Torque Penetrometric Test for the in-situ characterisation of historical mortars: fracture mechanics interpretation and experimental validation

The assessment of historical structures requires appropriate knowledge of the behaviour of the investigated materials. Concerning masonry, its mechanical characterisation is a challenging task, since its composite nature requires the careful evaluation of the behaviour of its material components. In...

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Detalles Bibliográficos
Autores: Marastoni, Diego, Benedetti, Andrea, Pelà, Luca|||0000-0001-7760-8290, Pignagnoli, Giacomo
Tipo de recurso: artículo
Fecha de publicación:2017
País:España
Institución:Universitat Politècnica de Catalunya (UPC)
Repositorio:UPCommons. Portal del coneixement obert de la UPC
Idioma:inglés
OAI Identifier:oai:upcommons.upc.edu:2117/108607
Acceso en línea:https://hdl.handle.net/2117/108607
https://dx.doi.org/10.1016/j.conbuildmat.2017.09.120
Access Level:acceso abierto
Palabra clave:Masonry--Testing
Historical construction
Masonry
Brickwork
Mortar
In-situ testing
Minor Destructive Testing (MDT)
Compressive strength
Penetrometric test
Fracture mechanics
Fracture energy
Estructures de murs
Àrees temàtiques de la UPC::Enginyeria civil::Materials i estructures
Descripción
Sumario:The assessment of historical structures requires appropriate knowledge of the behaviour of the investigated materials. Concerning masonry, its mechanical characterisation is a challenging task, since its composite nature requires the careful evaluation of the behaviour of its material components. In particular, the experimental assessment of the strength of existing mortar in historical structures still encounters several difficulties. This study investigates a novel Minor Destructive Testing (MDT) technique virtually equivalent to the vane test used for soils. The instrumentation, called herein Torque Penetrometric Test (TPT), is composed of a steel nail with four protruding teeth and a torque wrench. The test consists in inserting the toothed nail into a mortar joint and then applying a torque by means of a dynamometric key, until reaching the failure of the material. This work presents a novel interpretation theory based on basic concepts of fracture mechanics and applied to the micro-mechanical analysis of the stress state induced by the instrument on the investigated mortar. The proposed interpretative theory is validated through the execution of experimental tests in the laboratory and in a historical masonry building. The test proves to be effective for a quick in-situ MDT evaluation of the strength of existing mortars.