Fatigue failure micromechanisms in recycled aggregate mortar by μCT analysis

Sainz-Aja, José; Carrascal, I.; Polanco, Juan A.; Thomas, Carlos

doi:10.1016/j.jobe.2019.101027

Cited by 27 publications

(17 citation statements)

References 35 publications

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“…It can be observed that the paste had a different colour. It should be noted that, based on the colour of the paste of the concrete with OPC-25CDW, it was possible to estimate that the specimen was "very dry", which is in agreement with what was observed once the test Several authors have concluded that the cracking of the specimens occurs because the cracks propagate through the weaker planes [62][63][64][65]. Based on the previously mentioned observations, it is possible to ensure that in those concretes with 0% replacement, and the cracks occur through the paste-aggregate interface (ITZ), i.e., the weakest zone of the specimens is the paste-aggregate interface.…”

Section: Morphological Analysis Of Fracturessupporting

confidence: 83%

“…In this figure, the following patterns can be seen: (i) in the case of aggregates from structural concrete, it can be seen that the fracture surface had generated a plane through the aggregate and (ii) in the case of an aggregate of ceramic origin, it can be seen that this aggregate had been pulverized. Several authors have concluded that the cracking of the specimens occurs because the cracks propagate through the weaker planes [62][63][64][65]. Based on the previously mentioned observations, it is possible to ensure that in those concretes with 0% replacement, and the cracks occur through the paste-aggregate interface (ITZ), i.e., the weakest zone of the specimens is the paste-aggregate interface.…”

Section: Morphological Analysis Of Fracturesmentioning

confidence: 99%

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Resonance Fatigue Behaviour of Concretes with Recycled Cement and Aggregate

et al. 2021

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The huge increase in production of construction and demolition waste (CDW) worldwide is leading to the valorisation of as recycled aggregates. One of the most promising alternatives is its use as a recycled aggregate in the manufacture of structural concrete, which motivates the study of the dynamic behaviour of these materials in order to ensure their suitability for use in elements subjected to dynamic loads. This work evaluated the resonant compressive fatigue behaviour of structural concretes with 25% or 50% recycled mixed aggregates, either individually or in combination with 25% recycled cement of clay-based materials both from CDW. All mixes were subjected to compressive fatigue tests using the accelerated Locati method. Regarding the fatigue limit, the results showed that for all mixes, it was between 30% and 45% of the compressive strength. In addition, a correlation was also found between the resonance frequency of the test and the deformation suffered by the specimen. This correlation enabled the estimation of the fatigue limit through a more stable parameter than the strain measured by strain gauges, namely, the resonance frequency. In addition, it was found that the resonance frequency of the test changed as the specimen damage increased. This observation enabled the estimation of the fatigue limit through a more stable parameter than the strain measured by strain gauges, namely, the resonance frequency.

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Section: Morphological Analysis Of Fracturessupporting

confidence: 83%

Section: Morphological Analysis Of Fracturesmentioning

confidence: 99%

Resonance Fatigue Behaviour of Concretes with Recycled Cement and Aggregate

et al. 2021

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“…Another interesting practice in recovery/recycling strategies (in addition to incorporating EAFS aggregates) is to incorporate recycled aggregates from Construction and Demolition Wastes (C&DW) to self-compacting concrete [2,9,10]. It has been demonstrated that their mechanical properties and durability [2,[11][12][13] are suitable for structural concrete and they can be recycled several times [14].…”

Section: Introductionmentioning

confidence: 99%

High Performance Self-Compacting Concrete with Electric Arc Furnace Slag Aggregate and Cupola Slag Powder

et al. 2020

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The development of self-compacting concretes with electric arc furnace slags is a novelty in the field of materials and the production of high-performance concretes with these characteristics is a further achievement. To obtain these high-strength, low-permeability concretes, steel slag aggregates and cupola slag powder are used. To prove the effectiveness of these concretes, they are compared with control concretes that use diabase aggregates, fly ash, and limestone supplementary cementitious materials (SCMs, also called fillers) and intermediate mix proportions. The high density SCMs give the fresh concrete self-compacting thixotropy using high-density aggregates with no segregation. Moreover, the temporal evolution of the mechanical properties of mortars and concretes shows pozzolanic reactions for the cupola slag. The fulfillment of the demands in terms of stability, flowability, and mechanical properties required for this type of concrete, and the savings of natural resources derived from the valorization of waste, make these sustainable concretes a viable option for countless applications in civil engineering.

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“…Innovative techniques, such as micro computed tomography (micro- CT) have also been used to analyze the behavior of concrete at fatigue, both in compressive fatigue [12] and bending fatigue [17]. Moreover, some micro-CT studies, which is a technique able to analyse the pores and cracks on concrete [18,19], had been developed to understand the concrete damage fatigue micromechanism [20,21]. In general, fatigue is known to lead to microcracks in concrete growing at lower loads than in static tests, which can lead to concrete failure earlier than expected [22].…”

Section: Introductionmentioning

confidence: 99%

High-Frequency Fatigue Testing of Recycled Aggregate Concrete

et al. 2019

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Concrete fatigue behaviour has not been extensively studied, in part because of the difficulty and cost. Some concrete elements subjected to this type of load include the railway superstructure of sleepers or slab track, bridges for both road and rail traffic and the foundations of wind turbine towers or offshore structures. In order to address fatigue problems, a methodology was proposed that reduces the lengthy testing time and high cost by increasing the test frequency up to the resonance frequency of the set formed by the specimen and the test machine. After comparing this test method with conventional frequency tests, it was found that tests performed at a high frequency (90 ± 5 Hz) were more conservative than those performed at a moderate frequency (10 Hz); this effect was magnified in those concretes with recycled aggregates coming from crushed concrete (RC-S). In addition, it was found that the resonance frequency of the specimen–test machine set was a parameter capable of identifying whether the specimen was close to failure.

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Fatigue failure micromechanisms in recycled aggregate mortar by μCT analysis

Cited by 27 publications

References 35 publications

Resonance Fatigue Behaviour of Concretes with Recycled Cement and Aggregate

Resonance Fatigue Behaviour of Concretes with Recycled Cement and Aggregate

High Performance Self-Compacting Concrete with Electric Arc Furnace Slag Aggregate and Cupola Slag Powder

High-Frequency Fatigue Testing of Recycled Aggregate Concrete

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