Advanced State Of Deterioration Research Articles

Notch formation in vertical excavations in a deep hard rock mine and rock stabilization methodologies

This paper presents details of the early to mid-stage deterioration in the form of notch growth of two 3 m diameter bored raises that were excavated and slashed to 7.8 m to serve as an internal shaft (winze). In addition, the long-term deterioration of a series of ore/waste passes that were excavated with the bottom-up Alimak methodology is investigated. These excavations were completed at depths between 1200 and 1915 m below the surface in a hard rock mine in Sudbury, Ontario, Canada. The ability to see a cross-section of fracturing around the bored raises while slashing into them and observing the progressive growth of fractures was critical for understanding the factors leading to deterioration. The Alimak-driven ore/waste passes were in an advanced state of deterioration, which provided a late-stage notch growth profile that could be compared with the notch growth observed in the bored raises. The methods used to support and stabilize these excavations are detailed; in addition, methodologies to prevent some of the deterioration from occurring are also presented. The findings of this work are useful for understanding the mechanisms driving brittle rock failure in deep mining and subsequently for minimizing or preventing the deterioration from occurring.

Physiological quality of seeds of arabic coffee cultivars stored for a period of two years.

The rapid loss of viability, coupled with the difficulties and limitations in conserving coffee seeds, are some of the challenges that nurseries are currently facing. Thus, the objective of this work was to analyze the physiological quality of stored Arabica coffee seeds from cultivars recommended for planting in Brazilian mountainous regions. Seeds from 10 Arabica coffee cultivars were used: Catucaí-785/15, Catucaí-2SL, Catucaí-24/137, Japan, Arara, Acauã, Catuaí IAC-81, Mundo Novo IAC-379/19, Catuaí IAC-62, and Caturra IAC-479. The seeds were collected in the Arabica coffee seed production field, in the municipality of Marechal Floriano-ES. They were subsequently processed and dried in the shade, at room temperature, until reaching a humidity of 35 ± 1%, analyzed and stored in a natural laboratory environment (25 ± 2 °C), for 24 months. The following were analyzed: seed water content, germination, germination speed index, electrical conductivity and potassium leaching. The experimental design used was completely randomized, with ten cultivars, two storage times, with four replications of 25 seeds. Storing arabica coffee seeds for 24 months results in a drop in the germination percentage. Stored seeds of the Catucai 24/137 and Arara cultivars showed germination percentages similar to those of newly harvested seeds. Seeds of the Catuai IAC-62 cultivar maintain vigor during storage. The stored seeds of the Caturra IAC-476 and Japi cultivars showed a reduction in physiological quality. Electrical conductivity and potassium leaching tests are efficient in identifying seeds in an advanced state of deterioration. Seeds of Arabica coffee cultivars stored for 24 months, under the conditions of the present study, produce abnormal seedlings.

PUBLIC TRANSPORT IN URBAN-RURAL RELATIONS IN THE JACQUEVILLE DEPARTMENT (COTE DIVOIRE)

Urban-rural relations in the Jacqueville department are marked by daily mobility between rural and urban populations. These journeys are made possible by a network of taxi-brousses which provide links between these two geographical areas. This study aims to determine the central role of mobility between the town of Jacqueville and its hinterland. To achieve this main objective, a methodology based on documentary research, interviews and field surveys was favored. Investigations revealed that, despite relative mobility between the town of Jacqueville and its rural area, transport means and infrastructure between this urban center and its hinterland remain in an advanced state of deterioration, making mobility between these geographical areas difficult.

Jib crane bearing selection through simulation

Through the corrective maintenance process of a bearing, regardless of its origin, certain anomalies related to its main elements, due to the condition of the type of maintenance, are expected. This was the case of the jib crane of the Caribbean Submarine fleet, used mainly to load the wiring and charging sockets for the supply of electrical energy to the Submarines. During a routine operation, it malfunctioned and stopped working without warning. An inspection was carried out in which corrective maintenance was deemed necessary, it was at the time that the bearing support was uncovered and its advanced state of deterioration was observed. Being this the main failure, and through application of engineering principles and simulation software, the reason for the deterioration was determined, and the optimal bearings for the correct operation of the jib crane were selected.

