Kyushu University [Hidenori Hamada (Professor) Faculty of Engineering, ]

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Hidenori Hamada
Professor
Engineering of Construction and Environmental Material Design
Faculty of Engineering
Last modified date：2024.04.25

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Department of Civil and Structural Engineering
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Department of Earth Resources,Marine and Civil Engineering
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1.	JSCE Guideline for Electrochemical Corrosion Control Method.
2.	History Overview and Future Scope of Research on the Diagnosis of Steel Corrosion and Corrosion Prevention in Civil Engineering Field.
3.	Role of Surface Coating on Concrete Structures' Service Life Extension.
4.	Hidenori Hamada, Basic Details about Corrosion and Corrosion Protection, 2012.08.
5.	Hidenori Hamada, Toru Yamaji, Yoshikazu Akira, Steel Sheet and Pipe Piles for Port Steel Structures -Corrosion Protection Technology : Today and Tomorrow-, 2011.07.
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8.	Y. MIYATA, H. NAKANO, M. ABE, H. AKUTAGAWA and H. HAMADA, Effectiveness of Polyyethlene Coating for Steel Pipe Piles, 2006.12.

1.	Application of Impressed current System Cathodic Protection to the Steel Bars in Seawater Mixed Concrete -Test Result at 4years Application-.
2.	Deterioration of PC Beam Specimen Exposed under Marine Environment for More Than 30 years .
3.	A Discussion on Utilization of Zinc Anode Applied in Cross-section Repair of RC Member Damaged by Chloride Attack - Time-Lag Application of Different Zinc Anodes -.
4.	Amry Dasar, Dahlia Patah, Hidenori Hamada, Daisuke Yamamoto, Yasutaka Sagawa, Life performance of 40-years-old RC beams with different concrete covers and bar diameters in natural corrosion environments, Structures, https://doi.org/10.1016/j.istruc.2022.11.033, 46, 12, 2031-2046, 2022.12, This study entailed an experimental evaluation of the life performance of 40-year-old reinforced concrete (RC) beams with different concrete cover depths and tensile bar diameters. Beams that were naturally corroded in a marine environment were used in this study, and no artificial process was employed to accelerate the corrosion. Most existing evaluations of beams employ electrical acceleration, admixture, or exposure to designed chloride environments to aid corrosion. Given the paucity of studies on naturally corroded beams, this study is of significance regarding the design, service, and life assessment of RC structures. Two-point load bending test was employed to examine the residual mechanical performance. The corroded bars were extracted to assess the corrosion properties, while the mechanical properties were evaluated via a tensile test. The focus of this study was on evaluating the progress of deterioration and capacity loss in naturally aged beams. The results indicated that a concrete cover of 50 mm satisfies the requirements of a design service life of 50 years. Furthermore, the cross-sectional loss–ultimate capacity loss relationship is consistently linear for the RC beams. Thus, the estimation of ultimate capacity loss based on cross-sectional loss is acceptable in case of natural corrosion of the RC beams. Hence, the findings can contribute to the prediction of the life performance and maintenance of existing structures as well as to designing new structures..
