Дисертації з теми "Lime and Stone dust"

For the period of several centuries, the influence of several distinct cultures produced rich and diverse cultural heritage that we see today in East Africa countries. The most tangible remains of these heritages are stone built buildings and structures including, palaces, mosques, residential houses and tombs. At present, these heritages are in different physical state, some are in relatively good condition while many are in an appalling condition. The presence of these historical monuments has benefited these countries economically and culturally therefore, it is essential to ensure that these monuments continue to exist. Material characterisation of the historical buildings and associated structures was used to develop a suitable method of intervention that is sympathetic to the original materials. Mortar is the most damaged material therefore, historical mortar from Stone Town historical buildings and associated structures has been characterised by visual examination, optical microscopy, x-ray diffraction and hydrostatic weighing and the results have been compared. The historical mortar is mainly comprised of calcite, quartz and feldspar. The mortar condition has been divided into hard mortar, soft mortar and, soft and friable mortar. The deteriorated mortar that required consolidation is soft mortar and, soft and friable mortar with a porosity of approximately 27%. Calcium hydroxide solution (limewater) has been selected as consolidant and the consolidation procedure involves two steps. Firstly a limewater impregnation procedure has been developed and secondly, the effect of limewater treatment has been determined. For the application procedure it has been observed that, when limewater comes into contact with calcium carbonate a precipitation reaction occurs and that is the cause of poor penetration ability of calcium hydroxide solution. Major influencing factors on the penetration ability of calcium hydroxide solution have been established as, application method and absorption capacity of the treated material during the impregnation process. Optimization of the penetration ability of calcium hydroxide solution has been achieved by impregnating from the middle of the impregnated specimen. Sugar has been used to study the influence of additive on enhancing calcium hydroxide solubility. It has been verified that solubility of calcium hydroxide in a solution of sugar is proportional to the amount of sugar in the solution. Porosity and strength tests have been used to study the effectiveness of calcium hydroxide treatment. Under the conditions studied no appreciable change of porosity has been detected. It is postulated that the calcium hydroxide was deposited at the binder/aggregate interface and at the secondary pores. In terms of strength, evidence has been found to suggest the strength increment varies quantitively with the amount of calcite crystals deposited.
QC 20100803

Для приготування будівельної суміші і бетону широко використовують цемент, вапно і гіпс у вигляді високодисперсних попрошків, які при змішуванні з водою утворюють в’яжучетісто, тобто пластично – в’яжучу масу, яка легко формується. В’яжуча суміш поступово густішає, затвердіває і перетворюється на штучний камінь [1].

The Italian and European regions are characterized by a wide diffusion of structures in the minor historical centres. The decay condition, in which part these buildings are, makes often necessary structural interventions to preserve they integrity. This way, during last decades several new intervention methodologies were developed, employing both innovative and traditional materials, with the aim to avoid further damages, particularly those induced by seismic events. However, these new materials and techniques are often commercialized and employed without any preliminary exhaustive study to verify their applicability and their effectiveness. The present research joins in this contest considering the multi-leaf stone masonries, one of the most diffuse structural systems widely employed on minor historical buildings. This masonry typology is constituted by more approached leaves and it is characterized by a high percentage of internal voids. Furthermore, the employment of hydraulic lime-based grout injection is also considered as strengthening technique suitable for this masonry typology. This study aims to validate the application of this intervention methodology, widely applied since many years employing materials different for chemical composition, trough an extensive experimental campaign and a subsequent numerical modelling. First experimental phase involves a series of dynamic tests on whole building models, considering a reducing scale factor, realized with multi-leaf stone masonry, subsequently strengthened trough injection of grout. The execution of these shaking table tests allowed to evaluate the influence of the considered strengthening technique on the overall dynamic behaviour of the injected structure. Furthermore, also the increasing of strength and the seismic response of the building models could be evaluated. A complementary experimental phase involved several further quasi-static laboratory tests tests on single structural elements. Compression tests allowed to study the strength increasing of this elements as well as their failure mechanisms after the grout injection. Further shear compression tests provided important informations about the mechanical behaviour of single structural elements subjected to in-plane cyclic forces. Finally, a numerical modelling of the mechanical behaviour of specimens subjected to compression load was developed. This analysis allowed to deepen the study of the stress distribution and of the failure mechanisms of single structural elements subjected to strengthening trough grout injection.
Il territorio italiano, così come quello europeo, è caratterizzato da un’ampia diffusione di strutture appartenenti all’edilizia storica minore. Lo stato di degrado, in cui talvolta si trovano tali edifici, rende spesso necessari interventi strutturali volti a garantirne l’integrità. In tale senso, negli ultimi decenni sono state sviluppate nuove metodologie d’intervento, sfruttando sia di materiali tradizionali che innovativi, per preservare tali strutture da ulteriori danni, in particolare quelli indotti da eventi sismici. Tuttavia, nuovi materiali e tecniche d’intervento vengono spesso commercializzati ed applicati senza l’esecuzione di un esaustivo studio preliminare che ne verifichi l’applicabilità e l’efficacia. La presente ricerca si inserisce in questo contesto prendendo in considerazione le murature multi-strato in pietra, una delle tipologie costruttive maggiormente impiegate nell’edilizia storica minore. Tale muratura è costituita da più paramenti accostati ed è caratterizzata da un’alta percentuale di vuoti interni. Inoltre, si considera l’impiego dell’iniezione di miscela, a base di calce idraulica naturale, come tecnica di consolidamento applicabile a tale tipologia muraria. Lo studio si propone di validare l’impiego di questa metodologia d’intervento, già da tempo ampiamente utilizzata sfruttando materiali di diversa composizione chimica, mediante la realizzazione di un’ampia campagna sperimentale e di una successiva modellazione numerica. La prima fase sperimentale comprende una serie di prove dinamiche su modelli di edificio, in scala ridotta, realizzati in muratura multi-strato di pietra, successivamente sottoposta ad iniezione di miscela. L’esecuzione di tali prove su tavola vibrante ha permesso di valutare l’influenza della tecnica di consolidamento considerata sul comportamento dinamico globale della struttura su cui si interviene. Inoltre, si è potuto valutare l’incremento di resistenza oltre che la variazione della risposta sismica dei modelli di edificio. Una complementare fase sperimentale ha coinvolto numerose ed ulteriori prove di laboratorio, realizzate in ambito quasi-statico, su singoli elementi strutturali.L’esecuzione di prove di compressione ha permesso di verificare sia l’incremento di resistenza di tali elementi strutturali che la variazione delle loro modalità di rottura a seguito dell’iniezione di miscela legante. Ulteriori prove di taglio e compressione hanno fornito importanti indicazioni riguardo al comportamento meccanico di singoli elementi strutturali soggetti a forze cicliche nel piano. Infine, si è sviluppata una modellazione numerica del comportamento meccanico di campioni sottoposti a carico di compressione monoassiale. Quest'analisi ha dunque permesso di approfondire lo studio della distribuzione delle tensioni e delle modalità di rottura di singoli elementi strutturali, soggetti ad intervento di consolidamento mediante iniezioni di miscela legante.

