Influência da substituição de areia natural por pó de pedra no comportamento mecânico, microestrutural e eletroquímico de concretos

The construction industry is one of the largest consumers of natural raw materials, and concrete is considered today the most used material wide. This accentuated consumption of natural resources has generated concern with the preservation of the environment, and has motivated various studies related to the use of resid ues, which can partially or entirely substitute, with satisfactory performance, some materials such as the aggregate, and in so doing, decrease the impact on the environment caused by the produced residues. Research has been done to better understand and improve the microstructure of concrete, as well as to understand the mechanism of corrosion in reinforced steel. In this context, this work was developed aiming at discovering the influence of the substitution of natural sand by artificial sand, with rega rd to mechanical resistance, microstructure, and durability. To obtain the electrochemical parameters, an adaptation was made to the galvanostatic electrochemical method to study the corrosion in reinforced steel. Concretes of categories 20 MPa and 40 MPa were produced, containing natural sand, and concretes of the same categories were produced with artificial sand substituting the natural sand, and with the addition of sodium nitrate and sodium chloride. Due to the use of rock dust reject (artificial sand), an evaluation was made of its environmental risk. The results indicate that the concretes of category 20 MPa present a better performance than the concrete made with natural sand, thus making it a viable substitute. For the category 40 MPa, the better performance is from the concrete containing natural sand. The adaptation of the galvanostatic electrochemical technique to the study of the corrosion of reinforced steel within concrete proved to be valid for obtaining electrochemical parameters with a high degree of reliability, considering the number of degrees of freedom

Desenvolvimento de sistemas de aditivos químicos para aplicação em cimentações de poços de petróleo

The primary cementing is an important step in the oilwell drilling process, ensuring the mechanical stability of the well and the hydraulic isolation between casing and formation. For slurries to meet the requirements for application in a certain well, some care in the project should be taken into account to obtain a cement paste with the proper composition. In most cases, it is necessary to add chemicals to the cement to modify its properties, according to the operation conditions and thus obtain slurries that can move inside the jacket providing a good displacement to the interest area. New technologies of preparation and use of chemicals and modernization of technological standards in the construction industry have resulted in the development of new chemical additives for optimizing the properties of building materials. Products such as polycarboxylate superplasticizers provide improved fluidity and cohesion of the cement grains, in addition to improving the dispersion with respect to slurries without additives. This study aimed at adapting chemical additives used in civil construction to be used use in oilwell cement slurries systems, using Portland cement CPP-Special Class as the hydraulic binder. The chemical additives classified as defoamer, dispersant, fluid loss controller and retarder were characterized by infrared absorption spectroscopy, thermogravimetric analyses and technological tests set by the API (American Petroleum Institute). These additives showed satisfactory results for its application in cement slurries systems for oil wells. The silicone-based defoamer promoted the reduction of air bubbles incorporated during the stirring of the slurries. The dispersant significantly reduced the rheological parameters of the systems studied. The tests performed with the fluid loss controller and the retarder also resulted in suitable properties for application as chemical additives in cement slurries

Entre o cartão-postal e a cidade real: um estudo sobre paisagem e produção imobiliária em Natal/RN

Recent studies concerning the landscape have investigated the most important activities that contribute for its modification and have tried to better understand the society through the marks left by its quotidian. It is understood that singular landscapes constitute the cultural patrimonies of the cities, once they are part of the daily life of the citizens and are present in their social representations. Some contemporary authors defend the preservation of the natural and urban landscape trying, specially, to keep its importance for the local population. Natal is a city where the ambient qualities are well defined and known by the beauty of the area where it is located. Situated just between a river and the sea, the city grew following its geographic characteristics. The Potengi River, the Atlantic Ocean and the vast dunes ecosystem represented natural limits to the urban expansion; at the same time they have favored the development of a landscape pattern marked by the dialectic between the natural elements and the human interventions. However, this relationship changed after the intensification of the high rising development process that took place since the 1960s. The urban legislation tried to preserve the features of the local landscape delimiting Areas for Controlling Building High , destined to protect the scenic value of some parts of the city. On the other hand, the civil construction sector has made constant pressure in sense to abolish or to modify this legal instrument, aiming profits that have increased, in the 1990s, because of the consumption and the qualification of the urban space for tourist activities. It is necessary the raising of new elements to stimulate the quarrel about the landscape preservation, the process of the urban space production and the best way for the legislation implementation. This work tries to raise elements about the subject at local level, in sense to use Natal City experience to contribute for the formulation of indicators to raise the question about the lack of measure for subjective values, for example the cultural and affective value of the landscape. The natural elements inserted in the urban profile, represent strong visual references and supply identity to the town; they are part of the collective imaginary and are detached in the social context of the city. Then, why the preservation of the landscape, that estimates the improvement in the quality of life, is not enough to justify the controlling building high already previewed as part of Natal City Legislation? These questions send us to the approach of the landscape, as a community patrimony, alerting that some of its significant esthetics attributes must be preserved as a legacy for the future generations

