In the past, steel hoops were applied over the height of columns to increase their load-bearing capacity. Currently, innovative strengthening techniques, namely fiber-reinforced composites, are successfully replacing traditional systems. Although fiber-reinforced polymers were demonstrated to be effective in the confinement of columns, the use of fabric-reinforced cementitious matrix (FRCM) systems is preferred in the case of masonry columns belonging to architectural heritage buildings because of the compatibility with the masonry substrate as well as the reversibility of the intervention. In this paper, the influence of different matrices on the effectiveness of confinement of masonry columns is investigated both experimentally and analytically. Three different matrices are considered to assemble the composite: a natural lime mortar with poor mechanical properties, a cement mortar, and a commercial mortar with high compression strength. The FRCM system was obtained by embedding a polyparaphenylenebenzobisoxazole fabric within these matrices. Results of axial compression tests demonstrate the effectiveness of confinement in all cases, highlighting the different increases in the load-bearing capacity and ductility of the columns provided by the use of different matrices. The main predictive formulas available in the literature were used to compute the increase in the load-bearing capacity of the tested columns, providing values very different than those obtained experimentally. For this reason, the authors believe that these formulas, which are affected by coefficients fine-tuned by the various authors based on their experimental results, need to be further calibrated and tuned to be successfully used in practical applications. Accordingly, the use of two different equations in the case of matrices having a compression strength higher or lower than the strength of the unconfined column is proposed.
Usually, energy and structural improvements for historic masonry buildings are addressed separately using distinct methods and protocols. This paper covers an integrated assessment of new composite materials to reduce the seismic vulnerability of historic masonry buildings while complying with sustainable conservation requirements, emissions’ reduction, and energy savings. Firstly, this study focused on selecting suitable thermal mortars that could serve as the base material for the innovative composite. Subsequently, the mechanical characteristics of these mortars were examined by subjecting them to compressive and three-point bending tests. Dynamic thermo-hygrometric simulations were conducted using commercially available software to check the energy performance of the composite material when used on walls of existing masonry buildings. The thermal mortar that exhibited the most favorable mechanical and thermal properties was subsequently reinforced with a basalt fabric. A composite sample was assembled and subjected to direct tensile testing to determine its stress–strain behavior.
16 January 2024 in Bulletin of Earthquake Engineering
Reducing energy consumption in the building sector has driven the search for more sustainable construction methods. This study explores the potential of cork-modified mortars reinforced with basalt fabric, focusing on optimizing both mechanical and hygroscopic properties. Six mortar mixtures were produced using a breathable structural mortar made from pure natural hydraulic lime, incorporating varying percentages (0–3%) of cork granules (Quercus suber) as lightweight aggregates. Micro-computed tomography was first used to assess the homogeneity of the mixtures, followed by flow tests to evaluate workability. The mixtures were then tested for water absorption, compressive strength, and adhesion to tuff and clay brick surfaces. Adhesion was measured through pull-off tests, to evaluate internal bonding strength. Additionally, this study examined the relationship between surface roughness and bond strength in FRLM composites, revealing that rougher surfaces significantly improved adhesion to clay and tuff bricks. These findings suggest that cork-reinforced mortars offer promising potential for sustainable construction, achieving improved hygroscopic performance, sufficient mechanical strength, internal bonding, and optimized surface adhesion.