Natural pozzolanic materials played an important role in Ancient architecture. In the last decades and nowadays it is artifical pozzolan which especially finds its use as an additive to mortar and concrete to improve some, especially the mechanical properties. This master thesis deals with study of pozzolan type of fine brick powder which is a by-product of the production of calibrated bricks. Along with studying pozzolanic activity of brick powder, lime mortar with different proportions of brick powder as an additive or replacement of lime dust are investigated. What is observed is its impact on the consistency of these mortar, water absorption, strength in time or fracture-mechanical parameters of mortar. The results may indicate the possible potential use of this source of pozzolanic admixture in lime mortar and plaster which are nowadays mainly used for the restoration of facades of historic buildings.

To produce enough food for a growing population, soil remediation is crucial unless more forests are to be cleared to make way for agriculture land. Finely ground rocks have been proposed as a soil amendment for highly weathered soils. In Chontales, Nicaragua most of the forest has been converted to cattle pasture. In fertile soils, crop agriculture is more lucrative per unit of area than cattle grazing, but the low nutrient content of Chontales soils makes it uneconomic. The purpose of the study was to examine whether incorporation of rock dust is a sustainable way to increase the fertility in Chontales and thus can be part of a strategy that encourages farmers to adopt crop agriculture as an alternative to animal husbandry. A field experiment was conducted in which basaltic rock dust and compost was applied to soil for cultivation of common beans. Three sustainability parameters were analyzed and the diffusion potential of the proposed technology was assessed. The experiment failed to confirm the positive result obtained in previous studies on yield in similar soils and no correlation between pest resistance and rock dust applications was found. The failure to produce a confident result on yield was partly due to a leaf hoppers invasion and harm caused by intruding calves into the experiment site. Rock dust was found to be typically free of toxic agents and little environmental damage is associated with the practice, provided that the source of extraction is close to the application site. The relative disadvantage in terms of social prestige and incompatibility with the current cattle oriented production system were found to be the main obstacles for diffusion of the technique in Chontales.

INTRODUCTION: Dietary factors in the form of citrus juices (e.g orange, grapefruits, cranberry, lemonade and lime) appear to affect the ability of urine to inhibit calcium oxalate crystallization. In South Africa, previous studies have demonstrated that black and white individuals respond differently to lithogenic and antilithogenic dietary supplements. OBJECTIVES: The current project was undertaken to study the inhibitory activity of lime in artificial urine and in the real urine of South African black and white subjects and also to assess the effects on urinary risk factors in these subjects after its ingestion. SUBJECTS AND METHODS: Experiments commenced with the preparation of artificial urine (AU) in which the effects of lime solutions (0.125-1.00 mglml) were tested by carrying out various crystallization experiments. These included the determination of the calcium oxalate (CaOx) metastable limit (MSL); particle volume-size distribution (PSD), nucleation, aggregation and growth assays. Crystal deposition was studied using scanning electron microscopy (SEM). In vitro experiments were then conducted in 24 hour urine samples from healthy South African black (n = 5) and white males (n = 5). The above-mentioned crystallization experiments were repeated in these urines. In addition, free Ca²⁺ values and the Bonn risk index (BRI) of CaOx crystallization were determined. Thereafter, a trial study in which 5 black and 4 white subjects ingested solutions of lime powder for 7 days was conducted. 24 hour urine samples were collected by subjects before and after the ingestion of lime. Urines were analysed for pH, sodium, potassium, calcium, oxalate, citrate, uric acid chloride, magnesium, phosphate, and creatinine. Urine composition values were used as input data for the calculation of relative supersaturation (RS) values for calcium oxalate monohydrate (COM), calcium oxalate dihydrate (COD), brushite and uric acid using the computer programme EQUIL and Tiselius Risk Index (TRI) was also determined. The above-mentioned CaOx crystallization experiments were also performed. Urine compositions, crystallization data and physicochemical risk indices were analyzed statistically using analysis of variance (ANOVA). RESULTS: None of the lime solutions did affect the CaOx MSL of the AU or the real urine (in vitro). However CaOx crystal nucleation was promoted while CaOx crystal growth and aggregation were inhibited. In the trial study, after ingestion of lime solutions, significant increases in urinary magnesium (1.80 vs 2.75 mmol/24h, p = 0.0001) and phosphate (20.9 vs 24.6 mmol/24h, p = 0.023) were observed in black subjects. On the other hand, in white subjects, a significant decrease in urinary oxalate (0.313 vs 0.205 mmol/24h, p = 0.023) and TRI (304 vs 187, p = 0.0102) were noted. However, lime did not increase citrate levels to a significant degree in either group. CONCLUSIONS: The results presented in this dissertation have shown that lime may be regarded as a potential therapeutic agent for reducing the risk of CaOx kidney stones in the white group based on the trial study. The results also provide further evidence in support of the hypothesis that there is a difference between the black and white populations with respect to their handling of lithogenic and antilithogenic dietary challenges. However, rigorous controlled trials in healthy subjects and in kidney stone patients need to be conducted in future studies to explicitly confirm these findings.

