Influencing Factors on the Healing Performance of Microcapsule Self-Healing Concrete

The amounts of the components in a microcapsule self-healing system significantly impact the basic performance and self-healing performance of concrete. In this paper, an orthogonal experimental design is used to investigate the healing performance of microcapsule self-healing concrete under different pre-damage loads. The strength recovery performance and sound speed recovery performance under extensive damage are analyzed. The optimum factor combination of the microcapsule self-healing concrete is obtained. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) are carried out on the concrete samples before and after healing to determine the healing mechanism. The results show that the healing effect of self-healing concrete decreases with an increase in the pre-damage load, and the sound speed recovery rate increases with an increase in the damage degree. The influence of the sodium silicate content on the compressive strength and compressive strength recovery rate of the self-healing concrete increases, followed by a decrease. The optimum combination of factors of the microcapsule self-healing system is 3% microcapsules, 30% sodium silicate, and 15% sodium fluosilicate. The results can be used for the design and preparation of self-healing concrete.

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Mechanical responses of microencapsulated self-healing cementitious composites under compressive loading based on a micromechanical damage-healing model

International Journal of Damage Mechanics ◽

10.1177/10567895211011239 ◽

2021 ◽

pp. 105678952110112

Author(s):

Kaihang Han ◽

Jiann-Wen Woody Ju ◽

Yinghui Zhu ◽

Hao Zhang ◽

Tien-Shu Chang ◽

...

Keyword(s):

Fracture Toughness ◽

Compressive Strength ◽

Micromechanical Model ◽

Cementitious Composites ◽

Self Healing ◽

Damage Degree ◽

Healing Efficiency ◽

The Matrix ◽

Healing Agent ◽

Damage Healing

The cementitious composites with microencapsulated healing agents have become a class of hotspots in the field of construction materials, and they have very broad application prospects and research values. The in-depth study on multi-scale mechanical behaviors of microencapsulated self-healing cementitious composites is critical to quantitatively account for the mechanical response during the damage-healing process. This paper proposes a three-dimensional evolutionary micromechanical model to quantitatively explain the self-healing effects of microencapsulated healing agents on the damage induced by microcracks. By virtue of the proposed 3 D micromechanical model, the evolutionary domains of microcrack growth (DMG) and corresponding compliances of the initial, extended and repaired phases are obtained. Moreover, the elaborate studies are conducted to inspect the effects of various system parameters involving the healing efficiency, fracture toughness and preloading-induced damage degrees on the compliances and stress-strain relations. The results indicate that relatively significant healing efficiency, preloading-induced damage degree and the fracture toughness of polymerized healing agent with the matrix will lead to a higher compressive strength and stiffness. However, the specimen will break owing to the nucleated microcracks rather than the repaired kinked microcracks. Further, excessive higher values of healing efficiency, preloading-induced damage degree and the fracture toughness of polymerized healing agent with the matrix will not affect the compressive strength of the cementitious composites. Therefore, a stronger matrix is required. To achieve the desired healing effects, the specific parameters of both the matrix and microcapsules should be selected prudently.

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Influence of triethanolamine on reactivity of hydrated matrix in sodium silicate self-healing system and the mechanism

Construction and Building Materials ◽

10.1016/j.conbuildmat.2018.07.040 ◽

2018 ◽

Vol 185 ◽

pp. 445-452 ◽

Cited By ~ 7

Author(s):

Miaomiao Hu ◽

Jintang Guo ◽

Yang Xu ◽

Jinjie Fan ◽

Lei Cao ◽

...

