Cl PA 2003 XIX ,h International Symposium, 30 September - 04 October, 2003, Antalya, Turkey 
572 
2. THE CAUSES OF DETERIORATION ON MORTARS 
AND PLASTERS USED IN HISTORICAL BUILDINGS 
It is possible to list the causes of damage in mortars and plasters 
as atmospheric effects, effects of use and production conditions 
and destructive effects of restoration. However it is possible to 
group the most commonly observed causes of damage in two 
basic groups. Table 1 shows causes of damage and their types 
(Torraca, G., 1981). 
A. The Destructive Effects of the Environment 
Factor 
Effect 
Damage Type 
Acidic waters (with C0 2 , S0 2 ) that 
come with rain or snow water. 
Dissolve the carbonates of lime binder. 
Adhesion and Cohesion features of the 
mortar is decreased. Aggregates are 
decomposed. 
The continuity of freezing/thawing 
cycles. 
The bonds of the mortar among the 
binding aggregates are dissolved. 
Leads to the dissolution of the mortar. 
Exposion to extreme amount of water 
vapour (in case of fire). 
The critical water vapour content the 
mortar can carry is exceeded. 
Leads to the hanging of the mortars in folds 
through decomposition. 
If the sand used in mortar has clay in 
content. 
The swelling of clay in a moisturous 
environment, leading to internal stresses. 
Crumbling of the mortar is observed, 
regional swellings and draping are seen. 
Sea water, air pollution, use of dirty 
material. 
Anionic salt crystals i.e. Chlorur, 
Sulphates and Nitrates are formed. 
Decomposition of the mortar, deep cracks 
nad draping of the mortar are observed. 
Formation of plants 
Especially some plant roots lead to the 
dissolution of the mortar. 
Biological decay, colouring of the mortar 
and dissolution. 
Existance of organic growth 
With the formation of insects, the binding 
quality of the mortar is reduced. 
Microbiological decay and dissolution of 
the mortar. 
B. The Destructive Effects of the Repair Mortars 
Factor 
Effect 
Damage Type 
Using more cement than lime. 
Formation of highly stiff mortar, 
cracking. 
Shrinkage cracks and diffusion of water 
through cracks, drapings due to different 
work. 
Salts that may come from the cement. 
Efflourescence on the surface of the 
mortar. 
The salts cause the efflourescence and lead 
to internal stresses. 
Adding synthetic resin, (if it is too 
much). 
The water and vapour permeability 
regime of the original mortar is 
deteriorated. 
Dissolution in the form of shells on the 
surface of the mortar. 
Table 1. Some factors that cause damage on original mortar and plaster and damage types 
3. AN EVALUATION OF MORTARS AND PLASTERS 
PRODUCED FOR USING IN THE RESTORATION OF 
HISTORICAL BUILDINGS 
Mortars and plasters used in historical buildings provide 
important helpful information about the building technology of 
their historical period and they are as important as historical 
documents. Therefore, the evaluation analyses of original 
mortar and plaster during the restoration should be made based 
on a scientific base. The work may require to include scholars 
with various professions such as art historians, restorators, 
physicians, chemists, biologists, engineers and architects within 
the same team during the analyses process from time to time. 
However, method determination practices that shall be used in 
applications on the subject matter have not been standardized. 
In addition it is not possible to utilize all the experiments and 
the standards that check and control the quality of binding 
products and raw material applied on mortar and plaster 
analysis of historical buildings. The purpose of mortar and 
plaster analysis of historical buildings is not to make a quality 
control of the material used, but to determine the physical, 
chemical and mechanical properties. Therefore, it is required to 
provide the information that explains the current condition of 
the material as well as the factors that have led to the formation 
of the current situation of the material used in the building. 
In order to be able to make the ideal repair mortar choice that 
will be used in the restoration of the historical buildings, it is 
necessary to know the properties of traditional mortar very well. 
Consequently, this should be compared with comparative 
mortars. After making such a comparison, production of a 
mortar that carries the advantegous properties of traditional and 
comparative mortar is possible. Since there is a lack of 
academic publication on this issue in our country, different 
problems in reaching the accurate and sufficient information are 
encountered. This leads to the use of incompatible material 
during the restoration process. 
An experimental method that can be used in evaluating the 
analyses of traditional mortar as well as mortar and plaster that 
shall be used in restoration is suggested below. This method is 
composed of 4 basic phases. Phase I; Visual Analysis and 
Documentation, Phase II; Experimental Research, Phase III; 
Evaluation of experiments made in Phase II in order to produce 
the repair mortar, Phase IV; Decision making on the 
appropriateness of the repair mortar. (Fig.l)