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A NP EN 13670:2010 versus a NP ENV 13670-1:2007
No full textComparam-se as duas normas portuguesas sobre execução das estruturas de betão – a actual NP ENV
13670-1 “Execução de estruturas de betão. Parte 1: Regras gerais”, em vigor conforme o Decreto-Lei
n.º 301/2007, de 23 de Agosto, e a que está em preparação, NP EN 13670 “Execução de estruturas de
betão”, e que irá substituir aquela, conduzindo, oportunamente, à alteração desta legislação.
A comparação é feita secção a secção, relacionando-a também, onde for o caso, com outra legislação
tratando de aspectos ligados à construção de obras públicas ou particularesDE/NCE201010 a 12 de Novembr
Basic Characteristics of Concrete Durability as the Criteria for Curing Classes Selection According to EN 13670:2009
No full textAbstractIn EN 13670:2009 standard: Execution of concrete structures there are general rules of moisture curing of concrete in structures. In the standard 4 classes of concrete curing are described. Determination of curing class depends on required level of compressive strength immediately after curing (percentage of required characteristic strength after 28 days). Time of curing depends on rate of strength development and concrete surface temperature. In the standard there is a lack of information about influence of curing class on concrete durability characteristics.The main condition to obtain durable concrete is proper curing regime. Not cured on improperly cured concrete has weakened surface layer. Extremely faults in curing process could lead to defects visible on the concrete surface. More often defects are latent inside the concrete and could be revealed during exploitation, leading to durability reduction. The main effect is increase of surface layer porosity (reinforcement cover) and decrease of its protective properties and tightness. Consequently worsening of mechanical properties could be observed as well as water-tightness, frost resistance, chemical aggression resistance, carbonation resistance and diffusivity of chloride.The analysis shown in the paper are the result of 3-yers long investigation conducted by authors, which main goal was to determine appropriateness and way to include durability requirements in designing of curing class according to EN 13670:2009. Thawing-freezing resistance, scaling with salts resistance, depth of water penetration under pressure and absorptivity were adopted as the basic durability factors. Concretes with different cement types, different rate of compressive strength development, air-entrained and non-air-entrained were tested. Time of curing was differentiated in the range of classes 1,3,4 following standard EN 13670:2009 requirements. Practical conclusions were formulated which allows to consider durability presumptions in technological requirements contained in concrete works specifications
O descimbramento na NP EN 13670
No full textA remoção dos cimbres e escoras dum elemento de betão estrutural é um momento particular do seu comportamento estrutural na medida em que o betão não terá ainda atingido a resistência de projecto. A presente comunicação descreve como foi obtida, na NP EN 13670, uma expressão para estima de prazos de descimbramento em função da razão entre as cargas no momento da remoção e
as cargas de projecto, da temperatura e do nível de desenvolvimento da resistência à compressão do betão.9410ppDM/Chefia201224 a 26 de outubro de 201
Classes of concrete maintenance in accordance with PN-EN 13670:2011 – selection and influence on the properties of concrete
No full textŚwieży beton powinien być pielęgnowany tak, aby zminimalizować skurczliwość plastyczną oraz zapewnić odpowiednią wytrzymałość i trwałość strefy powierzchniowej. Prawidłowa pielęgnacja jest warunkiem koniecznym do zapewnienia trwałości betonu. Celem prowadzonych badań było określenie wpływu przyjętej, zgodnie z normą PN-EN 13670:2011, klasy pielęgnacji betonu na właściwości związane z jego przypowierzchniową strukturą.Fresh concrete should be cured so as to minimize plastic shrinkage and ensure adequate strength and durability of the surface zone. Proper concrete curing is necessary to ensure the sustainability of concrete. The aim of the research was to determine the effect adopted in accordance with PN-EN 13670:2011, class of concrete curing on the characteristics associated with the subsurface structure
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Construction of industrial concrete floors according to the norm PN-EN 13670:2011
No full textDługoletnie marginalizowanie tematyki posadzek przemysłowych spowodowało, że niemal wyłącznymi posiadaczami wiedzy związanej z prawidłowym wykonawstwem posadzek stali się ich wykonawcy. Pomimo znacznej popularyzacji zagadnień związanych z podłogami przemysłowymi nadal nie opracowano krajowych norm i przepisów, które opisywałyby procedury projektowe, wykonawcze, a także wymagania jakościowe dotyczące podłóg betonowych. Artykuł ma na celu zasygnalizowanie, że zarówno podczas opracowywania specyfikacji, jak i w czasie realizacji betonowej posadzki przemysłowej powinna znaleźć zastosowanie norma PN-EN 13670:2011.As a result of long-standing marginalization of the subject of industrial floors, constructors of such floors have become almost the only people with the knowledge regarding their appropriate construction. Despite significant popularization of the issues connected with industrial floors, we still lack national norms and regulations which would describe the designing and construction procedures as well as quality requirements regarding concrete floors. The aim of this article is to draw attention to the fact that both
during preparation of specifications as well as during construction of an industrial concrete floor, the norm PN-EN 13670:2011 should be applied
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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