5.	Pinta Astuti, Rahmita Sari Rafdinal, Daisuke Yamamoto, Volana Andriamisaharimanana, Hidenori Hamada, Effective Use of Sacrificial Zinc Anode as a Suitable Repair Method for Severely Damaged RC Members Due to Chloride Attack, Civil Engineering Journal, https://doi.org/10.28991/CEJ-2022-08-07-015, 8, 7, 1535-1548, 2022.07, In many cases, the repair strategy by using sacrificial anodes for cathodic protection in real RC structures requires additional zinc anodes after several years due to the decreasing protective area. This experimental study evaluates the effectiveness of time lag application of sacrificial anode cathodic protection applied to RC beam specimens that deteriorated severely due to chloride attack. In the experiment, sacrificial anodes and cathodic protection (SACP) were applied to 41-year-old RC beam specimens exposed to natural marine environments in which the embedded steel bars were significantly corroded. The repair work was performed in three stages. Instant-off and rest potential tests of steel bars were conducted periodically to demonstrate the time-dependent depolarization value. In the first stage, a polymer-modified mortar as a patch repair material was cast to replace the concrete in the middle tensile part with small sacrificial anodes embedded in the mortar. After the protective current reaches an equilibrium state, the sacrificial anodes are disconnected from the steel bars for a year, defined as the second stage. During the one year in the second stage, the steel bar in the patch repair area remained passive, without any sign of corrosion. As for the third stage, additional sacrificial anodes were installed in the existing concrete part to protect the steel in it. From one year of observation after applying sacrificial anodes to old concrete parts, the time lag SACP application of both in patch and non-patch repair parts was clarified to be effective in stopping the corrosion of steel bar in both parts until 20–30 years based on the service life prediction..
6.	Application of Cathodic Protection to the Steel Bars in Seawater Mixed Concrete.
7.	Adiwijaya, Hidenori Hamada, Yasutaka Sagawa, Daisuke Yamamoto, Evaluation of Seawater Mixing and Curing on Strength Characteristics and Porosity of Fly Ash Concrete, Proceedings of the 9th International Conference of Asian Concrete Federation (ACF2020/2021), Advanced & Innovative Concrete Technology", 2021.11, This paper presents the strength characteristics and porosity of concrete mixed with seawater and tap water incorporating Fly Ash (FA) with a water binder ratio of 40%, 50%, and 60%. The effect of seawater mixing, FA, and curing conditions such as tap water curing (TC), seawater curing (SC), and air curing (AC) on the strength performance of concrete was evaluated. Moreover, the total pore volume (porosity) and thermogravimetric-differential thermal analysis (TG-DTA) were also observed to verify the results of compressive strength of concrete cylinder specimens. Eight series of concrete mixtures using tap water or seawater as mixing water were prepared by OPC and FA as a binder specified in Japan Industrial Standard. Concrete specimens were demolded at 24 hours after casting, then cured in tap water, in seawater, and in air (20ºC, R.H. 60% controlled room). After certain curing of 28 days and 365 days, compressive strength was measured in accordance with Japan Industrial Standard. Based on the investigation result, it was obtained that seawater mixing improved the strength of OPC concrete and FA concrete up to 365 days in all curing conditions, in TC, SC, and AC. The Porosity of seawater-mixed OPC concrete and FA concrete was decreased compared to tap water-mixed concrete. It was also found that the mass change (weight loss) of hydration product (CH) of seawater-mixed OPC concrete was higher than that of tap water-mixed OPC concrete in TC and AC. KEYWORDS: Seawater mixing, curing condition, strength, porosity, fly ash concrete.
8.	A Study on the Corrosion Preventive Effectiveness of Repair Method or Reinforced Concrete Structures Damaged by Salt Attack.
9.	FUNDAMENTAL CHARACTERISTICS AND DURABILITY UNDER MARINE ENVIRONMENT OF CONCRETE INCORPORATING CLASSIFIED FLY ASH.
10.	QUANTITATIVE EVALUATION OF THE PREVENTIVE EFFECTSOF MINERAL ADMIXTURES AND SURFACE COATING MATERIALSON CONCRETE STRUCTURES AGAINST CHLORIDE ATTACK.
