Thesis (D. Tech. ( Mechanical Engineering )) - Central University of technology, Free State, 2012 / In this study an alternative indirect Rapid Tooling process is proposed. It essentially consists of producing sand moulds by Additive Manufacturing (AM) processes followed by casting of tools in the moulds. Various features of this tool making method have been investigated. A process chain for the proposed tool manufacturing method was conceptually developed. This process chain referred to as Rapid Casting for Tooling (RCT) is made up of five steps including Computer Aided Design (CAD) modeling, casting simulation, AM of moulds, metal casting and finishing operations. A validation stage is also provided to determine the suitability of the tool geometry and material for RCT. The theoretical assessment of the RCT process chain indicated that it has potential benefits such as short manufacturing time, low manufacturing cost and good quality of tools in terms of surface finish and dimensional accuracy. Focusing on the step of AM of the sand moulds, the selection of available AM processes between the Laser Sintering (LS) using an EOSINT S 700 machine and Three Dimensional Printing using a Z-Corporation Spectrum 550 printer was addressed by means of the Analytic Hierarchy Process (AHP). The criteria considered at this stage were manufacturing time, manufacturing cost, surface finish and dimensional accuracy. LS was found to be the most suitable for RCT compared to Three Dimensional Printing. The overall preferences for these two alternatives were respectively calculated at 73% and 27%. LS was then used as the default AM process of sand moulds in the present research work. A practical implementation of RCT to the manufacturing of foundry tooling used a case study provided by a local foundry. It consisted of the production of a sand casting pattern in cast iron for a high pressure moulding machine. The investigation confirmed the feasibility of RCT for producing foundry tools. In addition it demonstrated the crucial role of casting simulation in the prevention of casting defects and the prediction of tool properties. The challenges of RCT were found to be exogenous mainly related to workmanship. An assessment of RCT manufacturing time and cost was conducted using the case study above mentioned as well as an additional one dealing with the manufacturing of an aluminium die for the production of lost wax patterns. Durations and prices of RCT steps were carefully recorded and aggregated. The results indicated that the AM of moulds was the rate determining and cost driving step of RCT if procurement of technology was considered to be a sunk cost. Overall RCT was found to be faster but more expensive than machining and investment casting. Modern surface analyses and scanning techniques were used to assess the quality of RCT tools in terms of surface finish and dimensional accuracy. The best surface finish obtained for the cast dies had Ra and Rz respectively equal to 3.23 μm and 11.38 μm. In terms of dimensional accuracy, 82% of cast die points coincided with die Computer Aided Design (CAD) data which is within the typical tolerances of sand cast products. The investigation also showed that mould coating contributed slightly to the improvement of the cast tool surface finish. Finally this study also found that the additive manufacturing of the sand mould was the chief factor responsible for the loss of dimensional accuracy. Because of the above, it was concluded that light machining will always be required to improve the surface finish and the dimensional accuracy of cast tools. Durability was the last characteristic of RCT tools to be assessed. This property was empirically inferred from the mechanical properties and metallographic analysis of castings. Merit of durability figures of 0.048 to 0.152 were obtained for the cast tools. It was found that tools obtained from Direct Croning (DC) moulds have merit of durability figures three times higher than the tools produced from Z-Cast moulds thus a better resistance to abrasion wear of the former tools compared to the latter.

