Report rep028 : Characterisation of Old Mortars with Respect to their Repair - Final Report of RILEM TC 167-COM

RILEM TC "Characterization of old mortars with respect to their repair" (TC 167-COM) was created in October 1996 as a response to the realisation that the frequency of damage cases in repaired historic masonry over the last few decades was increasing. The problems were due to either a lack of workmanship skills or more likely a fundamental lack of knowledge of the materials in use. Analysis of these damage cases has shown that the damage often occurred within a relatively short period of time after the repair had been carried out; furthermore in many of the cases it was found that modern materials (especially binders) and treatments appeared to be the cause of the damage. Therefore in order to obtain a better insight into the poor performance of the repair mortars the TC focused on the characterisation of the old mortars. The premise behind this decision was that characterisation should provide links to technical performance of masonry.

Over the past 7 years RILEM TC 167-COM has made progressive headway in characterising historic masonry in a chemical, mineralogical, physical and mechanical way. At the halfway term in the project the members believed that it would be beneficial to discuss the provisional results with a wider audience and to publish completed papers at a workshop. In May 1999 a workshop, “Historic Mortars: characteristics and tests”, was organised by members of the TC at the University of Paisley.

The proceedings of the workshop were published in 2000 and together with discussions held during the workshop helped to broaden the objectives of the TC by, not only focussing on characterising old mortars but introducing further practice related subjects such as i) sampling, ii) the analysis of damage cases and iii) requirements and functions of repair mortars. The committee recognises the fact this work is not a complete/exhaustive study but does believe this publication provides useful theoretical and practical information on the characterisation of old mortars and is the culmination of the work carried out to date.

The discussions at the Workshop strengthened the TC’s awareness that the next logical step forward should be the formation of a new technical committee the subject of which was “Repair Mortars for Historic Masonry”. The focus of the work will be aimed at the classification of types of masonry and masonry problems, technical requirements for their repair and guidelines for the design of repair mortars.

Contents

CHAPTER 1

CHAPTER 2: CHARACTERISATION

CHAPTER 3

CHAPTER 4

CHAPTER 5