본 연구에서는 내진성능향상을 목표로 CNT-복합소재로 보강된 콘크리트 구조물의 휨 인장 거동을 다루었다. 다양한 CNT 함유량에 따른 복합소재의 재료적 물성은 수정된 Halpin-Tasi 모델을 적용하여 멀티스케일해석 이론으로부터 도출하였다. 휨인장 시험은 복합소재의 종류, CNT 함유비율, 도포제의 유무, 그리고 보강 방법에 따라서 수행하였다. 변수 실험 결과는 CNT-복합재로 보강된 콘크리트 구조의 향상된 휨인장 거동에 대하여 CNT 함유량과 적절한 도포제의 적용 (부착)의 중요성을 보여주었다.

Multi-walled carbon nanotube (MWCNT)–copper (Cu) composites are successfully fabricated by a combination of a binder-free wet mixing and spark plasma sintering (SPS) process. The SPS is performed under various conditions to investigate optimized processing conditions for minimizing the structural defects of CNTs and densifying the MWCNT–Cu composites. The electrical conductivities of MWCNT–Cu composites are slightly increased for compositions containing up to 1 vol.% CNT and remain above the value for sintered Cu up to 2 vol.% CNT. Uniformly dispersed CNTs in the Cu matrix with clean interfaces between the treated MWCNT and Cu leading to effective electrical transfer from the treated MWCNT to the Cu is believed to be the origin of the improved electrical conductivity of the treated MWCNT–Cu composites. The results indicate the possibility of exploiting CNTs as a contributing reinforcement phase for improving the electrical conductivity and mechanical properties in the Cu matrix composites.

The effect of CNT diameters on properties of CNT-polyamide composites was investigated such as electrical conductivity, tensile strength and thermal conductivity. To get different diameter distributions of CNTs, several portions of Mo and Fe in Mo-Fe/MgO catalysts were synthesized by a combustion method at 600℃. And all CNTs growed at 900℃ with 3 SLM methane and 1 SLM hydrogen for 40min. Four kinds of CNTs with different diameter distributions, such as 1~3nm, 3~7nm, 7~13nm, and 10~30nm, were selected to make CNT-polyamide composites. Each composite was manufactured by a solution mixing using bar-type ultra-sonicator in the CNT portions from 1phr to 50phr. And electrical conductivity, tensile strength, and thermal conductivity were measured. Three properties of CNT-polyamide composite, manufactured with 10nm diameter, were more excellent compared to other composites, with electrical conductivity  Ω at 7phr, thermal conductivity 2.4.W/mK at 40phr, tensile strength 60MPa at 30phr. CNTs with a diameter of 10nm were superior to other diameters for the multi-functional composite such as CNT-polyamide composites.

TiH2 nanopowder was made by high energy ball milling. The milled TiH2 and CNT powders were then simultaneously synthesized and consolidated using pulsed current activated sintering (PCAS) within one minute under an applied pressure of 80 MPa. The milling did not induce any reaction between the constituent powders. Meanwhile, PCAS of the TiH2-CNT mixture produced a Ti-TiC composite according to the reaction (0.92TiH2 + 0.08CNT→0.84Ti + 0.08TiC + 0.92H2, 0.84TiH2 + 0.16CNT→0.68Ti + 0.16TiC + 0.84H2). Highly dense nanocrystalline Ti-TiC composites with a relative density of up to 99.7% were obtained. The hardness and fracture toughness of the dense Ti-8 mole% TiC and Ti-16 mole% TiC produced by PCAS were also investigated. The hardness of the Ti-8 mole% TiC and Ti-16 mole% TiC composites was higher than that of Ti. The hardness value of the Ti-16 mole% TiC composite was higher than that of the Ti-8 mole% TiC composite without a decrease in fracture toughness.

This study investigates the flexural properties of multi-walled carbon nanotube (MWCNT) reinforced basalt/epoxy composites under conditions with and without moisture absorption. The basalt/CNT/epoxy composites were fabricated using 1 wt% silanized MWCNTs and kept in seawater for over 4 months. The flexural properties of the moisture absorbed specimens were evaluated and compared with those of dry specimens. The flexural properties of basalt/CNT/epoxy composites were found to decrease with moisture absorption. The flexural strength and modulus of moisture absorbed specimens were 22% and 16% lower, respectively, than those of the dry specimen. Scanning electron microscope examination of the fracture surfaces revealed that the decreases of flexural properties in the moisture absorbed specimen were due to the weakening of interfacial bonding from swelling of the epoxy matrix.

Titanium dioxide (TiO2) particles deposited on different quantitative Fe-treated carbon nanotube (CNT) composites with high photocatalytic activity of visible light were prepared by a modified sol-gel method using TNB as a titanium source. The composites were characterized by BET, XRD, SEM, TEM and EDX, which showed that the BET surface area was related to the adsorption capacity for each composite. From TEM images, surface and structural characterization of for the CNT surface had been carried out. The XRD results showed that the Fe-ACF/TiO2 composite mostly contained an anatase structure with a Fe-mediated compound. EDX results showed the presence of C, O, and Ti with Fe peaks in the Fe-CNT/TiO2 composites. The photocatalytic activity of the composites was examined by degradation of methylene blue (MB) in aqueous solution under visible light, which was found to depend on the amount of CNT. The highest photocatalytic activity among the different composites was related to the optimal content of CNT in the Fe-CNT/TiO2 composites. In particular, the photocatalytic activity of the Fe-CNT/TiO2 composites under visible light was better than that of the CNT/TiO2 composites due to the introduction of Fe particles.

