1,721,029 research outputs found
Design, mechanical and structural characterization of sustainable and high-performance concrete
No full textRecent advancements in concrete technology have led to the development of new materials in order to meet the urgent environmental needs. The need to reduce CO2 emissions has led to the popularity of geopolymer binders as a viable alternative to ordinary Portland cement. Additionally, the search for more durable and long-lasting structures that can reduce maintenance costs has led to the development of very high-performance concretes (VHPFRC) with added fibers. The aim of this research is to design and mechanically characterize both geopolymer concrete mix and VHPFRC mix, which cover different aspects of the same goal - making concrete a sustainable material
Design, mechanical and structural characterization of sustainable and high-performance concrete
No full textBond behavior of geopolymer concrete with steel and GFRP bars
No full textIn the last years geopolymer concrete (GPC) has shown great potential for use in structural elements. In this context, it has become fundamental to investigate on the bond behavior of this new concrete matrix with reinforcing bars. Data found in literature showed that GPC performs better than ordinary Portland cement (OPC) concrete in terms of bonding with deformed steel bars. In addition, few authors have focused in the study of the bond stress-slip behavior between GPC and glass fiber-reinforced polymer (GFRP) rebars. In this paper the bond-slip behavior of GPC with both steel and GFRP reinforcing bars will be investigated by means of pull-out test with centered bar setup also considering the effect of the bond length. The main results showed that little difference in bond-slip behavior occur between the two different steel bar diameters used. On the other hand, sand-coated GFRP bars showed lower bond capacity in respect to deformed steel bars. Finally, an increase in ultimate bond load has been observed when the bond length was increased
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Bond behavior of geopolymer concrete with steel and GFRP bars
No full textIn the last years geopolymer concrete (GPC) has shown great potential for use in structural elements. In this context, it has become fundamental to investigate on the bond behavior of this new concrete matrix with reinforcing bars. Data found in literature showed that GPC performs better than ordinary Portland cement (OPC) concrete in terms of bonding with deformed steel bars. In addition, few authors have focused in the study of the bond stress-slip behavior between GPC and glass fiber-reinforced polymer (GFRP) rebars. In this paper the bond -slip behavior of GPC with both steel and GFRP reinforcing bars will be investigated by means of pull-out test with centered bar setup also considering the effect of the bond length. The main results showed that little difference in bond-slip behavior occur between the two different steel bar diameters used. On the other hand, sand-coated GFRP bars showed lower bond capacity in respect to deformed steel bars. Finally, an increase in ultimate bond load has been observed when the bond length was increased
Variations on the Author
Full text link“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
Full text linkWe 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
Geopolymer Concrete Structures: Bond with Deformed Steel Bars
No full textThe promising performances showed by geopolymer concrete led several researchers to investigate about possibilities of using this material in reinforced structural elements. Since geopolymer binder has a different microstructure from Ordinary Portland Cement (OPC) it is necessary to investigate, also, on its bonding behavior with steel bar that as well-known influences the service and ultimate conditions. For this reason, in the last decades both direct pull-out and beam-end tests were carried out with this material. Generally, it has been observed that Geopolymer Concrete (GPC) has higher bond strength than OPC concrete due to the higher compression strength and the dense and compact microstructure of GPC. This means that the existing design equation for bond strength prediction of ordinary concrete can be conservatively used also for GPC. In this paper the bond-slip behavior between GPC and steel reinforcing bar with two different diameters has been investigated
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