Flexible decision analysis procedures for optimizing the sustainability of ageing infrastructure under climate change

Currently, there is significant interest in ensuring the sustainability and serviceability of infrastructure systems in the context of climate change. Indeed, a large proportion of existing structures already are in an advanced state of deterioration, thus affecting the sustainability and usefulness of these structures, and highlighting the need for better planning and decision analysis tools. Such tools would benefit from improved models to predict the residual life of structures, to estimate benefits derived from infrastructures, to account for uncertainties associated with physical and financial processes, and to provide more flexibility in decision-making strategies. These concepts are investigated through application of a risk-based decision-making model for reinforced concrete bridge decks in Montreal to estimate the optimal timing for deck repairs. A probabilistic deterioration model is used to predict the residual life of concrete decks as a function of exposure to de-icing salts using historical data and predictions from climate change scenarios. Historical data are used to validate model assumptions by comparing predicted condition states to observations from periodic inspections, while the climate scenarios are used to evaluate the impact of climate change on deterioration rates assuming that current deck design and de-icing salt management strategies are not modified. In this instance, the optimal timing for the first major repair is influenced by the uncertainty involved with climate change predictions and the future availability of funds, while ensuring the safety of users and the required level of service. The proposed framework, based on a cost-benefit analysis, is applicable to any infrastructure project.

Markov Chain-Based Stochastic Modeling of Chloride Ion Transport in Concrete Bridges

Over the last decade, there has been a lot of interest in models for evaluating and predicting the condition of existing bridges in North America due to the large number of them in an advanced state of deterioration. The models have been used to develop optimal strategies to prolong the service life of bridges, allocate limited financial and technical resources and maintain the required level of reliability of the bridges. The main process of deterioration of concrete bridges is corrosion of the reinforcing steel due to chloride ions and models for this type of deterioration can be classified as physical or statistical. The physical models describe the diffusion of chloride ions in concrete and chemical reactions while the statistical models, such as Markov chains, are used to model the progression of states of deterioration of the concrete structures. The physical models are appropriate to analyze deterioration processes for various structures and conditions of exposure but are computationally too demanding for the portfolio analysis of a large number of structures. Markov chain models have been extensively used for the latter purpose but require an extensive historical database to correctly estimate transition probabilities between deterioration states. The objective of this paper is to propose a novel procedure for estimating transition probabilities for Markov chain models by utilizing targeted simulations from physical models. The transition probabilities can be derived from specific climatological regions and concrete properties. The proposed framework provides the required input for portfolio analyses for a large number of different types of structures exposed to different climatological conditions. The procedure is demonstrated with the TransChlor® software and for a group of structures located in Montreal, Canada.

Approaching on Colorimetric Change of Porous Calcareous Rocks Exposed in Urban Environmental Conditions from Iasi – Romania

According to the scientific literature, the pollution phenomenon is strongly related by the urban activity from the last decades, with direct effects on the state of conservation of the stone constructions also. This paper presents a preliminary study on the colorimetric evolution of the lithic surfaces exposed under strongly traffic influence from the urban microclimate conditions. The analysed lithic surfaces are similar with the building stone from the structure of an historical monument (from 19th century), such as the Stone Bridge in Iasi-Romania, located in the immediate vicinity of the roadside loop with the same name. The colour change monitoring for the above-mentioned geomaterials aims at anticipating the effects of postponing the decongestion of car traffic and implicitly initiating the assessment of the effects of pollution over this historic monument, which is in an advanced state of deterioration and degradation.

Las Complejas relaciones entre paisaje, puerto, ciudad y sus efectos en el patrimonio cultural en la bahía de Pasaia = The complex relationships between landscape, harbor, town and its effects on cultural heritage in the bay of Pasaia

This study aims to determine the characteristics of the different neighborhoods around the bay of Pasaia and its evolution. Several aspects are highlighted: the importance of cultural heritage, which justifies the classification of certain urban environments as “cultural landscapes”, as well as the complex social relationships that help explain their advanced state of deterioration and the threats that loom over them. To achieve this, a review of the literature and the statistical analysis of secondary data are used. This case study will help us understand the current socio-economic situation of the bay, the conflict between port authorities and the city councils, the cultural landscape and the lack of heritage assets.