11.	Hiroto Tado, Toru Yamaji, Atsushi Kobayashi, Yoshiyuki Kawase, Michio Yoshida, Hidenori Hamada, A Study on Evaluation Index of Cathodic Protection Effect in Port Steel Structure Based on Test Piece Survey Result, Materials Transactions, 10.2320/matertrans.C-M2021815], 62, 6, 774-780, 2021.06, The prevention rate (PR: the index calculated from the corrosion rate of the non-protection and protection time) is generally employed as the evaluation index of the effect of the cathodic protection of the port steel structures in Japan. When designing the cathodic protection, the prevention rate has been employed as 90% since ancient times. However, if the corrosion rate of the steel is sufficiently close to zero, it is considered that the prevention rate is theoretically close to 100%. In this paper, firstly, we investigated aging changes of the cathodic prevention effect for 4 years by using test pieces installed in Japanese 4 ports. We arranged aging changes of the evaluation index which showed as the effect of the cathodic protection based on the result. Next, based on the above survey results, by using a large number of test pieces (total of 650 pairs) installed at port facilities in the whole country, we grasped the actual condition of the effect of the cathodic protection and verified while comparing evaluation index which shows the effect of the cathodic protection. On the result, it was considered that it was desirable to evaluate the effect of the cathodic protection as “corrosion rate during the cathodic protection” which is a state at the time of the cathodic protection and includes factors of time as the index of the effect of the cathodic protection. In addition, it was suggested that the value of “corrosion rate at the cathodic protection” as an evaluation index of the effect of the cathodic protection was about 0.01mm/y..
12.	Amry Dasar, Dahlia Patah, Hidenori Hamada, Yasutaka Sagawa, Daisuke Yamamoto, Applicability of seawater as a mixing and curing agent in 4-year-old concrete, Construction and Building Materials, 259, 22 page, 2020.12, In certain scenarios, seawater may be the only mixing/curing agent available; hence, it is necessary to optimize conditions for its application in concrete structures. In this study, the applicability of seawater as a mixing and curing agent in 4-year-old mortar cement specimens is evaluated. Unlike previous studies, we focused on evaluating the long-term performance of reinforced mortar specimens exposed to seawater. Specimens comprised ordinary Portland cement (OPC), grand granulated blast furnace slag (GGBFS), and reinforced concrete with plain steel, epoxy-coated, or stainless-steel bars; they were subjected to wetting–drying cycles (mimicked for tidal/splash zones) in the laboratory, and the corrosion was evaluated through electrochemical techniques. The results indicate that the effect of seawater on corrosion activity is considerably higher as a curing agent than that as a mixing agent. Further, GGBFS exhibited better performance than OPC; similarly, epoxy-coated and stainless-steel bars exhibited better corrosion resistance than plain steel bars. The results obtained in this study highlight the need to study the application of seawater in concrete mixing..
13.	An Applicability of Seawater as Concrete Mixing Water.
14.	Tarek Uddin Mohammed, Hidenori Hamada, Toru Yamaji, Long-Term Durability of concrete Made with Slag Cements under Marine Environment, ACI Materials Journal, American Concrete Institute, 1-12, 2019.09.
15.	A Study on Evaluation Index of Cathodic Protection Effect in Port Steel Structure Based on Test Piece Survey Result.
16.	Amry Dasar, Hidenori Hamada, 佐川康貴, 山本大介, ELECTROCHEMICAL BEHAVIOR OF STEEL IN CRACKED CONCRETE – INFLUENCE OF CRACK WIDTH, COVER, EXPOSURE CONDITIONS AND SUPPLEMENTARY CEMENTITIOUS MATERIALS (SCMs), コンクリート工学年次論文集第39巻（2017）, 第39巻, 1045-1049, 2017.07, Reinforced concrete prism with w/b ratio of 0.5 had dimensions of 150x150x500 mm, while concrete cover were 30 mm, 50 mm and 70 mm. The crack widths investigated were 0.3 mm and 0.5 mm. These specimens were exposed to three conditions: (1) dry-wet cycles in tap water; (2) dry-wet cycles in sea-water; and (3) continuously immersed in 3% NaCl solution. The results show crack width has influence at constant concrete cover. However, by increasing concrete cover, the crack width has less affected. Further, exposure condition and SCMs (BFS) has an effect particularly in high chloride environment..
