Littérature scientifique sur le sujet « MIX CLAY »

This paper studies the process adaptability of reclaimed clay sand with core sand, and discovers that the reclaimed clay sand with furan resin self-setting sand can be used to mix the water-glass sand and hot core box sand; but it can not be used to mix the cold core box sand and coated sand. The reclaimed clay sand with water-glass sand can not be used to mix the hot core box sand, cold core box sand and coated sand; the reclaimed clay sand with hot core box sand can be used to mix the water-glass sand, cold core box sand and coated sand; the reclaimed clay sand with cold core box sand can be used to mix the water-glass sand, coated sand and hot core box sand. The reclaimed clay sand with coated sand can be used to mix the water-glass sand, but when it is used to mix the hot core box sand and cold core box sand, it can meet general requirements of the casting production; the completely reclaimed clay sand can not be used to mix the resin self-setting sand.

Aflatoxin occurrence in poultry feed causes aflatoxicosis in birds and poses health hazards to the consumers. Aflatoxin B1 (AfB1) is the most predominant and toxic metabolite that is controlled through addition of argillaceous clays as non-nutritive additives. Non-smectitic indigenous clay reserves need testing as AfB1 adsorbent. With detailed mineral and adsorption characteristics, three indigenous non-smectitic clays: (i) palygorskite, (ii) palygorskite-smectite mix, and (iii) interstratified smectite with hydroxy interlayered smectite were tested against 250 µg kg-1 AfB1 contamination in a poultry feeding trial with three replications at 1% and 2% (w/w) with positive and negative controls. A total of 330 Ross-308 male broiler chicks, initially reared on clean feed under controlled conditions of light and humidity, were distributed into eleven treatment combinations in a completely randomized design with 30 birds in each treatment on an equal weight basis with three replications at day 14 and fed on experimental feeds for three weeks. Three birds from each pen were randomly slaughtered at day 35 and for each replicated treatment, body weight gain, feed intake, and internal organs weight and morphology were recorded. AfB1 contamination reduced weight gain (p 0.0001), feed conversion ratio (p 0.0001) and feed intake (p 0.0001) while clays addition in the toxin feed effectively controlled AfB1 toxicity as suggested by improved body weight, weight gain rate and feed consumption compared to the toxin fed birds. The liver morphology was comparatively better in palygorskite-smectite mix treatment when applied at 1% and the darkish colour was also improved with addition of the clay in the toxin feed. AfB1 feeding caused a 75% reduction in weight gain compared to the clean feed. Palygorskite and palygorskite-smectite mix clays were better than interstratified clay in increasing weight gain and caused a 60% and 65% increase over toxin feed treatment when applied at 1% and 2%, respectively. In conclusion, the indigenous clay sources overall and palygorskite-smectite mix in particular has the potential for use as a mycotoxin binder for controlling AfB1 incidence in poultry

The research program developed by the authors and presented in this paper designate the Bahlui clay Romania fitting the clays with specific behaviour such as the Addis Ababa clay, London clay, Dharwad clay, New Yorkshire clay, Ankara clay and Weald clay. Its behaviour is mainly characterized by high swells and shrinkages at moisture variations. The utilization of the Bahlui clay as good foundation soil or material for compacted soil cushion required the determination of the parameters characterizing its behaviour during moisture variation: swell-shrinkage, compressibility and respectively shear strength. The research experiments to define the physical and mechanical behaviour of the Bahlui clay were performed on both natural and remoulded samples with 2.5÷10% mix from the dry soil mass with Portland with/or eco-cement. The paper presents graphs and tables displaying the Portland/eco-cement stabilization influence on the main physical and mechanical indices characterizing the Bahlui clay behaviour during moisture variations as well as conclusions its usage.

As part of the Canadian Nuclear Fuel Waste Management Program, Ontario Hydro has, over several years, conducted research into the behaviour and performance of buffer–backfill for the proposed nuclear fuel waste disposal vault. In this paper, a review has been made of laboratory studies made at Ontario Hydro on the thermal properties, strength, hydraulic conductivity, and compactability of clay-based buffer materials. The results of this work have enabled the formulation of selection criteria for the buffer material mix for the prototype Canadian nuclear fuel waste disposal scheme. Key words: bentonites, buffer, backfill, nuclear waste disposal, thermal conductivity, clays, hydraulic conductivity, compaction, clay barriers, clay seals, shrinkage.

Clay shale merupakan batuan lunak yang memiliki potensi masalah pada kekuatan dan durabilitas bila tersingkap. Perbaikan tanah diperlukan bila digunakan sebagai lapis dasar jalan. Salah satu metodenya adalah stabilisasi menggunakan semen. Penelitian ini bertujuan untuk mengetahui perbandingan nilai CBR dan pengembangan clay shale sebelum dan sesudah penambahan semen. Semen yang ditambahkan sebesar 10% dari berat total tanah kering. Semen dicampur dengan metode dry mix dan spray mix. Pengujian CBR menggunakan 3 variasi pemadatan yaitu 10, 25, 56 kali pukulan. Hasil penelitian menujukkan bahwa penambahan semen 10% pada 56 pukulan akan meningkatkan nilai CBR 38,40% dan menurunkan pengembangan 0,60%. Nilai CBR dengan metode dry mix lebih tinggi dibandingkan dengan metode spray mix.Clay shale is a soft rock that has potential problems in strength and durability when exposed. Soil Improvement Required when used as the subgrade. One of the repair methods is stabilization using cement. This study aims to determine the value of CBR and clay shale swelling after the addition of cement. Cement added by 10% of dry soil weight. The cement is mixed by dry mix and spray mix methods. CBR testing uses three variations of compaction 10, 25, 56 blows. The results showed that adding 10% cement and 56 blows increased the CBR value by 38.40% and decreased the swelling by 0.60%. The CBR value with the dry mix method is higher than the spray mix method.

The present study involved assessing the replacement of fine aggregate in the mortar with sustainable local materials like clay bricks and glass included 168 specimens (cubes and prisms). Seven mixtures were cast for this work, one control mix (R1) with 100% natural sand whereas mixes from R2 to R5 have 10% and 20% replacing natural sand with waste clay bricks and waste glass separately and respectively. Mix R6 was included 20% replacing sand with combination waste materials (10% waste clay bricks with 10% waste glass). Mix R7 has involved the same percent of replacing the previous mix R6 but with adding Polypropylene fibers 1% by volume. The samples have put in an electrical oven for one hour at 200, 400, and 600 ᵒC then cooled to room temperature to be tested and compared with samples at normal temperature 24 ᵒC. Different mechanical tests were adopted involved flow tests, density, weight loss, compressive strength, flexural strength, and water absorption. The results at different temperatures were discussed where many findings were specified. The flexural strength at 400 ᵒC was showed improving by 56% for 20% waste clay brick and 69% with 10% waste glass, as well all combination mixes illustrated higher strength than the control. Doi: 10.28991/cej-2021-03091729 Full Text: PDF

Highbush blueberry is adapted to well-drained sandy soils containing some organic matter, but these are often unavailable in many areas where blueberry production is desired. I tested the concept of using freely available by-products to produce an artificial medium for growing blueberries. In June 1997, 1-year-old tissue-cultured plants of `Bluecrop' and `Sierra' blueberry were planted into 15-L plastic pots filled with soil or soilless medium in a total of 10 treatments. Soils used were Berryland sand (alone) and Manor clay loam (alone or amended with 25% or 50% compost mix 1); soilless media were composed of coal ash amended with 25% municipal biosolid compost (B), 25% leaf compost (L), 25% or 50% compost mix 1 (1 B: 1 L),\ or 25% or 50% compost mix 2 (1 compost mix 1: 1 acid peatmoss). pH of all mixes containing compost was adjusted to ≈4.5 with sulfur. After the first year, plants of both cultivars in Berryland sand had significantly more shoot growth than in any other treatment except for Manor clay loam. The least growth was produced by plants growing in Manor clay loam amended with compost mix 1 and in coal ash amended with unblended compost (B or L). After the second year, plants in the best treatments were 90 to 100 cm tall. More shoot growth was produced by plants in Berryland sand and in coal ash amended with 25% or 50% of compost mix 1, followed by plants in coal ash amended with 50% compost mix 2 or 25% compost B; plants in Manor clay loam, whether or not amended with compost, had the least growth. In 1998, 95% of the plants flowered and most set fruit, but differences among treatments were not significant. `Sierra' plants produced more growth than those of `Bluecrop' in all treatments.

