The European Cultural Heritage deals with a great variety of structures of high intrinsic value. Among these are the Natural Building (NB) stones, the key elements of our historical monuments. The NB stones, which have been used in the past in historical monuments in Europe, are various types of metamorphic, sedimentary and igneous rocks. NB stones are inhomogenous as they consist of grains of various minerals, they contain defects, such as pores and cracks, and frequently they are highly anisotropic. Historical monuments usually have been subjected through time to mechanical loads, and to various types of weathering (i.e. temperature variations, atmospheric pollution, freeze and thaw, moisture transport etc.), which affect their quality and impose damage of certain type and degree. The induced damage on NB stones due to aggressive urban environment may lead to significant losses of the elasticity and strength properties of the outermost layers of stone and result in erosion features, cohesionless appearance and disintegration forms. Damage diagnosis of NB stones is the first stage in the planning of the remedial steps to which the success of the restoration will be entrusted. An erroneous diagnosis may be very harmful to the cultural, structural and economic outcome of the operation. Up-to-now the classical processes for measuring the mechanical properties and effectiveness of the consolidation treatment of stones are observational, empirical and destructive: a sample is taken from the structure - if it is permitted - it is cut and then standard rock mechanical tests are performed on it. However, the knowledge of the mechanical properties and damage must result from non-destructive tests if we want to use the structure thereafter. Up-to-now there is not available in the market a valid "stone-friendly" technology, procedure or apparatus for the in situ assessment of damage and effectiveness of consolidation treatments of stones. The main Project goal is to develop this technology for the in situ indirect characterisation of (a) the mechanical properties and damage of untreated NB stones, and (b) the effectiveness and durability of consolidation techniques (e.g. penetration depth, enhancement of stone mechanical properties and variation with time) used in the restoration of exposed NB stones in historical monuments, buildings and other structures. The proposed technology is independent of: (1) the environmental conditions, (2) the type, heterogeneity or physico-mechanical characteristics of the stone, (3) the degree and type of stone degradation due to weathering, (4) possible previous consolidation measures in the monument site, and (5) the depth of stone damage or consolidation. This goal will be achieved by developing an integrated portable Drilling-Indentation-Acoustics of Stones (DIAS)
- DIAS - Integrated tool for in situ characterization of effectiveness and durability of conservation techniques in historical structures (CONTRACT EVK4 CT-2002-00080).
2005
Abstract
The European Cultural Heritage deals with a great variety of structures of high intrinsic value. Among these are the Natural Building (NB) stones, the key elements of our historical monuments. The NB stones, which have been used in the past in historical monuments in Europe, are various types of metamorphic, sedimentary and igneous rocks. NB stones are inhomogenous as they consist of grains of various minerals, they contain defects, such as pores and cracks, and frequently they are highly anisotropic. Historical monuments usually have been subjected through time to mechanical loads, and to various types of weathering (i.e. temperature variations, atmospheric pollution, freeze and thaw, moisture transport etc.), which affect their quality and impose damage of certain type and degree. The induced damage on NB stones due to aggressive urban environment may lead to significant losses of the elasticity and strength properties of the outermost layers of stone and result in erosion features, cohesionless appearance and disintegration forms. Damage diagnosis of NB stones is the first stage in the planning of the remedial steps to which the success of the restoration will be entrusted. An erroneous diagnosis may be very harmful to the cultural, structural and economic outcome of the operation. Up-to-now the classical processes for measuring the mechanical properties and effectiveness of the consolidation treatment of stones are observational, empirical and destructive: a sample is taken from the structure - if it is permitted - it is cut and then standard rock mechanical tests are performed on it. However, the knowledge of the mechanical properties and damage must result from non-destructive tests if we want to use the structure thereafter. Up-to-now there is not available in the market a valid "stone-friendly" technology, procedure or apparatus for the in situ assessment of damage and effectiveness of consolidation treatments of stones. The main Project goal is to develop this technology for the in situ indirect characterisation of (a) the mechanical properties and damage of untreated NB stones, and (b) the effectiveness and durability of consolidation techniques (e.g. penetration depth, enhancement of stone mechanical properties and variation with time) used in the restoration of exposed NB stones in historical monuments, buildings and other structures. The proposed technology is independent of: (1) the environmental conditions, (2) the type, heterogeneity or physico-mechanical characteristics of the stone, (3) the degree and type of stone degradation due to weathering, (4) possible previous consolidation measures in the monument site, and (5) the depth of stone damage or consolidation. This goal will be achieved by developing an integrated portable Drilling-Indentation-Acoustics of Stones (DIAS)I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
