Physical and mineralogical changes of Hungarian monumental stones exposed to different conditions: stone-testing in-situ and under laboratory conditions

The Székesfehérvár Ruin Garden is a unique assemblage of monuments belonging to the cultural heritage of Hungary due to its important role in the Middle Ages as the coronation and burial church of the Kings of the Hungarian Christian Kingdom. It has been nominated for “National Monument” and as a consequence, its protection in the present and future is required. Moreover, it was reconstructed and expanded several times throughout Hungarian history. By a quick overview of the current state of the monument, the presence of several lithotypes can be found among the remained building and decorative stones. Therefore, the research related to the materials is crucial not only for the conservation of that specific monument but also for other historic structures in Central Europe. The current research is divided in three main parts: i) description of lithologies and their provenance, ii) physical properties testing of historic material and iii) durability tests of analogous stones obtained from active quarries. The survey of the National Monument of Székesfehérvár, focuses on the historical importance and the architecture of the monument, the different construction periods, the identification of the different building stones and their distribution in the remaining parts of the monument and it also included provenance analyses. The second one was the in situ and laboratory testing of physical properties of historic material. As a final phase samples were taken from local quarries with similar physical and mineralogical characteristics to the ones used in the monument. The three studied lithologies are: fine oolitic limestone, a coarse oolitic limestone and a red compact limestone. These stones were used for rock mechanical and durability tests under laboratory conditions. The following techniques were used: a) in-situ: Schmidt Hammer Values, moisture content measurements, DRMS, mapping (construction ages, lithotypes, weathering forms) b) laboratory: petrographic analysis, XRD, determination of real density by means of helium pycnometer and bulk density by means of mercury pycnometer, pore size distribution by mercury intrusion porosimetry and by nitrogen adsorption, water absorption, determination of open porosity, DRMS, frost resistance, ultrasonic pulse velocity test, uniaxial compressive strength test and dynamic modulus of elasticity. The results show that initial uniaxial compressive strength is not necessarily a clear indicator of the stone durability. Bedding and other lithological heterogeneities can influence the strength and durability of individual specimens. In addition, long-term behaviour is influenced by exposure conditions, fabric and, especially, the pore size distribution of each sample. Therefore, a statistic evaluation of the results is highly recommended and they should be evaluated in combination with other investigations on internal structure and micro-scale heterogeneities of the material, such as petrographic observation, ultrasound pulse velocity and porosimetry. Laboratory tests used to estimate the durability of natural stone may give a good guidance to its short-term performance but they should not be taken as an ultimate indication of the long-term behaviour of the stone. The interdisciplinary study of the results confirms that stones in the monument show deterioration in terms of mineralogy, fabric and physical properties in comparison with quarried stones. Moreover stone-testing proves compatibility between quarried and historical stones. Good correlation is observed between the non-destructive-techniques and laboratory tests results which allow us to minimize sampling and assessing the condition of the materials. Concluding, this research can contribute to the diagnostic knowledge for further studies that are needed in order to evaluate the effect of recent and future protective measures.

Entwicklung einer Anordnung zur Nutzung von Massenschwerebewegungen beim Quarzitabbau im Rheinischen Schiefergebirge

