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

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 Superabsorbent Polymers on the Microstructure and Self-Healing Properties of Cementitious-Based Composite Materials

Applied Sciences ◽

10.3390/app11020700 ◽

2021 ◽

Vol 11 (2) ◽

pp. 700

Author(s):

Irene A. Kanellopoulou ◽

Ioannis A. Kartsonakis ◽

Costas A. Charitidis

Keyword(s):

Mechanical Properties ◽

Composite Materials ◽

Hybrid Structure ◽

The Self ◽

Self Healing ◽

Cementitious Composite ◽

Superabsorbent Polymers ◽

Porosity Reduction ◽

Environment Control ◽

The Impact

Cementitious structures have prevailed worldwide and are expected to exhibit further growth in the future. Nevertheless, cement cracking is an issue that needs to be addressed in order to enhance structure durability and sustainability especially when exposed to aggressive environments. The purpose of this work was to examine the impact of the Superabsorbent Polymers (SAPs) incorporation into cementitious composite materials (mortars) with respect to their structure (hybrid structure consisting of organic core—inorganic shell) and evaluate the microstructure and self-healing properties of the obtained mortars. The applied SAPs were tailored to maintain their functionality in the cementitious environment. Control and mortar/SAPs specimens with two different SAPs concentrations (1 and 2% bwoc) were molded and their mechanical properties were determined according to EN 196-1, while their microstructure and self-healing behavior were evaluated via microCT. Compressive strength, a key property for mortars, which often degrades with SAPs incorporation, in this work, practically remained intact for all specimens. This is coherent with the porosity reduction and the narrower range of pore size distribution for the mortar/SAPs specimens as determined via microCT. Moreover, the self-healing behavior of mortar-SAPs specimens was enhanced up to 60% compared to control specimens. Conclusively, the overall SAPs functionality in cementitious-based materials was optimized.

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A probabilistic approach for design and certification of self-healing advanced composite structures

Proceedings of the Institution of Mechanical Engineers Part O Journal of Risk and Reliability ◽

10.1177/1748006x10397847 ◽

2011 ◽

Vol 225 (4) ◽

pp. 435-449 ◽

Cited By ~ 5

Author(s):

H R Williams ◽

R S Trask ◽

I P Bond

Keyword(s):

Composite Structures ◽

High Performance ◽

Probabilistic Approach ◽

Healing Time ◽

Self Healing ◽

Structural Failure ◽

Healing System ◽

Order Of Magnitude ◽

Damage Tolerant

Design and certification of novel self-healing aerospace structures was explored by reviewing the suitability of conventional deterministic certification approaches. A sandwich structure with a vascular network self-healing system was used as a case study. A novel probabilistic approach using a Monte Carlo method to generate an overall probability of structural failure yields notable new insights into design of self-healing systems, including a drive for a faster healing time of less than two flight hours. In the case study considered, a mature self-healing system could be expected to reduce the probability of structural failure (compared to a conventional damage-tolerant construction) by almost an order of magnitude. In a risk-based framework this could be traded against simplified maintenance activity (to save cost) and/or increased allowable stress (to allow a lighter structure). The first estimate of the increase in design allowable stresses permitted by a self-healing system is around 8 per cent, with a self-healing system much lighter than previously envisaged. It is thought these methods and conclusions could have wider application to self-healing and conventional high-performance composite structures.

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Mechanical Properties of Engineered Cementitious Composites Mixture

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.567.428 ◽

2014 ◽

Vol 567 ◽

pp. 428-433 ◽

Cited By ~ 1

Author(s):

Bashar S. Mohammed ◽

Muhammad Hafiz Baharun ◽

Muhd Fadhil Nuruddin ◽

Odu Paul Duku Erikol ◽

Nadhir Abdulwahab Murshed

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Flexural Strength ◽

The Self ◽

Cementitious Composite ◽

Fresh Properties ◽

Self Compacting Concrete ◽

Engineered Cementitious Composite ◽

Hardened Properties ◽

Pva Fiber

The aim of the research is to develop engineered cementitious composite mixtures satisfying the self-compacting concrete requirements and to evaluate the hardened properties of self-compacted ECC mixtures. To enhance the concrete performance, PVA is used. The PVA improved some characteristics and properties of the concrete. Ten mixes with different Polyvinyl Alcohol (PVA) fiber contents (0.0%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5% and 5.0%) have been prepared. Three cubes (100mm x 100mm x 100mm), three beams (100mm x 100mm x 500mm) and three cylinders (150mm diameter and 300mm height) have been cast for each mix and tested at the age of 7 and 28 days for compressive strength and at age of 28 days for splitting and flexural strength. The V-funnel, L-box and slump test also have been conducted to access the fresh properties like workability and flowability of the concrete. The results indicated the increase in the strength of the concrete and the formulas for predicting the compressive, splitting and flexural strength from PVA (%) has been developed.