Quarrying activity usually generates significant amounts of waste. Generally, the processed quarrying production accounts for 30% of total stone extracted, whilst waste (quarrying waste and processing waste) amounts to about 70% of total stone extracted. Not only could coping with waste be environmentally damaging, but it is also economically expensive for the stone industry, which in addition has to deal with the economic loss caused by the lower efficiency of quarrying. Some re-uses of natural stone waste, such as the production of aggregates, have already been investigated, but they are not profitable for most quarrying companies. Other re-uses of stone waste are related to economic fields which are too distant from quarrying companies to foster their commitment on their re-use (such as agriculture; paper industry; etc.). In fact, they are encouraged to sell waste at increasingly lower prices so as to get rid of it, reducing landfill costs. This research identifies the re-use of stone waste in the construction industry as the most profitable use, since quarrying activity is strictly related to the building industry. Hence, quarrying companies have the necessary skills and expertise to evaluate the economic risks, thus they are more eager to undertake the production of new by-products. Therefore, the generic goal of this work is to convert natural stone waste into some by-products with a renewed environmental and economic value. To this purpose, the production of cementbased and lime-based materials such as mortars (mixtures of a binder, fine aggregates and water) was identified amongst the possible re-uses as the most suitable one, since stone waste can be reused to some extent as a substitute of the binder (cement or lime) fraction and for the production of the aggregate fraction, thus achieving a higher re-use rate. In fact, since mortars have no structural use, their requirements are far more flexible than materials such as concrete and it is possible to reuse higher percentages of waste in their manufacture. A further goal of this dissertation was to enhance the environmental advantages of re-using stone waste for the production of mortars by investigating their CO2 sequestration capacity, since a percentage of CO2 emissions from the production of mortars is reabsorbed as the mortar hardens, owing to carbonation. Indeed, Portland cement production is responsible for 7% of annual CO2 emissions, due to the calcination reaction. Nonetheless, a secondary effect of carbonation is the uptake of atmospheric CO2, which reacts with calcium hydroxide in mortars and precipitates as calcium carbonate. Although CO2 uptake figures are far from the performance of other materials (such as coal ash and industrial residues), it should be pointed out that mortars have great potential, since their use in all built-up environments is impressively widespread. Initially, the assessment of the CO2 uptake of some selected commercial mortars by means of accelerated carbonation tests was undertaken through an experimental procedure, in order that a standard methodology and a set of operative parameters could be established. Then, some mortar mixtures constituted by stone waste were manufactured and henceforth called “ecological mortars”. These mixtures underwent the same carbonation tests as the commercial mortars, so as to permit a comparison between their performance. The obtained experimental results showed that both the commercial and the ecological mortars are capable to take up CO2. In particular, despite showing fairly lower figures, the “ecological mortars” reported a carbon absorption during the first 28 days of curing exceeding 6% of that emitted in the calcination reaction occurring during the production process. Low though they may seem, this value could represent a significant amount considering the period of service life, and after the service life (i.e. after demolition) of mortars.