Die (Wieder-)Nutzung auf Schwerkraft basierender Fördertechniken, die insbesondere durch das niedrige Energiepreisniveau in den Jahrzehnten nach dem 2. Weltkrieg in der Tagebautechnik nahezu vollständig verdrängt wurden, ist bei den heutigen wirtschaftlichen Randbedingungen und anzustrebenden ökologischen Standards eine Herausforderung für die bergbautreibende Industrie. Seit Aufnahme der Entwicklung des Förderkonzeptes – Geführte Versturztechnik – Mitte der 1990er Jahre haben sich die Kosten für Rohöl vor Steuern nach dem Tiefstand um das Jahr 1998 bis heute mehr als verdreifacht, alleine seit 2004 mehr als verdoppelt. Gesetzliche Regelwerke wie die europäische IVU-Richtlinie 96/61/EG zur „integrierten Vermeidung und Verminderung der Umweltverschmutzung“ fordern, Genehmigungen nur noch bei Einsatz der besten verfügbaren Techniken (BVT oder BAT: „best available techniques“) zu erteilen. Die Umsetzung in nationale Vorschriften wie das Bundes-Immissionsschutzgesetz und nachgeordnete Regelwerke fordern hierauf aufbauend, dass Umweltbelastungen nicht in andere Medien verlagert werden dürfen. Die Anordnung einer Versturzrinne zur Nutzung von Massenschwerebewegungen am Beispiel von Quarzitabbau im Rheinischen Schiefergebirge bei denen die Förderbezugsebene unterhalb der Strossen liegt, die zur sichern und selektiven Gewinnung des Rohstoffs aufgefahren werden müssen, erfüllt durch Rückgriff auf ein vermeintlich „archaisches“ Förderkonzept durch Nutzung der Schwerkraft die obigen Anforderungen. Offenkundige Umweltbelastungen, die alleine durch die Verbrennung von Dieselkraftstoff und hieraus resultierender Schadstoff- und Wärmeeinträge in die Luft beim verbreiteten Einsatz von SLKW zur Abwärtsförderung entstehen, können erheblich vermindert werden. Der Aspekt der Betriebssicherheit einer solchen Anordnung kann durch Auffahren eines geradlinigen Bauwerks mit an das Fördergut angepassten Dimensionen sowie Einrichtungen zur Beschränkung der kinetischen Energie erreicht werden. Diese stellen auch gleichzeitig sicher, dass die Zerkleinerung des durch die Versturzrinne abwärts transportierten Materials betrieblich zulässige Grenzen nicht überschreitet. Hierfür kann auf das umfangreiche Wissen zu Massenschwerebewegungen Rückgriff genommen werden. Dem Aspekt des Umweltschutzes, der sich in Bezug auf das Medium Luft auf den autochtonen Staub reduziert, kann durch Vorrichtungen zur Staubniederschlagung Rechnung getragen werden. Vertiefende Untersuchungen sind erforderlich, um die mit komplexen, aber erprobten Techniken arbeitende Tagebauindustrie auch in dicht besiedelten Regionen wieder an die Nutzung von Schwerkraft (-gestützten) Fördertechniken heranzuführen. Auch das Konzept – Geführte Versturztechnik – ist auf konkrete Anwendungsfälle hin in Details anzupassen.

Procedure e strumenti innovativi per lo sfruttamento sostenibile delle risorse minerarie

L'approvvigionamento di risorse minerali e la tutela dell'ambiente sono spesso considerate attività contrapposte ed inconciliabili, ma in realtà rappresentano due necessità imprescindibili per le società moderne. Le georisorse, in quanto non rinnovabili, devono essere valorizzate in maniera efficiente, adoperando strumenti che garantiscano la sostenibilità ambientale, sociale ed economica degli interventi estrattivi. La necessità di tutelare il territorio e migliorare la qualità della vita delle comunità locali impone alla Pubblica Amministrazione di implementare misure per la riqualificazione di aree degradate, ma fino ai primi anni '90 la normativa di settore non prevedeva strumenti a tal proposito, e ciò ha portato alla proliferazione di siti estrattivi dismessi e abbandonati senza interventi di recupero ambientale. Il presente lavoro di ricerca fornisce contributi innovativi alla pianificazione e progettazione sostenibile delle attività estrattive, attraverso l'adozione di un approccio multidisciplinare alla trattazione del tema e l'utilizzo esperto dei Sistemi Informativi Geografici, in particolare GRASS GIS. A seguito di una approfondita analisi in merito agli strumenti e le procedure adottate nella pianificazione delle Attività Estrattive in Italia, sono stati sviluppati un metodo di indagine ed un sistema esperto per la previsione ed il controllo delle vibrazioni indotte nel terreno da volate in cava a cielo aperto, che consentono di ottimizzare la progettazione della volata e del sistema di monitoraggio delle vibrazioni grazie a specifici strumenti operativi implementati in GRASS GIS. A supporto di una più efficace programmazione di interventi di riqualificazione territoriale, è stata messa a punto una procedura per la selezione di siti dismessi e di potenziali interventi di riqualificazione, che ottimizza le attività di pianificazione individuando interventi caratterizzati da elevata sostenibilità ambientale, economica e sociale. I risultati ottenuti dimostrano la necessità di un approccio esperto alla pianificazione ed alla progettazione delle attività estrattive, incrementandone la sostenibilità attraverso l'adozione di strumenti operativi più efficienti.