Purpose: The building industry has a big environmental impact. The timber construction can reduce the impact of the industry because timber is an environmentally friendly material. One of the biggest problems with lightweight construction is sound insulation. The aim of this report is to study two floor construction with different sound insulation materials from an environmental perspective. The materials that will be studied in this report are sand and macadam. The aim of the report is to create a clear comparison between these floor layers and to suggest an improvement proposal. Method: The methods that have been used in the report are literature studies, life-cycle assessment, document analysis and interview. The LCA, document analysis and literature studies are the starting point, based on these methods, the first two questions in this paper will be answered. Using the interview was able to conduct information for the last question. Findings: This study has shown that sand has a less environmental impact than what macadam has. The improvement proposal that has been suggested in this study is using sawdust with sand as sound insulations layer. Decreasing the amount of sand in floors can have a positive effect on the environment. Implications: As a conclusion of this paper, it is proven that sand as a sound insulation material is more favorable for the environment than the macadam. The reason is caused by the process of extracting macadam. The process is more complicated and more energy demanding. Another conclusion is that reducing the amount of sand and replacing the missing amount with sawdust can reduce the environmental impact and increase the sound insulation ability. A recommendation for similar papers more abilities could be included in the analysis to provide a more including and fair result. Limitations: This paper is limited to investigate sound insulation materials combined with CLT-slabs exclusively. The methods which have been used provided relevant data to help this paper create conclusions. The goal was to create an all-around answer so that the result could be applicable in other analysis. Keywords: LCA, sand, macadam, lightweight construction, impact sound insulation, environment.

When Biosand filters cannot be constructed with crushed quarry rock due to resource limitations, a suitable alternative filter media is needed. In this research, two crushed quarry rock alternatives were examined. Three bench-scale Biosand filters with crushed rock, beach sand, and heat-treated beach sand media were simultaneously dosed with Willamette River water seeded with K-12 E. coli for 31 days. Influent and effluent filtrate was analyzed for E. coli using 3M Petrifilm E. coli/Coliform plate counts; influent and effluent pH, conductivity, turbidity, dissolved oxygen, and temperature were monitored. All three filters achieved stable E. coli removal efficiencies of 99% or greater after filter maturation, suggesting that it is possible to effectively use beach sand and heat-treated beach sand in Biosand filters for pathogenic bacteria removal. Mean effluent E. coli concentrations for crushed rock, beach sand, and heat-treated beach sand filters were 12, 29, and 30 CFU/mL respectively. Crushed rock filter effluent was significantly lower in mean effluent E. coli concentration than beach sand (P < 0.001) and heat-treated beach sand (P < 0.001) filter effluents, suggesting that beach sand and heat-treated beach sand media should only be used as a secondary option to crushed rock media due to potentially greater exposure risk to pathogenic bacteria. / Graduation date: 2013

I förskolans utemiljö är det vanligt att det finns en sandlåda på gården. Den är centralt placerad och barnen är där och leker. Enligt den nya Skollagen och förskolans reviderade läroplan ska verksamhetens innehåll vila på vetenskaplig grund och beprövad erfarenhet. Detta gäller även den verksamhet som pågår i sandlådan. Men vad är det som sker när sanden, barnen och lekredskapen möts i sandlådan? Detta är en kvalitativ studie som utifrån ett intra-aktivt perspektiv syftar till att synliggöra hur sanden i sandlådan, lekredskap och de yngsta barnen (1-3 år) skapar möjligheter och villkor för lek och meningsskapande. Utifrån fotografier, anteckningar och videofilm har nya begrepp skapats för att kunna beskriva och förklara det som sker i sandlådan. Resultaten visar på en ständig rörelse där sand, barn och lekredskap förflyttas, förändras och förvandlas. Barn, sand och lekredskap leker tillsammans i ömsesidiga och sammanvävda intra-aktioner. Studiens resultat bidrar till att visa på dessa komplexa processer och hur små barn, med hela sin kropp och alla sinnen, medvetet tillsammans med sanden och lekredskapen skapar ny mening och nya möjligheter. / In the preschool outdoor environment, it is common that there is a sandbox. It is centrally located and the children are there and play. According to the new Education act and Curriculum for the Preschool Lpfö 98 (Revised 2010) the content should be based on scientific evidence and proven experience. This also applies to the activities being performed in the sandbox. But what is happening in the sand, when the children and play equipment come together in the sandbox? This is a qualitative study based on an intra-active perspective, whose purpose is to visualize how the sand in the sandbox, the playground equipment and the youngest children (1-3 years) create opportunities and conditions for play and meaning. Based on photographs, notes and video, new concepts are created to describe and explain what happens in the sandbox. The results show a continuous movement in which sand, children, and playground equipment is moved, changed and transformed. Children, sand and playground equipment play together in mutual and intertwined intra-actions. The findings in the study help to demonstrate how these complex processes and young children, with the whole body and the senses, consciously together with the sand and play equipment create new meaning and new possibilities.