Sammanfattning Stendamm förekommer på alla väg och anläggningsprojekt men kunskapen om hur farligt det är att exponeras för de respirabla kvartspartiklar som stendamm innehåller är bristfällig. Det respirabla kvartsdammet kan framkalla bland annat Silikos och cancer i lungorna men även påverka hjärtat negativt då lungornas funktion blir nedsatt. Syftet med rapporten var att undersöka hur bra information och kunskap det finns om kvarts i stendamm samt hur och om olika åtgärder som exempelvis andningsskydd förekommer. Då tiden för examensarbetet är begränsat avgränsas en del informationshämtning till Skanska AB väg och anläggning i region mitt. En enkät arbetades fram och användes som metod för att ta reda på dagens kunskapsnivå hos Skanska samt hur bra Skanska informerar när det gäller kvarts. Denna skickades ut till samtliga anställda på Skanska AB väg och anläggning i region mitt. Intervjuer gjordes också med personer som har en chefsroll eller tillhör arbetsledningen inom Skanska AB. Enkätundersökningens resultat visade att kunskapen om kvarts i stendamm finns hos de flesta anställda men att informationen bör bli bättre och upprepas oftare. Resultatet visade även att användandet av andningsskydd är bristfällig då det är jobbigt att andas i och att det blir varmt att bära det en hel dag. Det framkom även att personlig andningsutrustning inte fanns att tillgå för alla som har ett behov av det. En guide togs fram som ett resultat från enkäten och intervjuer. Guiden ska hjälpa arbetsledningen med hur de kan förebygga exponering för kvartsdamm i sina projekt samt ge yrkesarbetare en information som ska påminna om de enklare sätten att skydda sig mot stendamm. Under rubriken diskussion diskuteras bland annat möjligheterna om att använda olika hygieniska gränsvärden inom olika näringsgrenar, detta för att ett sänkt gränsvärde inom väg och anläggning skulle kunna leda till hårdare arbete för en ännu bättre arbetsmiljö. Kunskapen om hur hälsan kan påverkas av respirabelt kvarts kan alltid bli bättre och det gäller särskilt yrkesarbetare som främst utsätts för stendamm. Slutsatserna för detta examensarbete blev att arbetstagare som riskerar att utsättas för stendamm bör informeras oftare, helst inför varje nyetablerad arbetsplats, samt att behovet av personliga andningsskydd med tillhörande utbildning bör överses. Vidare konstaterades att arbetsberedningen som görs i riskbedömningen bör utföras av personer som har fått en likvärdig utbildning så att tiden för arbetsberedning kan effektiviseras samt att alla arbetsberedningar blir konsekventa i sitt utförande.
Stone dust exists in all road and public work projects yet the knowledge about how dangerous exposure to the respirable quartz particles that stone dust contains is lower than what could be preferred. The respirable quartz can cause silicosis and lung cancer as well as heart diseases when the capacity of the lungs is reduced. The purpose of this project was to investigate if there is sufficient information and knowledge about quartz in stone dust in this business today. The purpose was also to realize whether there are quartz-prohibiting measures, such as the usage of breathing aid, taken or not. Because of the time-limit of this project much of the gathering of information was limited to “Skanska AB väg och anläggning, region mitt”. A survey was produced and used as a method in order to get information about the level of knowledge that Skanska employees have, as well as how good Skanska is at informing their employees, about quartz. This survey was sent to all of Skanska Sweden’s staff members in road and public works, central region. In addition to this, interviews were held with supervisors and managers in the same region. The survey results revealed that most employees have some sort of knowledge about quartz but that the information should be made more extensive and be repeated more often. The results also show that the usage of personal breathing aid is inadequate, this is because the aid is hard to breathe through and during long and warm days they’re an annoyance to wear. In addition, it was also brought to light that not everyone who needs a breathing aid have access to one. As another result of the survey and the interviews a guide was made. This guide was formed as a helping hand for the staff management when they’re making risk evaluations and work preparations but also as a short information for all staff members to make it easier for them to remember the easiest and most efficient ways to avoid and protect yourself from quartz particles. In the discussion the possibilities about lowering the hygienic limits of quartz for different parts of the economy was debated. A lowering of the hygienic limit in road and public works should lead to more work, such as this, being done towards a better work environment. The knowledge about how personal health is affected by respirable quartz can always get better and that goes especially for employees that work in direct contact with stone dust. The conclusions of this project were that employees that are exposed to stone dust should be informed more often, preferably before the start of every project, and also the need for personal breathing aid with appurtenant education should be attended to. Furthermore, the work preparations made with every risk evaluation should always be made by staff members with the same qualifications and information. Thus, all work preparations will look consistent and also, the creation of them will be more time efficient.

This diploma thesis will discuss possibilities of using nanofibres to increase the strenght of the brick body, replacement of the current schrinkage reducing agent – quartz sand by stone dust, the use of flocculants as pore-forming agent and coloration of the body using iron trioxide.

The diploma thesis describes admixtures for concrete. It deals with the influence of admixtures on the properties of cement composites in the fresh and hardened state. The theoretical part described the individual components of concrete, where the main attention was focused to inert admixtures and their effect on mechanical properties, shrinkage, resistance of cement composites to aggressive medium. Furthermore, the effect of admixtures on concretes with recycled aggregates was described. In the first stage of the practical part, cement mortars with 25, 35 and 50% replacement of cement admixtures were created. In the second stage, concretes with admixtures and a minimum strength class of C30/37 and C50/60 were created. Finely ground granulated slag, micronized limestone and granite stone dust were used as admixtures in mortars and concretes. The change of properties in the fresh and hardened state was observed on cement composites.