Petrologisch-geochemische Charakterisierung quartärer Laven der Eifel als Grundlage zur archäometrischen Herkunftsbestimmung römischer Mühlsteine

Lava aus der quartären Vulkanregion der Eifel wurde in römischer Zeit großmaßstäblich abgebaut, um daraus Mühlsteine hoher Qualität herzustellen, die in großen Mengen in weite Teile des Römischen Reiches exportiert wurden. Somit erweisen sich diese Mühlsteine als ideale Indikatoren für Handelsgebiete und –wege dieser Zeit. Für eine erfolgreiche Herkunftsanalyse von Fundstücken ist eine genaue Charakterisierung der infrage kommenden Rohstoffe die unbedingte Voraussetzung. Aus diesem Grund konzentriert sich diese Arbeit auf die geochemische Definition der 16 bekannten römischen „Basalt“-Abbaustellen in den Vulkanfeldern der Ost- und Westeifel, mit dem vorrangigen Ziel, eine möglichste eindeutige Charakterisierung der einzelnen Abbaustellen zu erreichen. Auf dieser Basis wird eine Vorgehensweise zur folgenden Provenienzanalyse der Mühlsteine entwickelt. Um die geochemische Variabilität der Laven zu erfassen wurden die Abbaustellen großflächig beprobt. Die Proben wurden zunächst petrographisch bestimmt und der Phasenbestand mittels Röntgendiffraktometrie (XRD) untersucht. Die Haupt- und Spurenelement-Zusammensetzung wurde anhand von Röntgenfluoreszenzanalysen und Laser-Massenspektrometrie mit induktiv gekoppeltem Plasma (LA-ICP-MS) ermittelt, die Sr-Nd-Pb-Isotopie ausgewählter Proben mittels Thermo-Ionen-Massenspektrometrie (TIMS). Es zeigte sich, dass auf Grundlage der Haupt- und Spurenelementzusammensetzung, gemessen mit RFA, eine Abgrenzung der Abbaustellen zueinander mittels einer Kombination aus geochemischer Diskriminierung mit Cluster- und Diskriminanzanalysen gelingt. Die anschließende Provenienzanalyse der Mühlsteinfundstücke erfolgt analog zur Charakterisierung der Abbaustellen. Im ersten Schritt wird eine geochemische Zuordnung des Fundstücks vorgenommen, um zu überprüfen, ob eine Eifeler Herkunft überhaupt in Frage kommt. Lässt der geochemische Vergleich mit den Referenzdaten aus dem Gelände eine Eifeler Herkunft zu, kommt im zweiten Schritt die Clusteranalyse zum Einsatz. Hier wird auf multivariater Ebene geprüft, ob das Fundstück einer Eifeler Abbaustelle oder einem Cluster von Eifeler Abbaustellen zugeordnet werden kann. Bei einer positiven Zuordnung wird ergänzend als dritter Schritt die Diskriminanzanalyse angewendet, anhand der das Mühlstein-Fundstück einer Abbaustelle mit einer bestimmten Wahrscheinlichkeit zugewiesen wird. Bei 68 analysierten Mühlsteinen aus verschiedenen Regionen Mitteleuropas konnte so für 49 Fundstücke eine Eifeler Provenienz festgestellt werden. Alle römischen Eifeler Mühlsteine entstammen dem Bellerberg bei Mayen, ein mittelalterliches Stück aus dem Niedermendiger Lavastrom. Die Zuordnung der übrigen 19 Mühlsteine zu anderen möglichen Abbaugebieten erfolgt anhand geochemischer Daten aus der Literatur. Aufgrund der unzureichenden Datenlage sind im Falle dieser Proben jedoch im Gegensatz zur Lavastrom-genauen Zuordnung der Eifeler Mühlen lediglich Vermutungen über die Herkunftsregionen möglich. Damit zeigt sich, dass eine ausführliche Referenzdatenbank der in Frage kommenden Rohstoffe die erforderliche Basis für erfolgreiche Provenienzanalysen ist. Die Möglichkeit der genauen Zuordnungen von Mühlsteinen zu den Eifeler Abbaustellen belegt, dass die Verbindung von geochemischer Auswertung mit Cluster- und Diskriminanzanalysen ein hilfreiches Verfahren zur Provenienzanalyse darstellt.

Per un'archeologia del lavoro in eta' protobizantina. Organizzazione e committenza del cantiere edilizio attraverso i marchi dei marmorari

