• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.303-304
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• 2021

The present study aims to examine the practical potentials of crack self-healing pillet produced using inorganic materials.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.4
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• pp.561-568
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• 2022

In this study, the mechanical properties and self-healing performance of cement mortar containing clinker binder, calcium sulfoaluminate(CSA), and sodium sulfate(Na₂SO₄) were evaluated. The mechanical properties of cement mortar were investigated by measuring compressive strength and flexural strength, and the healing performance was evaluated through hydrostatic water permeability test and gas diffusion test. In addition, the healing products precipitated in the cracks were visually observed through an optical microscope and a scanning electron microscope(SEM). As a result, the incorporation of the clinker binder-based inorganic additives improved the initial and 28-day strength by about 20 %. Depending on the healing performance evaluation method, there was a difference in the healing rate, and the healing rate showed a tendency to be underestimated. Nevertheless, CaCO₃ was precipitated as the main healing product inside the 0.3 mm crack when the inorganic additives were mixed with cement mortar, improving the self-healing performance.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.6
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• pp.138-143
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• 2023

In this study, the crack healing performance of each crack healing agent manufacturing method was analyzed by adding crack healing agents in the form of alginate gel and spore suspension inoculated with endospores of calcium carbonate-forming bacteria to mortar. In addition, by applying it to an full-scale structure in the form of a box-type culvert, we attempted to create an environment in which the developed crack healing agent can be applied not only to a laboratory environment but also to an actual field. The crack healing agent using the dry heat drying method showed crack healing performance, but in the case of the freeze drying method, many spores were killed by freeze hardening and therefore the crack healing performance was lost. As a result of SEM and XRD pattern analysis of the presumed crack healing material extracted from the crack of a full-scale structure, it was found to be calcite, one of the calcium carbonate crystals produced by microorganisms applied to the crack healing agent. In conclusion, it was found that the crack healing by microorganisms can be implemented in a real structure.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.11a
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• pp.27-28
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• 2023

This study compared and analyzed the fluidity, compressive strength, and carbonation resistacne of amorphous metal fiber reinforced mortar according to the PCC mixing ratio as part of a study to improve the self-healing performance and tensile performance of concrete structures.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.1
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• pp.74-82
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• 2017

In this study, we prepared a core material based on the inorganic materials in liquid form for applying an inorganic-based core material to a core material for the self-healing capsules as a part of the basic study to manufacture of self-healing capsule that can heal cracks of cementitious composite. Manufactured core material based on the inorganic materials were applied directly to the cement composite before its encapsulation, were evaluated the effect on performance of cementitious composite as wall as repair performance of the cracks in the cracks. The test results showed that core material based on the inorganic materials was effective to improve the compressive and adhesion strength, had an absorption, permeation water, penetration of chloride iones and freeze-thaw resistance performance. Through the results of this paper, we want to utilize the results as a basis data of the performance of the cement composite that can be obtained when applied to inorganic core materials based on self-healing capsules and future advances localized self-healing capsule technology.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.1
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• pp.143-151
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• 2020

Recently, research on self-healing concrete has been actively conducted, and various methods have been attempted for use in the maintenance of structures. However, contrary to the technical development of self-healing concrete, the method for evaluating the performance is insufficient. Although surface observation and permeability experiments are widely used to observe the healing of cracks, microscopic observation of surface may be insufficient to assess the overall performance. Also, permeation experiments should consider the losses caused by the dissolution of self-healed product and viscosity of water. Although a gas diffusion experiment have been proposed to overcome the shortcomings of these two test methods, verification has not been made on specimens with actual healing. Therefore, in this study, gas diffusion experiments were performed on the mortar specimens that had healed, and the adequacy of self-healing evaluation by the gas diffusion experiment was verified.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.3
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• pp.375-382
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• 2021

Self-healing concrete is in the spotlight in that it can effectively extend the lifespan of concrete structures by healing cracks in the structure by themselves without additional repairing or retrofiting actions. Currently, self-healing concrete is a field that is being actively studied around the world, but since most studies focus on the improvement of healing performance, there is a lack of methods to rationally evaluate the self-healing performance of concrete. Although the gas diffusion test method has been developed for the use in the performance evaluation of self-healing concrete, it has revealed that for gas diffusion through the matrix affect the crack diffusion coefficients depending on the environmental conditions such as the saturation of the specimen, the temperature, and humidity during the experiment. Therefore, in this study, the method has been proposed to eliminate the influence of the matrix diffusion when calculating the crack diffusion coefficient. In addition, a pre-conditioning process was introduced to shorten the experimental time. As a result, the crack width could be estimated with an error level of less than 3% in the test time of about 20 minutes.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.4
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• pp.475-482
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• 2020

In this study, three levels of solid capsules were prepared according to the composition ratio of core materials for the crystal growth type self-healing solid capsule, and a cement mortar was prepared with the crystal growth type self-healing solid capsule. The prepared solid capsule was mixed with 3% of the cement mass to evaluate the healing properties according to the crack induction age of the cement mortar. As a result of test, the crack healing properties according to the crack induction age of cement mortar mixed of solid capsules, it was confirmed that the self-healing performance of the cement mortar with the solid capsules was increased self-healing performance of 7 days than 28 days. This is because the unhydrated binder remains.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.1
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• pp.92-100
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• 2022

In this paper, to evaluate the effect of SC on the crack self-healing performance and mechanical recovery performance of cement composites, encapsulated intumescent inorganic material-based solid healing materials were prepared. SC was mixed with cement composite materials to evaluate the basic properties, permeability test, and load reload test. SC slightly improved the flow of cement composites, and the compressive strength decreased by about 10 %. Also, the flexural strength decreased by about 30 %. It was found that when SC was mixed with the cement composite material by 5 %, the crack self-healing rate of Plain was improved by about 𝜟10 %. As a result of the load reload test, it was found that the mechanical recovery rate of Plain was improved by about 𝜟20 %. In addition, as a result of analyzing the correlation between the crack self-healing rate and the mechanical recovery rate by the load reload test, it is judged that the healing area of the Plain can be increased due to SC.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.3
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• pp.335-342
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• 2022

In this study, self-healing hybrid capsules were prepared by mixing self-healing solid capsules and self-healing microcapsules using inorganic materials as core materials. Self-healing hybrid capsules were mixed with 3 % according to the composition ratio of 3:7, 5:5, and 7:3 based on the mass of the cement to prepare a self-healing cement composite material. The healing properties of crack self-healing hybrid capsules were evaluated through hydrostatic water permeability test and surface crack monitoring. It was found that the self-healing hybrid capsules prepared by mixing the composition ratio of the self-healing solid capsules and the self-healing microcapsules at 7:3 has a great effect on improving the crack self-healing performance.