Improving methods of hydrocarbon production and developing new techniques for the creation of natural gas storage facilities are critically important for the petroleum industry. This dissertation focuses on two key topics: (1) mechanisms of sand production from petroleum reservoirs and (2) mechanical characterization of caverns created in carbonate rock formations for natural gas storage. Sand production is the migration of solid particles together with the hydrocarbons when extracted from petroleum reservoirs. It usually occurs from wells in sandstone formations that fail in response to stress changes caused by hydrocarbon withdrawal. Sand production is generally undesirable since it causes a variety of problems ranging from significant safety risks during high-rate gas production, to the erosion of downhole equipment and surface facilities. It is widely accepted that a better understanding of the mechanics of poorly-consolidated formations is required to manage sand production; which, in turn, enables the cost effective production of gas and oil resources. In this work, a series of large-scale laboratory experiments was conducted in fully saturated, cohesionless sand layers to model the behavior of a petroleum reservoir near a wellbore. We directly observed several key characteristics of the sand production phenomenon including the formations of a stable cavity around the wellbore and a sub-radial flow channel at the upper surface of the tested layer. The flow channel is a first-order feature that appears to be a major part of the sand production mechanism. The channel cross section is orders of magnitude larger than the particle size, and once formed, the channel becomes the dominant conduit for fluid flow and particle transport. The flow channel developed in all of our experiments, and in all experiments, sand production continued from the developing channel after the cavity around the borehole stabilized. Our laboratory results constitute a well constrained data set that can be used to test and calibrate numerical models employed by the petroleum industry for predicting the sand production phenomenon. Although important for practical applications, real field cases are typically much less constrained. We used scaling considerations to develop a simple analytical model, constrained by our experimental results. We also simulated the behavior of a sand layer around a wellbore using two- and three-dimensional discrete element methods. It appears that the main sand production features observed in the laboratory experiments, can indeed be reproduced by means of discrete element modeling. Numerical results indicate that the cavity surface of repose is a key factor in the sand production mechanism. In particular, the sand particles on this surface are not significantly constrained. This lack of confinement reduces the flow velocity required to remove a particle, by many orders of magnitude. Also, the mechanism of channel development in the upper fraction of the sample can be attributed to subsidence of the formation due to lateral extension when an unconstrained cavity slope appears near the wellbore. This is substantiated by the erosion process and continued production of particles from the flow channel. The notion of the existence of this surface channel has the potential to scale up to natural reservoirs and can give insights into real-world sand production issues. It indicates a mechanism explaining why the production of particles does not cease in many petroleum reservoirs. Although the radial character of the fluid flow eventually stops sand production from the cavity near the wellbore, the production of particles still may continue from the propagating surface (interface) flow channel. The second topic of the thesis addresses factors affecting the geometry and, hence, the mechanical stability of caverns excavated in carbonate rock formations for natural gas storage. Storage facilities are required to store gas when supply exceeds demand during the winter months. In many places (such as New England or the Great Lakes region) where no salt domes are available to create gas storage caverns, it is possible to create cavities in limestone employing the acid injection method. In this method, carbonate rock is dissolved, while CO₂ and calcium chloride brine appear as products of the carbonate dissolution