La ricerca riguarda lo studio del cantiere edilizio protobizantino, con particolare riferimento al ciclo della lavorazione del marmo. Quest’ultimo viene analizzato sotto il profilo amministrativo, tecnico, sociale ed artigianale. L’elemento guida della ricerca sono i marchi dei marmorari, sigle apposte da funzionari e maestranze durante il processo produttivo. Dapprima, fonti letterarie ed epigrafiche, tra cui le sigle di cava e officina su marmo, vengono esaminate per ricostruire il sistema alto-imperiale di amministrazione delle cave e di gestione dei flussi marmorei, nonché l’iter tecnico-artigianale adottato per la produzione dei manufatti. Il confronto con i dati disponibili per la tarda antichità, con particolare riferimento alle cave di Proconneso, evidenzia una sostanziale continuità della prassi burocratico-amministrativa, mentre alcuni cambiamenti si riscontrano nell’ambito produttivo-artigianale. Il funzionamento degli atelier marmorari viene approfondito attraverso lo studio dei marchi dei marmorari. Si tratta di caratteri greci singoli, multipli o monogrammi. Una ricognizione sistematica delle sigle dalla pars Orientalis dell’impero, reperite in bibliografia o da ricognizioni autoptiche, ha portato alla raccolta di circa 2360 attestazioni. Per esse si propone una classificazione tipologica tra sigle di cava, stoccaggio, officina. Tra le sigle di cava si annoverano sigle di controllo, destinazione/committenza, assemblaggio/posizionamento. Una particolare attenzione è riservata alle sigle di officina, riferibili ad un nome proprio di persona, ovvero al πρωτομαΐστωρ, il capo-bottega che supervisionava il lavoro dei propri artigiani e fungeva da garante del prodotto consegnato alla committenza. Attraverso lo studio comparato delle sigle reperite a Costantinopoli e in altri contesti si mette in luce la prassi operativa adottata dagli atelier nei processi di manifattura, affrontando anche il problema delle maestranze itineranti. Infine, sono analizzate fonti scritte di varia natura per poter collocare il fenomeno del marmo in un contesto socio-economico più ampio, con particolare riferimento alle figure professionali ed artigianali coinvolte nei cantieri e al problema della committenza.

AN ASSESSMENT OF BALLAST SOURCE'S QUALITY AND LOCATIONS WITH RESPECT TO MDOT'S UPGRADE OF THE WOLVERINE RAILROAD LINE FOR HIGH SPEED RAIL USEAGE

The Michigan Department of Transportation is evaluating upgrading their portion of the Wolverine Line between Chicago and Detroit to accommodate high speed rail. This will entail upgrading the track to allow trains to run at speeds in excess of 110 miles per hour (mph). An important component of this upgrade will be to assess the requirement for ballast material for high speed rail. In the event that the existing ballast materials do not meet specifications for higher speed train, additional ballast will be required. The purpose of this study, therefore, is to investigate the current MDOT railroad ballast quality specifications and compare them to both the national and international specifications for use on high speed rail lines. The study found that while MDOT has quality specifications for railroad ballast it does not have any for high speed rail. In addition, the American Railway Engineering and Maintenance-of-Way Association (AREMA), while also having specifications for railroad ballast, does not have specific specifications for high speed rail lines. The AREMA aggregate specifications for ballast include the following tests: (1) LA Abrasion, (2) Percent Moisture Absorption, (3) Flat and Elongated Particles, (4) Sulfate Soundness test. Internationally, some countries do require a highly standard for high speed rail such as the Los Angeles (LA) Abrasion test, which is uses a higher standard performance and the Micro Duval test, which is used to determine the maximum speed that a high speed can operate at. Since there are no existing MDOT ballast specification for high speed rail, it is assumed that aggregate ballast specifications for the Wolverine Line will use the higher international specifications. The Wolverine line, however, is located in southern Michigan is a region of sedimentary rocks which generally do not meet the existing MDOT ballast specifications. The investigation found that there were only 12 quarries in the Michigan that meet the MDOT specification. Of these 12 quarries, six were igneous or metamorphic rock quarries, while six were carbonate quarries. Of the six carbonate quarries four were locate in the Lower Peninsula and two in the Upper Peninsula. Two of the carbonate quarries were located in near proximity to the Wolverine Line, while the remaining quarries were at a significant haulage distance. In either case, the cost of haulage becomes an important consideration. In this regard, four of the quarries were located with lake terminals allowing water transportation to down state ports. The Upper Peninsula also has a significant amount of metal based mining in both igneous and metamorphic rock that generate significant amount of waste rock that could be used as a ballast material. The main drawback, however, is the distance to the Wolverine rail line. One potential source is the Cliffs Natural Resources that operates two large surface mines in the Marquette area with rail and water transportation to both Lake Superior and Lake Michigan. Both mines mine rock with a very high compressive strength far in excess of most ballast materials used in the United States and would make an excellent ballast materials. Discussions with Cliffs, however, indicated that due to environmental concerns that they would most likely not be interested in producing a ballast material. In the United States carbonate aggregates, while used for ballast, many times don't meet the ballast specifications in addition to the problem of particle degradation that can lead to fouling and cementation issues. Thus, many carbonate aggregate quarries in close proximity to railroads are not used. Since Michigan has a significant amount of carbonate quarries, the research also investigated using the dynamic properties of aggregate as a possible additional test for aggregate ballast quality. The dynamic strength of a material can be assessed using a split Hopkinson Pressure Bar (SHPB). The SHPB has been traditionally used to assess the dynamic properties of metal but over the past 20 years it is now being used to assess the dynamic properties of brittle materials such as ceramics and rock. In addition, the wear properties of metals have been related to their dynamic properties. Wear or breakdown of railroad ballast materials is one of the main problems with ballast material due to the dynamic loading generated by trains and which will be significantly higher for high speed rails. Previous research has indicated that the Port Inland quarry along Lake Michigan in the Southern Upper Peninsula has significant dynamic properties that might make it potentially useable as an aggregate for high speed rail. The dynamic strength testing conducted in this research indicate that the Port Inland limestone in fact has a dynamic strength close to igneous rocks and much higher than other carbonate rocks in the Great Lakes region. It is recommended that further research be conducted to investigate the Port Inland limestone as a high speed ballast material.

