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Steel corrosion is one of the major distress mechanisms that causes the deterioration of reinforced concrete structures around the world. It is an electrochemical reaction between the reinforcing steel and the surrounding concrete that produces a mass loss of the metal. Through the process of corrosion in reinforced concrete, iron ions get oxidized to form corrosion products (CP). Although multiple experiments and studies have been developed to understand the rheological behavior of corrosion products, this topic stays inconclusive. This work aims to characterize corrosion products at micro-scale in order to trace the progress of the formation of rust, to determine its nature and to analyse its rheological behavior in reinforced concrete. An experimental procedure to produce CP in the laboratory is also presented in this research. In addition, material characterization methods have been used to identify the iron oxide phases present in CP, determine their viscosity and rheological behavior and to study how CP flows in a porous media. In order to identify the different stages in the corrosion process, the CP was analysed at 2, 4, 6 and 8 weeks. The experiments identified four phases of iron oxide for each period. Furthermore, it was found that CP behaves as a shear-thinning slurry and as a result, its viscosity decreases with the applied shear rate. In addition, the damage caused by CP on concrete depends on the w/c ratio of the concrete mix and the exposure time to a corroding environment. The rebar mass loss results show that CP is formed in layers around the rebar, and the flow of each CP layer can differ.

The same fundamental questions that have driven enquiry into cytoskeletal mechanics can be asked of the considerably less-studied, yet arguably just as important, biopolymer matrix in the plant cell wall. In this case, it is well-known that polysaccharides, rather than filamentous and tubular protein assemblies, play a major role in satisfying the mechanical requirements of a successful cell wall, but developing a clear structure–function understanding has been exacerbated by the familiar issue of biological complexity. Herein, in the spirit of the mesoscopic approaches that have proved so illuminating in the study of cytoskeletal networks, the linear microrheological and strain-stiffening responses of biopolymeric networks reconstituted from pectin, a crucial cell wall polysaccharide, are examined. These are found to be well-captured by the glassy worm-like chain (GWLC) model of self-assembled semi-flexible filaments. Strikingly, the nonlinear mechanical response of these pectin networks is found

O presente trabalho propõe o entendimento do comportamento no estado fresco de argamassas colantes, com base na caracterização reológica e físico-química de diferentes composições comerciais, servindo de base para analisar o fenômeno de deslizamento, a partir do ensaio estabelecido na norma brasileira. Para isso, foi utilizado o ensaio “Squeeze flow" (escoamento por compressão axial), empregado na caracterização de argamassas de revestimento no laboratório de microestrutura do CPqDCC da EPUSP, como ferramenta de análise do comportamento de argamassas colantes. Neste ensaio, o escoamento do material decorre da aplicação de uma carga de compressão sobre a amostra no estado fresco, a qual ocasiona deslocamentos no seu interior devido a esforços de cisalhamento radiais originados durante o fluxo. O critério de seleção das argamassas colantes comerciais (tipo AC-I) se baseou nos resultados do ensaio de deslizamento, escolhendo-se duas com resultado muito abaixo do limite especificado, duas com resultado próximo do limite e outras duas com resultado acima do mesmo. A composição química e física foi caracterizada com o objetivo de embasar a análise dos resultados obtidos no “Squeeze flow". A separação da fração fina das argamassas na peneira no.200 contribuiu para o conhecimento da viscosidade da pasta e da sua influência no comportamento reológico das argamassas. Foi observado que as argamassas estudadas apresentam diferenças de composição físico-química e de comportamento reológico. As diferenças de comportamento reológico das argamassas decorrem, provavelmente, de ação sinérgica de alguns parâmetros da composição, com destaque para a distribuição granulométrica. O “Squeeze flow" mostrou-se uma ferramenta adequada na caracterização das argamassas colantes e contribuiu para explicar o deslizamento estabelecido na norma brasileira, pela proposição de modelos hipotéticos de comportamento. / Present thesis proposes the study of plastic-state behaviour of dry-set mortars based on the rheological and physicochemical characterization of different commercially available dry-set mortar compositions. Such characterization served as basis for the analysis of dry-set mortar slip phenomena using the tests recommended by brazilian standards (NBR). The Squeeze Flow test (slip by axial