17.	Rahmita Sari Rafdinal, Hidenori Hamada, 佐川康貴, 山本大介, EVALUATION OF EXHAUSTED CONDITION OF SACRIFICIAL ANODE EMBEDDED IN CONCETE BY CURRENT ACCELERATION METHOD, コンクリート工学年次論文集第39巻（2017）, 第39巻, 955-960, 2017.07, This study was carried out to observe the service life of the galvanic sacrificial anode to protect steel bar from corrosion in concrete. Current acceleration method was used by adjusting the current demand 10 times higher than initial current of anode. Results show that by increasing the current demand by 10 times, it makes the service life of anode reduced significantly after 70 days of exposure. It means the higher current delivery function of anode, the service life of anode become shorter. Current acceleration method is effective to investigate the service life of anode in short time..
18.	Amry Dasar, Hidenori Hamada, Yasutaka SAGAWA, Daisuke YAMAMOTO, Deterioration progress and performance reduction of 40-year-olad reinforced concrete beams in natural corrosion environments, Construction and Building Materials, 149, 690-704, 2017.05, Deterioration progress and performance reduction were experimentally evaluated in 40-year-old corroded reinforced concrete (RC) beams. The corrosion process was natural, without acceleration by current application, admixture inclusion, or exposure to an artificial chloride environment. The mechanical performance of the beams was evaluated through a four-point bending test. The corroded steel reinforcing bars were extracted for corrosion evaluation and tensile testing. A good correlation was established between crack width and cross-section loss, as well as between cross-section loss and ultimate capacity loss. Furthermore, the relationship between deterioration progress and performance degradation with the exposure period for each deterioration stage was elucidated..
19.	Amry Dasar, Hidenori Hamada, 佐川康貴, 山本大介, RECOVERY IN MIX POTENTIAL AND POLARIZATION RESISTANCE OF STEEL BAR IN CEMENT HARDENED MATRIX DURING EARLY AGE OF SIX MONTHS -SEA-WATER MIXED MORTAR AND CRACKED CONCRETE-, コンクリート工学年次論文集第38巻（2016）, 第38巻, 1198-1203, 2016.07, Sea-water contains high chloride ion concentration which can promote corrosion of steel bar. However, it has a potential to be used as mixing water. On the other hand, cracks should be avoided in reinforced concrete for durability reason..
20.	Caronge Muhammad Akbar, Hamada Hidenori, Irmawaty Rita, Sagawa Yasutaka, Yamamoto Daisuke, Application of Sacrificial Point Anode for Prevention of Steel Corrosion in Cracked Concrete, Journal of Advanced Concrete Technology, 10.3151/jact.13.479, Vol. 13, 10, 479-488, 2015.10, The effectiveness of a commercially available sacrificial point anode for corrosion prevention of steel in cracked concrete is presented. Reinforced concrete prisms with dimensions of 150 mm x 150 mm x 500 mm were prepared with a water to cement ratio (W/C) of 0.4 showing crack widths ranging from 0.1 to 0.4 mm obtained by pre-cracking. These specimens were exposed to three conditions: (1) laboratory air (temperature of 20±2°C and relative humidity of 60%); (2) immersed in 3% NaCl solution; and (3) dry/wet cycles of above mentioned conditions. Measurements included the free corrosion potential, polarization behavior of the sacrificial point anode, anodic-cathodic polarization curve of the reinforcement steel and visual observation. The test results show that the sacrificial point anode was effective to prevent the embedded steel from corrosion in cracked concrete. Specimens exposed to dry/wet cycles or immersed in 3% NaCl solution demonstrated a better protection than those exposed to laboratory air due to the high moisture condition. Thus, a sacrificial point anode becomes active to protect the steel bars even in cracked concrete..
