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Experimental Investigation of Basalt/Fibre Textile Reinforced Concrete Under Uniaxial Tensile Force
No full textAmong the various solutions to retrofit existing structures, local strengthening of structural elements with Textile Reinforced Concrete (TRC) is a relatively recent technology which is considered as a possible alternative to the well-known Fibre Reinforced Polymers (FRP). As a matter of fact, due to the drawbacks of FRP, such as the difficulty to be applied on wet surfaces, the hazardousness for the workers who apply the material, and the poor behaviour at high temperature, TRC is recently gaining more popularity. The current concern about environmental issues is leading to a higher interest about the impact of materials production and their disposal at the end of life. With reference thereto, basalt textile fabrics is a material that is gaining attention due to its mechanical performances and low environmental impact. Admixing short fibres in the cementitious matrix of the TRC leads to a new material called Fibre/Textile Reinforced Concrete (F/TRC), which performs significantly bet-ter on strengthening solutions.
The aim of this work is to investigate the different behaviour of a layer of Basalt-TRC (B-TRC) and Basalt-F/TRC (B-F/TRC) under tension via uniaxial tensile test. The experimental test campaign comprehends 3 B-TRC and 3 B-F/TRC specimens. The presence of short steel fibres in the cementitious matrix remarkably improves the performances of TRC in terms of maximum tensile force reached during the test and crack distribution. The significant improvement of performances of B-F/TRC com-pared to the B-TRC is expressed by the average maximum force, which increased of about 84%
CONFINEMENT OF COLUMNS WITH TEXTILE REINFORCED CONCRETE: AN EXPERIMENTAL COMPARISON BETWEEN BASALT AND CARBON TEXTILE REINFORCED CONCRETE
No full textConfinement of existing RC columns by means of Textile Reinforced Concrete (TRC) is a technology developed in recent times. When using TRC as a mean of confinement, basalt textile fabrics are of particular interest due to their mechanical properties combined with low environmental impact. Furthermore, research performed by the Authors shows that the concrete matrix admixed with short dispersed fibres significantly improves the performance of TRC strengthening solutions in general. The addition of short dispersed steel fibres in the concrete matrix leads to a new material called Fibre/Textile Reinforced Concrete (F/TRC). Through an experimental campaign, an investigation about the influence on the confinement of the following two variables was conducted: the material of the textile fabric (basalt and carbon), and the presence of short dispersed steel fibres admixed to the concrete matrix. A total of 15 short cylindrical RC columns were tested under uniaxial compression. The results show that the performances of basalt and carbon textiles used for confinement are comparable, both in terms of strength and, to some extent, of post-elastic behaviour, highlighting the possibility of using basalt as an alternative to carbon without significant performance losses and combined with reduced environmental impact. Furthermore, F/TRC solutions outperformed traditional TRC, showing the beneficial effect of the short dispersed steel fibres to the performance of the strengthened specimens
Experimental investigation on confinement of columns with TRC: a comparison between basalt and carbon textile fabrics
Full text linkThe use of Textile Reinforced Concrete (TRC) is a promising solution in the confinement of RC columns. Based on an experimental campaign on 15 short cylindrical RC columns, this work aims to get a better understanding about the performance of basalt textile in the confinement of short RC columns by comparing basalt and carbon TRC. Furthermore, the impact of mixing short steel fibers in the TRC concrete matrix (F/TRC) is investigated. The test results show that columns confined with basalt textile and carbon textile are, in terms of strength and, to some extent, post-elastic behaviour, comparable. Basalt textile seems to be a valid alternative to carbon, without significant loss of performance, and it provides less environmental impact. Columns reinforced with F/TRC show that adding 2.5 Vol.-% of short steel fibers has a beneficial effect in the confinement
Bond-slip behavior between stainless steel rebars and concrete
Full text linkMaintenance of reinforced concrete structures is a prevailing topic, especially with regard to lifeline structures and bridges, many of which are now designed with a service life beyond 100 years. Reinforcement made of ordinary (carbon) steel may corrode in aggressive environments. Stainless steel, being much more resistant to corrosion, is a valid solution to facilitate the protection of the works, increasing the service life and reducing the need for repair and maintenance. Despite the potential for stainless steel to reduce maintenance costs, studies investigating the influence of stainless steel on the behavior of reinforced concrete structures are limited. This study investigated the bond behavior of stainless steel rebars by means of experimental tests on reinforced concrete specimens with different concrete cover thicknesses, concrete strengths, and bar diameters. In each case, identical specimens with carbon steel reinforcement were tested for comparison. The failure modes of the specimens were examined, and a bond stress-slip relationship for stainless steel bars was established. This research shows that the bond behavior of stainless steel rebars is comparable to that of carbon steel bars
CONFINEMENT OF COLUMNS WITH TEXTILE REINFORCED CONCRETE: AN EXPERIMENTAL COMPARISON BETWEEN BASALT AND CARBON TEXTILE REINFORCED CONCRETE
No full textConfinement of existing RC columns by means of Textile Reinforced Concrete (TRC) is a technology developed in recent times. When using TRC as a mean of confinement, basalt textile fabrics are of particular interest due to their mechanical properties combined with low environmental impact. Furthermore, research performed by the Authors shows that the concrete matrix admixed with short dispersed fibres significantly improves the performance of TRC strengthening solutions in general. The addition of short dispersed steel fibres in the concrete matrix leads to a new material called Fibre/Textile Reinforced Concrete (F/TRC). Through an experimental campaign, an investigation about the influence on the confinement of the following two variables was conducted: the material of the textile fabric (basalt and carbon), and the presence of short dispersed steel fibres admixed to the concrete matrix. A total of 15 short cylindrical RC columns were tested under uniaxial compression. The results show that the performances of basalt and carbon textiles used for confinement are comparable, both in terms of strength and, to some extent, of post-elastic behaviour, highlighting the possibility of using basalt as an alternative to carbon without significant performance losses and combined with reduced environmental impact. Furthermore, F/TRC solutions outperformed traditional TRC, showing the beneficial effect of the short dispersed steel fibres to the performance of the strengthened specimens
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
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
Investigation of the Failure Modes of Textile-Reinforced Concrete and Fiber/Textile-Reinforced Concrete under Uniaxial Tensile Tests
Full text linkRecently, innovations in textile-reinforced concrete (TRC), such as the use of basalt textile fabrics, the use of high-performance concrete (HPC) matrices, and the admixture of short fibers in a cementitious matrix, have led to a new material called fiber/textile-reinforced concrete (F/TRC), which represents a promising solution for TRC. Although these materials are used in retrofit applications, experimental investigations about the performance of basalt and carbon TRC and F/TRC with HPC matrices number, to the best of the authors’ knowledge, only a few. Therefore, an experimental investigation was conducted on 24 specimens tested under the uniaxial tensile, in which the main variables studied were the use of HPC matrices, different materials of textile fabric (basalt and carbon), the presence or absence of short steel fibers, and the overlap length of the textile fabric. From the test results, it can be seen that the mode of failure of the specimens is mainly governed by the type of textile fabric. Carbon-retrofitted specimens showed higher post-elastic displacement compared with those retrofitted with basalt textile fabrics. Short steel fibers mainly affected the load level of first cracking and ultimate tensile strength
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