An Analytical Model for the Probability Characteristics of a Crack Hitting an Encapsulated Self-healing Agent in Concrete

Zemskov, S.V.; Jonkers, Henk M.; Vermolen, F.J.

doi:10.1007/978-3-642-15274-0_25

Cited by 13 publications

(5 citation statements)

References 8 publications

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“…We assume that the insights from the complete healing of such a part of the crack using the content of one capsule are sufficient to predict the complete crack healing, because the average distance between neighboring capsules in most types of self-healing concrete is comparable with R (more exactly from 0.6R to 1.1R (Zemskov et al, 2010). Furthermore, a crack with a depth exceeding 4R hits more than one capsule with high probability (0.86 and higher depending on the type of concrete).…”

Section: Resultsmentioning

confidence: 99%

“…In general, the crack can be considered as healed in the neighborhood of the capsule of radius R if the part of the crack situated directly between the halves of the capsule (of length 2R) is entirely filled up by limestone and adjacent crack segments of length R from each side are filled up for at least 50%. We assume that the insights from the complete healing of such a part of the crack using the content of one capsule are sufficient to predict the complete crack healing, because the average distance between neighboring capsules in most types of self-healing concrete is comparable with R (more exactly from 0.6R to 1.1R (Zemskov et al, 2010). Furthermore, a crack with a depth exceeding 4R hits more than one capsule with high probability (0.86 and higher depending on the type of concrete).…”

Section: Resultsmentioning

confidence: 99%

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A mathematical model for bacterial self-healing of cracks in concrete

Zemskov

Jonkers

Vermolen

2012

Journal of Intelligent Material Systems and Structures

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In the current research, a mathematical model for bacterial self-healing of a crack is considered. The study is embedded within the framework of investigating the potential of bacteria to act as a catalyst of the self-healing process in concrete, which is the ability of concrete to repair occurring cracks autonomously. Spherical clay capsules containing the healing agent (calcium lactate) and nutrients for bacteria are embedded in the concrete structure. Water entering a newly appearing crack initiates the release of the capsule content and activates the bacteria to convert calcium lactate to calcium carbonate (limestone). The crack is sealed through the metabolically mediated limestone precipitation. The model of the self-healing process is based on a moving boundary problem in which two fragments of the boundary move resulting from calcium carbonate precipitation and the dissolution of the capsule content, respectively. A Galerkin finite element method is used to solve the diffusion equations. The moving boundaries are tracked using a level set method.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

A mathematical model for bacterial self-healing of cracks in concrete

Zemskov

Jonkers

Vermolen

2012

Journal of Intelligent Material Systems and Structures

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“…Advantage of use of a porous carrier is that it forms, in comparison to regular aggregates, weak spots in the concrete matrix which attract forming cracks. The cracks that hit and split porous aggregate particles thus ensure effective release of embedded active healing agent compounds into the crack [18,19]. Disadvantage of use of porous carrier aggregates is that they significantly lower the compressive strength of the concrete [16,20].…”

Section: Development Of Bacteria-based Self-healing Agentmentioning

confidence: 99%

Bacteria-based self-healing concrete: evaluation of full scale demonstrator projects

Mors¹,

Jonkers

2020

RILEM Tech Lett

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Bacteria-based self-healing concrete is an innovative concrete that contains a self-healing agent that provides the material with enhanced autonomous crack-sealing performance. A specific type of this concrete, based on a healing agent composed of bacterial spores and lactate as carbon source, has been developed and applied by the Delft University of Technology for over ten years. Under laboratory conditions it was proven that, depending on the dosage of healing agent, self-healing of cracks up to 0.8 mm widths occurs. As such the material potentially allows reduction of steel reinforcement used for crack width limitation in watertight constructions. Application of self-healing concrete would therefore not only result in a reduction of costs but also in improvement of environmental performance (lower CO2 footprint) and ease of in situ casting due to reduction of use of steel in waterproof applications. However, according to the EN 1990 Eurocode (Basis of structural design), customary application of a novel type of concrete must be preceded by full scale demonstrators proving evidence for safe and functional performance. In this contribution we portray full scale application of bacteria-based self-healing agent as developed by the Delft research group in two repair mortar-and in two concrete construction demonstrator projects. These demonstrator projects show that addition of the bacteria-based self-healing agent to the concrete mix is safe as no negative side effects on construction performance was observed. However, it also proved difficult to find evidence for increased crack-healing performance as cracking in the demonstrator constructions hardly occurred. In further full scale demonstrators we therefore plan to drastically reduce amount of crack width-restraining reinforcement to show crackhealing capacity and potential to save on use of reinforcement steel in watertight concrete constructions.

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“…Compared to fineness of cement, water/cement ratio is the dominating factor for the self-healing capacity of concrete. Based on the concept of autonomous healing and elementary principles from probability theory, Zemskov and Jonkers (80,81) have recently developed analytical models for computation of the probability that a crack hits an encapsulated particle. The analytical models (random placement mode of capsules in a Figure 5.…”

Section: Modelling and Simulation Contributing To Self-healingmentioning

confidence: 99%

Overview of recent work on self-healing in cementitious materials

Lv¹,

Chen²

2014

Mater. construcc.

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ABSTRACT:Cracks, especially microcracks, in concrete are of paramount importance to the durability and the service life of cementitious composite. However, the self-healing technology, including autogenous healing and autonomous healing, is expected to be one of effective tools to overcome this boring problem. In this paper, we focus on the autogenous healing of concrete material and a few of recent works of autonomous healing are also mentioned. The durability and the mechanical properties improved by the self-healing phenomenon are reviewed from experimental investigation and practical experience. Several aspects of researches, such as autogenous healing capability of an innovative concrete incorporated geo-materials, self-healing of engineered cementitious composite and fire-damaged concrete, effect of mineral and admixtures on mechanism and efficiency of self-healing concrete are summarized to evaluate the presented progresses in the past several years and to outline the perspective for the further developments. Moreover, a special emphasis is given on the analytical models and computer simulation method of the researches of self-healing in cementitious materials. RESUMEN: Panorámica de trabajos recientes sobre materiales cementantes autorreparables.Las fisuras, y sobre todo las microfisuras, tienen una gran repercusión en la durabilidad y en la vida útil de los materiales cementantes. Ante este problema, la tecnología de la autorreparación, tanto autógena como autónoma, se presenta como una solución eficaz. El artículo se centra en la reparación autógena del hormigón, así como en algunos trabajos recientes sobre la reparación autónoma. Se describen las mejoras de las propiedades de durabilidad y de resistencia que proporciona la técnica del hormigón autorreparable, tanto desde el punto de vista de la investigación experimental como del de la experiencia práctica. A fin de evaluar los avances logrados en los últimos años y de trazar las grandes líneas de desarrollo futuro, se resumen varios de los aspectos investigados: capacidad de reparación de un hormigón innovador que incorpora geomateriales; autorreparabilidad tanto de los compuestos cementantes tecnológicos como de los hormigones que han sufrido daños por incendio; influencia de los aditivos minerales en el mecanismo y eficacia del hormigón autorreparable. Además, se destaca el papel de los modelos analíticos y los métodos de simulación informática en la investigación de los materiales cementantes autorreparables.

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An Analytical Model for the Probability Characteristics of a Crack Hitting an Encapsulated Self-healing Agent in Concrete

Cited by 13 publications

References 8 publications

A mathematical model for bacterial self-healing of cracks in concrete

A mathematical model for bacterial self-healing of cracks in concrete

Bacteria-based self-healing concrete: evaluation of full scale demonstrator projects

Overview of recent work on self-healing in cementitious materials

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