Phosphate rock is a key component in producing fertilizer and many other economically important products. Getting phosphate rock out of the ground produces a by-produce called phosphate clay, which mining operations must return to the landscape. However, phosphate clay retains large amounts of water, making them unsuitable for use as farmland or wildlife habitat. This 6-page fact sheet explains how using a sand-clay mix can more efficiently restore the landscape and put it to beneficial use. Written by Casey Beavers, Edward A. Hanlon, Matt Wilson, James “Bud” Cates, and George J. Hochmuth, and published by the UF Department of Soil and Water Sciences, July 2015.

Orientadores: Miriam Gonçalves Miguel, Gladis Camarini
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo
Made available in DSpace on 2018-08-19T22:52:46Z (GMT). No. of bitstreams: 1 Dias_DeboraRegina_M.pdf: 5560763 bytes, checksum: 51614110f36c40f8f18bd356accee7ea (MD5) Previous issue date: 2011
Resumo: Este trabalho vem contribuir com a técnica de tratamento de solos moles por meio do sistema de estabilização Dry-Mix, analisando parâmetros de resistência à compressão não confinada de corpos-de-prova, devidamente preparados com misturas plásticas de solo mole, aglomerante (cimento Portland) e água, em laboratório. O solo utilizado era oriundo da região da Baixada Santista, localizada no Estado de São Paulo. Duas diferentes dosagens de cimento, 100 e 200 kg de cimento por m³ de solo, além de dois diferentes tipos de cimento CP III e CP V, foram utilizadas neste estudo. Os corpos-deprova foram ensaiados à compressão não confinada nas idades de cura de 7, 28, 90 e 180 dias, e submetidos aos ensaios de ultrassom, durante 28 dias. As dosagens inferiores a 100 kg de cimento por m³ de solo apresentaram resultados de resistência à compressão não confinada inferiores a 200 kN/m², não sendo recomendadas para o tratamento Dry-Mix. Os módulos de elasticidade apresentaram valores crescentes até a idade de 28 dias, indicando perda da rigidez após essa idade de cura. Nos ensaios de ultrassom, foram observados resultados significativos somente para os corpos-de-prova com a dosagem de 200 kg de cimento por m³ de solo. Os resultados de resistência à compressão simples foram submetidos a uma análise estatística, na qual as médias dos resultados foram comparadas com o tipo de cimento, a dosagem, a quantidade de turfa e a idade dos corpos-de-prova, utilizando o teste de Tukey, ao nível de 95% de probabilidade estatística. No geral, os melhores resultados ficaram por conta do cimento CP V - ARI, e com a dosagem de 200 kg de cimento por metro cúbico de solo
Abstract: This work focuses on contributing with the soft soil treatment through the use of Dry-Mix stabilization system, analyzing the parameters of unconfined compressive strength tests performed in specimens properly prepared with plastic mixtures of soft soil, binder (Portland cement) and water, in laboratory. The soil used was from Santos city, located in the state of São Paulo. Two different amounts of cement, 100 and 200 kg per cubic meter of soil, as well as two different kinds of cement: CP III and CP V cement were used in this study. The tests were conducted under unconfined compressive strength at ages 7, 28, 90 and 180 days and underwent ultrasound tests for 28 days. The amounts below 100 kg of cement per m³ presented unconfined compressive strength results under 200 kN/m², which are not recommended for Dry-Mix treatment. The modules of elasticity presented increasing numbers up to the age of 28 days, indicating rigidity loss after this age. In the ultrasound tests, significant results were observed only in the test with the amount of 200 kg of cement per soil m³. The simple unconfined compressive strength results underwent a statistic analysis, in which the result averages were compared according to the type of cement and amount, as well as the amount of peat and the tests ages, by using the Tukey's range test at 95% of statistical probability. In general, the best results were presented by the CP V - ARI cement, with the amount of 200 kg cement per m³ of soil
Mestrado
Geotecnia
Mestre em Engenharia Civil

