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Marginal soils, including loose sands, soft clays, and organics are not adequate materials for construction projects. These marginal soils do not possess valuable physical properties for construction applications. The current methods for remediation of these weak soils such as stone columns, vibro-compaction, etc. are typically expensive. Waste materials such as scrap tires, ash, and wastewater sludge, offer a cheaper method for stabilizing marginal soils. As an added benefit, utilizing waste materials in soil stabilization applications keeps these materials from being dumped into landfills, thereby saving already depleting landfill space. Included in this report is an extensive investigation into the current state of research on waste and recycled materials in construction applications. Also included is an investigation on actual implementation of this research in construction projects. Upon completion of this investigation, an effort was made to determine waste materials specific to the state of Florida (waste roofing shingles, municipal solid waste ash, waste tires, and paper mill sludge) that could be used in stabilizing marginal soils through soil mixing techniques. Changes in the engineering properties of soils as a result of adding these waste materials were studied and recommendations on implementing these effects into construction applications are offered.

Orientadores: Ranulfo Monte Alegre, Lucielen Oliveira dos Santos / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-16T11:34:56Z (GMT). No. of bitstreams: 1 Anschau_Andreia_M.pdf: 29652981 bytes, checksum: e582c54f37db71e9fc13826b3422cc07 (MD5) Previous issue date: 2010 / Mestrado / Mestre em Engenharia de Alimentos

Este trabalho tem por objetivo o estudo de concretos leves com agregados inovadores de argila vermelha calcinada e subprodutos agroindustriais. A argila utilizada na pesquisa foi caracterizada por meio das técnicas de limites de liquidez (LL) e plasticidade (LP), análise granulométrica, análise química e difração de raios X (DRX). Foram confeccionados corpos de prova de argila vermelha calcinada com incorporações de serragem de madeira, cinza do bagaço da cana-de-açúcar e silicato de sódio. Os corpos de prova de argila vermelha calcinada, queimados à temperatura de 900 °C, foram caracterizados por meio da avaliação da retração linear, absorção de água, porosidade aparente, massa específica aparente, expansão por umidade e resistência à compressão. Após a caracterização dos corpos de prova de argila vermelha calcinada, foram produzidos dois tipos de agregados, sendo o primeiro composto por 57% de argila e 43% de cinza do bagaço de cana-de-açúcar, conformados com água e silicato de sódio (proporção 1:1), e o segundo composto por 70% de argila e 30% de serragem de madeira. Os corpos de prova de concreto leve foram caracterizados pelos ensaios de slump, massa específica fresca, resistência à compressão, módulo de deformação, retração por secagem, absorção de água, índice de vazios e massa específica aparente e condutividade térmica. Os resultados desta pesquisa indicam a viabilidade da produção de agregados leves de argila vermelha calcinada com incorporações de subprodutos agroindustriais para utilização em concretos, uma vez que, mesmo com grande quantidade de utilização de subprodutos agroindustriais na produção dos agregados leves, os concretos produzidos com esses agregados apresentaram características similares aos concretos produzidos com agregados comerciais, apresentando um ganho econômico e energético significativo. / This paper aims to study lightweight concrete with innovative calcined clay lightweight aggregates made with agro-industrial by-products. The clay used in this research was characterized by techniques of liquid and plastic limits, particle size analysis, chemical analysis and X-ray diffraction (XRD). Calcined clay specimens were made with incorporations of wood sawdust, sugar cane ash and sodium silicate. These specimens, burned at a temperature of 900°C, were characterized by evaluating of linear shrinkage, water absorption, apparent porosity, specific mass, moisture expansion and compressive strength. After characterization of calcined clay specimens, two types of calcined clay lightweight aggregates with agro-industrial by-products were produced, wherein the first made with 57% of clay and 43% of sugar cane ash, mixed with water and sodium silicate (proportion 1:1) and the second made with 70% clay and 30% wood sawdust, mixed with water and burned at 900 °C. Specimens of lightweight concrete were characterized by slump test, fresh specific mass, compressive strength, modulus of elasticity, water absorption, voids and bulk density and thermal conductivity. Results of this research indicates the viability to produce calcined clay lightweight aggregates made with agro-industrial by-products to use in concrete, even using large amount of agro-industrial by-products, once concretes made with lightweight aggregates with agro-industrial by-products presented similar characteristics than those made with commercial aggregates, presenting significant energetic gain.

