DOI: 10.5176/2251-3701_2.1.53
Authors: PArkadiusz KwiecieĊ
Abstract:
Damages existing in masonry engineering structures are caused by various loads and has to be repair because of structural and architectural requirements. Repair of cracked masonries using materials of high stiffness and low deformability, like lime and cement mortars or epoxy resins, does not increase significantly the tensile strength of the repair joint. This is because of the stress concentration occurrence. The use of highly deformable bonding materials allows reducing peaks of stress concentration, causing (after repair) increase of strength of cracked masonry elements. Proposed repair materials of high deformability can be easily covered with original masonry material to ensure protection of architectural value.
In the paper, there were tested masonry units (bricks), investigated in two kinds of loading. One of them was the four point bending test on Polish Bonarka bricks and the second one was the Single Lap Shear Test on Italian Rosso Vivo - A6R55W bricks, strengthened using CFRP and SRP strips bonded on epoxy resin. In both cases, the primary failure appeared in form of cracks (or detachment) going through the brick materials. The failure surfaces of both tests were repaired using materials of low and high deformability. More significant strength increase of the tested masonry elements (after repair) was obtained in the case of the use of highly deformable interface materials than of barely deformable bonding materials.
Efficiency of highly deformable repair materials was also examined as repair on cracked masonry walls in laboratory using polymer injection and externally bonded composite mats made of glass fibers bonded on highly deformable polymer. Additionally, the highly deformable polymer joints were tested dynamically in situ on a masonry building, up to failure also.
Keywords: repair of masonries, masonry units, reduction of stress concentration, high deformability, polymer flexible joints, dynamic test
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