reactions. Driven by the density difference, CO₂ rises towards the ceiling whereas the brine sinks to the bottom of the cavern. A zone of mixed CO₂ , acid, and brine forms near the source of acid injection, whereas the brine sinks to the bottom of the cavern. Characterization of the cavern shape is required to understand stress changes during the cavity excavation, which can destabilize the cavern. It is also important to determine the location of the mixture-brine interface to select the place of acid injection. In this work, we propose to characterize the geometry of the cavern and the location of the mixture-brine interface by generating pressure waves in a pipe extending into the cavern, and measuring the reflected waves at various locations in another adjacent pipe. Conventional governing equations describe fluid transients in pipes loaded only by internal pressure (such as in the water hammer effect). To model the pressure wave propagation for realistic geometries, we derived new governing equations for pressure transients in pipes subjected to changes in both internal and external (confining) pressures. This is important because the internal pressure (used in the measurement) is changing in response to the perturbation of the external pressure when the pipe is contained in the cavern filled with fluids. If the pressure in the cavern is perturbed, the perturbation creates an internal pressure wave in the submerged pipe that has a signature of the cavern geometry. We showed that the classic equations are included in our formulation as a particular case, but they have limited validity for some practically important combinations of the controlling parameters. We linearized the governing equations and formulated appropriate boundary and initial conditions. Using a finite element method, we solved the obtained boundary value problem for a system of pipes and a cavern filled with various characteristic fluids such as aqueous acid, calcium chloride brine, and supercritical CO₂ . We found that the pressure waves of moderate amplitudes would create measurable pressure pulses in the submerged pipe. Furthermore, we determined the wavelengths required for resolving the cavern diameter from the pressure history. Our results suggest that the pressure transients technique can indeed be used for characterizing the geometry of gas storage caverns and locations of fluid interfaces in the acid injection method.

Après avoir distingué trois aspects explicatifs propres au roman (aspects psychologique, social ou romanesque) et défini, grâce à eux, trois types de romans (romans de caractères, de mœurs ou d’intrigue), ce travail s’intéresse plus particulièrement au roman de mœurs à l’époque de la Restauration et de la Monarchie de Juillet. Héritant de toute une tradition, ce genre s’illustre particulièrement dans le roman historique à la Walter Scott, puis dans le roman contemporain des physiologies. Balzac, d’abord influencé par le roman de mœurs en tant que tel, développe dans La Comédie humaine une forme hybride (mêlant aspects social et psychologique, roman de caractères et roman de mœurs), que l’on peut appeler roman réaliste (on y note un surinvestissement du vraisemblable romanesque). Cette définition du réalisme n’aplanit en rien les différences entre tel ou tel auteur ; elle permet, au contraire, de prendre la mesure des poétiques bien particulières développées par des romanciers comme Stendhal, George Sand ou Champfleury. / After having distinguished three explicative aspects of the novel (the psychological, social and plot-driven aspects) and defined three corresponding types of novels (novels of characters, manners and plot), this work focuses on the novel of manners during the Bourbon Restoration and the July Monarchy. Heir to quite an old tradition, this genre is at its peak with the Scottian historical novel and the novel of contemporary manners of the 1820’s. Balzac, first influenced by the novel of manners, develops in The Human Comedy a hybrid form (combining social and psychological aspects, novel of characters and novel of manners), which we may call the realistic novel (characterized by an overloading of verisimilitude). This definition of realism does not erase the differences between the authors; it allows, on the contrary, to appreciate the specific poetics developed by Stendhal, George Sand or Champfleury.