Bricks are traditional building materials with ancient origin, but that can respond to the important challenges the industrial research is currently called to face, i.e. in reducing energy consumption, in lowering production costs and in improving physical properties and durability of the finished products. The growing demand for a sustainable production addressed research to obtain new materials designed to meet environmental issues and society welfare. A possible way to achieve these goals and satisfy these different aspects is the optimisation of new mix design, re-using waste materials produced from industrial, urban and excavation activities. The fulfilment of a sustainable production is twofold, determining a reduction in the exploitation of new geo-resources, and mitigating the problem of waste accumulation and management, reassessing residual materials as secondary sources for a new environmental-friendly material production. Although numerous studies have been carried out in the last decades addressing waste reuse as a successful alternative resource in the production of bricks, their implementation in the industrial sector is still very limited. The main reasons are: i) sporadic partnership between academic research and industry in this technological area; ii) lack of specific standards for the evaluation of processes and finished products; and iii) limited public education on the possible sustainable frontiers. Another important issue should be considered in the production of new materials: the maintenance of the aesthetic quality when substituting traditional materials. Bricks are building materials, and innovation should respect parameters such as the "cultural compatibility", understood as the recognition of the territorial identity of a community. This aspect has even of greater relevance when bricks are used as integration or replacement materials in the restoration of damaged historical buildings. This work aims at filling the gap between academic research and industrial development, through a close collaboration between university and industry and the achievement of common objectives. This was possible with the support of a leader company in the production of traditional bricks, SanMarco-Terreal srl (Noale, Italy), which contributed offering technical support, raw materials and consolidate experience in the production of traditional bricks. New mix designs have been developed according to the objectives of Horizon 2020, (https://ec.europa.eu/programmes/horizon2020/), particularly in the field of sustainable use of natural resources, optimization of firing conditions, recycling and gas emission control, in order to satisfy the goals related to the scientific excellence, the societal challenges and the industry leadership. Therefore, the study focused on: 1) the relationship between chemical-mineralogical characteristics and mechanical properties and durability under different stress conditions of bricks already on the market, obtained by different clays and fired at different temperatures (600, 950, 980, 1050°C); 2) the characterisation of the pore system in commercial bricks using a multi-analytical approach, in order to fully understand and describe porosity through a parameterization of the morphological characteristics of pores. This study was also addressed to the optimization of the pore system in fired bricks obtained from different raw materials and fired at different temperatures (600, 950, 1050°C), providing hints for the optimisation of production strategies that can affect the pore system and the brick quality; 3) the study of new mix designs obtained by adding waste material from quarrying activities and industrial sludge for the production of new bricks based on the concepts of reuse and sustainable use of natural resources. The type of waste specifically adopted were: i) trachyte fragments from quarrying activity (Euganean Hills, Italy); ii) sludge resulting from the ceramic industry. The study of the commercial bricks showed that the chemical-mineralogical and physical-mechanical properties, the porosity and the durability of the finished products are highly dependent on the raw material composition and the firing temperatures reached during the production process. The results obtained for the new experimental products demonstrated the real possibility to achieve new bricks reusing waste, maintaining the physical, mechanical and aesthetic features of the traditional materials and improving the quality of the finished product. More in detail, commercial bricks fired at temperature of 1050°C showed considerable mineralogical transformations, with the growth of new phases and a higher vitrification process in the matrix, which determined improvement of the mechanical properties. On the contrary, brick fired at 600°C had good water behaviour, but resulted weaker during accelerated ageing tests. This behaviour is due to the low compactness determined by the absence of vitrification in the matrix and the low rate of new phase crystallisation. Moreover, it was observed how hausmannite (Mn3O4) used as a dye, caused changes not only in the aesthetic aspect of the finished product determining a dark grey colour, but also in its mechanical properties and in the porous system, since it promotes the melting process. The detailed study of the porosity allowed knowing the pore system in each of the samples and assessing the influence of the raw materials and firing temperature on the development of the pore system. Bricks produced with carbonate clay showed higher porosity and pore interconnection due to the decomposition of the carbonate during the firing process. Moreover, in the bricks fired at higher temperatures (1050°C) changes in the morphology of pores occurred, which became larger and rounder due to the release of volatiles. On the contrary, in bricks obtained from the least carbonate clay and fired at 600°C, porosity displayed very different features, with less homogeneous and smaller pores. In the study on the influence of the waste materials used in the production of new bricks, two different cases were considered: i) addition of stone waste from trachyte quarrying activity; ii) addition of ceramic sludge. These materials were added as temper; influence on the physical-mechanical properties and durability were investigated. Results were satisfactory, recognising their potentiality as possible sustainable additives in the brick industry. It was observed that the alkali feldspars in trachyte act as fluxing agents and decrease the melting point. This effect was emphasized with different observations: textural and mineralogical analyses showed a considerable increase of the number of bridges among minerals and a wider recrystallization of the matrix, sonic data an overall increase in compactness, porometry a different evolution of the pores system upon firing. These changes developed not only at increasing temperature, but also at increasing trachyte content. Furthermore, the analysis of the thermal properties, carried out on infrared images showed that the increasing content of trachyte reduces heat transmittance. Only in one case (a brick with 15% of trachyte and fired at 1050°C) an increase in heat transmittance was observed, caused by the high degree of sintering achieved. In general, the good response to stress conditions (under freeze-thaw and salt crystallization cycles) and the relatively homogeneous features among the samples showed that trachyte can be considered as a valid alternative material to the currently used temper which also brings technical advantages. One important result is that the addition of a trachytic temper confers to bricks the same technical features of traditional ones already at a temperature as low as 900°C, opening the possibility to the reduction of production costs, in addition to that of exploitation and use of new geo-resources. The use of sludge from ceramic industry also showed satisfactory results. Colorimetry proved that these bricks have aesthetic characteristics very similar to those of bricks already on the market, as well as mechanical properties determined by uniaxial compressive and ultrasonic tests. Nonetheless, differences arose when durability was evaluated. While during the salt crystallisation tests the experimental bricks preserve almost intact their original appearance and mechanical properties, they resulted to be particularly vulnerable to freeze-thaw cycles. This suggests that they may represent a valid substitute of commercial bricks, but caution should be taken when using in cold climates. PhD thesis is an important starting point to address the improvement of the traditional bricks in a sustainable way, and the assessment of the characteristics for new materials derived from industrial wastes, evaluating quality and durability. Both case studies demonstrated that the reuse of industrial waste could indeed sustain the industrial sector of brick production, providing a reduction in the exploitation of geo-resources, energy consumption and costs. The comprehension of the intrinsic relationships between mineralogical composition, textural features and physical properties resulted to be fundamental for the development of new products.
BRICKTECH: Valutazione dell’utilizzo dei materiali di scarto nella produzione di laterizi. Caratterizzazione petrofisica di nuovi mix design e ottimizzazione delle condizioni di cottura. RIASSUNTO Il laterizio é un materiale della tradizione costruttiva dalle antiche origini, ma che può rispondere alle importanti sfide verso cui la ricerca in ambito industriale è attualmente rivolta, ossia il risparmio energetico, l’abbassamento di costi nella produzione e il miglioramento delle qualità del prodotto finito. Inoltre, la crescente domanda di una produzione sostenibile ha indirizzato la ricerca verso nuovi materiali che tengano conto della salvaguardia dell’ambiente e del benessere della società. Una delle strade percorribili per il raggiungimenti di tali traguardi e che congiunge questi diversi aspetti è l’ottimizzazione di nuovi mix design, utilizzando materiali di scarto, risultato di attività industriali, urbane e di escavazione. In questo modo il consolidamento di produzioni di tipo sostenibile ha un duplice valore in quanto non solo determina la diminuzione dell’utilizzo di nuove geo-risorse, ma si risolve anche il problema dell’accumulo e della gestione dei rifiuti, rivalutandoli come fonte secondaria di interesse per la realizzazione di nuovi materiali nel rispetto della tutela dell’ambiente. Nonostante negli ultimi decenni siano stati numerosi gli studi effettuati per la realizzazione di mattoni con materiali di riuso come risorse alternative e questi abbiano dimostrato una vasta applicabilità nel settore del laterizio, l’implementazione in ambito industriale è ancora oggi molto limitata, a causa della mancanza della compartecipazione tra ricerca accademica e le reali necessità industriali, della scarsità di standard specifici di valutazione dei processi di lavorazione e dei prodotti finiti e della limitata educazione pubblica rispetto alle possibili frontiere sostenibili. Un altro aspetto importante che deve essere considerato nella produzione di nuovi materiali è quello del mantenimento delle caratteristiche estetiche del materiale tradizionale. Il mattone, infatti, essendo un materiale da costruzione, deve rispondere a parametri di “compatibilità culturale”, intesa come riconoscimento della identità territoriale di una comunità. Questo aspetto ovviamente ha un valore ancor maggiore nel caso di materiali impiegati con funzione di integrazione o sostituzione per il ripristino e/o restauro di edifici storici danneggiati. Questo lavoro è, pertanto, rivolto a colmare la lacuna di uno scarso dialogo tra ricerca accademica e sviluppo industriale, attraverso la stretta collaborazione tra università e industria e il raggiungimento di obiettivi condivisi. Questo è stato possibile grazie all’affiancamento di una ditta leader nel settore della produzione di laterizi tradizionali, la SanMarco-Terreal srl (Noale, Italia), che ha apportato il suo contributo mettendo a servizio strumentazioni, materie prime e la gran esperienza maturata in quest’ambito lavorativo. I prodotti sono stati sviluppati in linea con gli obiettivi di Horizon 2020 (https://ec.europa.eu/programmes/horizon2020/), soprattutto in termini di sfruttamento sostenibile delle risorse naturali, di miglioramento dei processi di trasformazione delle materie prime, di riciclaggio e della ottimizzazione delle condizioni di cottura, al fine di soddisfare i punti relativi all’eccellenza scientifica, alle sfide per la società e alla leadership industriale. Pertanto, lo studio è stato rivolto a: 1) mettere in relazione le caratteristiche mineralogiche e chimiche con le proprietà meccaniche e la durabilità in diverse condizioni di stress di materiali già in commercio, ottenuti da differenti argille e cotti a diverse temperature (600, 950, 980, 1050°C); 2) analizzare il sistema poroso di materiali industriali al fine di ottenerne una conoscenza affidabile e completa come punto di partenza per definire un protocollo per la quantificazione e la parametrizzazione delle caratteristiche morfologiche dei pori attraverso l'uso combinato di metodi tradizionali e tecniche di elaborazione di immagine a seconda del tipo di materia prima utilizzata e le temperature di cottura raggiunte (600, 950, 1050°C); 3) sperimentare nuovi mix design ottenuti dall'aggiunta di rifiuti provenienti da attività di estrazione di materiale lapideo e industriali per la produzione di nuovi mattoni basata sui concetti di riciclo e di uso sostenibile delle risorse. Il tipo di materiali di ri-uso adottati nello specifico sono stati: i) lo scarto di escavazione di trachite della cava di Rovolon, Colli Euganei, Vicenza (Italia); ii) un fango refluo derivante dall’industria ceramica. Lo studio dei mattoni commerciali ha confermato come le proprietà chimico-mineralogiche, fisico-petrografiche, di porosità e di durabilità dei prodotti finiti siano strettamente dipendenti dalla composizione delle materie prime e dalle temperature di cottura raggiunte durante il processo di produzione. I risultati conseguiti dalle analisi dei mix design sperimentali hanno dimostrato la possibilità di ottenere nuovi laterizi utilizzando materiale di scarto e di implementare strategie industriali con soluzioni sostenibili e compatibili. Più in dettaglio, i mattoni commerciali (1) cotti a temperature superiori a 1050°C hanno mostrato una maggiore evoluzione mineralogica, con la crescita di nuove fasi, e fusione della matrice, con un conseguente miglioramento delle proprietà meccaniche. Al contrario il mattone cotto a 600°C si è distinto per un buon comportamento idrico, rilevandosi però il più debole durante i cicli di invecchiamento accelerato, a causa della bassa compattezza, a questa dovuta all’assenza di vetrificazione nella matrice e alla bassa evoluzione di nuove fasi a tale temperatura. Inoltre, è stato osservato come l’hausmannite (Mn3O4) utilizzata come colorante, comporti cambiamenti non solo sull’aspetto estetico del prodotto finito (determinando un colore grigio scuro), ma agisca anche nelle sue proprietà meccaniche e nel sistema poroso promuovendo il processo di fusione. Lo studio dettagliato della porosità (2) conseguito attraverso l’uso di differenti metodologie di studio ha permesso da un lato di comprendere in maniera più approfondita i limiti di ogni tecnica, dall’altro di conoscere il sistema poroso di ogni campione nella sua complessità. I mattoni prodotti con argilla carbonatica han mostrato una maggiore porosità e interconnessione dei pori, che derivano dalla decomposizione del carbonato durante il processo di cottura. Nei mattoni cotti a temperature più alte (1050°C) è stato riscontrato lo sviluppo della morfologia dei pori, che diventano più grandi e rotondi. Al contrario nel mattone ottenuto con l’uso di una argilla meno carbonatica e cotto a 600°C, la porosità è molto diversa, i pori sono meno omogenei e più piccoli. Nella valutazione dell’influenza dell’utilizzo di materiale di scarto (3) per la produzione di nuovi laterizi, in entrambi i casi di studio i) l’aggiunta di trachite di escavazione (5, 10, 15% in peso) e ii) l’aggiunta del fango ceramico (10% in peso) come inerte, i risultati sono stati soddisfacenti al fine di identificare possibili “alternative sostenibili” ai mattoni attualmente in commercio. i) Si è visto come la presenza di feldspati alcalini nella trachite agiscono come agenti fondenti e diminuiscono il punto di fusione. Questo effetto è stato osservato sotto differenti punti di vista, dall’aumento della connessione tra i minerali, dalla crescente compattezza, dalla maggiore evoluzione della tessitura e del sistema dei pori, tutte caratteristiche che si sviluppano, non sono in corrispondenza dell’aumento della temperatura, ma anche dell’aumento del contenuto di trachite. Inoltre, lo studio delle proprietà termiche, condotto attraverso l’analisi di immagini infrarosse, ha evidenziato come il crescente contenuto di trachite riduca la capacità di trasmissione di calore. Solo nel caso del mattone con 15% di trachite e cotto alla temperatura di 1050°C è stata osservata una trasmissione di calore più rapida, per l’alto livello di sinterizzazione raggiunto. In generale la buona risposta alle condizioni di stress (gelo-disgelo e cristallizzazione di sali) e l’assenza di una forte differenza tra i campioni hanno dimostrato che la trachite può essere considerata un inerte alternativo a quello normalmente utilizzato che inoltre può recare vantaggi nella produzione, con risparmio di energia e di costi, dal momento che agisce come agente fondente. Il suo impiego permette, infatti, di ottenere mattoni cotti a 900°C (temperatura inferiore a quella attualmente utilizzata dalla ditta) e che contengano più del 10% di inerte, limitando lo sfruttamento e l’uso di nuove geo-risorse. ii) Anche la miscela con l’aggiunta del fango di scarto dell’industria ceramica ha ottenuto risultati soddisfacenti. Le prove di colorimetria han dimostrato che il prodotto finito mantiene un aspetto molto simile ad un mattone di colore giallo già in commercio (ottenuto con la stessa argilla, ma con l’inerte standard) suggerendone la possibile sostituzione dal punto di vista estetico. Le prove di compressione uniassiale e l’analisi ad ultrasuoni hanno, inoltre, rilevato anche un comportamento meccanico molto simile a quello del mattone commerciale giallo, indice della sua compatibilità anche nella riposta al carico. Solo dal punto di vista della durabilità il mattone ottenuto con l’aggiunta del fango ha mostrato una risposta più debole. Mentre durante la cristallizzazione dei sali il suo aspetto originario è rimasto quasi intatti, a condizioni forzate di gelo e disgelo si è riscontrato il progressivo deterioramento dei campioni fino alla loro totale disgregazione alla fine della prova. Alla luce di quanto evidenziato questo nuovo mix design può essere a tutti gli effetti considerato un’alternativa sostenibile del mattone commerciale, in particolare per il mantenimento delle proprietà fisico-meccaniche e delle qualità estetiche, ma non può essere messo in opera in edifici situati in situazioni ambientali dove sono possibili cicli di gelo e disgelo. Questa tesi di Dottorato rappresenta un punto di partenza fondamentale per affrontare la riqualificazione di mattoni tradizionali in chiave sostenibile e permettere la valutazione in termini di qualità e durabilità dei mix sperimentali ottenuti con materiali di riciclo, nel caso specifico consistenti in trachite di cava e in un fango ceramico. Entrambi i casi di studio hanno dimostrato di rappresentare una valida alternativa al fine di ottenere nuovi mattoni di interesse per il miglioramento del settore industriale del laterizio, in termini di risparmio di sfruttamento di geo-risorse, energia e costi. Comprendere le relazioni intrinseche tra composizione mineralogica, caratteristiche tessiturali, la microstruttura e le proprietà fisiche del laterizio è la base di una consapevole conoscenza del materiale per lo sviluppo di nuovi mix design.

