Tatsuya Numao

Ibaraki University

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Effect of fly ash on setting times of concrete Comparison of result by using Kosovo’s and Japan’s fly ash

2017 UBT International Conference (2017)

Anjeza Alaj Tatsuya Numao

Coal fly ash is discharged from coal-fired plants and it is expected to be used in industrial world. However, it's known that fly ash highly resembles to cement characteristics in its chemical properties and also physical composition. In light of this fact, this study intended to develop further. So, the objective of this research is to investigate the using of fly ash in producing concrete by replacing of cement content in different percentage and the focus in this paper is analysing the effect of fly ash on setting time of cement also comparing results achieved by using Kosovo’s and Japanese’s fly ash. The research conducts fly ash’s basic chemical and physical properties, setting time for various contents of fly ash and also comparing results for both cases. All results are based on experimental tests according to ASTM and entire work took place in concrete laboratory in Japan. To develop this research 20 different mixes underwent to the testing procedures and results are compared by charts.

On the fly

10.33107/ubt-ic.2017.62

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DETECTION OF DEFECTS BETWEEN FRP SHEET AND CONCRETE BY INFRARED THERMOGRAPHY METHOD

Doboku Gakkai Ronbunshu (2000)

Masakazu Mitsui Kimio FUKUZAWA Tatsuya Numao

FRP接着工法では, 不適切な施工や時間経過に伴う劣化により剥離が生じると所要の補強効果が得られないので, その部分を検出し補修を行う必要がある. 本研究では非破壊検査法の一つである赤外線サーモグラフィ法によりFRPシート・コンクリート間の剥離検出の検討を実験的・解析的に行う. まず, 基本実験として周辺環境との温度差を与えた供試体を用いてFRPシートの種類および層数, 欠陥厚さおよび熱負荷方法の影響について検討を行った. さらに, 外気温の日較差や熱輻射の利用により欠陥検出の可能性を検討した. また, 赤外線放射計より得られた温度分布から, 欠陥の有無のみでなくその形状や厚さなどを定量的に同定するための支援手法を目的として, 非定常熱伝導FEM解析によるシミュレーション手法の提案を行った.

Thermography

10.2208/jscej.2000.655_107

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Citations (2)

Moisture migration and drying properties of hardened cement paste and mortar

Nuclear Engineering and Design (1995)

Tatsuya Numao Hirozo Mihashi Kimio FUKUZAWA

10.1016/0029-5493(94)00939-v

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Citations (5)

Development applications of neutron imaging in KUR

Yuji Kawabata Yasushi Saito Daisuke Ito Nobuyuki Takenaka Takao Tsukada

Neutron Imaging

Source

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Effect of Pigment Kinds on the Solar Heat Reflection Characteristics of Paint Film in Visible and Near-Infrared Ray Area

Journal of the Society of Materials Science Japan (2009)

Masashi Sakurada Kimio FUKUZAWA Tatsuya Numao Terumi Inagaki

In recent years, the global warming has been recognized as a serious problem throughout the world. In Japan, various global warming control technologies for slowing the global warming are being applied and verified. The high reflectance surface for structures has got a great deal of public attention as a promising technology that mitigates the heat island phenomenon which is a cause of the global warming. It is considered that the heat island phenomenon is generated by the temperature rise due to the heat release from the buildings which have a high heat absorptance and are warmed by the solar radiation during the daytime. Applying with solar heat high reflectance paint to the exterior surfaces of urban structures would suppress the increase in temperature, and make possible mitigating of the urban heat island. Solar heat high reflectance paint is composed of various raw materials to enhance the reflection in visible and near-infrared ray. This paper describes solar heat reflectance characteristics of the paint film by varying thickness of film, formulation of paint (pigments by binder mass ratio ; P/B) and kinds of pigments which are uesd for colorling structures in white, black, blue, red, and yellow. The conclusions obtained from this study are as follows : 1) With the increase in P/B, solar reflectance of paint films used organic pigments are devided into two groups. One is not influenced with the increase of P/B and the other is increased with the increase of P/B. The solar transmittance of paint films with most organic pigments is decreases with the increase of P/B. The solar reflectance and the solar transmittance of paint films with inorganic pigments are not influenced with the increase of P/B. 2) The solar reflectance is not influenced by the thickness of paint film and the solar transmittance decreases with the increase of thickness of paint film.

Urban Heat Island

Reflection

Absorptance

10.2472/jsms.58.62

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Relationships between Surface Roughness Indexes and Tensile Bond Strength between CFRP Sheets and Concrete.