Padronização e flexibilidade: proposta de um edifício tipo para uma escola técnica profissionalizante

Nowadays the acquisition of sustainable elements and concepts in construction has been increasingly discussed, improved and incorporated to buildings, since the sector directly interferes in the urban space and environment, representing environmental impact. In order to make a sustainable building (Green Building) it is vital to incorporate less damaging constructive practice, starting from the project until the operation of the enterprise, that means to consider an integrated process of conception, implementation, construction and operation. The more effective sustainable principles participation in architecture happens at the projecting step through minimal environment impact solutions. Among the issues varieties that goes with sustainability proposal of the buildings project, there were added to this work the elements that are directly attached to bioclimatic architecture, more specifically the climate variation, ventilation, lighting and sunlight, that directly affect the project conception. It is important to put in evidence that architecture role goes far beyond the simple activity of building spaces; it is the sequence of political, economic, social and cultural elements, having the users as the main apparatus to its materialization. Thereby this professional dissertation consists of an architecture draft for a professional and technological school in the Rio Grande do Norte State, this dissertation is based on the analysis of previous experience and the bioclimatic principles that implicate in building on hot and dry, hot and humid climates, and the use of strategic solutions that aim the optimization of natural light and ventilation

Desenvolvimento de pastas cimentantes utilizando cimentos portland compostos para cimentação de poços petrolíferos

The Compound Portland cements are commonly used in construction, among them stand out the CPII-Z, CPII-F and CPIV. These types of cement have limited application on oil well cementing, having its compositional characteristics focused specifically to construction, as cement for use in oil wells has greater complexity and properties covering the specific needs for each well to be coated. For operations of oil wells cementing are used Portland cements designed specifically for this purpose. The American Petroleum Institute (API) classifies cements into classes designated by letters A to J. In the petroleum industry, often it is used Class G cement, which is cement that meets all requirements needed for cement from classes A to E. According to the scenario described above, this paper aims to present a credible alternative to apply the compound cements in the oil industry due to the large availability of this cement in relation to oil well cements. The cements were micro structurally characterized by XRF, XRD and SEM tests, both in its anhydrous and hydrated state. Later technological tests were conducted to determine the limits set by the NBR 9831. Among the compound cements studied, the CPII-Z showed satisfactory properties for use in primary and secondary operations of oil wells up to 1200 meters cementing

O acesso à habitação no Brasil em tempos de capitalismo financeirizado : uma análise do Programa Minha Casa, Minha Vida

Dissertação (mestrado)—Universidade de Brasília, Instituto de Ciências Humanas, Departamento de Serviço Social, Programa de Pós-Graduação em Política Social, 2016.

Efeito da adição de cargas minerais leves na resistência mecânica de grautes para cimentação de poços offshore

The preparation of cement slurries for offshore well cementing involves mixing all solid components to be added to the mixing water on the platform. The aim of this work was to study the formulation of pre-prepared dry mixtures, or grouts, for offshore oilwell cementing. The addition of mineral fillers in the strength of lightweight grouts applied for depths down to 400 m under water depths of 500 m was investigated. Lightweight materials and fine aggregates were selected. For the choice of starting materials, a study of the pozzolanic activity of low-cost fillers such as porcelain tile residue, microsilica and diatomaceous earth was carried out by X-ray diffraction and mechanical strength tests. Hardened grouts containing porcelain tile residue and microsilica depicted high strength at early ages. Based on such preliminary investigation, a study of the mechanical strength of grouts with density 1.74 g/cm3 (14.5 lb/gal) cured initially at 27 °C was performed using cement, microsilica, porcelain tile residue and an anti-foaming agent. The results showed that the mixture containing 7% of porcelain tile residue and 7% of microsilica was the one with the highest compressive strength after curing for 24 hours. This composition was chosen to be studied and adapted for offshore conditions based on testes performed at 4 °C. The grout containing cement, 7% of porcelain tile residue, 7% of active silica and admixtures (CaCl2), anti-foaming and dispersant resulted satisfactory rheology and mechanical strength after curing for 24 hours of curing

ZONEAMENTO ecológico-econômico da região integrada de desenvolvimento do Distrito Federal e entorno: fase I.

v. 1: geologia, geologia estrutural, materiais para construção civil, insumos agrícolas e outros bens minerais, formações superficiais. + mapas temáticos: Geológico, Materiais para construção civil, Insumos agrícolas e outros bens minerais, Formações superficiais. v. 2: geomorfologia, solos, aptidão agrícola das terras. + mapas temáticos: Geomorfológico, Reconhecimento de Baixa Intensidade de Solos, Aptidão Agrícola das Terras. v. 3: levantamento geoquímico, estudos hidrológicos, hidrogeologia, uso atual e cobertura do solo, unidades de conservação e legislação, geoprocessamento. + mapas temáticos: Levantamento geoquímico, Rede hidrometeorológica, Hidrogeológico, Uso atual do Solo, Cobertura Vegetal e Unidades de Conservação.