21.	Adiwijaya, Hidenori Hamada, Yasutaka SAGAWA, Daisuke Yamamoto, EFFECT OF MINERAL ADMIXTURES ON CARBONATION OF SEAWATER MIXED CONCRETE, Proceedings of the 2nd Makassar International Conference on Civil Engineering (MICCE 2015)Makassar, Indonesia, August 11-12, 2015, 153-162, 2015.08, This study presents carbonation of seawater mixed concrete and tap water mixed concrete incorporating mineral admixtures such as Fly Ash (FA) and Ground Granulated Blast-Furnace Slag (GGBS) with W/B of 40%, 50% and 60% in tap water curing (TC), seawater curing (SC) and air curing (AC). The effect of seawater mixing, mineral admixtures, water-binder ratio, curing conditions and exposure condition on carbonation process of concrete were evaluated. Concrete prism specimens using tap water and seawater as mixing water were prepared. At 24 hours after casting, specimens were de-molded and followed by distinct curing conditions such as tap water curing, seawater curing and air curing. After curing until 28 days, specimens were exposed in air during 4 weeks before they were brought into accelerated chamber for carbonation and natural outdoor exposure. Based on experimental result, it was shown that carbonation depth of seawater-mixed concrete with and without mineral admixtures in AC was lower compared to tap water mixed concrete in both accelerated and natural exposure carbonation. Moreover, mineral admixtures increased carbonation rate of seawater mixed concrete in all curing condition. Besides, the carbonation rate of seawater-mixed concrete with and without mineral admixtures in SC was smaller than that of in TC. In addition, accelerated carbonation depth of seawater mixed or tap water mixed FA and GGBS concrete was seven times larger than natural exposure carbonation..
22.	Mohammad Akbar Caronge, Hidenori Hamada, Yasutaka SAGAWA, Daisuke Yamamoto, APPLICATION OF SACRIFICIAL ANODE TO PREVENT MACROCELL CORROSION IN REPAIRED RC MEMBER, Proceedings of the 2nd Makassar International Conference on Civil Engineering (MICCE 2015)Makassar, Indonesia, August 11-12, 2015, 163-170, 2015.08, This paper presents results of an experimental investigation on the effectiveness of sacrificial anode to prevent macrocell corrosion of steel in repaired RC member. Experimental tests were carried out in reinforced concrete beams with sizes of 150 mm x 150 mm x 500 mm and cover thickness of 30 mm. Each specimen consisted of plain steel bar (PS), plain steel bar with sacrificial anode (PSCP) and epoxy coated steel bar (PSE). Mix proportion was divided into two categories; firstly, existing concrete (EC) with 4 kg/m3 and 10 kg/m3 of chloride and W/C ratio of 53.5% and 40% were placed, namely N53.5, N40 and BB40. For BB40, replacement of cement with 50% of blast furnace slag (BFS) was added. Secondly, concrete with 47% of W/C ratio without chloride was placed as repaired concrete (RPC). The potential value of steel, depolarization tests, anodic-cathodic polarization curve, polarization behavior of sacrificial anode, and visual observation were evaluated after one-year exposure. From the test results, PSCP showed good passivation film and little corrosion than PS in RPC. It means sacrificial anode is effective to delay macrocell corrosion repaired section. Also, replacement of cement by 50% BFS can raise the resistance to penetration of chloride ions into repaired concrete..
23.	Nobuaki Otsuki, Hidenori Hamada, Nobufumi Takeda, Kei-ichi Imamoto, Toru Yamaji, Takashi Habuchi, Takahiro Nishida, INTRODUCTION OF A JCI TECHNICAL COMMITTEE REPORT ON THE USE OF SEAWATER IN CONCRETE, Proceedings of the 40th Conference on Our World in Concrete & Structures 27-28 August 2015, Singapore, 249-262, 2015.08, Effective use of resources is much needed. Particularly, water resources for drinking are predicted to be in serious shortage in 2050 due to increases in population and rapid urbanization throughout the world. In the field of concrete, billions of tons of freshwater is consumed annually for mixing, curing and washing concrete. Seawater, which exists in abundance on the globe, is presently not permitted to be used for these purposes. Active use of seawater in the field would help more effective use of freshwater resources. The Committee aims to: 1) collect information on use of seawater, such as for mixing and curing concrete, and investigate problems and remedies via experiments and reference studies, 2) survey technologies for using seawater in manufacture and curing of concrete by interviews and literature searches, and 3) summarize and investigate the results, and propose various possibilities, etc., for effective use of seawater. In this paper, introduction of the committee report is presented...
