Use of Scanning Electron Microscope and the Non-local Isotropic Damage Model to Investigate Fracture Process Zone in Notched Concrete Beams

Chabaat, Mohamed; Thimus, Jean-François

doi:10.1007/s11340-006-9001-0

Cited by 38 publications

(20 citation statements)

References 16 publications

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“…Different approaches were proposed to determine the length and width of the damaged zone using probability, statistic laws and different empirical relations [12].…”

Section: Characterization Of the Fpzmentioning

confidence: 99%

“…All those elements may be responsible of the observed discrepancy. Based on the localization maps, the width of the FPZ has also been estimated based on the horizontal line located at 20% of Nmax which separate the zone with a high number of events representing the localization of microcracking and the outside zone where the level of damage is lower [12] (Figure 7). The discrepancy between the widths of the FPZ is relatively important, and this could be due to different sources of error: the localization of AE events is realized in 2D on one face of the specimen.…”

Section: Characterization Of the Fpzmentioning

confidence: 99%

“…It presents a remarkable potential of applications, and has been used in the past to examine the influence of different parameters on the FPZ, such as the effect of aggregates [5,6], porosity [7], creep [8,9], notch depth [10], specimen geometry and type of loading [11]. The damage is then evaluated based on either statistical analysis of AE activity [12] or quantitative and signal-based techniques [4].…”

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confidence: 99%

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Analysis of Crack Evolution in Concrete through Combined Acoustic Emission Monitoring and Mesoscale Modelling

Saliba¹,

Matallah²,

Loukili³

et al. 2016

Proceedings of the 9th International Conference on Fracture Mechanics of Concrete and Concrete Structures

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Abstract:In this paper, the fracture process zone (FPZ) is investigated on unnotched and notched beams with different notch depths. Three-point bending tests have been realized on plain concrete under crack mouth opening displacement (CMOD) control. Crack growth is monitored by applying the acoustic emission (AE) technique. The comparison with a numerical model is also realized by using a mesoscopic approach. Such an approach is of particular interest in the analysis of interactions between the cementitious matrix and aggregates. Several AE parameters are examined during the entire loading process, and show that the relative notch depth influences the AE characteristics, the process of crack propagation, and the brittleness of concrete. The numerical load-CMOD curves show that the mesoscopic modelling reproduces well the notch effect and concrete failure. In order to improve our understanding of the FPZ, the width and length of the FPZ are followed based on the AE source locations maps in parallel with the numerical damage fields. An important energy dissipation is observed at the crack initiation in unnotched beams.

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“…Different approaches were proposed to determine the length and width of the damaged zone using probability, statistic laws and different empirical relations [12].…”

Section: Characterization Of the Fpzmentioning

confidence: 99%

Section: Characterization Of the Fpzmentioning

confidence: 99%

mentioning

confidence: 99%

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Analysis of Crack Evolution in Concrete through Combined Acoustic Emission Monitoring and Mesoscale Modelling

Saliba¹,

Matallah²,

Loukili³

et al. 2016

Proceedings of the 9th International Conference on Fracture Mechanics of Concrete and Concrete Structures

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“…The process of localization of cracks and movement of the FPZ was studied using AE techniques by Maji et al [12]. Hadjab et al [13] used AE to investigate characteristics of the FPZ (length, width and macro crack propagation) in a concrete specimen subjected to four-point bending, using probability and statistical methods. It is shown that these results agree more or less with those obtained using other techniques.…”

Section: Introductionmentioning

confidence: 99%

Comparison of the fracture process of the rubberized concrete and plain concrete under bending load

Zhang

Wang

et al. 2010

Sci. China Technol. Sci.