Journal of the Society of Materials Science Japan (2001)

Masakazu Mitsui Kimio FUKUZAWA Tatsuya Numao

The FRP adhesion method which uses carbon or aramid fiber sheets for the strengthening of the flexural member of building or bridge has lately become a subject of special interest. The bond strength between the FRP sheets and concrete influences the structural properties of the concrete elements which are strengthened by this method. The strength may be classified into three types according to the direction of force: the shear bond strength, the cleavage bond strength and the tensile bond strength. The authors have reported on the relationship between the shear bond strength and the surface roughness of the concrete. The present study describes the experiments concerning the tensile bond strength and the relations between the bond strength and various surface roughness indexes. The surface roughness of concrete varied by changing the treatment methods, such as, sandpaper polishing, diskgrinding, sandblasting and chipping. Surface roughness indexes, the maximum depth Dmax, the superficial area St, the form factor k, fractal dimension Df and the bearing ratio curve were determined based on the 3D profile measurements of the concrete surfaces. The mechanism for bonding between the FRP sheets and concrete was discussed based on the surface roughness indexes and the observations of the fracture surface of the tested specimens. The conclusions which were obtained from this study are as follows: 1) The superficial area St has the greatest influence on the tensile bond strength among the surface roughness indexes, 2) the chipping treatment reduces the bond strength significantly, and 3) the tensile bond strength increases as the concrete strength increases.

Sandpaper

Aramid

10.2472/jsms.50.895

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PROPOSAL OF ANALYTICAL METHOD OF REGIONAL CHARACTERISTICS FOR EVACUATION CENTER FOCUSED ON QUALITY OF LIFE

Journal of Japan Society of Civil Engineers Ser F3 (Civil Engineering Informatics) (2013)

Kosuke Kurihara Yuji Kuwahara Tatsuya Numao

災害時の避難所として公共施設が利用されることが多いが,これらの施設は,避難所を主要用途として設計されたものではなく,避難所として使用する際には,不安感やプライバシー確保などの生活環境上の問題が発生することが懸念される.東日本大震災時には,避難所になるべき施設に相応の設備や備蓄が十分に備わっておらず,避難所によって運営に大きな差があり,被災者のニーズ変化への対応や避難生活の改善が十分でなかったといった課題があった.本研究では,避難所における生活質として,(1)津波や洪水,土砂災害に対して避難所が安全な場所に立地しているか,(2)津波浸水想定域から津波到達時間内に避難可能であるか,(3)避難所の収容率や備蓄数,避難所と給水所との位置関係の3点に着目し,生活質の観点から見た避難所の地域特性分析手法を検討した.

Center (category theory)

10.2208/jscejcei.69.ii_13

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FLOW AND COMPRESSIVE STRENGTH OF GEOPOLYMER MORTAR USING FINE POWDER OF MELT-SOLIDIFIED SLAG FROM MUNICIPAL WASTE CHANGING STORAGE METHOD

Journal of Japan Society of Civil Engineers Ser E2 (Materials and Concrete Structures) (2016)

Tohru Kimura Tatsuya Numao Chihiro TOKUMOTO Yūki Yamashita

Slag (welding)

10.2208/jscejmcs.72.400

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Optimum utilization of fly ash for achieving properties of high performance concrete

2017 UBT International Conference (2018)

Anjeza Alaj Tatsuya Numao

Coal fly ash is obtained as final product by combustion of coal in power plants during process of producing electrical energy. In Kosovo electricity production and its generation is dependent largely based on coal burning power plants. Currently 97% of electrical energy is produced only from coal and based on reserves of this mine and the situation of other resources it seems that for long time coal will be the only source of energy. As result average of coal fly ash is around 1,16million t/year. [1] So, considering this situation, idea of substituting different percentage of cement with coal fly ash in producing concrete will help to reach the point of recycling waste material, reducing amount of cement production, increasing quality of concrete, protecting environment and it has positive effect in economical aspect too. The literature is rich in publications regarding influence of fly ash in concrete, especially for low-calcium fly ash (less than 10% of CaO) [2-4] but suitability of high-calcium fly ash in concrete still is considered with skepticism.[5] These happen especially related to chemical compositions high content of CaO and SO3 can effect volume stability and concrete stability.[6,7,8] Following this approach, an experimental investigation of quality of concrete with different percentage of content of high-calcium fly ash is carried out. In focus is high performance concrete C 50/60 and all work took place in concrete lab according to EN 206-1.

High calcium

10.33107/ubt-ic.2018.61

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<title>Remote sensing study of detecting of flaws in structural material</title>

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE (1993)

Yoshizo OKAMOTO Fumito KAMINAGA Terumi Inagaki Tatsuya Numao Kimio FUKUZAWA

A new thermal radiation technique using an infrared radiometer has been developed to detect flaws of materials, such as inclusion, crack and pinhole. In the present study, several incident radiation energies like sun, lamp and gas, were injected to the test material with an artificial internal flaw. Transient radiation temperature image of the flaw on the CRT represents the existence of the internal flaw with higher radiation temperature than that of the surface without the flaw. The characteristics of various incident energy methods were compared with each other. The detecting limitation of internal flaws is determined by the surface temperature variance of the tested materials. The heat flow around the flaw was numerically analyzed by solving a heat conduction equation to verify the surface temperature behavior above the flaws.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Optical engineering

Thermography

Pinhole (optics)

Thermal Radiation

10.1117/12.141971

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