24.	Adiwijaya, Hidenori Hamada, Yasutaka SAGAWA, Daisuke Yamamoto, EXPANSION CHARACTERISTICS OF SEAWATER MIXED CONCRETE DUE TO ALKALI-SILICA REACTION, Proceedings of the 40th Conference on Our World in Concrete & Structures 27-28 August 2015, Singapore, 311-320, 2015.08, This paper presents expansion characteristics of seawater mixed concrete and tap water mixed concrete in tap water curing (TC), seawater curing (SC) and moisture curing (MC). Six series of concrete mixture with 50% waterbinder ratio were prepared. Ordinary Portland Cement (OPC), Fly Ash (FA) and Ground Granulated Blast-Furnace Slag (GGBS) were used as binder, with replacement ratio of FA 30% and GGBS 50%, respectively. Andesite stone was selected as a reactive coarse aggregate used in the pessimum proportion. Concrete cylindrical specimens were cured in TC, SC and MC in 40°C, 100% R.H. chamber, and expansion of specimens was measured in accordance with contact gauge method. Results showed that seawater mixed OPC concrete caused expansion due to ASR in TC, SC and MC. The expansion level of seawater mixed OPC concrete was larger in MC than that in SC and TC. However, ASR-induced expansion of seawater mixed concrete was inhibited by incorporating mineral admixtures..
25.	Daisuke Yamamoto, Hidenori Hamada, Yasutaka SAGAWA, VARIATION AND ITS SUPPRESSION METHOD OF COMPRESSIVE STRENGTH OBTAINED BY SMALL DIAMETER CORE SPECIMEN, Proceedings of the 40th Conference on Our World in Concrete & Structures 27-28 August 2015, Singapore, 487-492, 2015.08, It is generally known that deviation of compressive strength test value increases when small diameter core specimen (25mm) is used. In this study, an experimental study was performed, focusing on its deviation of compressive strength. As a result, following conclusions were obtained, (1) Compressive strength of small diameter core tend to be larger if the coarse aggregate volume content of the specimen is higher, and (2) It is possible to control the variation of compressive strength to some extent by using anti-friction material. And then, the small diameter core compressive strength values with anti-friction material was found to be smaller compared to the 100mm core compressive strength values..
26.	Rahmita Sari Rafdinal, Hidenori Hamada, Yasutaka SAGAWA, Daisuke Yamamoto, EFFECTIVE LENGTH OF CATHODIC PROTECTION EMBEDDED STEEL WITH SACRIFICIAL ANODE UNDER NON-HOMOGENEOUS CHLORIDE ENVIRONMENT, コンクリート工学年次論文集, 第37巻, 955-960, 2015.07, This study was carried out to identify the effective length of embedded steel reinforcement element which can be protected by sacrificial anode under non-homogeneous chloride environment in partially-repaired concrete. The investigations were conducted on four reinforced concrete beams with embedded steel element both in chloride free repair OPC concrete and chloride contaminated OPC existing concrete. The electrochemical test includes the protective current, macro-cell current density, depolarization and anodic polarization curve of sacrificial anode. The results show that sacrificial anode is effective to protect the corroding steel around 120 mm until 200 mm from the border between repair and existing concrete..
27.	香田真生, 青山敏幸, Daisuke Yamamoto, Hidenori Hamada, 流電陽極方式における陽極被覆材および乾湿条件が防食効果に与える影響に関する実験的検討, コンクリート工学年次論文集, 第37巻, 1549-1554, 2015.07, 本実験は，電気防食工法のひとつである流電陽極方式において，陽極材の被覆条件および乾湿条件の違いが防食効果に与える影響に着目し，陽極被覆材の選定実験，および選定した被覆条件における複数本の鉄筋に対する防食効果の確認実験を行った。陽極被覆材に亜硝酸リチウムを混入することによって，陽極材が活性化することが確認され，また混入量の減少にって防食効果が低下することが確認された。また，水分が供給される環境では亜鉛および鉄筋の電位が卑化するがことが確認された。さらに，本実験の範囲では，複数本の鉄筋を埋設した試験体において，選定した陽極被覆材を用いることで十分な防食効果が確認された。.
