Influence of the Type of Coarse Lightweight Aggregate on Properties of Semilightweight Self-Consolidating Concrete

Kwasny, Jacek; Sonebi, Mohamed; Taylor, Su; Bai, Yun; Owens, Kieran; Doherty, William O.S.

doi:10.1061/(asce)mt.1943-5533.0000527

Cited by 28 publications

(17 citation statements)

References 11 publications

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“…When we working with more fluid concretes, it has as consequence a reduction in the time of handling and densification when applied in prefabricated elements, causing in the greater productivity and lower final cost in the concreting operation. The most important principles to maintain the characteristics of the SCC are the use of superplasticizers, mineral additions, high content of fine materials and mortar, resulting in a greater cohesion and fluidity of the paste, however, we have a concrete that absorbs less energy, that is, it becomes extremely sensitive to the presence of cracks and microcracks, compromising the integrity of the material [4,5]. In order to minimize this effect, the rubberized concretes present better capacity to the damping, due to the significant increase of the toughness and ductility [6].…”

Section: Introductionmentioning

confidence: 99%

Fresh and hardened properties of self-compacting concrete modified with lightweight and recycled aggregates

Angelin

Lintz

Barbosa

2018

Rev. IBRACON Estrut. Mater.

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A produção de concretos auto compactáveis de baixa massa específica tornou-se um grande desafio para a engenharia civil, principalmente quanto à dosagem e manutenção das resistências mecânicas. Nesse contexto, o objetivo deste trabalho foi analisar concretos autoadensáveis (CAA) produzidos com agregados leves e reciclados. Fixou-se as dosagens de sílica ativa, pó de pedra, pedrisco, argila expandida e superplastificante, variando-se a porcentagem do resíduo de borracha em 5% e 10%, em substituição ao agregado miúdo. As amostras foram submetidas aos ensaios de espalhamento, viscosidade, habilidade passante, resistências à compressão e à tração por compressão diametral e, massa específica. Verificou-se que os CAA produzidos apresentaram coesão e trabalhabilidade adequados, bem como atendem as condições normativas para uso em peças pré-moldadas e estruturais.

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Section: Introductionmentioning

confidence: 99%

Fresh and hardened properties of self-compacting concrete modified with lightweight and recycled aggregates

Angelin

Lintz

Barbosa

2018

Rev. IBRACON Estrut. Mater.

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“…It has been studied mainly in terms of mix proportion, workability and mechanical properties (Choi et al, 2006;Hwang and Hung, 2005;Kim et al, 2010;Kwasny et al, 2012;Madandoust et al, 2011;Mazaheripour et al, 2011;Shi and Wu, 2005;Topçu and Uygunoglu, 2010;Wang, 2009;Wu et al, 2009), but little attention has been paid to the bond behaviour of deformed bars in SCLC, especially when subjected to lateral pressure. It is thus necessary to investigate the bond characteristics between deformed bars and SCLC.…”

Section: Introductionmentioning

confidence: 99%

Bond behaviour of deformed bars in self-compacting lightweight concrete subjected to lateral pressure

Zheng

et al. 2013

Magazine of Concrete Research

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The purpose of this paper is to present an experimental investigation into the bond behaviour between deformed bars and self-compacting lightweight concrete (SCLC) under lateral pressure. SCLC pull-out specimens made with two types of lightweight aggregate were tested under two orthogonal lateral pressures p1 and p2, perpendicular and parallel to the transverse rib of deformed bars respectively. It was found that, under uniaxial lateral pressure, the ultimate bond stress increases with an increase of p2 but is independent of p1. Under biaxial lateral pressures, the ultimate bond stress increases monotonically with an increase in p1 and/or p2. The slip at the ultimate bond stress is an increasing function of lateral pressure for specimens failing by splitting, but basically remains constant for specimens failing by pull-out. The ratio of residual to ultimate bond stress is mainly related to the ratio of cover depth to bar diameter. It was also found that the lightweight aggregate type has little influence on the bond behaviour of deformed bars. Based on the experimental results, empirical formulae for the ultimate bond stress, the slip at the ultimate bond stress and the ratio of residual to ultimate bond stress are formulated. Finally, a bond stress–slip model is proposed and verified with experimental results.

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“…Using a particular case of the method proposed by Esmaeilkhanian et al [19] and using an unbiased stereology technique based on count pointing [20,21], Navarrete-Lopez have calculated a segregation index based on the volumetric fraction of aggregates at different heights of a specimen [9]. Each specimen was divided into three equals sections (top, middle and bottom).…”

Section: Methods Proposed By Lopez -Navarrete -Esmaeilkhanianmentioning

confidence: 99%

“…The results of the studies of Kwasny et al [20] suggest that lightweight concrete may be considered as non-segregated when VI values are below 20%. Esmaeilkhanian et al [22] have studied the dynamic segregation of self-compacting concrete and have proposed the value of VI = 25% as the limit for segregation.…”

Section: Methods Proposed By Lopez -Navarrete -Esmaeilkhanianmentioning

confidence: 99%

Image analysis applications for the study of segregation in lightweight concretes

Solak¹,

Tenza-Abril²,

Baeza-Brotons³

2017

Int. J. CMEM

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The use of lightweight concrete allows great flexibility and cost savings when it is used in building construction having a positive impact on the energy consumption of buildings due to its good thermal characteristics. However, it is also known that the differences between the densities of the materials used to produce these concretes make it highly susceptible to the segregation phenomenon. The main objective of the present work is to present a method to quantify this phenomenon using techniques of image analysis. In this work, a lightweight concrete produced was molded in cylindrical molds using different times of internal vibration and causing different degrees of segregation. The samples were cured, vertically saw-cut in two pieces (halves) and the sections were photographed. Subsequently, the halves were saw-cut horizontally in four equal parts and posteriorly their densities were determined experimentally. The densities obtained were used to calculate the segregation index of each sample (experimental method). Furthermore, the photographed sections were processed using image analysis software in order to determine the volumetric proportions of aggregates in each sample (noise reduction, threshold adjustment, binarization and fill holes). The processed images were used to calculate the densities and segregation index of the lightweight concrete produced through image analysis. In addition, using the photographed sections, a vertical density profile was programmed to analyze the distribution of the lightweight concrete components (mortar and aggregate). Finally, the results obtained experimentally and through image analysis were compared. This study demonstrates that the image analysis allows a deeper knowledge of the behavior of segregated concrete

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Influence of the Type of Coarse Lightweight Aggregate on Properties of Semilightweight Self-Consolidating Concrete

Cited by 28 publications

References 11 publications

Fresh and hardened properties of self-compacting concrete modified with lightweight and recycled aggregates

Fresh and hardened properties of self-compacting concrete modified with lightweight and recycled aggregates

Bond behaviour of deformed bars in self-compacting lightweight concrete subjected to lateral pressure

Image analysis applications for the study of segregation in lightweight concretes

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