compression) originally used for coating mortars characterization by the EPUSP CPqDDC Microstructure Laboratory was adopted as a test tool for analysing the dry-set mortar behaviour. In the mentioned test the material slip is obtained by compressing the sample in its plastic state which caused internal displacements due to radial shearing tensions originated during the mentioned slip. The dry-se mortars (all of them AC-I type) used in the study were selected based in the slip tests results against brazilian standards specified limits resulting in the selection of two dry-set mortars below the specified limit, two dry-set mortars close to the specified limit and dry-set mortars above the specified limit. Chemical and physical compositions were characterized in order to serve as basis for Squeeze Flow results analysis. Fine fraction segregation, using number 200 sieve contributed to understanding of plastic-state mortar viscosity and its influence in mortar rheological behaviour. It was observed diverse physicochemical and rheological behaviour among the studied dry-set mortars. The rheological behaviour diversity of dry-set mortars were due to the synergy among some composition parameters, specially the granular distribution. The Squeeze Flow was considered a suitable tool for the characterization of dry-set mortars and contributed to develop hypotetical behaviour models that allowed to explain the slip as stated by brazilian standards.

In the process of crushing concrete waste, significant amounts of fine by-products, the so called fine recycled concrete aggregates (FRCA), are generated and excluded from potential use. Limited research has thoroughly investigated the performance of concrete mixes with FRCA, very likely due to the complexity in analysing non-negligible amounts of adhered residual cement paste (RCP). Although some studies have proposed promising sustainable mix-design procedures accounting for the different microstructure when using coarse recycled concrete aggregates (CRCA), no similar approach exists for FRCA concrete. In this work, two promising procedures for mix-designing eco-efficient concrete with 100% FRCA are proposed accounting for the presence of RCP to reduce cement content in new mixtures. First, built on top of the existing procedure for CRCA mix-design, modifications to the Equivalent Volume (EV) method were introduced toconsider full replacement of fine natural sand by FRCA. Second, based on the concept of continuous Particle Packing Models (PPM), an optimized procedure was proposed to allow maximum packing density of FRCA mix linked to a given level of measured RCP content. Results verified the feasibility of producing eco-efficient concrete mixes with 100% FRCA, emphasizing the PPM mixes to report superior rheological and mechanical performance along with suitable durability-related properties. Yet, results also indicated the influence of simple or multistage crushed FRCA on the overall performance of mixes.

O presente trabalho propõe o entendimento do comportamento no estado fresco de argamassas colantes, com base na caracterização reológica e físico-química de diferentes composições comerciais, servindo de base para analisar o fenômeno de deslizamento, a partir do ensaio estabelecido na norma brasileira. Para isso, foi utilizado o ensaio “Squeeze flow” (escoamento por compressão axial), empregado na caracterização de argamassas de revestimento no laboratório de microestrutura do CPqDCC da EPUSP, como ferramenta de análise do comportamento de argamassas colantes. Neste ensaio, o escoamento do material decorre da aplicação de uma carga de compressão sobre a amostra no estado fresco, a qual ocasiona deslocamentos no seu interior devido a esforços de cisalhamento radiais originados durante o fluxo. O critério de seleção das argamassas colantes comerciais (tipo AC-I) se baseou nos resultados do ensaio de deslizamento, escolhendo-se duas com resultado muito abaixo do limite especificado, duas com resultado próximo do limite e outras duas com resultado acima do mesmo. A composição química e física foi caracterizada com o objetivo de embasar a análise dos resultados obtidos no “Squeeze flow”. A separação da fração fina das argamassas na peneira no.200 contribuiu para o conhecimento da viscosidade da pasta e da sua influência no comportamento reológico das argamassas. Foi observado que as argamassas estudadas apresentam diferenças de composição físico-química e de comportamento reológico. As diferenças de comportamento reológico das argamassas decorrem, provavelmente, de ação sinérgica de alguns parâmetros da composição, com destaque para a distribuição granulométrica. O “Squeeze flow” mostrou-se uma ferramenta adequada na caracterização das argamassas colantes e contribuiu para explicar o deslizamento estabelecido na norma brasileira, pela proposição de modelos hipotéticos de comportamento. / Present thesis proposes the study of plastic-state behaviour of dry-set mortars based on the rheological and