Lacustrine sediments from two setions in northern Greece

We investigated two lignite quarries in northern Greece for orbital and suborbital climate variability. Sections Lava and Vegora are located at the southern and northern boundaries of the Ptolemais Basin, a northwest southeast elongated intramontane basin that contains Upper Miocene to Lower Pliocene lacustrine sediments. Sediments show cyclic alterations of marl-rich (light), and coal-rich or clay-rich (dark) strata on a decimeter to meter scale. First, we established low-resolution ground-truth stratigraphy based on paleomagnetics and biostratigraphy. Accordingly, the lower 67 m and 65 m that were investigated in both sections Vegora and Lava, respectively, belong to the Upper Miocene and cover a time period of 6.85 to 6.57 and 6.46 to 5.98 Ma at sedimentation rates of roughly 14 and 22 cm/ka. In order to obtain a robust and high-resolution chronology, we then tuned carbonate minima (low L* values; high magnetic susceptibility values) to insolation minima. Besides the known dominance of orbital precession and eccentricity, we detected a robust hemi-precessional cycle in most parameters, most likely indicative for monsoonal influence on climate. Moreover, the insolation-forced time series indicate a number of millennial-scale frequencies that are statistically significant with dominant periods of 1.5-8 kyr. Evolutionary spectral analysis indicates that millennial-scale climate variability documented for the Ptolemais Basin resembles the one that is preserved in ice-core records of Greenland. Most cycles show durations of several tens of thousands of years before they diminish or cease. This is surprising because the generally argued cause for Late Quaternary millennial-scale variability is associated with the presence of large ice sheets, which cannot be the case for the Upper Miocene. Possible explanations maybe a direct response to solar forcing, an influence on the formation of North Atlantic Deep Water through the outflow of high-salinity water, or an atmospheric link to the North Atlantic Oscillation.

Selected Devonian/Carboniferous boundary profiles in the Sauerland area (Rhenish massif)

Selected sections, containing Devonian/Carboniferous boundary beds, are described from the northern and northeastern margin of the Rhenish massif, especially from the Seiler region near Iserlohn and the Warstein area. These sections are from prospecting trenches, quarries and road cuts. The dominantly carbonate sequences were investigated in regard to the development of conodonts. The Devonian/Carboniferous boundary could be placed precisely in both areas by means of the phylogenetic transition from Siphonodella praesulcata to S. sulcata. Compared investigations lead to the following conclusions: - The basal part of the Hangenberg limestone is heterochronous. - The Devonian/Carboniferous boundary lies distinctly below the Hangenberg limestone, i. e. at the same stratigraphical level as the Stockum limestone. - The Imitoceras limestone lens of Stockum and the Stockum limestone represent a special facies within the Hangenberg schists. 80th belong either to the praesulcata- and sulcata-zone or are restricted only to the sulcata-zone. - Protognathodus kuehni appears together with Siphonodella sulcata. Where S. sulcata is lacking, P. kuehni may be considered as a valid index conodont indicating the beginning of the Carboniferous. - The upper part of the Wocklum beds, following above the Wocklum limestone, usually consists up to the lower Carbonilerous boundary in a more or less consistent facies, that of the Hangenberg schists. Only in the section 01 the northeastern wall of the eastern Provincial Quarry at Drewer and in the road profile Rüthen - Nuttlar, the Devonian/Carboniferous boundary is to be placed in a continuous carbonate sequence. - The eastern Provincial Quarry at Drewer is therefore proposed as a new candidate section for the Devonian/Carboniferous boundary stratotype. - In many places the carbonates at the Devonian / Carboniferous boundary and the Hangenberg limestone are characterized by an impoverished conodont fauna. - Using platform conodonts, biofacies models are developed, permitting to conclude on the position of the respective setting 01 sedimentation area, either close to a rise or a basin.