Blue Pigment Colors from Wall Painting Churches in Danger (Portugal 15th to 18th Century): Identification, Diagnosis, and Color Evaluation

Samples of blue wall paint layers from selected 15th to 18th century religious mural paintings from southern Portugal (Alentejo) have been analyzed using a multi-analytical methodology involving the combination of in situ visible spectro-colorimetry with microanalytical techniques such as optical and scanning electron microscopy and Raman spectroscopy. In situ analyses and micro-sampling were carried out in nine different churches, many in an advanced state of deterioration. The objectives of this study were: (a) to identify and compare the pigments that were used in the blue paint layers across the Alentejo region and through time by analysis of the elemental and mineralogical composition and pictorial techniques, and (b) to correlate the data between the actual color of the paint layer and the state of conservation of the pigments. For the paintings dated from the 16th century forward, the results show a generalized use of smalt blue. To a lesser extent, natural azurite was used despite the geological richness of the region in copper and pyrite ores. In only one painting was an optical blue made of carbon black and lime found. The pigments, pure or mixed with red and yellow ochres, were coarsely ground and used in different concentrations to create three-dimensional effects. These parameters as well as the presence of iron oxides in underlayer paints influence the colorimetric coordinates in the more transparent smalt blue paint layers. The state of conservation of the pigments plays an important role in the alteration of the paint color. A clear example of this is the fading of the smalt blue in several paintings due to lixiviation processes.

Mechanical Properties and Strength of Aged Cast Iron Water Pipes

The problem of aging water pipes manifesting leaks and breaks is common to municipalities throughout the North American continent and the world. The age distribution of the failing pipes is broad and the pipe material originates from periods when different manufacturing technologies were employed. Consequently, cast iron pipes exhibit a significant variability of material properties. In addition, these pipes are also in a more or less advanced state of deterioration as a result of corrosion phenomena. A general knowledge of the properties and state of deterioration of a water main network is needed to understand the failure mechanisms contributing to water pipe failure. Among them, knowledge of the mechanical properties of the pipe material itself is fundamental. To achieve this goal, an extensive pipe and soil sampling and testing program was undertaken on excavated pipes in Toronto, Ontario. The mechanical tests performed on pipes included tension, compression, and ring bearing tests as well as full-scale longitudinal bending tests. The outcome of this experimental investigation contributes towards a better understanding of the complex phenomena involved in the pipe failure process.

Roman bricks in a marine environment

The technological characteristics of the bricks used to build, in the 2nd century A.D., the Roman “Terme a Mare” baths situated by the sea in Southern Sardinia have been studied. Theopus testaceum appears to be in an advanced state of deterioration due to exposure for more than a thousand years to a highly-aggressive marine environment. Successive salt crystallization/solubilization cycles subject both the porous structure of the bricks and the lime mortar joints to stress which leads to pulverization, fractures and the breaking off of large pieces.

The conservation of a Louis XIVTH Boulle Marquetry bracket clock case

Abstract A general description of Boulle Marquetry and its manufacture is followed by a discussion of factors involved in its deterioration and a description of the conservation and restoration of the case of a late Louis XIVth bracket clock. A discussion of treatment options is followed by a detailed description of each phase of the treatment. Because of the advanced state of deterioration of the object piecemeal treatments could not be used. Complete removal and replacement of the marquetry was therefore undertaken. To compensate for differences in thickness of the original components it was necessary to find a way of working from the back of the design. The method used involved remaking each panel in turn on jigs (moulds) obtained from the object itself and gluing on paper backing to compensate for the differences in thickness of different parts of the design. Treatment of the curved parts of the design is described as this presented some interesting problems not posed by the flat sections.

The use of organo-silanes for the treatment of limestone in an advanced state of deterioration

(1984). The use of organo-silanes for the treatment of limestone in an advanced state of deterioration. Studies in Conservation: Vol. 29, Preprints of the Contributions to the Paris Congress, 2-8 September 1984. Adhesives and Consolidants, pp. 171-176.