Dans le concept actuel de stockage de déchets radioactifs en couche géologique profonde tel qu’envisagé par l’Andra (projet CIGEO), les colis de déchets sont placés dans des alvéoles creusées dans l’argilite du Callovo-Oxfordien (COx) dont le chemisage est en acier faiblement allié. Le COx, et en particulier les pyrites qui le composent, peuvent s’oxyder lors du creusement. Grâce à un montage expérimental original, impliquant plusieurs mélanges pyrite/minéral et un réacteur couplé à un micro chromatographe en phase gazeuse, il est démontré, sur la base de la consommation d'O2 mesurée, qu'à 100°C en présence de calcite, moins de 50% de la pyrite est oxydée. Cette oxydation implique une acidité susceptible de corroder le chemisage des alvéoles. L’Andra a donc développé et breveté un coulis cimento-bentonitique bas pH (9
In the current concept of radioactive waste deep geological disposal planned by Andra (CIGEO project), waste containers are stored into disposal cells drilled into the Callovo-Oxfordian claystone (COx) and encircled by a carbon steel liner. COx and in particular its pyrites, can be oxidized during the drilling of cells. Thanks to an original experimental set-up, involving several pyrite/mineral mixtures and a reactor coupled to a micro gas chromatograph, it is demonstrated, based on the measured O2 consumption that at 100°C in presence of calcite, less than 50% of the pyrite is oxidized. This oxidation induces a transient acidic plume and consequently the corrosion of the steel liner. Andra has developed and patented a low-pH (9

