PARTNERS IN THE RECONSTRUCTION AND THE PROJECT
The sponsor of the initiative, the Cassa di Risparmio di Fermo bank, asked for Mapei’s collaboration to carry out the work and Mapei, as Technical Partner for the project, supplied experts from the company’s Technical Services Department and various cutting-edge product systems.
Consolidation of the vaulted ceiling was carried out in two phases.
Firstly, the damaged areas were repaired with a product chosen for its compatibility with the existing mortar’s mechanical properties and level of porosity, its resistance to physical and chemical aggression (freeze-thaw cycles) acting on the ceiling and its compatibility with the frescoed surfaces. A product suitable for repairing frescoed surfaces was chosen so that, during its application, the substrate would not need to be wetted and, while it was setting, it would not give off free lime that would have caused the formation of efflorescence and potentially damage the decorated surface.
The ceiling was then consolidated by applying on the outer face a composite system with an inorganic matrix. All the products used contained no cement, as specified by the local Heritage Board. For the upper part of the apse, a composite system with an organic matrix was proposed, which consisted of carbon fibre fabric and epoxy resin to guarantee a constraint on mechanisms out-of-plane of the macro-element.
VAULTS, WALLS AND APSE: THE SOLUTIONS FROM MAPEI
COMPOSITE MESH AND CEMENT-FREE MORTARS AND BINDERS FOR THE ANCIENT MASONRY AND TO SAFEGUARD THE FRESCOES
To consolidate the outer face of the existing vaulted roofs PLANITOP HDM RESTAURO was used, a product made of an inorganic matrix of natural hydraulic lime and Eco-Pozzolan. This product, which was applied in an even layer using a flat, metal trowel, allows to smooth and level off masonry surfaces such as stone, brickwork and tuff.
When applied in combination with MAPEGRID B 250 alkali-resistant basalt fibre mesh, as in this case, it is used to strengthen the structure of masonry buildings.
To ensure the strengthening of the side walls, MAPEWRAP B FIOCCO high-strength basalt fibre cords were prepared and then bonded in place with MAPEFIX EP 470 SEISMIC pure epoxy resin-based chemical anchor for structural loads.
MAPE-ANTIQUE F21 salt-resistant, 100% cement-free hydraulic binder made from lime and Eco-Pozzolan was poured into the frescoed vaulted ceilings.
To strengthen the masonry, it was rendered with MAPE-ANTIQUE STRUTTURALE NHL high-performance mortar made of hydraulic lime and Eco-Pozzolan, reinforced with MAPENET EM40 alkali-resistant glass fibre mesh and L-shaped MAPENET EM CONNECTOR fasteners made from alkali-resistant glass fibre and thermosetting vinylester-epoxy resin.
FRP SYSTEM TO FORM STRENGTHENING BANDS AROUND THE APSE
In the apse area a number of bands were applied using a typical FRP SYSTEM, which included the application of MAPEWRAP C UNI-AX 600 unidirectional, high modulus, high-strength carbon fibre fabric, MAPEWRAP PRIMER 1 epoxy primer, MAPEWRAP 11 epoxy grout to level off surfaces and for bonding, MAPEWRAP 31 medium viscosity epoxy adhesive to impregnate and bond the fabric and MAPEWRAPP C FIOCCO high-strength carbon fibre cord to form structural ties.
The FRP bands were then protected by covering them with a layer of MAPE-ANTIQUE ECOLASTIC cement-free, lime and Eco-Pozzolan-based, waterproof elastic coating, which is used to protect construction features and elements, including those of historical and artistic interest.