Na produção de concreto estrutural, apesar dos avanços tecnológicos, ainda se utilizam de materiais in natura, o que vem ocasionando problemas ambientais e econômicos a cadeia produtiva. Um dos problemas está associado à extração de areia do leito de rios, motivo pelo quais os profissionais envolvidos com a tecnologia do concreto vêm buscando alternativas ao uso dessa areia na produção de concreto estrutural. Uma alternativa que vem sendo estudada, pela grande disponibilidade, é o uso de uma areia produzida a partir da cominuição de rochas, chamada de areia de britagem. Na região de Caxias do Sul existem grandes reservas de rochas de origem basáltica (Riodacitos), a partir das quais é possível se produzir esse tipo de areia. Neste trabalho foi avaliada a viabilidade de se substituir à areia natural por areia de britagem de rochas basálticas produzidas em cinco empresas mineradoras localizadas na região de Caxias do Sul. O estudo foi desenvolvido em três etapas: na primeira foram avaliadas as características das areias decorrentes da mineralogia e petrografia das rochas e do processo de fabricação nas mineradoras; na segunda etapa foram avaliadas as propriedades do concreto através do método de dosagem EPUSP/IPT; na terceira etapa, para comprovar a eficiência do método de dosagem, foram produzidos traços específicos para cada tipo de areia. Os resultados de caracterização demonstraram que as areias de britagem possuem características diferentes das da areia natural e que apenas duas das cinco areias avaliadas apresentam propriedades que permitem a sua utilização em concreto estrutural. As propriedades decorrentes do processo de fabricação, como a presença de material pulverulento, forma e textura dos grãos provocaram um aumento no teor de argamassa, o que influenciou diretamente no proporcionamento dos materiais constituintes. Os resultados para a avaliação das propriedades do concreto demonstraram que, para um mesmo traço, a resistência a compressão axial e o módulo de elasticidade são menores nos concretos produzidos com areias de britagem. Corrigindo-se os teores de argamassa e produzindo-se traços específicos para cada tipo de areia é possível produzir concretos com resistências desejadas. Apesar das diferenças encontradas nas propriedades das areias foi comprovado que as areias de britagem estudadas podem ser utilizadas na produção de concreto estrutural de cimento Portland, substituindo totalmente à areia natural. / Submitted by Marcelo Teixeira (mvteixeira@ucs.br) on 2014-06-03T20:43:28Z No. of bitstreams: 1 Dissertacao Edison Humberto Viero.pdf: 1978943 bytes, checksum: fab5a6668b1624ae95d901331299a4d3 (MD5) / Made available in DSpace on 2014-06-03T20:43:28Z (GMT). No. of bitstreams: 1 Dissertacao Edison Humberto Viero.pdf: 1978943 bytes, checksum: fab5a6668b1624ae95d901331299a4d3 (MD5) / Despite the technological advances on the structural concrete production, in natura materials are still used. This fact has been causing environmental and economic problems to the manufacturing chain. One of the problems is related to the sand extraction from riverbeds, this is the reason why professionals involved with concrete technology are searching for alternatives to the use of this type of sand in the structural concrete manufacturing. One alternative that is being studied in various parts of the country, because its large availability is a sand produced from the rocks´ comminution, called crushing sand. In the Caxias do Sul region there are large reservations of basaltic rocks origin (Riodacitos), from which it is possible to produce this type of sand. In this work, it was evaluated the feasibility of substitute natural sand for crushing sand from basaltic rocks produced in five mining companies located at Caxias do Sul region. The study was developed in three stages: on the first one, the features of the sand that arises from rocks´ mineralogy and petrography and from the mining manufacturing process were evaluated; on the second the concrete properties through the EPUSP/IPT dosage method were evaluated; on the third they were produced specific trace to each type of sand in order to verify the efficiency of the dosage method. The characterization results established that the crushing sand have different features IF compared with natural sand and that Just two out of Five evaluated sands presented properties that allow its use in structural concrete. The properties arising from the fabrication process, for example the presence of powder material, the grains´ shape and texture caused the raise of the plaster content, which influenced directly on the constituents materials proportioning. The results of the concrete properties evaluation showed that, for the same trace, the resistance to axial compression and the elasticity module are smaller in the concretes produced with crushing sand. If the plaster content is corrected and the specific traces are produced for each type of sand it is possible to produce concretes with desired resistance. In spite of the differences found on the sand properties it was proven that the crushing sand produced at the Caxias do Sul region can be used on the portland cement structural concrete production, replacing totally the natural sand used.

