Self‐healing materials: what can nature teach us?

Dooley, Clodagh; Taylor, David

doi:10.1111/ffe.12595

Cited by 45 publications

(18 citation statements)

References 63 publications

(108 reference statements)

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“…The CS pH value was measured and found equal to 12 as determined by an Orion Star A214 pH/ISE Benchtop Meter. 8 At specific time intervals (5,10,15,20,30, 60 minutes, and 24 hours), the SAPs were centrifuged at 15,000 rpm for 5 minutes, the supernatant liquid was rejected, and the SAPs were weighed again (m 2 ). The AR(%) was calculated using Equation 1.…”

Section: Sap Characterizationmentioning

confidence: 99%

“…It was aforementioned that according to the literature, SAPs have been widely used as admixtures in cement due to the fact that they enhance the water availability and promote the hydration reactions during the entire service life of the cementitious structure. 6,10 Moreover, it should be noticed that thorough characterization of SAPs and key-property oriented pre-tests according to the targeted performance enhancement when used as admixtures in cementitious matrices can provide practical hints with respect to the evaluation the SAP performance in cement. 16 Therefore, it may be remarked that the coreshell hybrid submicron SAPs, produced in our work, have significant advantages over the SAPs of other studies, due to their novel chemical composition, structure, and morphology.…”

Section: Benefits/features Of the Novel Employed Sapsmentioning

confidence: 99%

“…One of the key parameters in self‐healing/sealing of cementitious structures is controlling the entrained water therein . To achieve this goal, the incorporation of superabsorbent polymers, SAPs, as admixtures in cement, has gained great scientific attention, as SAPs play a significant role in increasing the water availability and promoting the hydration reaction during the entire service life of the cementitious structure starting from the mixing procedure of the cement paste …”

Section: Introductionmentioning

confidence: 99%

“…9 To achieve this goal, the incorporation of superabsorbent polymers, SAPs, as admixtures in cement, has gained great scientific attention, as SAPs play a significant role in increasing the water availability and promoting the hydration reaction during the entire service life of the cementitious structure starting from the mixing procedure of the cement paste. 6,7,9,10 In general, SAPs are partially crosslinked, threedimensional (3D) polymer networks which can retain water from aqueous solutions in huge amounts (up to thousands of times their own dry weight) due to the presence of hydrophilic groups in their structure. [11][12][13] The swollen state of SAPs is known as hydrogels which can demonstrate a reversible behavior by de-swelling while they maintain their initial 3D structure and are not dissolved in water basically due to their crosslinking.…”

Section: Introductionmentioning

confidence: 99%

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Effect of submicron admixtures on mechanical and self‐healing properties of cement‐based composites

Kanellopoulou

Karaxi

Karatza

et al. 2019

Fatigue Fract Eng Mat Struct

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This study presents the development of novel submicron super absorbent polymers (SAPs) used as admixtures in cement‐based matrices with significant advantages over conventional products. The produced SAPs were characterized in respect of their morphology and composition, while their water absorption capacity was determined in different electrolyte solutions. The hybrid core‐shell spherical structure of the fabricated materials offered significant compatibility enhancement with cement while the workability of the mixture was maintained. The assessment of the cement‐based composites including SAPs revealed that their flexural strength increased by 78%. Self‐healing/sealing behavior was assessed by monitoring the crack sealing via SEM, elemental analysis of the healing products, and determination of the water absorbance coefficient for different times of treatment. The cement/SAPs composites with a concentration of SAPs 2% by weight of cement exhibited self‐healing/sealing responsive capability when an artificial crack was induced. According to the SEM characterization, the crack demonstrated complete healing for the better part of its length after 28 days of treatment.

