Material Investigation
Tests using flat jacks - for on-site determination of the mechanical behaviour of the wall; this is effected by inserting flat jacks, either individually or in pairs, into purposely cut gaps in the lime/cement mortar between stone courses;
Endoscopy testing - using highly-flexible integrated video systems (capable of access to even the most awkward locations) for frontal and lateral image acquisition of the hole under study; photos are taken in each zone investigated;
Sample extraction - coring is carried out using a water-cooled diamond-tipped tool engaged in the horizontal direction to produce samples having diameters lying in the range of 20 mm to 150 mm; this is used so as to avoid any undesirable mechanical or morphological changes in the sample. Further, the tests include the supply of storage containers for keeping extracted cores. Such tests enable coring to be performed on walls made of bricks, limestone, concrete, stone and so on;
Thermography testing - carried out using an AGEMA system featuring a maximum resolution of 0.2 °C; the test consists in the detection of electromagnetic radiation in the infrared band of the emission spectrum of the wall material under investigation; this is processed so as to give colour images which indicate isothermal regions;
Pull-off adherence testing - to obtain a measure of the adherence of plaster coatings and mortars on cement surfaces, adhesion of insulation coatings on structures, adhesion to the substrate of protective anti-corrosion coatings and of decorative coating finishes;
Ultrasonic testing
- reinforced concrete - determination of the uniaxial tensile rupture load, extent of heterogeneity, measurement of the modulus of elasticity in both the transverse and longitudinal directions, thickness measurement of elements which are accessible only from one end (e.g. buried foundations, etc.), pin-pointing individual internal cracks and measuring their depth, thickness measurement of the damaged concrete (by fire, chemical attack and so on);
- construction materials - ultra/sonic core drilling to estimate the uniaxial tensile rupture load, presence of cracks, extent of heterogeneity;
Hammer testing - for evaluating the rupture load; the test may be carried out in conjunction with the ultrasonic method;
Pull-out extraction testing - this done to determine the force required to extract a metal insert from a cast concrete element or one which had been inserted at a later stage. The value obtained for the force is employed as a parameter in establishing when the mechanical properties of the concrete have reached the required level, or in establishing the compressive strength in comparison with specific calibration curves, or else in estimating the compressive strength in combination with other non-destructive methods when calibration curves are unavailable;
Winsor probe tests - for determining the resistance of the concrete by the penetration method using a Winsor probe;
Locating and sizing of reinforcing bars and determination of the concrete cover.
Surveying the state of the site/s - this includes the morphology of the surrounding terrain with all its irregularities, by way of direct observation on site and relevant detailed photographic documentation. This form of survey should cover the entire site at hand and may be followed by more specific work, depending on the particular case. This is necessary in the case of all types of buildings;
Sample extraction from reinforcing bars - for mechanical testing, determination of chemical composition and so on;
Determination of the physical and mechanical characteristics of extracted samples
- dry weight
- effective volume
- apparent volumetric mass
- real volumetric mass
- porosity
- imbibition
- coefficient of capillarity
- degree of saturation
- compression properties
- tensile properties
- wear resistance properties
- resistance to freezing
- resistance to fracture after imbibition
- shear strength
- modulus of elasticity;
Chemical analysis of the concrete - for evaluating the presence of chlorides and sulphates and the composition of the concrete by x-ray diffractometry analysis; also an evaluation of the depth of carbonation by using a phenolphthalein treatment;
Petrographic analysis - this involves the litho-characterisation on a macroscopic scale and/or in this sections, inclusive of the relevant photographic documentation:
- macroscopic sample description;
- qualitative x-ray diffractometry analysis and
- mineralogic-petrographic description in thin sections, along with an estimate of the percentage porosity;
Chemico-physico-mineralogic analysis - of the building material and of the products of modifications complete with a determination of the elementary constituents, water content, carbonates, bicarbonates and other phases which result within the temperature range, stability, apparent density, porosity, aspects of topography and morphology, etc. so as to define the compatibility of the cleaning methods employed and / or the materials used for prevention, including the relevant tables of chemical analyses and interpretations, x-ray diffractograms and SEM analysis through:
- a macroscopic description of the sample;
- qualitative x-ray diffractometry analysis;
- mineralogic-petrographic description in thin sections along with a stratigraph of the degraded sample
- scanning electron microscopy analyses upon untreated samples (SEI) and on illuminated sections (BSEI), comprising qualitative EDS microanalysis and a study of the modifications :
- chemical analysis of the major and minor elements using AAS, ICP-MS;
- dosage of the total dissolved salts with a quantitative determination of chlorides, sulphates and nitrates;
- definition of the compatibility with cleaning methods for every lithotype;
Istochemical analysis - this is effected for the determination of organic constituents present within the composition of the paint layer by means of a stratigraphic study, complete with the determination of the relevant methods of cleaning as well as restoration techniques and comprising the necessary interpretation;
Microbiological analyses - to determine auto- and / or hetero-trophic bacterial microflora by way of identifying those micro-organisms which are responsible for the biodegredation of the building material; this is effected by extracting sterile samples and later ‘culturing’ them in an adequate area in the ground;
Sonic coring on piles (using the Crosshole method) - ultrasonic testing of the integrity of foundation piles to evaluate the integrity of the pile under test, its uniaxial tensile rupture load, the presence of cracks, degree of distortion and homogeneity.
Hygrometric surveying - effected by using a 10 x 10 cm sample for quantifying the level of superficial humidity via high-precision analogue instrumentation used for point tests.
Topological analyses of humidity in walls - this consists in a quantitative analysis of the percentage content of water in samples extracted at various levels and depths, so as to determine the origins of the invasive moisture.