Self-Healing Concrete Mix-Design Based on Engineered Cementitious Composites Principles

Toader, Tudor Panfil; Mircea, Anamaria Cătălina

doi:10.3390/proceedings2020063005

Cited by 6 publications

(5 citation statements)

References 11 publications

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“…As per RILEM [31], autogenous self-healing can be attributed to three primary physical, chemical, or mechanical factors, as illustrated in (Fig. 1) [7,32].…”

Section: Autogenous Self-healing Techniquementioning

confidence: 99%

“…This technique, also known as the self-tightening technique, does not involve any chemical reaction. Instead, it involves the obstruction of the crack by tiny particles at the crack face or the passage of small impurities through the crack [7,32,33], as shown in (Fig. 1).…”

Section: Mechanical Causementioning

confidence: 99%

“…As illustrated in (Fig. 5), the repair begins when the capsule is broken due to the crack initiation and propagation through it, releasing the healing agent, which can be chemicals or micro-organisms, filling the crack and preventing it from spreading further [32,94].…”

Section: Fig 4 Factors Affecting Bacterial Concretementioning

confidence: 99%

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Self-healing concrete techniques and performance, A review

Ghazy,

Emara,

Abdellah

et al. 2023

Res. Eng. Struct. Mat.

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Modern society faces the duality of rapidly expanding structure, making concrete one of the world's most traded materials. However, cement manufacturing can pollute the environment by releasing approximately one tonne of CO2 for every tonne of cement produced. Concrete cracks can provide superior access for aggressive substances such as chlorides and sulfates, resulting in structural deterioration. So, to fix concrete cracks, different traditional methods were used, which use cement and some chemical agents that are hazardous to the environment. Because of the environmental issues and sustainability challenges associated with cement and concrete, it is preferable to reduce the amount of cement used by developing promising and unique solutions to enable quick crack healing in concrete and extend the structure's lifetime. Therefore, incorporating self-healing mechanisms into construction materials has been proposed to improve their performance and durability while reducing the need for maintenance and repair. This review assesses the performance and causes of autogenous and autonomous self-healing techniques. The autogenous technique occurs naturally due to inherent material properties, while the autonomous technique uses various healing agents, such as chemical or biological substances. Both techniques rely on forming calcium carbonate (CaCO3) crystals as the principal agent for concrete healing. Previous findings showed that the autogenous technique has limited efficacy in repairing larger cracks with a width exceeding 0.3mm. In contrast, autonomous techniques have shown successful repai of cracks exceeding 2mm in width. The application of an autonomous methodology in the field of concrete has resulted in significant results, such as effectively repairing large cracks, enhancing structural integrity, and substantially decreasing permeability levels from high to exceedingly low levels

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“…As per RILEM [31], autogenous self-healing can be attributed to three primary physical, chemical, or mechanical factors, as illustrated in (Fig. 1) [7,32].…”

Section: Autogenous Self-healing Techniquementioning

confidence: 99%

Section: Mechanical Causementioning

confidence: 99%

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Self-healing concrete techniques and performance, A review

Ghazy,

Emara,

Abdellah

et al. 2023

Res. Eng. Struct. Mat.

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show abstract

“…The physical cause can be attributed to the volume increase of the hydrated cement paste near the crack face, leading to the expansion of calcium silicate hydrate gel (C-S-H) (Ghazy et al 2023;Ter Heide 2005). The mechanical cause, also known as the self-tightening technique, only involves filling the cracks with tiny particles or small impurities, with no involvement of chemical reactions (De Rooij et al 2013;Ter Heide 2005;Toader et al, 2020). The most crucial cause is the chemical cause, which can be divided into two mechanisms: continued hydration and carbonation.…”

Section: Introductionmentioning

confidence: 99%

Innovative Strategies for Enhanced Concrete Durability: A Comparative Analysis of Autogenous and Autonomous Self-healing Mechanisms

Ghazy,

Emara,

Abdellah

et al. 2024

Iran J Sci Technol Trans Civ Eng

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This study explores incorporating self-healing mechanisms into concrete to address cracks compromising structural integrity. Two self-healing techniques, autogenous and autonomous, are compared. Specimens with excessive cement were created to investigate the impact of cement content on autogenous healing. The autonomous technique used Bacillus subtilis bacteria with a constant concentration, using two insertion methods: direct and immobilization. Crumb rubber was used to immobilize bacteria, assessing its effect in preserving them over long periods. Calcium lactate was used as a source of calcium in some of the autonomous mixtures. Healing techniques were evaluated using compression tests, chloride permeability, visible crack inspection, and microscopic investigation. The test results showed a reduction of 32% in compressive strength at 7 days when using calcium lactate with bacteria. However, after 28 days, the strength was enhanced by about 15% compared to the control mix. Despite the strength reduction, the crack healing ability exceeded the control mix in 7- and 28-day cracked specimens. The best results were achieved using bacteria immobilized in rubber without calcium lactate by healing 2mm cracks with a 71% compressive strength increase and 89% strength recovery. The immobilization method outperformed the direct method in preserving bacteria, as confirmed by scanning electron microscope images revealing bacterial presence after 100 days, accompanied by a substantially reduced chloride permeability to very low levels. For the autogenous mixture, adding excess cement enhanced the crack healing efficiency by 67%, healing a 0.5mm crack width. SEM results showed calcite precipitation in both autogenous and autonomous mixtures. However, autonomous mixtures exhibited denser and sharper crystal morphology, confirmed by energy dispersive spectrometer results since the bacterial concrete achieved a calcium weight of 36.52% compared to its control mixture of 8.69%.

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“…Therefore, scientists are focusing on limiting Portland cement production by finding environmentally friendly and energy efficient concrete binders. A first step is to substitute a quantity of Portland cement with fly ash and obtain concrete with self-healing properties [ 15 , 16 ].…”

Section: Introductionmentioning

confidence: 99%

Influence of Fe2O3, MgO and Molarity of NaOH Solution on the Mechanical Properties of Fly Ash-Based Geopolymers

et al. 2022

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The use of waste from industrial activities is of particular importance for environmental protection. Fly ash has a high potential in the production of construction materials. In the present study, the use of fly ash in the production of geopolymer paste and the effect of Fe2O3, MgO and molarity of NaOH solution on the mechanical strength of geopolymer paste are presented. Samples resulting from the heat treatment of the geopolymer paste were subjected to mechanical tests and SEM, EDS and XRD analyses. Samples were obtained using 6 molar and 8 molar NaOH solution with and without the addition of Fe2O3 and MgO. Samples obtained using a 6 molar NaOH solution where Fe2O3 and MgO were added had higher mechanical strengths compared to the other samples.

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Self-Healing Concrete Mix-Design Based on Engineered Cementitious Composites Principles

Cited by 6 publications

References 11 publications

Self-healing concrete techniques and performance, A review

Self-healing concrete techniques and performance, A review

Innovative Strategies for Enhanced Concrete Durability: A Comparative Analysis of Autogenous and Autonomous Self-healing Mechanisms

Influence of Fe2O3, MgO and Molarity of NaOH Solution on the Mechanical Properties of Fly Ash-Based Geopolymers

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