Keyword(s):

Sodium Silicate ◽

Self Healing ◽

Healing System

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Mechanical Properties of Self-Healing System in Cementitious Material with Microcapsule

Materials Science Forum ◽

10.4028/www.scientific.net/msf.913.1090 ◽

2018 ◽

Vol 913 ◽

pp. 1090-1096 ◽

Cited By ~ 1

Author(s):

Peng Liang ◽

Qian Jin Mao ◽

Zi Ming Wang ◽

Su Ping Cui

Keyword(s):

Particle Size ◽

Compressive Strength ◽

In Situ Polymerization ◽

Urea Formaldehyde ◽

Strength Loss ◽

Cementitious Materials ◽

Self Healing ◽

Healing System ◽

The Matrix

In this paper, several urea–formaldehyde/epoxy microcapsules with different particle sizes were synthesized by in-situ polymerization. The chemical structure and compressive rupture load of microcapsule were characterized. The effect of microcapsule dosage, particle size and preload pressure on compressive strength of cementitious materials was studied. The result shows: when the particle size of microcapsule is 2 mm~2.5 mm, the rupture load of microcapsule is highest, more than 3N; When the microcapsule dosage is less than 2.5%, the strength loss of the matrix is relatively small; With the increase of the particle size of the capsule, the strength of the matrix decrease greatly; When the dosage of microcapsule is 2.5%, the particle size is 1.5 mm and the preload pressure is 30%~45%fmax, the compressive strength of the self-healing specimen is 8% higher than that of the non-preloaded specimens, which shows a certain self-healing performance.

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Preparation and Mechanical Properties of Microcapsule-Based Self-Healing Cementitious Composites

Materials ◽

10.3390/ma14174866 ◽

2021 ◽

Vol 14 (17) ◽

pp. 4866

Author(s):

Shiping Jiang ◽

Zhiyang Lin ◽

Can Tang ◽

Wenfeng Hao

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Composite Structures ◽

Healing Time ◽

The Self ◽

Self Healing ◽

Cementitious Composite ◽

Healing System ◽

Cement Based Materials ◽

Curing Agents

Self-healing concrete designs can protect against deterioration and improve durability. However, there is no unified conclusion regarding the effective preparation and mechanical properties of self-healing concrete. In this paper, microcapsules are used in cement-based materials, the reasonable dosage of microcapsules is determined, and the self-healing performance of the microcapsule self-healing system under different curing agents is explored. The microcapsules and curing agent are shown to enhance the flexural and compressive strength of mortar specimens at relatively low contents. The optimal microcapsule content in terms of compressive strength is 1–3%. When the content of the microcapsule reaches 7%, the strength of the specimen decreases by approximately 30%. Sodium fluorosilicate is better-suited to the microcapsule self-healing cement-based system than the other two fluorosilicates, potassium fluorosilicate and magnesium, which have similarly poor healing performance as curing agents. Healing time also appears to significantly influence the microcapsule self-healing system; mortar specimens that healed for 28 days are significantly higher than those that healed for 7 days. This work may provide a valuable reference for the design and preparation of self-healing cementitious composite structures.

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The Effect of Dry Mix Sodium Hydroxide onto Workability and Compressive Strength of Geopolymer Paste

International Journal of Integrated Engineering ◽

10.30880/ijie.2020.12.09.014 ◽

2020 ◽

Vol 12 (9) ◽

Author(s):

A. Z. Mohd Ali ◽

◽

N. A. Jalaluddin ◽

N. Zulkiflee ◽

◽

...

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Sodium Hydroxide ◽

Sodium Silicate ◽

Alkaline Solution ◽

High Emission ◽

New Material ◽

Curing Regime ◽

Solid Form ◽

Geopolymer Paste

The production of ordinary Portland cement (OPC) consumes considerable amount of natural resources, energy and at the same time contribute in high emission of CO2 to the atmosphere. A new material replacing cement as binder called geopolymer is alkali-activated concrete which are made from fly ash, sodium silicate and sodium hydroxide (NaOH). The alkaline solution mixed with fly ash producing alternative binder to OPC binder in concrete named geopolymer paste. In the process, NaOH was fully dissolved in water and cooled to room temperature. This study aims to eliminate this process by using NaOH in solid form together with fly ash before sodium silicate liquid and water poured into the mixture. The amount of NaOH solids were based on 10M concentration. The workability test is in accordance to ASTM C230. Fifty cubic mm of the geopolymer paste were prepared which consists of fly ash to alkaline solution ratio of 1: 0.5 and the curing regime of 80℃ for 24 hours with 100% humidity were implemented. From laboratory test, the workability of dry method geopolymer paste were decreased. The compressive strength of the dry mix of NaOH showed 55% and the workability has dropped to 58.4%, it showed strength reduction compared to the wet mix method.

