Use of lime-based mortar joints to improve compatibility and performance of TRM retrofit layer with historic masonry

Carbon textile reinforced cement masonry retrofit solutions are often evaluated in literature in an attempt to control the cracks formation on degraded masonry elements. The research of the past three years in this field has reached the conclusion that both cement and carbon textiles are materials with superior stiffness and of higher rigidity compared to historic masonries, which are often composed of non-industrial bricks and lime-based mortar joints. In order to improve the materials’ compatibility and provide a retrofit solution that will follow up the deformation and fracture process of the historic masonry, lime-based glass textile retrofitted layers are tested as well. The masonry-retrofit interaction is improved and the damage mechanism that dominates failure of the retrofit layer is shifted from premature instant interfacial cement-textile debonding to retrofit cracking, textiles sliding and progressive debonding along the retrofit-masonry interface. Acoustic Emission and Digital Image Correlation contribute to the damage monitoring providing continuous and online view of the damage onset, propagation and failure.