Edvard P. G. Bruun, Olga Kovaleva and Karl Peterson
Edvard P. G. Bruun, MASc. Candidate, Department of Civil Engineering, University of Toronto, 35 St. George Street, Toronto, ON, Canada, Edvard.bruun@mail.utoronto.ca
Olga Kovaleva Asst. Professor, Department of Civil Engineering, University of Toronto, 35 St. George Street, Toronto, ON, Canada, karl.peterson@utoronto.ca
ABSTRACT
In 1907 the city of Sofia, the capital of Bulgaria, made a financial commitment to beautify its urban core – a decision that today is still clearly manifested in the iconic bright yellow bricks that formthe wearing surface of the main squares and roads of the downtown region. The inevitable fracturing and crumbling of blocks due to heavy traffic loads has reduced the area covered to half its original extent. Yet a surprising number of these bricks have not needed replacement since their installation over one hundred years ago, which is more than doubling their intended life expectancy. Visual inspection of the bricks also belies the fact that they have been in heavy usesince their placement – exposed to pedestrian and vehicular traffic for over a century. Recent research efforts within Bulgaria have focused on the characterization of the historic bricks, and the manufacture of new replacement bricks. Additional microscopic investigations of the original brick are presented here, including results from x-ray diffraction, optical microscopy, microhardness testing, and scanning electron microscopy.
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