Carbon nanotube (CNT) reinforced hydroxyapatite (HAp) composites were fabricated by using the spark plasma sintering process with surfactant modified CNT and HAp nano powder. Without the dependency on sintering temperature, the main crystal phase existed with the HAp phase although a few contents of (Tri calcium phosphate) phase were detected. The maximum fracture toughness, was obtained in the sample sintered at and on the fracture surface a typical intergranular fracture mode, as well as the pull-out pmhenomenon of CNT, was observed.

In this study, the effect of compressive loading of carbon nanotube (CNT) mixed cement composites was investigated. To evaluate the electrical resistivity variation of 30%∼60% of compressive load of cement composites containing 1.0% CNT, 1.0% CNT was added to cement composites and compressive strength was calculated. The greater the change in electrical resistance to compressive load, the more vulnerable to internal conductive networks. Also, as the amount of CNT mixed increases, the electrical resistance to the load is more sensitive and it is expected to be mixed more than 1.0%.

This study was conducted to evaluate the effect of self-sensing performance on strain-hardening cement composite containing CNT by curing age. The mixing amount of CNT was set at 1.0%, and SHCC fibers were mixed with PE 1.0% and steel fiber 0.5%. The electrical resistance measurement for the tensile strain sensing performance was based on AC method and 4 probe methods. Test results indicated that electrical sensitivity of SHCC decreased with an increase in curing age.

This research uses carbon nanotubes (CNTs) that are actively used to develop convenient and systematic management of building blocks and structural performance monitoring, away from the difficulties of structural health monitoring such as RC structures. The change in electrical resistance was evaluated according to the amount of load and compressive load. Experiments were carried out with 1.0% and 2.0% CNT, and 30% and 60% compressive strength, respectively. Experimental results show that the compressive strength of CNT 2.0% is lower than the compressive strength of CNT 1.0% but is more sensitive to changes in electrical resistance due to compressive load.

최근 우수한 전기전도도와 넓은 비표면적을 갖는 탄소나노튜브(CNT)를 활용하여 고강도 및 고내구성 콘크리트의 생산을 위한 연구가 많은 연구자들에 의하여 활발히 이루어지고 있다. CNT의 혼입을 통한 콘크리트의 고강도에 대한 연구가 주를 이루고 있으나, 그 외의 연구는 미흡한 실정이다. 이에, 본 연구에서는 CNT 첨가량에 대한 시멘트 복합체의 역학성능 및 발열성능에 대한 평가를 실시하였다. 낮은 물-바인더 비를 기반으로 하는 시멘트-플라이애시 배합에 대하여, 바인더 중량대비 0.2% 및 0.5%의 CNT 첨가에 따른 재령별 압축강도, 수화특성분석을 위한 미소수화열 분석, 페이스트 내 CNT의 분산 및 주변 수화물과의 관계를 규명하기 위한 SEM분석, 기준전극 삽입을 통한 발열실험 및 열 중량 분석을 실시하였다. CNT 첨가량의 증가에 따라 발열성능은 증가하며, CNT가 첨가되지 않은 기준 배합 CNT가 첨가된 배합의 경우 동등수준의 역학성능을 갖는 것으로 나타났다.

In this study, the rate of change of electrical resistance with respect to the strength and load of cement composites was investigated by incorporating Carbon Nanotube(CNT) at 0.25, 0.5, 0.75, 1.0% of the binder weight. Compressive strength test It was shown that the load of 30% was repeatedly applied to impart conductivity through the rate of change of electrical resistance. The incorporation rate of CNT greatly affected the compressive strength and the rate of change of electrical resistance.

This study was aimed to investigate the difference in strength of Carbon Nanotube (CNT) reinforced cement mortars with different types of surfactants and doses. In the experimental program, CTAB, SDBS and TX10 which were common surfactants adopted to improve CNTs dispersion in fabricating CNT composites in many industrial fields were included and superplasticizer which was revealed to be effective to disperse CNTs especially in CNT reinforced cementitious composites were added as well. Superplasticizer presented less strength reduction in cement mortar and more strength gain by adding CNTs among four types of surfactants. Higher dosage of superplasticizer caused lower strength of cement mortar. Adding CNTs of 0.4 wt.% or less to cement didn’t show strength enhancement by adding CNTs but 0.8 wt.% of CNTs resulted in strengthening effect after all. Finally, a combination of 0.1 wt.% of CNTs, superplasticizer and sonication treatment could lead to strength improvement by adding CNTs in cement mortar.

In this study, we intended to estimate the heat of hydration of carbon nanotubes-cement composites. It was tried to present the basic data of the heat of hydration characteristics of the CNT-reinforced cement composite by the simple adiabatic temperature rise test. The results indicated that adding CNT reduced the heat of hydration of cement composites.

This study was intended to estimate the effect of adding CNTs into cement paste on the rheological properties. it was found that higher content of CNTs increase yield stress but there was no noticeable correlation between CNTs dosage and plastic viscosity.

In this study, AC/DC responses of CNT-filled cement composites are measured and compared. Based on the results, it is found that AC measurement method is more reliable to measure the electrical resistance of CNT-filled cement composites.

In this study, an equivalent circuit model of CNT-filled cement composites is proposed. Both the polarization effect of electrode/composite interface and the complex resistance effect due to dielectric property of CNT cement composite are considered in the proposed model. Effective of the proposed model will be experimentally validated.

Cementitious material is widely used as a consturction material but they have a quasi-brittle behavior and low tensile strength. We tried to use CNT as a filler for improving such a problem. For achieving good dispersion of CNT, superplasticizer was used as a dispersion agent and sonication process was appiled.