Investigación previa del conjunto catedralicio de Granada

Antes de emprender la restauración o estudio de los procesos de alteración de un monumento, es imprescindible la realización de una serie de estudios preliminares conocidos genéricamente como investigación previa; estos estudios deben proporcionar suficiente información sobre muy diversos aspectos al objeto de poder estar en condiciones de realizar una adecuada interpretación de los datos que se obtengan en las investigaciones siguientes a fin de garantizar, en la medida de lo posible, que las futuras intervenciones sean las más adecuadas. Es necesario, en primer lugar, realizar una investigación profunda que permita conocer las diversas etapas constructivas del monumento, las modificaciones que se han realizado sobre el proyecto original, así como todas aquellas incidencias que puedan haber tenido una repercusión directa sobre el monumento,tales como derrumbamientos, terremotos, modificaciones urbanísticas del entorno, etc. En segundo lugar, se ha de realizar una investigación bibliográfica que permita conocer la procedencia de los materiales pétreos empleados en la construcción; esta información será esencial tanto para el investigador como para el arquitecto restaurador. Al primero le servirá para poder obtener grandes cantidades de material inalterado para la realización de ensayos de laboratorio, que no puede detraerse del monumento sin causar en la mayor parte de los casos graves daños; al restaurador, esta información le permitirá disponer de material de las mismas o similares características al original por si fuese necesario realizar reposiciones. La localización de las canteras de procedencia de los materiales es a veces una tarea no demasiado fácil por diversas razones, entre las que se encuentra el hecho de que muchas de ellas no se encuentran en explotación desde hace muchos años, o el nombre por el que son mencionadas en los antiguos documentos no se corresponde con el actual, etc., no obstante, diversos estudios químicos y petrográficos pueden permitir la identificación inequívoca de las mismas comparando con los materiales del edificio . Por último, el conocimiento de las condiciones ambientales a las que se encuentra sometido el monumento resulta de un particular interés debido a que muchos procesos de alteración tendrán su origen en las mismas y, además, las tareas de restauración a realizar se pueden ver fuertemente condicionadas por aquellas

Mechanical properties of natural hydraulic lime-based mortars

180 different mortars made with a natural hydraulic lime and different kinds of aggregates were prepared in order to be used in restoration works. The factors affecting the mechanical behavior have been studied at long-term test. Compressive and flexural strengths of the specimens were discussed according to curing time, binder:aggregate ratios, attributes of the aggregates and porosity. Three phases of hardening have been established as a function of the chemical composition: C3S contributes to the strength at early ages. C2S and the carbonation process give their strengths at long term. Specimens with larger binder amounts have shown higher porosity and strength. The characteristics of the aggregates have been correlated with the strength and porosity. Limestone aggregates contribute to the strength. Rounded shaped aggregates, increasing large pores, cause a strength reduction, so their use is not advisable. Aggregates with small grain size show a good cohesion at the interface improving the strength

Lime-pastes with different kneading water: Pore structure and capillary porosity

Lime-mortars to be used in restoration works of Cultural Heritage are being more and more studied. The knowledge on the lime-pastes allows understanding the behaviour of the binder fraction. The aim of this work is to study the influence of the kneading water on two critical aspects of the lime-pastes: pore structure and capillary porosity, because both of them are related to the service life of the material, particularly with the moisture transport. Mercury intrusion porosimetry has been performed to establish the pore size distribution: one pore range has been checked in the different pastes tested, setting linear relationships between the pore diameter and the water/lime ratio. Fractal geometry has been used from the MIP results in order to evaluate the pore surface complexity, as a function of the kneading water. From the results, it can be concluded that kneading water is only responsible for a swelling of the structure, but it does not change the pore surface (keeping constant the surface fractal dimension). DIA analysis has been carried out, confirming the previous results. Finally, the correlation obtained between the capillary coefficient and the water/lime ratio confirms the postulated pore structure for the different amount of kneading water in lime-pastes

Mechanical properties of masonry repair dolomitic lime-based mortars

180 different mortars made with a dolomitic lime and different aggregates were prepared in order to be used in restoration works. This paper focuses on the effect of technological variables on pore structure and mechanical properties of magnesian lime-based mortars. Compressive and flexural strengths of the specimens were discussed according to curing time, binder : aggregate ratios, attributes of the aggregates and porosity, at long-term tests. A strong increase in the strength of mortars has been found after 365 curing days as compared to 28 curing days. The strength has been mainly attributed to the portlandite carbonation, because no significant changes have been observed in the brucite. However, higher strengths than similar aerial lime-based mortars led us to think of other mechanism which increases the strength: the calcite formation through a reaction of dedolomitization (alkali carbonate reaction, ACR) and the brucite crystallization were discussed. The pore structure has presented a significant influence on the strength. More binder amounts mean more strength due to the higher values of open porosity, which allows the carbonation process. The aggregate characteristics have been correlated with the strength and porosity. Limestone and angle-shaped aggregates, reducing large pores, cause a strength increment

Measuring KS0K± interactions using Pb–Pb collisions at √sNN=2.76 TeV

We present the first ever measurements of femtoscopic correlations between the K0 S and K± particles. The analysis was performed on the data from Pb–Pb collisions at √sNN = 2.76 TeV measured by the ALICE experiment. The observed femtoscopic correlations are consistent with final-state interactions proceeding via the a0(980) resonance. The extracted kaon source radius and correlation strength parameters for K0 SK− are found to be equal within the experimental uncertainties to those for K0 SK+. Comparing the results of the present study with those from published identical-kaon femtoscopic studies by ALICE, mass and coupling parameters for the a0 resonance are tested. Our results are also compatible with the interpretation of the a0 having a tetraquark structure instead of that of a diquar