physicochemical characterization of different commercially available dry-set mortar compositions. Such characterization served as basis for the analysis of dry-set mortar slip phenomena using the tests recommended by brazilian standards (NBR). The Squeeze Flow test (slip by axial compression) originally used for coating mortars characterization by the EPUSP CPqDDC Microstructure Laboratory was adopted as a test tool for analysing the dry-set mortar behaviour. In the mentioned test the material slip is obtained by compressing the sample in its plastic state which caused internal displacements due to radial shearing tensions originated during the mentioned slip. The dry-se mortars (all of them AC-I type) used in the study were selected based in the slip tests results against brazilian standards specified limits resulting in the selection of two dry-set mortars below the specified limit, two dry-set mortars close to the specified limit and dry-set mortars above the specified limit. Chemical and physical compositions were characterized in order to serve as basis for Squeeze Flow results analysis. Fine fraction segregation, using number 200 sieve contributed to understanding of plastic-state mortar viscosity and its influence in mortar rheological behaviour. It was observed diverse physicochemical and rheological behaviour among the studied dry-set mortars. The rheological behaviour diversity of dry-set mortars were due to the synergy among some composition parameters, specially the granular distribution. The Squeeze Flow was considered a suitable tool for the characterization of dry-set mortars and contributed to develop hypotetical behaviour models that allowed to explain the slip as stated by brazilian standards.

Cette étude porte sur le broyage en voie humide (nanobroyage) de produits organiques à usage pharmaceutique dans un broyeur à billes agité. L'objectif des travaux réalisés était d'analyser la faisabilité de l'opération de nanobroyage et d'améliorer la compréhension des processus de réduction de taille dans le cas de produits organiques cristallins. Dans un premier temps, des expériences préliminaires ont été menées pour le choix d'agents mouillants et dispersants adéquats pour les matériaux choisis (ciclopirox, ibuprofène) et pour la mise au point du mode de fonctionnement du procédé de broyage. Nous avons également testé différentes techniques comme la spectroscopie acoustique et la diffusion dynamique de la lumière pour caractériser la distribution de taille des particules broyées, en se basant sur une étude expérimentale conduite sur la calcite, utilisée dans cette étude comme matériau de référence. La seconde partie a été consacrée au broyage par microbilles appliqué aux différents matériaux choisis. Nous avons étudié l'influence des paramètres opératoires tels que le débit de suspension, la vitesse de rotation de l'agitateur, la taille des billes de broyage et la concentration en solide sur l'efficacité énergétique du procédé et la qualité des produits broyés. Les critères de qualité pris en compte dans cette étude sont la distribution de taille des particules, la stabilité et le comportement rhéologique des suspensions broyées ainsi que les propriétés structurales du produit. L'effet du broyage sur les changements microstructuraux des différents produits a enfin été analysé. Une attention particulière a également été portée sur l'effet de la température sur le procédé de réduction de taille et les propriétés de l'ibuprofène broyé. / This work focuses on wet grinding (nanogrinding) of organic materials for pharmaceuticals using a stirred media mill. The aim of the work was to examine the feasibility of nanogrinding process and to improve the understanding of size reduction processes applied on crystalline organic products. Firstly, preliminary investigations were conducted to make a choice of appropriate wetting agents and dispersants for the selected materials (ciclopirox, ibuprofen), and for the development of the operation mode of the grinding process. We also tested different techniques such as acoustic attenuation spectroscopy and dynamic light scattering to characterize the ground particle size distribution, based on an experimental study conducted on calcite, used in this study as reference material. The second part was devoted to the milling process by grinding beads applied to the selected materials. The influence of operating parameters such as suspension flow rate, stirrer tip speed, grinding media diameter and solid mass concentration on grinding process efficiency and ground products quality were investigated. The quality criteria considered in this study are particle size distribution, stability and rheological behaviour of the products, as well as their structural properties. The effect of grinding process on the microstructural change of different materials was finally analysed. Particular attention was also focused on the effect of temperature on size reduction process and ground ibuprofen properties.