Chemical and isotopic compositions of Archean magmatic and metasedimentary rocks and minerals from the Podolia domain, Ukrainian Shield

Zircons from the oldest magmatic and metasedimentary rocks in the Podolia domain of the Ukrainian shield were studied and dated by the U-Pb method on a NORDSIM secondary-ion mass spectrometer. Age of zircon cores in enderbite gneisses sampled in the Kazachii Yar and Odessa quarries on the opposite banks of the Yuzhnyi Bug River reaches 3790 Ma. Cores of terrigenous zircons in quartzites from the Odessa quarry as well as in garnet gneisses from the Zaval'e graphite quarry have age within 3650-3750 Ma. Zircon rims record two metamorphic events around 2750-2850 Ma and 1900-2000 Ma. Extremely low U content in zircons of the second age group indicates conditions of the granulite facies metamorphism in Paleoproterozoic within the Podolia domain. Measured data on orthorocks (enderbite-gneiss) and metasedimentary rocks unambiguously suggest existence of the ancient Paleoarchean crust in the Podolia (Dniester-Bug) domain of the Ukrainian shield. They contribute in our knowledge of scales of formation and geochemical features of the primordial crust.

Long-term persistence of Mediterranean pine forests in the Duero Basin (central Spain) during the Holocene: The case of Pinus pinaster Aiton

In the southern Duero Basin of central Spain, there are vast areas of aeolian sand sheets and dune fields. A comprehensive survey of the sand quarries in this area identified a number of palaeosols in sedimentary sequences. The identification and AMS radiocarbon dating of soil charcoal fragments collected in these palaeosols indicate the persistence of Pinus pinaster in this area throughout most of the Holocene. Although potential natural vegetation models have usually considered the Pinus pinaster forests in this inland area of artificial origin, soil charcoal analysis provides firm evidence of a natural origin. Our data fit perfectly with the pattern of Holocene vegetation development for inland areas of Iberia, which are characterised by stability of pine forests throughout the Holocene. Finally, the growing body of palaeobotanical evidence from Iberia (macrofossils and pollen) is contributing to improve our knowledge of P. pinaster ecology, showing that this species has been present in most Iberian regions during the Holocene, where it has inhabited areas characterised by a very diverse set of climatic and soil conditions.

Asymmetric propagation of airblast from bench blasting

This paper investigates the propagation of airblast from quarry blasting. Peak overpressure is calculated as a function of blasting parameters (explosive mass per delay and velocity at which the detonation sequence proceeds along the bench) and polar coordinates of the point of interest (distance to the blast and azimuth with respect to the free face of the blast). The model is in the form of the product of a classical scaled distance attenuation law times a directional correction factor. The latter considers the influence of the bench face, and attenuates overpressure at the top level and amplifies it at the bottom. Such factor also accounts for the effect of the delay by amplifying the pressure in the direction of the initiation sequence if the velocity of initiation exceeds half the speed of sound and up to an initiation velocity in the range of the speed of sound. The model has been fitted to an empirical data set composed by 134 airblast records monitored in 47 blasts at two quarries. The measurements were made at distances to the blast less than 450 m. The model is statistically significant and has a determination coefficient of 0.869

Prediction of near field overpressure from quarry blasting

This paper investigates the propagation of airblast or pressure waves in air produced by bench blasting (i.e. detonation of the explosive in a row of blastholes, breaking the burden of rock towards the free vertical face of the block). Peak overpressure is calculated as a function of blasting parameters (explosive mass per delay and velocity at which the detonation sequence proceeds along the bench) and the polar coordinates of the position of interest (distance to the source and azimuth with respect to the free face). The model has been fitted to empirical data using linear least squares. The data set is composed of 122 airblast records monitored at distances less than 400 m in 41 production blasts carried out in two quarries. The model is statistically significant and has a determination coefficient of 0.87. The formula is validated from 12 airblast measurements gathered in five additional blasts.

