203-RHM : Repair mortars for historic masonry

Technical Committee 203-RHM

General Information

Chair: Dr. Caspar J.w.p. GROOT
Deputy Chair: Dr. John J. HUGHES
Activity starting in: 2003
Cluster E

Subject matter

Classification of types of masonry and types of repair problems
Development of (quantified) technical requirements and design guidelines for compatible and durable repair mortars for restoration.

Terms of reference

The objectives will be achieved by reviewing and comparing the results of recent research and practical experiences, at international expert level.
The time needed for achieving deliverables of practical relevance to the research world and the building practice is rated at 3 to 4 years.
The regular and correspondent members to be recruited are well known experts with outstanding academic as well as practical experience in the field of restoration of masonry structures.
Several of them already participated in the former RILEM Committee TC-COM 167.

Detailed working programme

- General classification of types of masonry
- General classification of types of repair problems
- Development of technical requirements of repair mortars
- Development of guidelines for the design of repair mortars
- Round robin testing

Technical environment

- European project COMPASS (Compatibility of plasters and renders with salt loaded substrates in historic buildings)
- European project ASSET (Assessment of suitable products for the conservative treatment of sea salt decay)
- European Network EDSCON (Salt damage in historic buildings)

Contacts of the individual members of the TC with many organisations, research institutes, universities, practitioners working in the field of historic masonry

Expected achievements

1) Report on the classification of the types of masonry and the types of repair problems
2) Report on the (quantified) technical requirements regarding characteristics/properties of repair material compatible to surrounding old material environmental conditions
3) Guidelines dealing with the methodology of mortar design, the preparing, the testing, the monitoring and the applying of mortars for restoration and repair
4) Workshops; the first one after the classification is finished (after 1 year), the second one at the end of the TC's activities.

Group of users

The target groups of these products are especially practitioners like engineers, architects, industrialists and specialized contractors.
Masonry practice shows that many mistakes are made in choosing mortars for pre-existing masonry. Recommendations, based on the explanation of the phenomena which play a role in regard to the compatibility of mortar and brick and aspects like long-term quality and durability of masonry, are badly needed.
Guidelines dealing with the methodology of choosing, preparing and applying mortars for restoration and repair are meant to avoid future mistakes in the choosing of a mortar for specific applications. The economic impact is supposed to be significant; however, precise estimations are not available.

Specific use of the results