durable mortars combine natural and brick aggregates with smooth granulometry, in combination with strong binders. The blending of good quality lime with reactive natural pozzolan formed a strong binding system consisting of micro-grained, well-connected crystals.

Online publication :2019
Publication type : full_text
Public price (Euros) : 00