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A MICROCAPSULE TECHNOLOGY BASED SELF-HEALING SYSTEM FOR CONCRETE STRUCTURES

Journal of Earthquake and Tsunami ◽

10.1142/s1793431113500140 ◽

2013 ◽

Vol 07 (03) ◽

pp. 1350014 ◽

Cited By ~ 12

Author(s):

BIQIN DONG ◽

NINGXU HAN ◽

MING ZHANG ◽

XIANFENG WANG ◽

HONGZHI CUI ◽

...

Keyword(s):

Urea Formaldehyde ◽

Concrete Structures ◽

The Self ◽

Polymerization Reaction ◽

Formaldehyde Resin ◽

Self Healing ◽

Cementitious Composite ◽

Healing System ◽

Healing Efficiency ◽

Healing Agent

In the study, a novel microcapsule technology based self-healing system for concrete structures has been developed. Through situ-polymerization reaction, the microcapsule is formed by urea formaldehyde resin to pack the epoxy material, which is applied to cementitious composite to achieve self-healing effect. The experimental results revealed that the self-healing efficiency of the composite can be accessed from the recovery of the permeability and strength for the cracked cementitious specimens as the healing agent in the microcapsule acting on the cracks directly. Scanning electronic microscope (SEM/EDX) results show that the epoxy resin is released along with the cracking of the cementitious composite and prevent from cracks continued growth. Further studies show that the self-healing efficiency is affected by the pre-loading of composite, particle size of microcapsule, aging duration of healing agent and so on.

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Sustainable Polyurethane Networks Based on Rosin with Reprocessing Performance

Polymers ◽

10.3390/polym13203538 ◽

2021 ◽

Vol 13 (20) ◽

pp. 3538

Author(s):

Jiawei Li ◽

Weiming Yang ◽

Zhao Ning ◽

Bin Yang ◽

Yanning Zeng

Keyword(s):

Mechanical Properties ◽

Mechanical Analysis ◽

Healing Time ◽

The Self ◽

Self Healing ◽

Hot Press ◽

Polyurethane Networks ◽

Network Topologies ◽

Superior Mechanical Properties ◽

First Time

Rosin is an abundant natural product. In this paper, for the first time, a rosin derivative is employed as a monomer for the preparation of polyurethane vitrimers with improved properties. A novel rosin-based polyurethane vitrimers network was constructed by the reaction between isocyanates (HDI) as curing agent and monomers with alcohol groups modified from rosin. The dynamic rosin-based polyurethane vitrimers were characterized by FTIR and dynamic mechanical analysis. The obtained rosin-based polyurethane vitrimers possessed superior mechanical properties. Due to the dynamic urethane linkages, the network topologies of rosin-based polyurethane vitrimers could be altered, contributing self-healing and reprocessing abilities. Besides, we investigated the effects of healing time and temperature on the self-healing performance. Moreover, through a hot press, pulverized samples of 70%VPUOH could be reshaped several times, and the mechanical properties of the recycled samples were restored, with tensile strength being even higher than the of that of the original samples.

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

Materials ◽

10.3390/ma14154139 ◽

2021 ◽

Vol 14 (15) ◽

pp. 4139

Author(s):

Yanju Wang ◽

Zhiyang Lin ◽

Can Tang ◽

Wenfeng Hao

Keyword(s):

Compressive Strength ◽

Sodium Silicate ◽

Recovery Rate ◽

Sound Speed ◽

Orthogonal Experimental Design ◽

Self Healing ◽

Damage Degree ◽

Strength Recovery ◽

Healing System ◽

Recovery Performance

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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Nanoparticle-Hydrogel Composites: From Molecular Interactions to Macroscopic Behavior

Polymers ◽

10.3390/polym11020275 ◽

2019 ◽

Vol 11 (2) ◽

pp. 275 ◽

Cited By ~ 28

Author(s):

Corinna Dannert ◽

Bjørn Torger Stokke ◽

Rita S. Dias

Keyword(s):

Mechanical Properties ◽

Molecular Design ◽

The Self ◽

Self Healing ◽

Sensor Applications ◽

Composite Gels ◽

Equilibrium Swelling ◽

Hydrogel Composites ◽

Materials Used ◽

Network Component

Hydrogels are materials used in a variety of applications, ranging from tissue engineering to drug delivery. The incorporation of nanoparticles to yield composite hydrogels has gained substantial momentum over the years since these afford tailor-making and extend material mechanical properties far beyond those achievable through molecular design of the network component. Here, we review different procedures that have been used to integrate nanoparticles into hydrogels; the types of interactions acting between polymers and nanoparticles; and how these underpin the improved mechanical and optical properties of the gels, including the self-healing ability of these composite gels, as well as serving as the basis for future development. In a less explored approach, hydrogels have been used as dispersants of nanomaterials, allowing a larger exposure of the surface of the nanomaterial and thus a better performance in catalytic and sensor applications. Furthermore, the reporting capacity of integrated nanoparticles in hydrogels to assess hydrogel properties, such as equilibrium swelling and elasticity, is highlighted.