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Section: Sap Characterizationmentioning

confidence: 99%

Section: Benefits/features Of the Novel Employed Sapsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effect of submicron admixtures on mechanical and self‐healing properties of cement‐based composites

Kanellopoulou

Karaxi

Karatza

et al. 2019

Fatigue Fract Eng Mat Struct

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“…High-energy wide-area blunt impacts (HEWABI) are a type of this damage (e.g. 105 Continued operational safety (COS) is always the authorities' highest priority, without compromising innovation and the development of new solutions. 101 In addition, non-conformities and damages occurred during the production and assembly line have a higher importance in this type of structures, requiring increased attention on all possible damages that may affect the structural part.…”

Section: Effect Of Scatter On Life Estimationmentioning

confidence: 99%

An overview of fatigue in aircraft structures

Tavares

Castro

2017

Fatigue Fract Eng Mat Struct

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From safe‐life to fail‐safe and damage‐tolerance approaches, the last one emerged as the main design philosophy for aerostructures, allowing weight savings and at the same time increasing reliability and structural integrity in the presence of damages which may have occurred during the manufacturing process or during service. The application of damage‐tolerance philosophy requires extensive know‐how of the fatigue and fracture properties, corrosion strength, potential failure modes and non‐destructive inspection techniques, particularly minimum detectable defect and inspection intervals. To face scatter in material properties, conservative approaches considering the worst scenario or statistical methods dealing with the variability of material have been employed in the fatigue assessment of structures. The fatigue life estimation can display substantial variability, illustrating the need for a probabilistic assessment in practical applications. As an example, the variation in the fatigue life for the common scenario of a through crack in an Al alloy plate was evaluated taking into account scatter of properties. The 2010 FAA rule establishing a limit of validity (LOV) puts a bound in the indefinite operational life allowed for by earlier regulations. This requirement, together with the diminishing role of aluminium in airframes, will certainly shape the directions of fatigue, fracture and damage mechanics research in years to come, expanding the knowledge base upon which substantiation of LOV values is made, and ensuring safety under sustainable conditions.

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Self‐Healing Phenomena in Metals

Dijk

Zwaag

2018

Adv Materials Inter

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puters) would not be possible in their current form without highly developed metallic materials.Currently all metallic materials are developed along the so-called "damage prevention" paradigm, [1] i.e., their composition and microstructure are optimized such that the initiation and propagation of mechanical damage (in the form of internal damage such as pores or surface initiated cracks) leading to catastrophic failure of the product is postponed as much and as long as possible. Such a performance needs a careful tuning of the constituent atoms forming the matrix and its secondary phases, the grain size and the dislocation structure in the "pristine" state. Of course, the word "pristine" state is somewhat a misnomer as engineering metals generally have undergone multiple thermomechanical treatments once casted and are in a far-from-equilibrium state. Yet, in this context "pristine" metallic products are those in the shape and condition at the start of their life in an actual construction. All current metallic engineering materials have in common that once a local crack or defect is generated, either by the preceding plastic deformation or simply by mechanical overload of the material, this damage will remain forever and could be the initiator of the final catastrophic fracture event. In simple mathematical termsTypical examples of such an accumulation of microscopic damage leading to macroscopic failure are (low and high cycle) fatigue as well as creep failure. Generally speaking metallic systems perform very well under such conditions due to the high bond strength between the metallic atoms as well as a stable dislocation network, which tend to keep the atoms more or less in place or at least in registry, even in case of severe loading or deformation.The same positive attributes responsible for the excellent mechanical properties of metals are also the attributes for the modest success (in comparison to the field of self-healing polymers, [2][3][4] self-healing composites, [5] self-healing concrete [6] ) in developing self-healing metallic materials. For a material to become self-healing local processes leading to "local In comparison to other materials, in metals and metallic systems self-healing of cracks and crack-initiating defects is difficult to achieve due to the fact the solute atoms that act as healing agents are relatively small and generally have a relatively low mobility at the prevailing operating temperatures. In this review, the scientifically most interesting and industrially most promising approaches to self-healing metals are presented and discussed. The various approaches are separated in autonomous healing methods based on an intrinsic (solid-state diffusion) mechanism and assisted healing methods that need an external intervention. Some promising routes are identified while in other cases the approach has too many intrinsic limitations. Recently, a number of computational studies using molecular dynamics and finite element modeling have been performed to analyze the self-healing potential of...

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Self‐healing materials: what can nature teach us?

Cited by 45 publications

References 63 publications

Effect of submicron admixtures on mechanical and self‐healing properties of cement‐based composites

Effect of submicron admixtures on mechanical and self‐healing properties of cement‐based composites

An overview of fatigue in aircraft structures

Self‐Healing Phenomena in Metals

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