Estudio experimental sobre la reacción álcali-sílice en el hormigón producida por áridos de reacción lenta

La finalidad de esta investigación se enmarca dentro de los estudios sobre hormigones de presas llevados a cabo en el Laboratorio Central de Estructuras y Materiales del CEDEX. En España se han diagnosticado 18 obras afectadas tanto por la reacción álcali-sílice de tipo rápido como por la de tipo lento. Dos de de las obras, fabricadas con áridos graníticos, no presentan signos de deterioro pero en laboratorio se han hallado productos expansivos. En las 16 presas españolas restantes, el hormigón de 10 de ellas estaba fabricado con áridos graníticos, de las cuales, 7 están afectadas por la reacción de tipo lento. Sin embargo, en las clasificaciones internacionales de las rocas potencialmente reactivas se establece habitualmente que las rocas graníticas son inocuas o de reactividad muy baja. En los casos puntuales encontrados en la literatura, la reactividad de este tipo de áridos se encuentra frecuentemente asociada al cuarzo microcristalino que contienen y ocasionalmente se asocia esta reactividad también al cuarzo deformado y/o microfisurado. En la tesis doctoral de Víctor Daniel Lanza Fernández, también realizada en el CEDEX, se han tratado los áridos de reacción rápida, dando una descripción detallada de los componentes que intervienen en este tipo de reacción y presentando un ensayo eficaz para su detección en el laboratorio. La investigación desarrollada en la presente tesis doctoral se ha centrado en los áridos de reacción lenta, mucho menos estudiados. A partir del estudio bibliográfico realizado sobre este tipo de reacción se ha detectado ciertas lagunas, basadas principalmente en la falta de un método de detección en el laboratorio para los áridos de reacción lenta. No se ha encontrado un procedimiento en el estudio petrográfico que sea fiable y cuantificable para este tipo de áridos. El ensayo acelerado de barras de mortero, que para los áridos de reacción rápida supone un método rápido y fiable, falla en la detección de los áridos de reacción lenta al aplicar los límites normalizados. Si bien en publicaciones recientes se ha propuesto la posibilidad de ampliar el tiempo de tratamiento hasta los 90 días, la duración del ensayo es más larga de lo deseado. Para resolver estas lagunas, se han tomado áridos de obras reales afectadas por la reacción álcali-sílice (en algún caso también de las canteras de donde se extrajeron los áridos para la ejecución), con lo que la reactividad de estos áridos queda demostrada por su comportamiento en obra. Al objeto de aumentar la muestra de ensayo y utilizar también áridos inocuos, se han tomado muestras de canteras, tanto en uso como abandonadas. Sobre estos áridos se ha realizado una caracterización completa con los ensayos actualmente disponibles para el estudio de su reactividad con los álcalis del cemento: estudio petrográfico, ensayo acelerado de barras de mortero y Gel-Pat modificado. En la investigación se ha desarrollado una metodología de tinción de geles álcali-sílice para la cuantificación de los mismos en el interior de las barras de mortero. Se ha relacionado el volumen de gel generado en la reacción con la expansión producida, tanto para áridos lentos, como rápidos, estableciendo analogías y diferencias en el comportamiento de ambos. La cuantificación de este tipo de compuestos realizada en las barras de mortero, abre la posibilidad de estudiar la capacidad expansiva que presentan en testigos de hormigón de obras afectadas. Este dato podría ser una herramienta importante para el desarrollo de modelos matemáticos que puedan predecir el futuro comportamiento de las estructuras afectadas por la reacción álcali-sílice. La tinción ha sido asimismo utilizada para establecer un método de detección de áridos reactivos basado en el ensayo de Gel-Pat modificado. La metodología de detección propuesta para estos áridos es cuantitativa y proporciona los resultados en 14 días, suponiendo una ventaja importante sobre los métodos actuales, que permiten detectarlos en 90 días (de forma orientativa en 56 días). This research is part of the studies on durability of concrete dams carried out in the Laboratorio Central de Estructuras y Materiales of CEDEX during the last years. At the present time, 18 public works affected by alkali-silica reaction have been diagnosed in Spain. In 12 of them the concrete was mixed with granitic aggregates, 7 of which were damaged by the slow alkali-silica reaction, 3 by the rapid alkali-silica reaction and in the other 2 cases, although there was no visual evidence of the reaction in field, the laboratory tests showed the presence of expansive products inside the concrete. However, in the international classifications of potentially reactive aggregates granitic rocks are pointed out as innocuous or as low reactivity and usually their reactivity is attributed to the presence of microcrystalline quartz and occasionally with the strained and microcracked quartz. The rapid reactive aggregates were deeply studied in a previous research (Víctor Daniel Lanza’s Thesis) also carried out in CEDEX. In this research, a detailed description of the components involved in the rapid alkali-silica reaction was given. Also, a fast method to detect them in the laboratory was developed. The research of the present PhD Thesis is focused in the slow-reactive aggregates, much less studied. The state of the art has shown some gaps in the knowledge about this reaction, mainly the absence of a reliable method to detect slow-reactive aggregates. On one side, there is no systematic and quantitative petrographic test for these aggregates. On the other side, the accelerated mortar bar test has been proved to be effective to detect rapid reactive aggregates but the standard limits fail in the detection of the slowreactive aggregates. In recent investigations it has been proposed extending the test until 90 days, but this period is considered too long. In this research, aggregates taken from affected structures have been used in the test, so their reactivity has been shown in practice. With the aim of increasing the number of samples aggregates from quarries have been also used. A method to stain alkali-silica gels has been applied to mortar bars, thereby quantifying the volume of gel generated inside. This volume has been related to the expansion of the bars, both for rapid for slow reactive aggregates, establishing similarities and differences. The quantification of the gel volume, applied to concrete cores extracted from affected structures, could be an important tool in mathematical models to predict the future behaviour of the structures affected by the alkali-silica reaction. The staining method has been also used to develop a method to detect slow reactive aggregates, based on the optimised Gel-Pat test, obtaining results in 14 days. This represents a major improvement compared to the actual methods (accelerated mortar bar test) which give an indicative value of reactivity at 56 days, and a final result at 90 days.