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Self-Healable Supramolecular Vanadium Pentoxide Reinforced Polydimethylsiloxane-Graft-Polyurethane Composites

Polymers ◽

10.3390/polym11010041 ◽

2018 ◽

Vol 11 (1) ◽

pp. 41 ◽

Cited By ~ 4

Author(s):

Ali Berkem ◽

Ahmet Capoglu ◽

Turgut Nugay ◽

Erol Sancaktar ◽

Ilke Anac

Keyword(s):

Tensile Strength ◽

Vanadium Pentoxide ◽

Coupling Reaction ◽

Optical Microscope ◽

Mechanical Tests ◽

Healing Time ◽

The Self ◽

Supramolecular Polymer ◽

Self Healing ◽

Healing Efficiency

The self-healing ability can be imparted to the polymers by different mechanisms. In this study, self-healing polydimethylsiloxane-graft-polyurethane (PDMS-g-PUR)/Vanadium pentoxide (V2O5) nanofiber supramolecular polymer composites based on a reversible hydrogen bonding mechanism are prepared. V2O5 nanofibers are synthesized via colloidal route and characterized by XRD, SEM, EDX, and TEM techniques. In order to prepare PDMS-g-PUR, linear aliphatic PUR having one –COOH functional group (PUR-COOH) is synthesized and grafted onto aminopropyl functionalized PDMS by EDC/HCl coupling reaction. PUR-COOH and PDMS-g-PUR are characterized by 1H NMR, FTIR. PDMS-g-PUR/V2O5 nanofiber composites are prepared and characterized by DSC/TGA, FTIR, and tensile tests. The self-healing ability of PDMS-graft-PUR and composites are determined by mechanical tests and optical microscope. Tensile strength data obtained from mechanical tests show that healing efficiencies of PDMS-g-PUR increase with healing time and reach 85.4 ± 1.2 % after waiting 120 min at 50 °C. The addition of V2O5 nanofibers enhances the mechanical properties and healing efficiency of the PDMS-g-PUR. An increase of healing efficiency and max tensile strength from 85.4 ± 1.2% to 95.3 ± 0.4% and 113.08 ± 5.24 kPa to 1443.40 ± 8.96 kPa is observed after the addition of 10 wt % V2O5 nanofiber into the polymer.

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Self-Healing of Concrete Cracks by Ceramsite-Loaded Microorganisms

Advances in Materials Science and Engineering ◽

10.1155/2018/5153041 ◽

2018 ◽

Vol 2018 ◽

pp. 1-8 ◽

Cited By ~ 11

Author(s):

Jing Xu ◽

Xianzhi Wang ◽

Junqing Zuo ◽

Xiaoyan Liu

Keyword(s):

Heat Treatment ◽

Compressive Strength ◽

Heating Temperature ◽

Concrete Strength ◽

The Self ◽

Self Healing ◽

Healing Efficiency ◽

Maximum Crack ◽

Harsh Conditions ◽

Urea Decomposition

Protective carrier is essential for the self-healing of concrete cracks by microbially induced CaCO3 precipitation, owing to the harsh conditions in concrete. In this paper, porous ceramsite particles are used as microbial carrier. Heat treatment and NaOH soaking are first employed to improve the loading content of the ceramsite. The viability of bacterial spores is assessed by urea decomposition measurements. Then, the self-healing efficiency of concrete cracks by spores is evaluated by a series of tests including compressive strength regain, water uptake, and visual inspection of cracks. Results indicate that heat treatment can improve the loading content of ceramsite while not leading to a reduction of concrete strength by the ceramsite addition. The optimal heating temperature is 750°C. Ceramsite particles act as a shelter and protect spores from high-pH environment in concrete. When nutrients and spores are incorporated in ceramsite particles at the same time, nutrients are well accessible to the cells. The regain ratio of the compressive strength increases over 20%, and the water absorption ratio decreases about 30% compared with the control. The healing ratio of cracks reaches 86%, and the maximum crack width healed is near 0.3 mm.

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Low Strength Self Compacting Concrete Compressive Strength Test

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.275-277.2041 ◽

2013 ◽

Vol 275-277 ◽

pp. 2041-2044

Author(s):

Feng Yan ◽

Nan Pang

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Compression Strength ◽

Strength Test ◽

The Self ◽

Concrete Compressive Strength ◽

Self Compacting Concrete ◽

Intensity Index ◽

Compressive Strength Test ◽

Low Strength

In this paper,the mechanical properties were studied,the self compacting concrete cubic compression strength,prismatic compressive strength test,discussed two kinds of relationship between intensity index.

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