FAVELA DA VERGUEIRO E MODERNIZAÇÃO À BRASILEIRA: APONTAMENTOS SOBRE INDUSTRIALIZAÇÃO E TRABALHO NA FORMAÇÃO DO CAPITALISMO NO BRASIL

A presente pesquisa trata da favela da Vergueiro, em São Paulo. Surgida nos anos 1950, foidespejada na década de 1970, representando um momento em que o fenômeno das favelas ainda não assumira grandes proporções na cidade. Sua análise se integra num estudo mais amplo sobre a modernização brasileira. Retomam-se debates sobre a indústrialização e o desenvolvimento do capitalismo brasileiro, que frequentemente situaram as favelas enquanto marginalidade ou atraso; inversamente, pressupõe-se que o desenvolvimento do capital amplia tais fenômenos. Recoloca-se a noção centro-periferia enquanto oposição necessária. Faz-se leituras de "O Capital" de Marx considerando a determinação da socialização mediada por abstrações, assumindo potencia explicativa a teoria do valor, o fetiche e a crise enquanto imanência do processo reprodutivo do capital. Coloca-se a discussão sobre o trabalho produtivo x improdutivo e a autonomização da reprodução do capital e capital fictício, verificando a importância das condições de trabalho para o surgimento e formação de favelas. Até o momento, verificou-se que a população daquela favela empregava-se na construção civil e serviços domésticos, tendo sido posteriormente deslocada para os extremos da metrópole (para outras favelas e loteamentos periféricos). Este trabalho é um mestrado em andamento.

INDUSTRIALIZAÇÃO, DINÂMICA TERRITORIAL E IMPLICAÇÕES SOCIOAMBIENTAIS EM MATO GROSSO DO SUL/BR

O trabalho se refere a um estudo sobre a industrialização, a dinâmica territorial e as implicações socioambientais em Três Lagoas/MS. O Parque Industrial decorre do processo de (des)concentração/(re)concentração industrial, no Brasil. Há intensa dinâmica territorial, que se dá a partir do processo industrial, que se circunscreve em três Distritos Industriais. Analisaram-se a estrutura e a dinâmica industrial, bem como os conflitos estabelecidos entre as forças produtivas. Também se avaliaram as alterações decorrentes da incorporação de tecnologia, produtividade e os reflexos no uso e ocupação das terras no campo. Ainda averiguou-se se há riscos de contaminação pelas indústrias, seja pela contaminação das águas subterrâneas e do solo, seja pela emissão de gases na atmosfera, os quais foram avaliados com vista à elaboração de um plano de redução dos riscos de eventos perigosos e contaminação ambiental. No Distrito Industrial I, há 22 empresas, sendo 11 ligadas a construção civil, de baixa periculosidade, e, perigosas destacam-se 3 metalúrgicas, uma química, uma de plástico e uma carvoaria. No Distrito Industrial II, concentram-se 27 empresas, destas apenas 3, a de alimentos, bebidas e de construção civil não são perigosas. Destacando-se dentre a perigosas, 8 indústrias têxteis, 6 metalúrgicas e 6 petroquímicas. O Distrito Industrial III situa-se fora do núcleo urbano, e se destina às megaindústrias: fábricas de papel e celulose, - consórcio Fibria/Internacional Paper - e uma de fertilizantes da Petrobras. As indústrias do Distrito Industrial II contam com aparato tecnológico mais avançado, isto é, coadunam as novas tecnologias do atual período técnico-científico e os incentivos fiscais – doação de terreno, isenções de impostos - com o aparato de objetos espaciais que o município oferece - vias intermodais, energia elétrica, e, a possibilidade da exploração da força de trabalho com baixos salários. Esses empreendimentos promoveram nova dinâmica territorial, criando novos sentidos e funções, impondo novos valores e cultura, inclusive os estilos de moradia, pois a expansão da periferia da cidade agora, não dá lugar somente aos conjuntos habitacionais populares, mas também aos luxuosos condomínios horizontais fechados; além do aumento da opção de moradias em condomínios horizontais. A paisagem urbana se metamorfoseia, pois a territorialização do capital industrial delineia novas territorialidades, a cidade ganha ares de cidade grande.