Este trabalho tem por objetivo o estudo de concretos leves com agregados inovadores de argila vermelha calcinada e subprodutos agroindustriais. A argila utilizada na pesquisa foi caracterizada por meio das técnicas de limites de liquidez (LL) e plasticidade (LP), análise granulométrica, análise química e difração de raios X (DRX). Foram confeccionados corpos de prova de argila vermelha calcinada com incorporações de serragem de madeira, cinza do bagaço da cana-de-açúcar e silicato de sódio. Os corpos de prova de argila vermelha calcinada, queimados à temperatura de 900 °C, foram caracterizados por meio da avaliação da retração linear, absorção de água, porosidade aparente, massa específica aparente, expansão por umidade e resistência à compressão. Após a caracterização dos corpos de prova de argila vermelha calcinada, foram produzidos dois tipos de agregados, sendo o primeiro composto por 57% de argila e 43% de cinza do bagaço de cana-de-açúcar, conformados com água e silicato de sódio (proporção 1:1), e o segundo composto por 70% de argila e 30% de serragem de madeira. Os corpos de prova de concreto leve foram caracterizados pelos ensaios de slump, massa específica fresca, resistência à compressão, módulo de deformação, retração por secagem, absorção de água, índice de vazios e massa específica aparente e condutividade térmica. Os resultados desta pesquisa indicam a viabilidade da produção de agregados leves de argila vermelha calcinada com incorporações de subprodutos agroindustriais para utilização em concretos, uma vez que, mesmo com grande quantidade de utilização de subprodutos agroindustriais na produção dos agregados leves, os concretos produzidos com esses agregados apresentaram características similares aos concretos produzidos com agregados comerciais, apresentando um ganho econômico e energético significativo. / This paper aims to study lightweight concrete with innovative calcined clay lightweight aggregates made with agro-industrial by-products. The clay used in this research was characterized by techniques of liquid and plastic limits, particle size analysis, chemical analysis and X-ray diffraction (XRD). Calcined clay specimens were made with incorporations of wood sawdust, sugar cane ash and sodium silicate. These specimens, burned at a temperature of 900°C, were characterized by evaluating of linear shrinkage, water absorption, apparent porosity, specific mass, moisture expansion and compressive strength. After characterization of calcined clay specimens, two types of calcined clay lightweight aggregates with agro-industrial by-products were produced, wherein the first made with 57% of clay and 43% of sugar cane ash, mixed with water and sodium silicate (proportion 1:1) and the second made with 70% clay and 30% wood sawdust, mixed with water and burned at 900 °C. Specimens of lightweight concrete were characterized by slump test, fresh specific mass, compressive strength, modulus of elasticity, water absorption, voids and bulk density and thermal conductivity. Results of this research indicates the viability to produce calcined clay lightweight aggregates made with agro-industrial by-products to use in concrete, even using large amount of agro-industrial by-products, once concretes made with lightweight aggregates with agro-industrial by-products presented similar characteristics than those made with commercial aggregates, presenting significant energetic gain.

Στην παρούσα διατριβή ερευνήθηκε η αξιοποίηση μεταλλευτικών, βιομηχανικών παραπροϊόντων, των στερεών Υπολειμμάτων Βορίου (ΥΒ), που δημιουργούνται σε διάφορα στάδια κατά την παραγωγική διαδικασία προϊόντων βορίου. Τα εν λόγω παραπροϊόντα, που κατηγοριοποιούνται σε πέντε ποιότητες, SBW, DBW, SSBW, TBW και MBW, χρησιμοποιήθηκαν ως πρόσθετο Α’ υλών για την παραγωγή τούβλων και κεραμιδιών, και ως Α΄ ύλη για την παρασκευή τεχνητών ελαφροαδρανών. Πραγματοποιήθηκε φυσικοχημικός χαρακτηρισμός και θερμική ανάλυση όλων των ΥΒ. Στη συνέχεια μελετήθηκε η επίδραση προσθήκης διαφορετικών συγκεντρώσεων ΥΒ (SBW και SSBW) σε αργιλούχες Α΄ ύλες. Έγινε μια πρώτη προσέγγιση παρασκευής και ελέγχου κεραμικών δοκιμίων με τη μέθοδο της ξηρής ανάμιξης και αξονικής συμπίεσης, προκειμένου να περιοριστεί το φαινόμενο διάχυσης υδατοδιαλυτών ενώσεων βορίου που περιέχονται στα ΥΒ. Η προσθήκη 5%κβ SSBW και θερμοκρασία όπτησης 900-950°C οδήγησε σε κεραμικά με παραπλήσιες ή ακόμα και βελτιωμένες ιδιότητες (αυξημένες μηχανικές αντοχές) συγκριτικά με τα κεραμικά αναφοράς. Επιπλέον εξετάστηκε η παραγωγή δειγμάτων με ΥΒ (SBW) και διάλυμα εμπορίου με βορικό (Evansite®) ακολουθώντας διαδικασία παραπλήσια της βιομηχανικής πρακτικής. Στους 1000°C, παρατηρήθηκε μείωση της απορρόφησης νερού και αύξηση της αντοχής σε κάμψη για τα