Investigation of the Pozzalonic Additives Used in Horasan Mortars and Plasters

Project No

İÇTAG – 1674

Supported by

Scientific and Technical Research Council of Turkey (TÜBİTAK)

Director of the Project

Assoc. Prof. Dr. Hasan BÖKE


Assoc. Prof. Dr. Başak İPEKOĞLU, Assist.Prof.Dr. Sedat AKKURT,
Res. Assist. Elif UĞURLU

Project Budget

18.300.000.000 TL.

Project Term

18 months (November 2002 – May 2004)

Horasan mortars and plasters had been used in the construction of ancient monuments and buildings due to their hydraulic properties. These materials are composed of a mixture of finely ground brick and lime which form a hydraulic compound if the crushed bricks are pozzolanic. Historical mortars and plasters need conservation due to their deterioration problems. During their conservation, the new mortars and plasters must be compatible with the existing ones.

Modern bricks used in the conservation of Horasan mortars and plasters are seldom pozzolanic because they are fired at higher temperature and they have low clay contents. Therefore, the choice of bricks used in the preparation of new Horasan mortars and plasters is important.

In this work, sound historic Horasan mortars and plasters collected from historic bath buildings will be examined. Brick powders and fragments will be separated with dilute hydrochloric acid from calcium carbonate. The mineralogical composition, firing temperature and pozzolanicities of the brick powder samples will be determined. Modern bricks will also be examined and compared with the old ones aiming at identifying potential usage in new restoration mortars and plasters. X-ray diffraction (XRD), optical microscopy and scanning electron microscopy (SEM) coupled with EDS (EDAX) will be used to determine the minerological composition and the morphologies of the old and new brick powders. Differential thermal analysis (DTA) will be used in the determination of firing temperatures. Pozzolanicity will be measured by following the calcium, sodium and potassium ions during the reaction of lime with brick powders by flame photometry.

At the completion of this work, the correct type of brick to be used for conservation work will be defined.