Phenomenological models are presented which predicts transpiration rates (E) of individual leaves of Scaevola plumieri, an indigenous dune pioneer, and Ammophila arenaria, an exotic grass species introduced to stabilise mobile sand. In both cases E is predictably related to atmospheric vapour pressure deficit (VPD). VPD is calculated from measurements of ambient temperature and humidity, hence, where these two environmental variables are known, E can be calculated. Possible physiological reasons for the relationships of E to VPD in both species are discussed. Scaling from measurements of E at the leaf level to the canopy level is achieved by summing the leaf area of the canopy in question. E is predicted for the entire canopy leaf area by extrapolation to this larger leaf area. Predicted transpiration rates of individual shoot within the canopy were tested gravimetrically and shown to be accurate in the case of S. plumieri, but less so in the case of A. arenaria. Using this model, the amount of water used by a known area of sand dune is shown to be less than the rainfall input in the case of S. plumieri in wet and dry years. The water use of A. arenaria exceeds rainfall in the low-rainfall year of 1995, while in 1998 rainfall input is slightly higher than water extraction by the plants. Using a geographic information system (GIS), regional maps (surfaces) of transpiration were calculated from surfaces of mean monthly temperature and mean monthly relative humidity. Monthly surfaces of transpiration were subtracted from the monthly median rainfall to produce a surface of mean monthly water deficit. Areas of water surpluses along the coast correspond with the recorded distribution of both species in the seasons that the plants are most actively growing and reproducing. This suggests that unfavourable water availability during these two species growth periods limit their distributions along the coast. In addition to unfavourable water deficits, additional climatic variables that may be important in limiting the distribution of these two species were investigated using a discriminant function analysis.

« L'art, c'est la vie qui s'adresse à la vie » écrivait Pierre Leroux. Ces mots très simples proposent en vérité un programme complet. Socialiste, philosophe, critique littéraire et journaliste, Pierre Leroux a développé une théorie de l'évolution vitale sur tous les fronts ; l'agriculture, la politique, et aussi la littérature qui obéit aux mêmes lois de développement, à une même doctrine de la perfectibilité. Cette thèse vise à expliquer comment Leroux inscrit sa critique littéraire au coeur de sa philosophie de l'histoire, dans ce qu'il appelait la philosophie de l'histoire littéraire. Il s'agit de comprendre à la fois la tradition philosophique dans laquelle il s'inscrit, en regard des nombreuses philosophies de l'histoire qui se sont développées en France et en Allemagne depuis le XVIIIème siècle, quels sont les tenants et aboutissants de cette doctrine de la perfectibilité appliquée à la littérature, en synchronie comme en diachronie, en quoi la littérature tient une place capitale dans ce système, et quel a été son impact sur les auteurs de son temps, notamment George Sand dont il influença beaucoup les oeuvres à partir de 1837. A la fois continuateur de Perrault, de Rousseau, de Germaine de Staël, et de Saint-Simon, Leroux a accueilli favorablement dès 1830 le cri de douleur des romantiques qui raisonnait dans toute l'Europe, et théorisait « le style symbolique » tout en les mettant en garde contre les dérives que pouvait entrainer une littérature passéiste, faite uniquement pour les yeux, préférant les encourager à suivre la voie du progrès continu, et à se faire les vrais représentants de leur époque dans un siècle de douleur et de désir. / Pierre Leroux used to say: 'Art is life which is speaking to life'. These simple words offer a truly full program. Socialist, philosopher, literary critic and journalist, Pierre Leroux (17971871 developed a theory of vital evolution on all fronts; agriculture, politics, and literature which also obeys the same laws of development, the same doctrine of perfectibility. This thesis aims at explaining how Leroux entered his literary criticism at the core of his philosophy of history, in what he called the philosophy of literary history. This work deals with understanding both the philosophical tradition to which he belongs, comparing with the numerous philosophies of history that have developed in France and in Germany since the eighteenth century. It is about what the ins and outs of this doctrine of perfectibility which has been applied to literature are, as well as its synchrony and diachrony, and about the crucial place literature holds ; and what its impact on the authors at the time was, including George Sand. Pierre Leroux had influenced many of her works from 1837. Thanks to Perrault's, Rousseau's, Germaine de Stael's, and Saint-Simon's legacy, Leroux welcomed in 1830 the romantic call of pain that was heard throughout Europe, and theorized "the symbolic style" while warning them, for instance Victor Hugo and Alphonse de Lamartine, against the drifts that an outdated literature which focused itself on the form could cause. Thus, Pierre Leroux used to preferred to encourage them in order to follow the path of constant improvement, and to make them become the true representatives of their time in a century of pain and desire.