Thesis (M.S.)--Georgia State University, 2005.
Title from title screen. Beth A. Christensen, committee chair; W. Crawford Elliott, Eirik J. Krogstad, Deborah Freile, committee members. Description based on contents viewed Dec. 22, 2006. Includes bibliographical references (p. 107-112).

Large areas prone to clay slides are present in Canada, Sweden and Norway. Traditionally, mainly geotechnical approaches have been used to solve clay-slide issues. However, there is great potential to utilise interdisciplinary studies in order to prevent or reduce possible slide damage. The present study combines geology, morphology and geophysical investigations, with geotechnical data. The purpose is to better understand landscape development, formation of quick clay and sliding in clay.

Thick, marine clay deposits in valleys along the Norwegian coast are occasionally subjected to large landslides involving quick clay. The development of quick clay is closely related to the deglaciation history of the coastal parts of Norway. During and after the last ice age, up to several hundred metres of glaciomarine and marine deposits accumulated in Norwegian fjords. These sediments were subsequently exposed on land due to glacioisostatic rebound. Leaching of salt from the marine clay by groundwater resulted in the development of quick-clay layers or pockets, which completely liquefy when remoulded.

The study area of this thesis is the small valley Buvika, located in the Trondheimsfjorden area, Mid Norway. Buvika is characterised by its undulating terrain with numerous slide scars and ravines. There are thick occurrences of quick clay in the subsurface.

The existing geotechnical and geophysical data, combined with sedimentology, structural geology, morphology, geophysical results, and 14C-datings, have given input to the understanding of the landscape development of the study area. From this, a deglaciation history has been deduced, indicating at least one, and possibly two, minor glacier re-advances in Late Allerød/Early Younger Dryas time. This implies that there have been more and larger ice-front oscillations in the study area than earlier documented.

The lowered relative sea level led to incision by rivers accompanied by numerous slides involving quick clay. The erosion pattern of a valley filled with glaciomarine and marine deposits can be quite complex, but careful analyses have helped outlining the interplay between river and ravine incision, groundwater erosion and sliding. The study of sediments and structures in large excavated sections have resulted in the detection of slide material from old flake-type slides, where only a thin layer of quick clay acted as a slide plane. Younger slide scars cutting into theses older slide deposits show further quick-clay development. Mapping of the morphology in Buvika has identified numerous slide scars and ravines. A relative chronology of slide events has been established based upon the slide scars’ position in the terrain and/or results from 14C-datings of terrestrial organic material. Most of the historical slide scars are located in the northern part of the valley.

Detailed mapping of the quick-clay extent is of great interest for planning and protection purposes, as the position of quick clay within slopes has a major impact on the landslide risk. In this study, the resistivity method is found to be potentially well suited for outlining quick-clay occurrences since quick clay has a slightly higher electrical resistivity (10-80 Ωm) than intact unleached clay (1-10 Ωm). This is due to a higher salt content in the latter. These relationships are supported by pore water salt content measurements. The resistivity profiles that were acquired show good correlation with other geophysical data and geotechnical drillings. However, the resistivity method must be combined with other investigations, since both leached, non-quick clay and silty, non-sensitive material may give resistivity values of the same range as quick clay.

The stratigraphy of an area strongly influences the landscape development. It determines the morphology, such as ravine development, and size, shape and distribution of slides. To the east of Buvika, thick and frequent layers of sand and gravel in the dominant clay deposits drain the slopes, leading to development of deeply incising ravines. To the south and north, thinner layers of coarse material in the clay lead to pore-pressure build-ups and quick-clay development, resulting in numerous slide scars.

Abstract This thesis examines the Mid-Pliocene climatic extreme ca. three million years ago (Ma) which was the latest longtime warm period. It is an important topic because the climate back then was warmer compared with the present. The bipolar regions are studied because they represent the largest areas that control the global climate. This study is based on clay mineral research that may significantly improve our knowledge of the Mid-Pliocene climate when combined with other palaeoenvironmental data. The paleoclimatological objectives of this study were: 1) to investigate how clay minerals reflect the Mid-Pliocene Global Warmth event, 2) to study ice sheet development at high latitudes, especially in East-Antarctica, and the history of ice rafting and sea ice, especially in the Arctic Ocean. This thesis deals with the clay mineral distribution and compositional analysis of the Pliocene-aged marine sediment sequences provided by the Ocean Drilling Program (ODP). The first studied site, Site 1165, is located at the continental rise of Prydz Bay, East Antarctica, and the second studied site, Site 911, is located at the Yermak Plateau, north of Svalbard, in the Arctic Ocean. The Pliocene smectite clay minerals at Site 1165 were mainly derived from Antarctic continental sources and transported to the site primarly by bottom currents related to warm events during the last 5 Ma. The evidence obtained in this study shows that the East Antarctic ice sheet may have been a dynamic ice sheet during the past 5 Ma, especially during the Mid-Pliocene. The results from the Mid-Pliocene possibly suggest a general warming trend. Based on the composition of the heavy minerals and clay minerals, at Site 911, the Pliocene smectite clay minerals were mainly transported within sea ice by the Siberian branch of the Transpolar Drift. The results indicate a warming trend at approximately 3 Ma after which they indicate a shift back to glacial conditions. Based on this study, the Mid-Pliocene Global Warmth can be observed in both the Arctic and Antarctic regions.

