Résistance à l'arrachement d'armatures ancrées dans du béton autoplaçant

Daoud, A.; Lorrain, M.; Elgonnouni, M.

doi:10.1007/bf02483142

Cited by 8 publications

(2 citation statements)

References 5 publications

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“…For the 54 MPa class cylinders (60 MPa cube), the difference is about 10%:2.58 instead of 2.37, which confirms the results obtained in our study. The difference for the normalized bond strength, weighted by the compressive strength, is only 5% according to Daoud et al [30]. For both parameters (strength and toughness), there is therefore a good coherence of our results with those of the literature.…”

Section: Resultssupporting

confidence: 80%

Interfacial Indentation Test for the Study of Reinforcement bar/concrete matrix Adhesion i n High Performance Self Compacting Concretes

Graira¹,

Chrait²,

Montagne³

et al. 2018

jmes

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The adhesion between the concrete and its metallic reinforcement is a fundamental property that characterizes the level of load that can undergo a reinforced concrete structure, and thus allows estimating its possible degradation and therefore its residual lifetime. We note that the steel works well as reinforcement for concrete because it bonds well with concrete and this bond strength, which characterizes the adhesion, is proportional to the contact surface of the steel to the concrete. The adhesion greatly varies with changes in mix design and grade of cement used and by providing intensive heat curing, high early adhesion can be achieved [1]. Moreover, concretes compressive strength, water to binder (w/b) ratio, bar diameter, concrete cover, embedded length, and pre-flexural crack length also affect this adhesion [2]. There are 3 ways in which cement concrete is bonded to a steel reinforcement: (i) adhesion between concrete and steel bars, (ii) mechanical Interlock through ribs of steel bar and (iii) chemical reaction between steel and concrete [3]. The interfacial bond strength, which always characterizes the adhesion between the steel bar and the matrix in reinforced concrete, is generally estimated by a bending test (Beam test) or pull-out test defined in ISO 14916 standards [4]. These tests are often controversial, sensitive to experimental conditions, and not very reproducible since the dispersion of the results can reach 50% in inter-laboratory comparisons [5].In composite materials, constituents and interactions (adhesion) between them play an important role in global behavior of final material. In this regard, numerous researches have been conducted all over the world to clarify this adhesion. VC and SCC have a substantially different mix design; especially regarding the amount and proportion of coarse aggregates, water to binder (w/b) ratio and fine material, which inevitably results in distinct adhesion behavior. Interfacial Indentation AbstractThe interfacial indentation test is experimented for the first time in order to characterize the adhesion between the concrete and its steel reinforcement. This technique, developed to estimate the adhesion of thick coatings (thermal barrier, plasma torch deposits, etc.), is used here to create and propagate a crack along the concrete/reinforcement interface. The length of this crack makes it possible to calculate an apparent interfacial toughness which can then be linked to the concrete/reinforcement adhesion, and therefore to the resistance of the elaborate structure. The mechanical properties, hardness and Young's modulus of the various constituents were determined from indentation tests, and micro cracks at the concrete/reinforcement interface are generated by Vickers macro-hardness tests using indentation loads ranging from 300 to 1200 N. The properties of three concretes are compared: a high-performance vibrated concrete HPVC (VC54) and two high-performance self-compacting concretes HPSCCs (SCC54 and SCC62), both developed in the laboratory. The adhes...

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Section: Resultssupporting

confidence: 80%

Interfacial Indentation Test for the Study of Reinforcement bar/concrete matrix Adhesion i n High Performance Self Compacting Concretes

Graira¹,

Chrait²,

Montagne³

et al. 2018

jmes

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“…The quality of concrete as well as the process followed in the mixing, curing, and producing, certainly, affect the resulted bond capacity . Indeed, any alterations in composition affect the forming of the concrete model and may lead to significant effects in the characteristics of bond . Such composition alterations include water, the cement content variations, or supplementary inert (hydraulic or pozzolanic materials).…”

Section: Introductionmentioning

confidence: 99%

Experimental and analytical study on behavior of pull‐out failure of reinforcing bar embedded in concrete blocks

Al-Fouadi

Mohammed

Abdullah

2018

Structural Concrete

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The bond between concrete and steel reinforcing bars is a very important functional requirement of reinforced concrete as a composite building material. This paper focuses on the comparison between the outcomes of the investigation dealing with bond strength at different levels of depth of concrete. The levels of concrete can be found in reinforced concrete columns, walls, and slabs. This paper presents an experimental and analytical analysis of the pull-out test on 32 concrete specimens. In the experimental part, eight concrete specimens grouped into normal selfcompaction concrete (SCC) and lightweight SCC, as well as mixtures between them, were tested. In each sample, four steel bars were embedded in concrete at different locations: at the top, two samples in the middle, and at the bottom of the sample. Moreover, the slip and bond strength of each steel bar was measured using the pull-out test. It was found that, in all the studied mixes, the average bond strength is greater in normal SCC than in lightweight SCC. This study recorded about 27.86% difference for mix CM compared with mix MCF100. An analytical analysis of nonlinear finite element (FE) was conducted for 12 reinforced concrete specimens; three different mixes are considered. A nonlinear FE analysis has been carried out to analyze the specimens that were tested experimentally. The results obtained from the experimental analyses and FE are compared with each other. The results revealed that the FE failure behavior indicates a good agreement with the test behavior. K E Y W O R D Scomputer modeling, concrete, finite element, lightweight concrete, selfcompaction

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