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A concepção de desenvolvimento sustentável tem resultado no aumento de pressões ambientais para a melhoria da eficiência na utilização de recursos, e para a redução das emissões e da geração de resíduos. No processo de fabricação de aço, nas siderúrgicas com fornos elétricos a arco (FEA), ocorre a geração do resíduo sólido denominado pó de aciaria elétrica (PAE). O PAE é constituído por diferentes óxidos metálicos. Contém os elementos químicos cromo (Cr), chumbo (Pb) e cádmio (Cd) e, por isso, é classificado como resíduo classe I – Perigoso pela NBR 10004. Gerado em grandes quantidades diariamente em todo o país, o PAE ainda tem como principal destinação final o aterro industrial. A indústria de papel e celulose, outra atividade de destaque na indústria nacional, gera uma grande quantidade de resíduos em diferentes etapas do processo, entre os quais está o resíduo do forno de cal (RFC), cuja geração está associada a interrupções no funcionamento do forno de cal. A indústria da construção civil, devido a quantidade de matérias-primas consumida e variedade de materiais empregados – cimento, concreto, agregados, cerâmica, entre outros – apresenta-se como alternativa para a reciclagem de resíduos gerados em outros setores da economia. A incorporação do PAE no cimento e concreto produz retardo no tempo de pega em razão da presença de zinco (Zn) no resíduo. Estudos sugerem que em quantidades próximas a 1%, a incorporação de PAE não afeta de forma significativa as propriedades do cimento. O objetivo deste trabalho foi avaliar a influência do uso combinado de PAE e RFC no processo de endurecimento e evolução da hidratação de pastas de cimento. Para tanto, foi realizada a caracterização dos resíduos através dos ensaios de distribuição granulométrica, perda ao fogo, massa específica, área superficial específica, análise química elementar, difração de raios X com refinamento por Rietveld e microscopia eletrônica de varredura. A influência dos resíduos nas pastas de cimento foi avaliada através do ensaio de tempo de pega de acordo com a NBR NM 65 (ABNT, 2003b) e evolução da temperatura semi-adiabática das pastas em estado fresco, além de DRX, com refinamento por Rietveld, e microscopia eletrônica de varredura nas pastas de cimento com diferentes teores de substituição de resíduos (REF, 1%, 2%, 3%, 5% e 10%) em diferentes idades (1, 4 e 7 dias). Os resultados de tempo de pega e evolução da temperatura semi-adiabática indicaram a influência do PAE na hidratação das pastas de cimento. Nas pastas de cimento com substituição de 1% de PAE combinado ou não com RFC, não foram verificados retardos significativos no tempo de pega, demonstrando o potencial do uso de PAE e do RFC na produção de artefatos de cimento.
The sustainable development conception has resulted in increased environmental pressures to improve the efficient use of resources and reduction of emissions and waste generation. In the steelmaking process through electric arc furnaces (EAF), dust generation occurs which is called electric arc furnace dust (EAFD). EAFD is composed by different metal oxides. Some common elements those constitute this dust is chromium, lead and cadmium, and therefore, waste is classified as class I – hazardous by NBR 10004. EAFD has been generated in large quantities every day across the country and it still has mainly landfilled. The pulp and paper industry, another important activity in the domestic industry, generates a lot of waste in different stages of the process, among which is the lime kiln waste (LKW), whose generation is associated with disruptions in the lime oven. Due to expressive amount of raw materials consumed in civil construction industry and also the variety of products available - cement, concrete, aggregates, ceramics, among others - this seems to be an alternative for waste recycling generated in other sectors. The incorporation of EAFD in the cement and concrete produces delayed setting time due to the presence of zinc (Zn) in the waste. Studies suggest that in amounts up to 1%, EAFD incorporation does not affect significantly cement properties. The aim of this work was to evaluate the influence of the combined use of EAFD and LKW in the process of hardening and evolution of the cement pastes hydration. Therefore, were evaluated the characterization of the waste performed through the grain size distribution, loss on ignition, specific gravity, specific surface area, elemental chemical analysis, pH, X ray powder diffraction with refinement by Rietveld and scanning electron microscopy.. The influence of the waste on the cement pastes was evaluated through the setting time tests in accordance with the NBR NM 65 (ABNT, 2003b) and evolution of semi-adiabatic temperature in fresh conditions, XRD with refinement by Rietveld, and SEM in cement pastes with different levels of waste substitution (REF, 1%, 2%, 3%, 5% e 10%) at different ages (1, 4 and 7 days). The setting time results and evolution of semi-adiabatic temperature indicated an increase in the setting time with the increase of the EAFD in cement pastes. In cement pastes with replacement of 1% EAFD combined or not with LKW, significant delays were not verified in the setting time, demonstrating the potential use of EAFD in the production of cement artifacts.

Ankur Mudgal: Geotechnical Engineering, DTU Page | 18 ABSTRACT Black cotton soil have the tendency to swell when their moisture content is increased and shrink when their moisture content is decreased. The moisture may come from rain flooding, leaking water or sewer lines or from reduction in surface evapotranspiration when an area is covered by a building or pavement. To achieve the economy and for proper performance of structures it is necessary to improve the geotechnical properties of expansive soil. Due to the for construction purpose, rubble and aggregates are high demanded rubble quarries and aggregate crushers are very common. Out of the different quarry wastes, quarry dust is one, which is produced in abundance. About 20–25% of the total production in each crusher unit is left out as the waste material-stone dust. Bulk utilization of this waste material is possible through geotechnical applications like embankments, back-fill material, sub-base material and the like. Lime treatment of soils is a proven method to save time and money on construction projects. Lime drying of wet soils minimizes weather-related construction delays and permits the return to work within hours. Lime modification chemically transforms clay soils into friable, workable, compactable material. Lime stabilization creates long-term chemical changes in unstable clay soils. For our project work we collected Black cotton soil sample from shivpuri (M.P). About 125 Kg soil sample was brought by us to soil mechanics lab for carrying out our project work. In this project the results of an experimental program undertaken to investigate the effect of stone dust & lime combined at different percentage with expansive soil, the test results such as X-ray diffraction analysis, scanning electronic microscopic, index properties, Proctors compaction, differential free swelling test and unconfined compression strength, California bearing ratio obtained on expansive clays mixed at different proportions of lime and stone dust admixture are presented and discussed. From the results, it is observed that at optimum percentages, i.e., 6% lime +25 % stone dust , it is found that the swelling of expansive clay is almost controlled and also noticed that there is a marked improvement in the other properties of soil. The conclusion drawn from this investigation is that the combination of equal proportion of stone dust and lime is more effective than the addition of stone dust/lime alone to the expansive soil in controlling the swelling behavior