Cette recherche vise à analyser et à identifier, par des essais, le comportement au fluage d'une argile de type kaolinite sous un état de contraintes triaxial. Une investigation fine de l’état microstructural, avant et après fluage, a par ailleurs été réalisée. Les résultats macroscopiques ont permis de constater que des phénomènes de dilatance et de contractante s’amplifient pendant le fluage. Les résultats montrent également que la position, sur le plan des contraintes (p'-q), du niveau de contrainte vis-à-vis des différents domaines volumétriques, contrôle le développement de la déformation au fluage et du taux de déformation. Les résultats de MEB ont montré que l'évolution microstructurale de l'argile, après le chargement mécanique, dépend fortement de l'histoire du chargement
The objective of this research is to analyze the creep behavior of a typical clay along triaxial tests, moreover, to analyze the microstructural mechanisms of creep. Analysis on the macroscopic results ascertained that both dilatancy and contractancy phenomena could occur during creep. The magnitude of the dilatancy/contractancy during creep was guided by the test conditions: stress level and the over consolidation ratio, which specifically governed the direction of the volumetric strain variations. The results of SEM indicated that the microstructural evolution of the clay after the mechanical loading depend on the stress history. Afterwards, the structural evolution in creep phase depends on the structural pattern developed in monotonic loading

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Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES
The pitaya or Cereus undatus pitaya or, synonymy: Hylocereus guatemalensis, H.undatus is exotic fruit consumption and slightly increasing in our country. The functional assignments given to this fruit, common sense encourages the study of their physical, chemical and microbiological. It should be noted that the fruits are primary sources of several vitamins and other bioactive compounds, for example, phenolic fibers, and sugars. The intake of these compounds increases the immunity of individuals, leading to improved levels of health, physical and mental performance. The reference values for these nutrients pitaya, also, are unknown to the general public, as this is a fruit intake of a wealthy class, for its price is too high for our Brazilian standards. In food matrices are very complex, given its inherent characteristics. Thus, there are several techniques used for quantitative analysis of bioactive compounds, among them, have a High Performance Liquid Chromatography (HPLC) and UV-visible spectrophotometry. The objective of this study is to quantify the presence of vitamin C, anthocyanins and sugars in pitayas white and red pulp by HPLC, as well as to determine, although the content of antioxidant activity by the method of capturing the radical 2,2 '- azinobis ( 3-etilbenzenotiazolina-6-sulfonic acid - ABTS), soluble solids (? Brix) is determined in a digital refractometer, as well as acidity and pH. The soluble solids found can confirm that the samples of red pitaya have higher sugar content than the white pulp. The pH and total acidity (g citric acid/100g fruit), should also be monitored and analyzed, possibly under conditions of controlled cultivation of this food because it is an exotic fruit and consumption in our country recently. As for the results of anthocyanins, because it is a dye that rapidly degrades, its presence became insignificant, being found only in the halo of red pulp pitaya, requiring further analysis and monitoring standards in a more specific. There was a low antioxidant activity in the samples, as well as its content of vitamin C, these values should be found, first, the storage time, which decreases the levels of these analytes.
A pitaya ou Cereus undatus, sinon?mia: Hylocereus guatemalensis, H.undatus ? uma fruta ex?tica e de consumo ligeiramente crescente no nosso pa?s. As atribui??es funcionais dadas a essa fruta, pelo senso comum, incita ao estudo das suas caracter?sticas f?sicas, qu?micas e microbiol?gicas. Deve-se ressaltar que as frutas s?o fontes prim?rias de v?rias vitaminas e outros compostos bioativos, como por exemplo, os compostos fen?licos, fibras e a??cares. A ingest?o desses compostos aumenta a imunidade dos indiv?duos, induzindo a melhoria dos n?veis de sa?de, rendimento f?sico e mental. Os valores de refer?ncia desses nutrientes para a pitaya, ainda, s?o desconhecidos do grande p?blico, por ser esta uma fruta de consumo de uma classe abastada, por seu pre?o ser demasiadamente alto para os nossos padr?es brasileiros. As matrizes em alimentos s?o muito complexas, dadas as suas caracter?sticas intr?nsecas. Diante disso, v?rias s?o as t?cnicas utilizadas para determina??es anal?ticas de compostos bioativos, dentre elas, t?m-se a Cromatografia L?quida de Alta Efici?ncia (CLAE) e espectrofotometria U.V vis?vel. O objetivo deste trabalho ? quantificar a presen?a de vitamina C, antocianinas e a??cares nas pitayas de polpas branca e vermelha por CLAE, bem como, determinar, ainda, o teor de atividade antioxidante pelo m?todo de captura do radical 2,2?- azinobis (3-etilbenzenotiazolina-6-?cido sulf?nico ? ABTS), teores de s?lidos sol?veis (?Brix) determinado em um refrat?metro digital, al?m da acidez e pH. O teor de s?lidos sol?veis encontrados pode confirmar que as amostras de pitaya vermelha t?m maiores teores de a??cares que a de polpa branca. Quanto ao valor de pH e acidez total titul?vel (g de ?cido c?trico/100g de fruta), precisam, ainda, ser monitorados e analisados, possivelmente, sob condi??es de cultivo controlado desse alimento por se tratar de uma fruta ex?tica e de recente consumo no nosso pa?s. Quanto aos resultados das antocianinas, por se tratar de um corante que degrada rapidamente, a sua presen?a mostrou-se irris?ria, sendo encontrada somente no halo da pitaya de polpa vermelha, necessitando de mais an?lises e padroniza??es em condi??es mais espec?ficas de monitoramento. Houve baixa atividade antioxidante nas amostras analisadas, bem como o seu teor de vitamina C, esses valores encontrados devem-se, primeiramente, ao tempo de armazenamento, que diminui os teores desses analitos.

AbstractConstruction on weak expansive soils is challenging due to their low bearing capacity and high-volume susceptibility under moisture fluctuation. The uplift pressure from expansive clay can induce significant swelling pressure on foundations, but on the other hand, shrinkage of clay can result in substantial foundation settlement during dry seasons. This differential movement of the foundation can distress the superstructure of a building, resulting in serviceable and ultimate limit state failures. The current approach to dealing with foundations in expansive clay soils is to construct a rigid slab that can withstand the anticipated movement or a pier-type approach using engineering design principles or a normal-type slab based on the fill being placed under controlled conditions. We introduce a capping layer under the foundation to control moisture fluctuation and increase the bearing capacity of the foundation using a recycled glass-based stabilization approach. A prototype foundation was constructed in the laboratory using an optimum stabilization mix design that was derived using glass and other sustainable additives. Slab movements and soil conditions were monitored over a 6 month period under simulated dry/wetting moisture fluctuations and operational loads. Results revealed that the performance of the foundation under controlled conditions was outperformed by the capping layered foundation during service loadings including seasonal moisture fluctuation. The outcomes from this research will have a significant impact on improving foundation performance in expansive soils, as well as proposing a sustainable foundation construction process using recycled glass waste.

Locally available and with infinite recycling possibilities, the use of earth as building material leads to one of the lowest environmental impacts in the construction sector. Recent advances in the earth materials field have been made based on concrete and ceramics technologies to facilitate its uses in dense areas. It is possible to modify clay particle interactions and the material's whole behavior by adding inorganic dispersants and flocculants into clay paste. Earth becomes easy to cast and unmold into formworks, and by removing cement in its composition, poured earth can reach a low CO2 emission rate. Even if this technology is promising, further work has to be performed, as it cannot be implemented on earth from excavation sites with high variability. Tackling the clay nature variability is now the main issue to push this product on the market with robust properties. This research investigates the robustness of the poured earth binder. In this way, several clays (three montmorillonites, two kaolinites, and binary mixes at different proportions) were investigated. Their compacity (C) was determined following the water demand protocol with Vicat apparatus and compared to their consistency properties (liquidity and plasticity limits), and a correlation between these values is established. Different clay pastes prepared at different solid volume fractions were tested to define the influence of the clay nature on the paste consistency evolution. The results showed that clay nature for paste at high solid volume fraction does not influence constituency's evolution when their respectivecompacity is taking into account. It can be suggested that for a clay binder with a consistency close to C, which might be mandatory for poured earth application, only the swelling capacity might influence the mix design.