<p>Masna punjenja predstavljaju grupu proizvoda koje se<br />koriste u konditorskoj i pekarskoj industriji. Kako ona<br />najče&scaron;će sadrže između 30-40% masti, teži se dobijanju<br />formulacija sa redukovanim sadržajem masti. To se<br />može postići zamenom dela masne faze uz upotrebu<br />zamenjivača masti, najče&scaron;će hidrokoloida koji imaju<br />osobine slične osobinama zamenjene masti.<br />Maltodekstrini i njihovi geli mogu se koristiti kao<br />zamenjivači masti. Oni predstavljaju produkte hidrolize<br />skroba koji su rastvorljivi u vodi, mogu da poseduju<br />osobine formiranja gela, imaju slične mazive osobine<br />kao i masti i blagi i neutralni ukus.<br />U ovom radu ispitivane su reolo&scaron;ke osobine različitih<br />maltodekstrina kao i sme&scaron;a namenske biljne masti i<br />rastovora/gela maltodekstrina u odnosu 9:1. Na<br />osnovu dobijenih rezultata utvrđeno je da su od svih<br />ispitivanih komercijalnih maltodekstrina,<br />maltodekstrini <em>01970 </em>i <em>N-Lite D</em> sa namenskom biljnom<br />masti davali stabilne sisteme. Stoga su maltodekstrini<br /><em>01970</em> i <em>N-Lite D</em> kori&scaron;ćeni za dalja istraživanja.<br />Namenska biljna mast zamenjivana je sa 15 i 20%<br />gelima maltodekstrina <em>01970</em> i <em>N-lite D</em> u tri različita<br />odnosa: 16,7% gela maltodekstrina i 83,3% namenske<br />biljne masti; 33,3% gela maltodekstrina i 66,7%<br />namenske biljne masti i 50% gela maltodekstrina i<br />50% namenske biljne masti. Određivane su reolo&scaron;ke<br />osobine metodom histerezisnog postupka,<br />viskoelastične osobine, kao i teksturne osobine<br />pripremanih sme&scaron;a. Dobijeni rezultati su ukazivali da<br />prisustvo maltodekstrinskih gela u sme&scaron;i sa<br />namenskom biljnom masti utiče na pad tiksotropnosti i<br />čvrstoće i povećanje prividnog viskoziteta i<br />viskoelastičnosti ispitivanih sistema. Sve sme&scaron;e<br />namenske biljne masti i gela maltodekstrina služile su<br />kao komponenta masne faze za pripremu masnih<br />punjenja sa smanjenim sadržajem masti. Povećanjem</p><p>zamene dela masne faze maltodekstrinskim gelima u<br />masnim punjenjima uzrokovalo je povećanje<br />tiksotropnosti i čvrstoće kao i promenu boje krajnjeg<br />proizvoda. Na osnovu senzorske ocene sprovedene od<br />strane iskusnog senzorskog panela i na osnovu testa<br />prihvatljivosti od strane netreniranih potro&scaron;ača,<br />najbolje ocenjena masna punjenja bila su ona kod kojih<br />je 5% masti zamenjeno maltodekstrinskim gelima.<br />Međutim, na osnovu rezultata testa prihvatljivosti<br />uočeno je da su i sistemi sa 15% zamene masti bili<br />senzorski prihvatljivi. Takođe je i na osnovu rezultata<br />sprovedenog upitnika na uzorku od 250 ispitanika<br />utvrđeno da su potro&scaron;ači (64,4%) zainteresovani za<br />konzumiranje konditorskih proizvoda sa smanjenim<br />sadržajem masti.</p> / <p>Confectionery fat fillings are products used in<br />confectionery and baking industry. They contain<br />approximately 30-40% of fat. Due to the high fat<br />content, fat fillings have considerable high caloric<br />value. Therefore, there is a trend to decrease fat<br />content in fat filling formulation. That can be achieved<br />by replacing the portion of the fat phase with fat<br />replacers, most often with hydrocolloids having<br />characteristics which tend to mimic properties of<br />replaced fat. Maltodextrins and their gels can be used<br />as potential fat replacers. Maltodextrins represent<br />starch hydrolysis products soluble in water. Also they<br />posses gel forming ability, spreading ability similar to<br />fats, and bland and non sweet taste.