Black cotton soil have the tendency to swell when their moisture content is increased and shrink when their moisture content is decreased. The moisture may come from rain flooding, leaking water or sewer lines or from reduction in surface evapotranspiration when an area is covered by a building or pavement. To achieve the economy and for proper performance of structures it is necessary to improve the geotechnical properties of expansive soil. Due to the for construction purpose, rubble and aggregates are high demanded rubble quarries and aggregate crushers are very common. Out of the different quarry wastes, quarry dust is one, which is produced in abundance. About 20–25% of the total production in each crusher unit is left out as the waste material-stone dust. Bulk utilization of this waste material is possible through geotechnical applications like embankments, back-fill material, sub-base material and the like. Lime treatment of soils is a proven method to save time and money on construction projects. Lime drying of wet soils minimizes weather-related construction delays and permits the return to work within hours. Lime modification chemically transforms clay soils into friable, workable, compactable material. Lime stabilization creates long-term chemical changes in unstable clay soils.For our project work we collected Black cotton soil sample from shivpuri (M.P). About 125 Kg soil sample was brought by us to soil mechanics lab for carrying out our project work. In this project the results of an experimental program undertaken to investigate the effect of stone dust & lime combined at different percentage with expansive soil, the test results such as X-ray diffraction analysis, scanning electronic microscopic, index properties, Proctors compaction, differential free swelling test and unconfined compression strength, California bearing ratio obtained on expansive clays mixed at different proportions of lime and stone dust admixture are presented and discussed. From the results, it is observed that at optimum percentages, i.e., 6% lime +25 % stone dust , it is found that the swelling of expansive clay is almost controlled and also noticed that there is a marked improvement in the other properties of soil. The conclusion drawn from this investigation is that the combination of equal proportion of stone dust and lime is more effective than the addition of stone dust/lime alone to the expansive soil in controlling the swelling behavior.

Dusting is one of the major problems in the operation of lime kilns because dust particles interfere with kiln operation and reduce its efficiency. A numerical model is developed to predict the rate of dust formation in rotary lime kilns. The model consists of four major components: 1) a 3D model for the kiln gas, solving fluid flow, heat transfer, and combustion in the gas region; 2) a 1D model for the kiln bed, solving for variation of the solids composition, including moisture content, along the kiln; 3) a 3D model to predict the motion of the solids in the bed, and to estimate the reaction rates; 4) a mathematical model to predict the rate of particle pickup from the bed. Additionally, motion of dust particles was modeled, for the first time, using Stochastic Separated Flow model (a Lagrangian approach). The developed model of particle tracking enables the user to predict distribution of dust particles in the gas section of the kiln. Different components of the model were validated using experimental data published in the literature. The developed model was used to simulate operation of a full-scale lime kiln at typical operating conditions, i.e. at different fuel and air flow-rates. Dusting signatures were also estimated for each setting to determine the effect each operating condition has on dusting. The results presented in this thesis indicate that dust formation is mainly affected by the kiln gas velocity. Effect of other operating conditions was found to be negligible within the ranges studied. The results presented here suggest that dust formation can be controlled by minimizing the input gas flow rate.

With increased population their need and necessities also increasing day by day and to fulfill their needs industry ,urbanization are growing at a rapid rate and to provide energy various power plants as thermal, nuclear, hydro power plant also increasing. Due to rapid industrialization and power plant produces wastes which are a hazard to society such as Kota stone dust and Fly ash. Kota stone dust is a waste by product of Kota stone mines, Kota stone finishing industries. This waste product is disposed in river, on inhabited land area or on river sides. With wind or water this waste moves from their parent location and may come in contact with human and vegetation’s and cause pollution, gives inhalation problem and various diseases. To find out any kind of engineering use of this ecological hazard an attempt is made by mixing Kota stone dust with different proportion with expansive soil. This mix was tested for various engineering properties such as Atterberg’s limit, Standard proctor test and unconfined compression tests are performed. To compare the economy of Kota stone dust we did the all test as atterberg’s limit, standard proctor test, unconfined compression test are performed on samples formed by mixture of soil, Kota stone dust and fly ash in different proportion. Addition of Kota stone dust and fly ash both show increase in UCS value, increase in maximum dry density an decrease in optimum water content takes place.

A dissertation submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in fulfillment of the requirements for the degree of Master of Science in Engineering
Regulation 10.24 of the Minerals Act (1991) of the Republic of South Africa is applied for the purpose of preventing the development and propagation of coal-dust explosions in underground coal mines. ( Abbreviation abstract )
AC2017

This project report shows the result of laboratory study to investigate Kota stone dust mixing with black cotton soil and its effect on index properties of black cotton soil. Black cotton soil is very weak soil to bear the load of the structure and contains swelling and shrinking and highly compressible properties whenever change in water content takes place. So it is required to make it suitable for construction activities. So that improvement of black cotton soil is required with the mixing of admixture like as Kota stone dust. The essence of this project is to check out the feasibility of Kota stone dust as soil stabilization material. Number of laboratory experiments is required to investigate the effect of Kota stone dust with black cotton soil with the different proportion of it with 0% to 30% in the interval of 5%. Test results represent a quite change in consistency limit or Atterberg’s limit. Liquid limit decreases from 53.26% to 37.8%. Plastic limit changes from 29.76% to 29.12% with a very slight change in mixed proportion of soil. Liquid limit and plastic limit of black cotton soil decreases with increase in proportion of Kota stone dust. A big change is found in liquid limit but slight change in plastic limit takes place so overall plasticity index which shows plasticity behavior of soil also decreases up to a great extent. Plasticity index decreased from 23.5% to 8.68% with the addition of Kota stone dust from 0% to 30%. The differential free swell index decreased from 64.24% to 39.82% which shows that a reduction in swelling property of soil due to increase in the proportion of Kota stone dust which is a pozzolanic material and exerts friction in it due to coarser size particle of pozzolanic Kota stone dust. The unconfined compressive strength of soil is found maximum when Kota stone dust is mixed 10-20% with black cotton soil. The unconfined compressive strength of soil increases up to a certain limit after that it decreases. We found maximum UCS strength at the mixing of 15% Kota stone dust. Black cotton soil showed good UCS strength in the range of 10- 20% Kota stone dust. When soaked CBR test was performed so that improvement in CBR value was found maximum within the range of 20-25% mixing of Kota stone dust, it gives maximum CBR value so it is desirable to mix Kota stone dust in black cotton soil with a proportion of 20- 25% of mixing. CBR value mainly shows the soil behavior according to highway projects so Kota stone dust is useful in highway pavement design because it shows pozzolanic behavior of soil and frictional properties that causes good binding found in soil. Kota stone dust mixing with black cotton soil increases its maximum dry density in the range of 15-25% mixing of Kota stone dust. We found that in the range of 15-25% Kota stone dust maximum compaction of soil occur So it is helpful to make the soil dense by providing proper compaction and maximum dry density of soil. Standard Procter test was performed with heavy compaction during experiments so that it was found that dry density of soil increases up to a particular proportion of Kota stone dust in the range of 15-25% but continuous increase in water content was found with increase in its proportion. So a range of 15-25% is batter to make a highly compacted and dense soil. So that lots of experiment has conducted during this project and results are positive to stabilize soil by mixing of Kota stone dust mainly in the range of 15-20%. This range shows best mixture of kota stone dust with black cotton soil because all the laboratory results are giving satisfactory improvement in the geotechnical.