The term ‘Sustainable’ environmentally means “green”. The deteriorating environment is driving the worldwide focus on sustainable development. It is to be noted that the largest impact on nature and environment is by the construction industry. Previously, the concern on environment formed a small part of construction development. We know that cement is the main constituent of concrete. Production of large quantity of cement results in increasing CO2 emissions and the consequence being Greenhouse Effect .The purpose of this paper is to investigate the feasibility of using basalt aggregates in concrete mixes. Concrete is the most important engineering material and the addition or replacement of some of the materials may change the properties of the concrete. In recent years a lot of research been carried out in order to obtain more durable and long term performance of concrete structures in the dynamic environment. An experimental program is set up to test the effect of basalt aggregate content and its combinations with calcined clay with variation of percentages in concrete mixes. Different aggregate percentage combinations were used in this study for basalt and calcined clay respectively. The laboratory investigation included measurement of compressive strength, tensile strength and flexural strength. In addition the source aggregate properties were considered in this study: specific gravity and absorption for coarse aggregates and fine aggregate. The result of this investigation indicates a general improvement in mix properties with the introduction of basalt aggregates in the mix.

The term ‘Sustainable’ environmentally means “green”. The deteriorating environment is driving the worldwide focus on sustainable development. It is to be noted that the largest impact on nature and environment is by the construction industry. Previously, the concern on environment formed a small part of construction development. We know that cement is the main constituent of concrete. Production of large quantity of cement results in increasing CO2 emissions and the consequence being Greenhouse Effect. The purpose of this paper is to investigate the feasibility of using basalt aggregates in concrete mixes. Concrete is the most important engineering material and the addition or replacement of some of the materials may change the properties of the concrete. In recent years a lot of research been carried out in order to obtain more durable and long term performance of concrete structures in the dynamic environment. An experimental program is set up to test the effect of basalt aggregate content and its combinations with calcined clay with variation of percentages in concrete mixes. Different aggregate percentage combinations were used in this study for basalt and calcined clay respectively. The laboratory investigation included measurement of compressive strength, tensile strength and flexural strength. In addition the source aggregate properties were considered in this study: specific gravity and absorption for coarse aggregates and fine aggregate. The result of this investigation indicates a general improvement in mix properties with the introduction of basalt aggregates in the mix.

Soft clay is a natural soil that spreads in the south of Iraq and many countries in the world. It is a problematic soil causing trouble for the structures built on it because of, high water content, low shear strength, and high compressibility. This work investigated the geotechnical behavior of soft clay by using mix of Metakaolin (M) and Sugarcane Straw Ash in air (SCSAA).The experimental work contains the following tests: chemical tests, physical tests, Compaction tests and shear test. These tests were carried out on soil samples prepared from soft soil; the replacement materials by weight of dry unit weight for different percentages of M (4%, 6%, 8%, 10%) mix with different percentages of SCSAA (4%, 6%, 8%, 10%). The tests results showed that the best percentage for the plasticity test was M1B4. Also,the percentage which gave the best value for undrained shear strength test was M4B4 (135).Finally, the treatment soil is good sub grade materials and also can be used in highway sub-base material.

The incorporation of sustainable materials in the civil construction sector has grown in recent years to minimize environmental impacts. Among these materials, the use of earth, a local raw material that does not require much energy for its processing, appears as an advantageous and promising alternative. Earth mortars stabilized with natural binders, when compared to conventional mortars, can have technological, economic and environmental advantages. The objective of this work was to develop an earth-based mortar stabilized with mineral binders using a 1:3 binder to aggregate mass proportion, and to evaluate its fresh and hardened state properties, as well as its environmental impacts using Life Cycle Assessment (LCA) with a cradle to gate scope. The selected materials were divided in four groups: (i) cement, hydrated lime, fly ash and metakaolinite (binders), (ii) natural sand and coarse fraction of the earth (aggregates), (iii) calcium chloride and superplasticizer (additives) and (iv) water. In the matrix formulation the clay fraction from earth constituted the majority of the binder. The selection of supplementary cementitious materials as additional binders provided improvements in workability and mechanical properties of the mortar. A mix design was carried out using different cement (5; 7.5 and 10%) and fly ash (11; 13.5 and 16%) mass percentages. The water/binder material ratio, superplasticizer content and calcium chloride content were 0.65; 2% and 1%, respectively. The results showed that an increase in fly ash content combined with a decrease in cement content provided an increase in workability and a decrease in mechanical properties of mortars. Nevertheless, the mechanical performance of the mortars remained above the minimum values prescribed in Brazilian construction codes. From the results analysis it was concluded that partial replacement of cement by fly ash provided greater workability in the fresh state and reduced the environmental impacts of the earth-based mortar.

The Southern Ventilation Building (SVB) is located on newly reclaimed land where 15-20 m of Sand Fill overly 15m of soft to firm silty clay Marine Deposit which was improved with prefabricated band drains. The SVB sits directly above the Tuen-Mun Chek Lap Kok Tunnels (TMCLKL). The original design required installation of over 330 number of shaft grouted piles. Due to the presence of the tunnels the pile design was relatively inefficient and required 3m thick pilecaps. An alternative design was developed to delete the piled foundations by carrying out additional ground improvement within the soft soil layer using a combination of Jet Grouting and Deep Cement Mix using Cutter Soil Mix (CSM) and support the building on a raft foundation. The ground improvement scheme was also leveraged to reduce the temporary wall depth and shoring quantities. In order to rationalise and minimise the ground improvement quantities, the CSM panels formed a grid of orthogonal underground beams which allowed an efficient Area Replacement Ratio to be achieved.

This preliminary work deals with potential use of additive manufacturing to print a bio-based composite. For this, mixture of clay and flax fibers was used. First, we proceeded to the optimization of the printability conditions by ensuring that the water dosage allows a good extrusion with a continuous volume flow rate. Moreover, the yield stress obtained must allow to deposit several layers without loss of stability. This criterion was verified and then we printed a square element of 20 cm length where 4x4x16cm3 specimens were cut and used to evaluate bending strength. We have shown that under some conditions we are able to print with different layers this composite. To improve the limit height of a printed element, additional tests are necessary to increase the resistance of this type of composite. This study will be continued by Optimizing mix design using other additives and introducing of reinforcement.

ABSTRACT Proppants are one of the main components/ingredients used in hydraulic fracturing for reservoir stimulation in order for fractures to have conductivity and maintain it. In hydraulic fracturing, usually when dealing with high parting pressure or harsh environment, high strength durable proppants are used that are expensive and require more expensive fracture fluids. Thus, the idea of developing a new type of proppant that has high compressive strength, high durability, resistant to corrosion and erosion, and economical became the focus of this research. Fly ash, a by-product from any combustion process, and a very prominent by-product from cement production, was used to develop a new type of proppant that is durable, is environmentally friendly. Sodium metasilicate and water were used in the mix designs. The samples were subjected to high temperature, pressure, acidic, and alkaline environments to test their durability. The samples showed high durability and minimum erosion, with no corrosion in all of the environments that were subjected to. 20% binder mix design showed the best results having minimum to no deterioration of the samples. INTRODUCTION As the industry of petroleum engineering is developing and more technologies are being introduced to optimize the production, stimulating the reservoirs has been an area of development and research that is gaining more attention and attraction, especially with the rise of unconventional reservoirs. The global production ratio of conventional to unconventional reservoirs is 2:8, and in unconventional reservoirs, stimulation is a default practice (Lan et al., 2020). One way to stimulate the reservoir is by hydraulic fracturing, in which proppants are used where the rock is ductile, meaning there is high clay content, closing the fractures that are made. Proppants come in different shapes and sizes being angular, such as natural sand, spherical or rods (Ba Geri et al., 2019). The shape of the proppant is connected to the way it will be placed and arranged inside of the fractures, which the better placement the proppant has the better conductivity the fracture will have, thus better and higher production rate for a long period of time (Wang et al., 2022; Li, 2021).