<br />Rheological properties of different types of<br />maltodextrins were examined. Also, blends prepared<br />with 90 % of vegetable fat and 10% of maltodextrin<br />solution/gels were rheologically characterised.<br />According to obtained results, it was found that among<br />all tested commercial maltodextrins,<em> 01970</em> and <em>N-Lite<br />D</em> built stable systems. Therefore, they were used in<br />further measurements.<br />Vegetable fat was partially replaced by 15 and 20% of<br /><em>01970</em> and <em>N-Lite D</em> maltodextrin gels in three different<br />ratios (16.66%, 33.33% and 50% respectively). Steady<br />shear, dynamic oscillatory measurements as well as<br />textural measurements were performed. The obtained<br />results indicated that the presence of maltodextrin gels<br />in blends with vegetable fat influenced the decrease of<br />thixotropy and hardness and increase of viscosity and<br />viscoelasticity of the tested systems. All maltodextrin<br />gel/vegetable fat blends were further used for</p><p>preparation of confectionery fat fillings. The increase in<br />the amount of fat reduction resulted in the increase of<br />thixotropy and hardness and change in colour of the<br />final product. According to sensory analysis performed<br />by trained sensory panel as well as by measurement of<br />product acceptance&ndash;preference performed by<br />untrained panellists (consumers), fat filling with 5% fat<br />reduction had the highest scores. However, according<br />to product acceptance&ndash;preference measurements it<br />was estimated that the final product with 15% fat<br />reduction was also sensory acceptable. The results of<br />survey performed on 250 participants showed that<br />consumers (64.4%) were interested in consuming low<br />fat confectionery product</p>

The use of recycled concrete aggregates (RCA) has gained increased attention in the past few decades as an alternative to decrease the carbon footprint of concrete construction. Yet, most of the research performed so far demonstrates that RCA concrete displays inferior performance in the fresh and hardened states when compared to conventional concrete (CC). The latter is believed due to the fact that very often the different microstructure of RCA is not accounted for while the mix-proportioning of RCA concrete. Recently, a number of mix-design procedures accounting for RCA microstructure have been proposed. Amongst them, the Equivalent Volume (EV) method seems to be quite promising. The EV method may proportion RCA concrete made of coarse (CRCA) or fine (FRCA) RCA and is based on a companion CC. Previous research has demonstrated that the fresh and hardened properties of EV mix-designed CRCA are suitable for structural applications. Yet, very few research, analysis and quantification have been conducted on the fresh behaviour of EV mix- proportioned FRCA concrete. This work presents a comprehensive study on the rheological behaviour of EV mix-designed CRCA and FRCA concrete presenting distinct features (i.e. inner qualities, mineralogy, fabrication process, etc.) through the use of a planetary rheometer (IBB). Results show that the EV is capable of proportioning low embodied energy CRCA and FRCA concrete with shear thinning profiles. The latter suggests that these mixtures are suitable for applications under high torque regimes such as vibrated or pumped concrete.