The health risk of breathing very fine particles of respirable crystalline silica (RCS) dust, resulting in poor lung health is not well defined in Australia, even though many hundreds of thousands of workers are exposed to uncontrolled dusty activities daily. It is now clear from international studies that lung health of workers continues to be affected at relatively low exposures to RCS, even at occupational exposure limits (OEL) including the current Safe Work Australia Exposure Standard (SWA-ES). This has prompted the United States to reduce their permissible exposure limit (PEL) to one half of the Australian SWA-ES, to 0.05 mg/m3, and challenges the adequacy of the current Australian SWA-ES, which is 0.1 mg/m3. In terms of numbers of workers affected, the mining industry employs approximately 267,000 workers, which is 2.3 percent of the total workforce, and accounts for about 10.2 % of Australia’s Gross Domestic Product (GDP). Approximately 55,000 workers are employed in Queensland mining, many of whom work in quarries and dimension stone mines where exposure to RCS is known to be elevated. A recent assessment estimated that about 440,000 deaths from cancer attributable to RCS exposure will occur throughout Europe from 2010 to 2069. Unless exposure to RCS is well controlled, many hundreds of thousands of lives will also be cut short from silicosis and chronic obstructive pulmonary disease (COPD). As the weight of evidence grows in Australia, the disease risks attributable to RCS will increasingly become more obvious. This study evaluated the health risk from exposure to RCS for 47 quarry and dimension stone mine workers throughout Queensland, Australia. Personal exposures to RCS were measured across a range of exposures, and lung function testing was carried out in parallel. Findings revealed that about one in four workers were exposed to RCS above the SWA-ES, and more than one in ten were being exposed at a concentration of more than twice this limit. A major finding for those workers exposed to RCS at the SWA-ES was loss of lung function greater than 20%. The increased loss of lung function was positively correlated with jobs associated with increased RCS exposure. When similar exposure groups were combined into three RCS exposure ranges categorised as high (≥ 0.09 - ≤ 0.20 mg/m3), medium (≥ 0.04 - ≤ 0.08 mg/m3) and low (< 0.04 mg/m3), analysis of variance (ANOVA) confirmed that the loss of lung function below the lower limit of normal (LLN) at the current SWA-ES, is significant (p < 0.05). Abnormal lung function patterns were also more pronounced for smokers who were exposed to RCS ≥ 0.04 mg/m3 and not as obvious for smokers exposed to RCS < 0.04 mg/m3. This demonstrated that both smoking and RCS had a combined impact resulting in poor lung health. In this study, vehicles fitted with standard heating, ventilation and air-conditioning systems (HVAC) were tested for ingress of respirable dust into the operator’s cabin, and compared with more recent technology. Evaluation of the effectiveness of newer technology, a RESPA® pre-cleaner, filter and pressurization (PFP) unit, demonstrated up to a four-fold reduction in RCS entering the cabin, when compared with standard air-conditioning systems. Electron microscopy (EM) was used to describe the physical characteristics of respirable silica and dust particles collected on respirable sample filters previously analysed for silica by infrared spectroscopy. Data revealed that silica particles were generally less than 5 μm in physical diameter and many particles were elongated. These smaller particles are known to be most hazardous to lung health. Findings also demonstrated that larger length elongated particles were collected by the cyclone sampler, which influenced the particle size distribution curve. There was a good fit between the physical cumulative silica particle size distribution, representing particle counts for selected workplace samples, when plotted against the theoretical AS2985-2009 (density dependent) Equivalent Aerodynamic Diameter (EAD) sampling efficiency curve. This means that density is not the only factor for particle capture in the cyclone sampler. These silica particles do not behave as perfect spheres, which is the premise underpinning the International Organization for Standardization (ISO) 7708-1995, sampling efficiency curve and AS2985-2009, adopted by the Australian Standard for sampling respirable dust. The science for these standards is based on information that is at least twenty years old, and results from the current study confirmed that particle shape must be considered in the sampling efficiency curve and lung health risk assessment. An unexpected finding from analysis of RCS dust by EM was the identification of fibrous mineral particles in several samples, with both morphology and elemental composition similar to erionite. Erionite is known to cause mesothelioma, which is typically associated with asbestos when inhaled at high enough concentrations. Further investigation and characterization of respirable dusts at mining sites where erionite is a potential contaminant is recommended. Confirmation of the presence and extent of erionite, and further characterization of exposure will assist in determining the extent of health risk to quarry and dimension stone mine workers in Queensland and elsewhere. Overall, the findings from this study challenge the adequacy of RCS health risk assessment standards in Australia. In addition, typical operator cabin air-conditioning technology will not reduce exposure to RCS where silica is present in dusty workplaces. The study also demonstrates the importance of health surveillance, to identify gaps, raise awareness about primary prevention, and drive timely intervention.