Transportation has an enormous impact on the U.S. economy and on the lives of all Americans. Many modes of transportation rely on pavement, but pavement conditions deteriorate over time because of the combined effects of traffic and climate. Exposure to moisture often causes premature failure of asphalt pavements as it reduces the stiffness of the asphalt and enables stripping of the asphalt from the aggregate. This research evaluates the effectiveness of clay nanomaterials (i.e., nanoclays) in improving the resistance of hot mix asphalt (HMA) to moisture damage and compares the enhancement results to anti-stripping additives commonly used in pavement construction. Two types of surface-modified nanoclay, lime-treated aggregate, and two amine-based liquid antistripping agents (HP Plus and LOF 6500) were evaluated for improving HMA’s moisture resistance. All additives tested for reducing moisture damage resulted in dry and wet tensile strength of the modified mixes higher than the minimum specified by Caltrans 2018 Standard Specifications (100 psi for dry tensile strength and 70 psi for wet tensile strength). The Tensile Strength Ratio (TSR) of all HMA modified mixes was higher than 0.80, which is the minimum specified by the Superpave mix design method (Asphalt Mix Design Methods MS-2, Asphalt Institute) and exceeded the TSR of the control mix. The TSR for HMA mixes modified using nanoclays were comparable to those for HMA mixes modified using liquid antistripping and lime slurry treated aggregate. Liquid antistripping agents tested herein were the least costly additive at an approximately $2.0/ton added cost. This research can be used to better understand pavement deterioration to enable the most efficient and cost-effective construction and preservation of our nation's critical transportation infrastructure.

There is a variety of impressed current anode materials available for onshore applications, including High Silicon Cast Iron (HSCI), Mixed Metal Oxides (MMO), graphite, platinum (or platinum coated titanium), and conductive polymers. Many end users simply select the anode material that they have experience with. What is lacking is a clear, direct comparison of relative anode consumption rates conducted under identical conditions. The present study examined the behavior of the various anode types under different current loads and soil conditions in an effort to establish baseline consumption rates under controlled conditions. Variables that were examined included soil resistivity, the presence of coke backfill, current load, and soil type (sand or 50/50 clay/sand mix). The consumption rates of the anodes evaluated decreased in the order of: AnodeFlex, HSCI, Graphite, Pt, and MMO. A survey of field experiences yielded a slightly different order in terms of anode life with Graphite and HSCI lasting the longest. However, given the wide range of anode sizes used in the various field sites, it is difficult to directly link the field results to the consumption rates measured in the laboratory. Soil composition and resistivity were not observed to have a significant influence on anode consumption rates. The presence of coke, however, led to a decrease in consumption for all anodes in some cases by as much as a factor of nearly 70. Utilizing anode cost estimates and neglecting installation costs, the life-cycle material costs for MMO and Pt anodes are much lower than the other anode materials. Furthermore, AnodeFlex was noted to be the highest cost system from a materials perspective. This may be slightly misleading since installation and replacement costs are not factored in. Given that the installation of AnodeFlex is often much easier and less expensive than the other anode types, this may prove to be a viable financial decision when the other factors are considered. ����������� The primary implications of the present study are: Despite higher material costs, MMO and Pt anodes may offer significant long-term cost savings as compared to other anode types for many applications Use of coke backfill is critical to ensure lower anode consumption rates for AnodeFlex, Graphite, and to a lesser extent HSCI; coke does not appear necessary for MMO or Pt Soil composition (sand vs. clay/sand mix) and resistivity do not appear to significantly influence anode consumption rates, thus consideration of the soil environment (except groundwater chemistry) is not needed in selection of an appropriate anode Because the influence of groundwater chemistry (as part of the soil environment) was not examined, the effects of sulfate, chloride, and pH will need to be evaluated in detail to better aid in anode material selection Field use survey responses showed a wide range in observed anode lifespan, with graphite and HSCI experiencing the longest life and cable anodes the shortest The field survey also revealed that a significant cause of anode failures was connector and cable problems

This report summarizes the results of eight field Jet Erosion Tests (JETs) performed on Benbrook Dam, TX. The results from these tests will be used by the U.S. Army Corps of Engineers, Fort Worth District, in assessments of the erosion resistance of the Benbrook Dam with regards to possible overtopping by extreme flooding. The JETs were performed at four different locations, i.e., two locations at the lowest crest elevation and two locations at the mid-slope face of the downstream embankment. Variations in estimated critical hydraulic shear stress and erosion rate values may have been caused by differences in soil composition, i.e., when the material changed from silt/sand to clay. The resulting values of the Erodibility Coefficient, Kd, and Critical Stress, τc, are very useful information in assessing the stability of Benbrook Dam during an overtopping event. Because of the observed natural variability of the materials, combining the erosion parameters presented in this report with the drilling logs and local geology will be imperative for assessing erosion-related failure modes of Benbrook Dam.

This Focused Condition Assessment examines the impacts of the recent 2000–2020 long-term drought on the vegetation and soils of Glen Canyon National Recreation Area (GLCA). With support from the NASA DEVELOP Program, summer (June–August) Normalized Difference Vegetation Index (NDVI) values from 1995 to 2017 (excluding 2012 which was not available), measuring greenness and phenology in the vegetation, were analyzed for two periods. The first period from 1995–1999 included the pre-drought period, when precipitation was average to above average. Most years of the second period, 2000–2020, were drier than average as part of the severe drought that began in late 1999 and has continued to present (Lukas and Payton 2020). The NDVI values included mean values and were analyzed for 42 soil units, 20 associated NRCS Ecological Sites (ecosites), and the 10 most widespread vegetation alliances derived from the GLCA vegetation classification. Unvegetated rock outcrops, other exposed bedrock areas, and cliffs, which are extensive in GLCA, were not included. With the exception of some riparian areas, mean NDVI values for all upland soils, ecosites and alliances declined from pre-drought conditions. The areas showing the largest declines were clay soils, shallow sandy loam and other shallow soils and associated ecosites and alliances. Talus vegetation and mid- to upper elevation pinyon-juniper (Pinus edulis-Juniperus osteosperma) woodlands showed the smallest declines. Deeper sandy and sandy loam sites showed intermediate declines. Particularly large declines occurred in shallow soil arid sites dominated by shadscale (Atriplex confertifolia) and other saltbush species. Blackbrush (Coleogyne ramosissima), one of the dominant species in the park, showed moderate declines, primarily on shallower soils. No evidence for widespread death in either blackbrush or pinyon-juniper woodlands were noted, although recent severe drought and a weakened Arizona Monsoon since 2018 may be causing impacts to the woodland species. Relationships with livestock grazing are also examined, based on data collected on long-term monitoring plots established between 2008 and 2020. There is evidence that areas with intensive livestock grazing have shown larger declines than ungrazed areas, but these impacts need to be explored more fully at the local allotment and pasture level, and correlated with actual grazing animal unit months (AUM)’s. Several management recommendations are made, including additional plot-based long-term monitoring, exploration of cultural resource inventories and erodible soils, how these observed changes can affect livestock grazing management decisions in the park, and further exploration using NDVI data from 2018 and forward.