Sub-hydraulic binders in historic mortars
Title: Sub-hydraulic binders in historic mortars
Author(s): J.E. Lindqvist, S. Johansson
Paper category : conference
Book title: Workshop Repair Mortars for Historic Masonry
Editor(s): C. Groot
Publisher: RILEM Publications SARL
Publication year: 2009
Pages: 224 - 230
Total Pages: 7
Nb references: 14
Abstract: The present nomenclature for pure lime binders and hydraulic binders is adapted to modern materials. A large proportion of historical mortars fall in the category of nonhydraulic mortars, although their functional properties often reflect a significant content of hydraulic components in the binder. It would be misleading to regard these mortars as pure lime mortars, although they generally do not harden under water. The hardening of these mortars occurs largely through carbonation, but the hydraulic components in the binder give additional hardening through hydration. This results in a mortar with higher final strength and generally lower porosity. The colour of these mortars is mostly white with warm yellow or grey tones due to the presence of iron and manganese. In the discussion of properties of historical mortars these mortars have been overlooked. It is the opinion of the authors that this is an important group of mortars that requires special attention and to some extent provides an opportunity to use more durable mortars in applications that are exposed to severe climatic conditions.
These properties are often attributed to mortars with a chemical composition of 0.15 to 0.30 using the cementation index described by Boynton. This compares with a binder of the composition CL 90-95 following the European norm EN 459-1 for building limes.
Online publication: 2009-06-08
Publication type : full_text
Public price (Euros): 0.00