Dissertação de Mestrado Integrado em Arquitetura apresentada à Faculdade de Ciências e Tecnologia
O tema escolhido para esta dissertação surge após a minha participação nas Oficinas de Muhipiti, realizadas na Ilha de Moçambique, em Julho de 2017. O evento decorreu com a composição de vários grupos de trabalho e eu integrei o grupo responsável pela proposta de Estratégias para o Desenvolvimento Sustentado da Ilha. A minha dissertação consiste num complemento ao trabalho realizado nas Oficinas, através do desenvolvimento de um dos eixos estratégicos propostos pelo grupo. O eixo escolhido incide na promoção do património cultural, de modo a permitir que as caraterísticas que definem a Ilha de Moçambique contribuam para a melhoria da qualidade de vida de quem lá habita.A Ilha de Moçambique possui património edificado, cultural e paisagístico com potencial para o usufruto turístico. O turismo contribui para o bem-estar da população, tornando-se uma atividade económica com potencial para a melhoria da economia interna. O envolvimento da população será essencial para a concretização da proposta de Desenvolvimento Sustentado focada no turismo cultural e para que lhe seja possível usufruir dos benefícios decorrentes dessas ações na Ilha. Através da análise de exemplos de estratégias do turismo cultural e criativo, executadas em Zanzibar, na Tanzânia e em África do Sul, e da compreensão da importância da potencialização do turismo para o desenvolvimento da Ilha, propõe-se uma estratégia de intervenção que pretende “Ancorar a Ilha” ao desenvolvimento. Assim, definem-se medidas e ações para melhorar as acessibilidades, melhorar a divulgação do turismo e conseguir o envolvimento da população.
The subject chosen for this dissertation comes after my participation in the Oficinas de Muhipiti, held on the Island of Mozambique, in July 2017. The event was composed of several working groups and I was part of the group responsible for the proposed Strategies for Sustainable Development of the Island. My dissertation is a complement of the work carried out in the Oficinas, through the development of one of the strategic axes proposed by the group. The chosen axis focuses on the promotion of cultural heritage, to allow that Island of Mozambique characteristics contribute to the improvement of the quality of life of those who live there.The Island of Mozambique has built, cultural and natural heritage with tourism potential. Tourism contributes to the well-being of the population, by becoming an economic activity with potential for improving the internal economy. The involvement of the population will be essential for the implementation of the Sustainable Development proposal focused on cultural tourism and for it to be able to enjoy the benefits derived from these actions in the Island.Through the analysis of examples of cultural and creative tourism strategies, implemented in Zanzibar, Tanzania and South Africa, and by understanding the importance of tourism potentiation for the development of the Island, an intervention strategy that intends to "Ancorar a Ilha" to the development is proposed. Thus, actions are defined to improve accessibility, dissemination of tourism and the involvement of the population.

abstract: Chloride solutions have historically been used to stabilize roads and to prevent dust; however, very little work has been done on investigating the soil stabilizing benefits from interactions between salt solutions and different soil types. The primary goal of this research was to analyze the feasibility of utilizing a salt waste product as an economically and environmentally responsible means of dust control and/or soil stabilization. Specifically, this study documents an investigation leading to the understanding of how the addition of saline based waste products, when using a soil stabilizer, modifies the strength behavior of soils. The scope of work included the evaluation of current literature, examination of the main challenges meeting relevant governmental regulations, and exploring the possibility of using saline waste to improve roadways. Three soils were selected, treated with varying amounts of salt (calcium chloride, CaCl2), and tests included soil composition and classification, correlation of soil characteristics and salt, and obtaining strength parameters that are typically used in pavement design and analysis. The work effort also included the determination of the optimum dosage of salt concentration for each soil. Because Lime treatment is also commonly used in soil stabilization, one of the soils in this study included a treatment with Lime for comparison purposes. Results revealed that when salt concentration was increased, a decrease in the plasticity index was observed in all soils. A modest to considerable strength gain of the treated material was also observed for two of the soils; however, a strength loss was observed for the third soil, which was attributed to its low clay content. When comparing the soil corrosive potential, the additional salt treatment showed promise for increasing strength, to an extent; however, it changes the chemical properties of the soil. The soils prior to treatment were corrosive, which could be managed with appropriate techniques, but the salt increases the values to levels that could be potentially cost prohibitive if salt was used by itself to treat the soil. The pavement design and performance investigation revealed that the Vineyard soil treated at 16% CaCl2 had an improvement that is comparable to the Lime treatment. On the other hand, the Eager soil showed very little pavement performance improvement at 8% CaCl2; this goes back to the effect of acid on the clay mineralogy. It was also postulated that using salt by-products to stabilize highway shoulders could be beneficial and save a lot of maintenance money when it comes to cleaning unwanted vegetation. A salt saturated soil structure could help in dust control as well. Future environmental challenges for salt leaching that could affect agriculture in developing countries will still need to be carefully considered. The chlorine levels in the soil would increase, and if not treated, can potentially have corrosive effects on buried structures. Future research is recommended in this area and to also evaluate soil stabilizing properties of varying proportions of Lime and salt using the approach provided in this study.
Dissertation/Thesis
Doctoral Dissertation Civil, Environmental and Sustainable Engineering 2017