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Evaluation of concrete self-healing with different fly ash contents and cracking ages by means of ultrasonic pulse velocity and compressive strength tests

Journal of Building Pathology and Rehabilitation ◽

10.1007/s41024-021-00104-7 ◽

2021 ◽

Vol 6 (1) ◽

Author(s):

Mayara Wons ◽

Letícia Camara ◽

Ian Esteves ◽

Priscila O. Trentin ◽

Ronaldo A. Medeiros-Junior

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Ultrasonic Pulse Velocity ◽

Ultrasonic Pulse ◽

Pulse Velocity ◽

Self Healing ◽

Strength Tests

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A new expansion material used for roof-contacted filling based on smelting slag

Scientific Reports ◽

10.1038/s41598-021-81891-4 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Hua Na ◽

Guocheng Lv ◽

Lijuan Wang ◽

Libing Liao ◽

Dan Zhang ◽

...

Keyword(s):

Mechanical Properties ◽

Hydrogen Peroxide ◽

Compressive Strength ◽

Sodium Silicate ◽

Utilization Rate ◽

Ammonium Bromide ◽

Foaming Agent ◽

Copper Nickel ◽

Smelting Slag ◽

Nickel Smelting

AbstractThe improper handling of smelting slag will seriously pollute the environment, and the unfilled roof of the goaf of the mine will threaten the safety of the mine. Expansion materials have attracted more and more attention because of their excellent properties. In this paper, copper-nickel smelting slag that has some active ingredients of gelling is used instead of traditional aggregate and some part of cement in order to reduce its pollution to the environment and its costs. For safety reasons, hydrogen peroxide was chosen as the foaming agent. Sodium silicate and hexadecyl trimethyl ammonium bromide (CTAB) are used as additives. Our results showed that after 28 days of curing, the material has better mechanical properties and the early compressive strength of the material was enhanced by sodium silicate. The efficiency of foaming was improved by CTAB. It also proves that copper–nickel smelting slag can be used in expansion material. At the same time, the utilization rate of the copper–nickel smelting slag of this formula can reach 70%, reduce its pollution to the environment.

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The Impact of Traffic-Induced Bridge Vibration on Rapid Repairing High-Performance Concrete for Bridge Deck Pavement Repairs

Advances in Materials Science and Engineering ◽

10.1155/2014/632051 ◽

2014 ◽

Vol 2014 ◽

pp. 1-9 ◽

Cited By ~ 5

Author(s):

Wei Wang ◽

Shuo Liu ◽

Qizhi Wang ◽

Wei Yuan ◽

Mingzhang Chen ◽

...

Keyword(s):

Compressive Strength ◽

High Performance ◽

Bridge Deck ◽

High Performance Concrete ◽

Reduction Rate ◽

Harmonic Vibration ◽

Hydration Reaction ◽

Self Healing ◽

The Impact ◽

Bridge Deck Pavement

Based on forced vibration tests for high-performance concrete (HPC), the influence of bridge vibration induced by traveling vehicle on compressive strength and durability of HPC has been studied. It is concluded that 1 d and 2 d compressive strength of HPC decreased significantly, and the maximum reduction rate is 9.1%, while 28 d compressive strength of HPC had a slight lower with a 3% maximal drop under the action of two simple harmonic vibrations with 2 Hz, 3 mm amplitude, and 4 Hz, 3 mm amplitude. Moreover, the vibration had a slight effect on the compressive strength of HPC when the simple harmonic vibration had 4 Hz and 1 mm amplitude; it is indicated that the amplitude exerts a more prominent influence on the earlier compressive strength with the comparison of the frequency. In addition, the impact of simple harmonic vibration on durability of HPC can be ignored; this shows the self-healing function of concrete resulting from later hydration reaction. Thus, the research achievements mentioned above can contribute to learning the laws by which bridge vibration affects the properties of concrete and provide technical support for the design and construction of the bridge deck pavement maintenance.

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