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Acoustic emission (AE) technique is employed to investigate the damage process of the notched plain concrete and rubberized concrete specimens under 3-point bending load. AE signals in the fracture process of notched specimens are illustrated by analyzing the distribution of amplitude and hit rate of AE signals. AE signals in the rubberized concrete have lower activity and amplitude than in the plain concrete. By AE location analysis, it is found that the high energy events mainly are distributed near the notch tip. According to AE energy, the fracture process zone (FPZ) is determined. By comparing the FPZ of both concretes, it is found that the incorporation of rubber particles in concrete can greatly alleviate the damage process of concrete specimens and the damage zone in the rubberized concrete is much smaller than in the plain concrete. The moment tensor is also used to analyze the type of cracks and it is found that tensile cracks dominate the early period of loading, while shear cracks become dominant with propagation of cracks in late load period. concrete, rubberized concrete, acoustic emission, damage, moment tensor Citation: Zhang Y M, Wang C, Lu Y, et al. Comparison of the fracture process of the rubberized concrete and plain concrete under bending load. Sci China

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“…Several specimens are experimented in order to match each cluster with corresponding damage mechanism of the material under loading. At the same time acoustic emission was used to investigate characteristic of the fracture process zone (length width and macro crack propagation) [4] and to measure energy associated with fracture of concrete test specimens [5]. It is further suggested that AE energy release can be related to actual crack formation energy and the study of the nature of waves release may explain different mechanism as friction and other internal energy dissipation or toughening mechanisms.…”

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confidence: 99%

Coupling creep and damage in concrete under high sustained loading: Experimental investigation on bending beams and application of Acoustic Emission technique

Saliba

Loukili

Grondin

2010

EPJ Web of Conferences

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Creep and damage in concrete govern the long-term deformability of concrete. Thus, it is important to understand the interaction between creep and damage in order to design reliable civil engineering structures subjected to high level loading during a long time. Many investigations have been performed on the influence of concrete mixture, the effect of the bond between the matrix and the aggregates, temperature, aging and the size effect on the cracking mechanism and fracture parameters of concrete. But there is a lack of results on the influence of the creep loading history. In the present paper, an experimental investigation on the fracture properties of concrete beams submitted to three point bending tests with high levels of sustained load that deals with creep is reported. The results aim first to investigate the ranges of variation of the time response due to creep damage coupled effects under constant load and secondly to evaluate the residual capacity after creep.For this purpose a series of tests were carried out on geometrically similar specimens of size 100x200x800mm with notch to depth ratio of 0.2 in all the test specimens. The exchange of moisture was prevented and beams were subjected to a constant load of 70% and 90% of the maximum capacity.Three point bending test were realized on specimen at the age of 28 days to determine the characteristics of concrete and the maximum load so we could load the specimens in creep. Threepoint bend creep tests were performed on frames placed in a climate controlled chamber [1]. Then after four months of loading, the beams subjected to creep were removed from the creep frames and then immediately subjected to three-point bending test loading up to failure with a constant loading rate as per RILEM-FMC 50 recommendations.The residual capacity on the notched beams and the evolution of the characteristics of concrete due to the basic creep was considered. The results show that sustained loading had a strengthening effect on concrete, probably because of the consolidation of the hardened cement paste. The influence of creep on fracture energy, fracture toughness, and characteristic length of concrete is also studied. The fracture energy and the characteristic length of concrete increases slightly when creep occurs prior to failure and the size of the fracture process zone increases too. The load-CMOD relationship is linear in the ascending portion and gradually drops off after the peak value in the descending portion. The length of the tail end portion of the softening curve increases with beams subjected to creep. Relatively more ductile fracture behavior was observed with beams subjected to creep.The contribution of non-destructive and instrumental investigation methods is currently exploited to check and measure the evolution of some negative structural phenomena, such as micro-and

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Use of Scanning Electron Microscope and the Non-local Isotropic Damage Model to Investigate Fracture Process Zone in Notched Concrete Beams

Cited by 38 publications

References 16 publications

Analysis of Crack Evolution in Concrete through Combined Acoustic Emission Monitoring and Mesoscale Modelling

Analysis of Crack Evolution in Concrete through Combined Acoustic Emission Monitoring and Mesoscale Modelling

Comparison of the fracture process of the rubberized concrete and plain concrete under bending load

Coupling creep and damage in concrete under high sustained loading: Experimental investigation on bending beams and application of Acoustic Emission technique

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