Environmental Deterioration Of Ancient AndModern Hydraulic Mortars

Abstract

Little is known about the nature and durability of hydraulic mortars in ancient buildings. Furthermore, the characterisation of the type of binder is important in order to proceed to the design of conservation interventions. A procedure has been set up to identify the type of binder used in historic hydraulic mortars. A number of mortars has been sampled from historic buildings, on which analyses have been performed to verify the set up methodology and evaluate their deterioration due to environmental deposition. Being sulphation one of the most important mechanisms of degradation found on historical buildings, SCV exposure tests were performed on different replicas of hydraulic mortars. The formation of sulphur containing species, such as gypsum, ettringite and thaumasite, has been studied in controlled conditions. The results obtained prove that the sulphation occurs on hydraulic mortars, depending on the composition of the binder. Transactions on the Built Environment vol 39 © 1999 WIT Press, www.witpress.com, ISSN 1743-3509