δείγματα με βορικά, σε σύγκριση με τα δείγματα αναφοράς. Η προσθήκη βορικών ευνόησε τη δημιουργία νέων κρυσταλλικών κατά την όπτηση. Δεδομένης της χημικής και ορυκτολογικής σύνθεσης των ΥΒ (πλούσια σε συλλιπάσματα και υψηλές απώλειες πύρωσης), πραγματοποιήθηκε επιπρόσθετα μελέτη των φυσικοχημικών μηχανισμών θερμικής διάσπασής τους. Σε θερμαινόμενη τράπεζα παρατηρήθηκε η ικανότητα διόγκωσης και ανάπτυξης ρευστής φάσης των ΥΒ, καθώς και μιγμάτων αυτών με άλλα υλικά, με σκοπό την εργαστηριακή παραγωγή ελαφροαδρανών. Βάσει των αποτελεσμάτων προτάθηκε ένα μίγμα αποτελούμενο από 70%κβ ΥΒ, 20%κβ αργιλούχο μίγμα και 10%κβ χαλαζιακή άμμο, για τη μορφοποίηση ξηρών σφαιριδίων. Απότομη θέρμανσή τους στους 760°C οδήγησε σε πορώδη υαλοποιημένα αδρανή με φαινόμενη πυκνότητα <1g/cm3. Το ενεργειακό κόστος παραγωγής των συγκεκριμένων αδρανών είναι χαμηλότερο, καθώς παρατηρήθηκε μείωση στη θερμοκρασία σε σχέση με άλλα τεχνητά ελαφροαδρανή, που παρασκευάζονται στους 1100°C. Για την αντιμετώπιση της διάχυσης ενώσεων βορίου προς την επιφάνεια των ξηρών σφαιριδίων, που οδήγησε σε προβλήματα κατά την πειραματική διαδικασία και σε υποβάθμιση της ποιότητας των τελικών προϊόντων, εξετάστηκε η προσθήκη φρουκτόζης ως παρεμποδιστή στο μίγμα Α’ υλών, με στόχο την βελτιστοποίηση της διαδικασίας παραγωγής ελαφροαδρανών από ΥΒ. Προσθήκη έστω και 0.5%κβ φρουκτόζης οδήγησε σε ικανοποιητικό έλεγχο, ενώ οι φυσικές ιδιότητες των παραχθέντων αδρανών τα κατατάσσουν στην κατηγορία των ελαφροαδρανών, σύμφωνα με το πρότυπο ASTM 330-97. Τα αποτελέσματα οδήγησαν στην κατανόηση βασικών φαινομένων θερμικής διάσπασης και στην ανάπτυξη μιας βέλτιστης διεργασίας παραγωγής τεχνητών ελαφροαδρανών χρησιμοποιώντας ΥΒ ως εναλλακτικές Α’ ύλες, με προφανές ενεργειακό και περιβαλλοντικό όφελος. / In the present thesis, the valorisation of mining and industrial by-products, the solid boron-containing Wastes (ΒW), which are created at various stages during the production process of concentrated and refined boron products, were investigated. The by-products under consideration, existing in five types SBW, DBW, SSBW, TBW and MBW, were used as additives and raw materials in clay mixes for the production of heavy clay ceramics (bricks, tiles and artificial lightweight aggregates). The BW were characterised in means of chemical and mineralogical composition and studied for their thermal behaviour. In addition, clay mixes with different amounts of BW (SBW and SSBW) were studied. A first approach was made on the formation of ceramic samples by dry pressing in order to minimize the borate migration towards the surface. The physical and mechanical properties, as well as the microstructure of the final products were studied. For 5 wt% SSBW addition and firing at 900-950°C, the sintered bodies presented comparable or improved physical and mechanical properties with respect to the reference formulation. Moreover, SBW or a commercial available borate solution (Evansite®) were introduced in a clay-based mix aiming to investigate their behaviour during a processing cycle comparable with that followed in the heavy clay industry. For firing at 1000°C, water absorption was reduced and bending strength increased for the samples with borates, compared to the reference samples. The addition of borates resulted in the formation of new crystalline phases during firing at high temperatures. BW consist of important fluxing oxides as well as of gas producing minerals during firing. Tests were performed on the bloating behavior of BW and mixes of them with other materials, by means of heating microscopy, aiming at the laboratorial production of lightweight aggregates (LWA). A new mix was proposed, according to the obtained results, consisting of 70wt% BW, 20wt% clay mixture and 10wt% quartz sand, for the formation of pellets. Abrupt heating of the dry pellets at 760°C, for 5min, resulted in porous LWA with bulk density <1g/cm3. The process was less energy demanding as the temperature was reduced compared to the one of the synthetic aggregates produced, where the firing temperature is 1100°C. During drying a white layer of boron salts was formed on the surface of the green pellets, which result on firing of a glassy layer causing alterations of their surface and experimental difficulties. In order to address this problem, fructose was added in the raw mix as a migration inhibitor. Addition of even 0.5wt% fructose inhibited the salt formation and a glassy impervious layer was formed after firing. The physical properties of the final samples meet the requirements of LWA according to the standard ASTM 330-97. The results of this thesis, led to the development of an optimised process for the production of artificial LWA with BW, as an alternative raw material.