Proyecto para la instalación de una planta de tratamiento de residuos de construcción y demolición en la comunidad de Madrid

La problemática actual de las canteras en la cercanía de las grandes ciudades, debido a la escasez de yacimientos y a las restricciones medioambientales, están poniendo en graves problemas el abastecimiento de áridos naturales y encareciendo su coste. El proyecto realizado responde a la actual necesidad de los países del mundo desarrollado por buscar soluciones a los problemas de abastecimiento de materias primas para la construcción en las zonas urbanizadas. La dependencia de nuestra sociedad hacia los recursos naturales y la consideración de su importancia hacen que se deban aprovechar al máximo, ya sea reciclando, reutilizando o revalorizando. Este proyecto está centrado en los residuos utilizados en el sector de la construcción y la viabilidad de su reutilización. Hemos evaluado la situación y la legislación acerca de la posibilidad de reciclar los materiales de la construcción para volverlos a introducir en el mercado; llevando a cabo una aplicación práctica en la Comunidad de Madrid. El proyecto se complementa con el diseño y estudio de viabilidad de una instalación de reciclaje de residuos de la construcción y demolición en este micromercado. ABSTRACT The current problems of the quarries in the vicinity of large cities, due to the scarcity of deposits and environmental restrictions are putting in serious trouble supplying natural aggregates and more expensive cost. The project undertaken reflects the current need for developed countries to seek solutions to the problems of supply of raw materials for construction in urbanized areas worldwide. The dependence of our society towards natural resources and consideration of its importance that should be made to maximize either by recycling , reusing or revalued. This project is focused on the waste used in the construction sector and feasibility of reuse. We have assessed the situation and legislation about the possibility of recycling construction materials for re- entering the market ; carrying out a practical application in the Community of Madrid. The project complements the design and feasibility study of a facility for recycling construction waste and demolition in this micro market

Interisland and interarchipelago transfer of stone tools in prehistoric Polynesia.

Tracing interisland and interarchipelago movements of people and artifacts in prehistoric Polynesia has posed a challenge to archaeologists due to the lack of pottery and obsidian, two materials most readily used in studies of prehistoric trade or exchange. Here we report the application of nondestructive energy-dispersive x-ray fluorescence (EDXRF) analysis to the sourcing of Polynesian artifacts made from basalt, one of the most ubiquitous materials in Polynesian archaeological sites. We have compared excavated and surface-collected basalt adzes and adze flakes from two sites in Samoa (site AS-13-1) and the Cook Islands (site MAN-44), with source basalts from known prehistoric quarries in these archipelagoes. In both cases, we are able to demonstrate the importing of basalt adzes from Tutuila Island, a distance of 100 km to Ofu Island, and of 1600 km to Mangaia Island. These findings are of considerable significance for Polynesian prehistory, as they demonstrate the movement of objects not only between islands in the same group (where communities were culturally and linguistically related) but also between distant island groups. Further applications of EDXRF analysis should greatly aid archaeologists in their efforts to reconstruct ancient trade and exchange networks, not only in Polynesia but also in other regions where basalt was a major material for artifact production.