Na produção de concreto estrutural, apesar dos avanços tecnológicos, ainda se utilizam de materiais in natura, o que vem ocasionando problemas ambientais e econômicos a cadeia produtiva. Um dos problemas está associado à extração de areia do leito de rios, motivo pelo quais os profissionais envolvidos com a tecnologia do concreto vêm buscando alternativas ao uso dessa areia na produção de concreto estrutural. Uma alternativa que vem sendo estudada, pela grande disponibilidade, é o uso de uma areia produzida a partir da cominuição de rochas, chamada de areia de britagem. Na região de Caxias do Sul existem grandes reservas de rochas de origem basáltica (Riodacitos), a partir das quais é possível se produzir esse tipo de areia. Neste trabalho foi avaliada a viabilidade de se substituir à areia natural por areia de britagem de rochas basálticas produzidas em cinco empresas mineradoras localizadas na região de Caxias do Sul. O estudo foi desenvolvido em três etapas: na primeira foram avaliadas as características das areias decorrentes da mineralogia e petrografia das rochas e do processo de fabricação nas mineradoras; na segunda etapa foram avaliadas as propriedades do concreto através do método de dosagem EPUSP/IPT; na terceira etapa, para comprovar a eficiência do método de dosagem, foram produzidos traços específicos para cada tipo de areia. Os resultados de caracterização demonstraram que as areias de britagem possuem características diferentes das da areia natural e que apenas duas das cinco areias avaliadas apresentam propriedades que permitem a sua utilização em concreto estrutural. As propriedades decorrentes do processo de fabricação, como a presença de material pulverulento, forma e textura dos grãos provocaram um aumento no teor de argamassa, o que influenciou diretamente no proporcionamento dos materiais constituintes. Os resultados para a avaliação das propriedades do concreto demonstraram que, para um mesmo traço, a resistência a compressão axial e o módulo de elasticidade são menores nos concretos produzidos com areias de britagem. Corrigindo-se os teores de argamassa e produzindo-se traços específicos para cada tipo de areia é possível produzir concretos com resistências desejadas. Apesar das diferenças encontradas nas propriedades das areias foi comprovado que as areias de britagem estudadas podem ser utilizadas na produção de concreto estrutural de cimento Portland, substituindo totalmente à areia natural. / Despite the technological advances on the structural concrete production, in natura materials are still used. This fact has been causing environmental and economic problems to the manufacturing chain. One of the problems is related to the sand extraction from riverbeds, this is the reason why professionals involved with concrete technology are searching for alternatives to the use of this type of sand in the structural concrete manufacturing. One alternative that is being studied in various parts of the country, because its large availability is a sand produced from the rocks´ comminution, called crushing sand. In the Caxias do Sul region there are large reservations of basaltic rocks origin (Riodacitos), from which it is possible to produce this type of sand. In this work, it was evaluated the feasibility of substitute natural sand for crushing sand from basaltic rocks produced in five mining companies located at Caxias do Sul region. The study was developed in three stages: on the first one, the features of the sand that arises from rocks´ mineralogy and petrography and from the mining manufacturing process were evaluated; on the second the concrete properties through the EPUSP/IPT dosage method were evaluated; on the third they were produced specific trace to each type of sand in order to verify the efficiency of the dosage method. The characterization results established that the crushing sand have different features IF compared with natural sand and that Just two out of Five evaluated sands presented properties that allow its use in structural concrete. The properties arising from the fabrication process, for example the presence of powder material, the grains´ shape and texture caused the raise of the plaster content, which influenced directly on the constituents materials proportioning. The results of the concrete properties evaluation showed that, for the same trace, the resistance to axial compression and the elasticity module are smaller in the concretes produced with crushing sand. If the plaster content is corrected and the specific traces are produced for each type of sand it is possible to produce concretes with desired resistance. In spite of the differences found on the sand properties it was proven that the crushing sand produced at the Caxias do Sul region can be used on the portland cement structural concrete production, replacing totally the natural sand used.