28.	Tarek Uddin Mohammed, Hidenori Hamada, Ariful Hasanat, Mohammed Abudullah Al Mamun, Corrosion of Steel Bars in Concrete with the Variation of Microstructure of Steel-Concrete Interface, Journal of Advanced Concrete Technology, Japan Concrete Institute,, Volume 13, 230-240, 2015.04.
29.	Hidenori Hamada, 山本大介, Yasutaka SAGAWA, 池田隆徳, An experimental study on relationship between chloride content in mortar and passivity condition of embedded steel bar, Proceedings of the fourth International Sysmposium on Life-cycle Civil Engineering, "Life-Cycle of Structural Systems: Design, Assessment, Maintenance and management", 1479-1484, 2014.11, In this study, properties related to corrosion of embedded steel in mortar, which contains chloride around threshold chloride content for steel corrosion, were discussed. Half-cell potential, polarization resistance and polarization curve of embedded steel were measured. Half-cell potential showed a linear relationship with chloride content in mortar. Polarization resistance and grade of passivity judged by polarization curve quickly decreased at the chloride content around 0.3 - 0.4% mass percent versus unit cement mass. This indicates that the destruction of passivity film on steel surface is occurred around this chloride level, which is believed pres-ently to be threshold chloride content for steel corrosion initiation..
30.	山路徹, Hidenori Hamada, S. Mizuma, T.Okabe, Corrosion resistant property of stainless steel bars in concrete under marine environment, Proceedings of the fourth International Sysmposium on Life-cycle Civil Engineering, "Life-Cycle of Structural Systems: Design, Assessment, Maintenance and management", 1524-1531, 2014.11, For the durability enhancement of port RC structures, corrosion resistant property of three types of stainless steel bars (SUS430, SUS304 and SUS316) in concrete was studied by the exposure tests under marine environment. Results obtained are as follows. i) No corrosion was observed at the sound part on all types of stainless steels under high concentration of chloride ion. Here, the threshold levels for corrosion were estimated larger than 13-14 kg/m3. ii) No corrosion was observed at the small cracked part on all types of stainless steels where the crack width was smaller than 0.5mm. On the other hand, slight corrosion was observed at the large crack regions where the crack width was larger than 0.5mm on SUS 304 and 316. iii) In case that stainless steel bar is applied to port RC structures, the life cycle cost can be lower than the case of carbon steel bar..
31.	Muhammad Akbar CARONGE, 濵田秀則, 佐川康貴, 山本大介, EFFECT OF CURING AND CRACK WIDTH ON POTENTIAL PERFORMANCE OF STEEL WITH SACRIFICIAL ANODE IN CRACKED CONCRETE, コンクリート工学年次論文集、第36巻、2014, 36巻, 1204-1209, 2014.07, The effectiveness of sacrificial anode to protect embedded steel in cracked concrete under different curing conditions; air curing, immersion in a 3% NaCl solution and dry/wet cycle is presented. Reinforced concrete prism in size of 150x150x500 mm with water-to-cement ratio of 0.4 and pre-crack of 0.1 to 0.4 mm in width was evaluated. The result showed that sacrificial anode was effective to protect the embedded steel in cracked concrete. Also, crack width significantly influences the corrosion rate..
32.	Nurazuwa MD NOOR, 濵田秀則, 佐川康貴, 山本大介, STRENGTH CHARACTERISTICS AND EFFECTIVE CHLORIDE DIFFUSION COEFFICIENT OF RUBBERIZED CONCRETE, コンクリート工学年次論文集、第36巻、2014, 36巻, 1864-1869, 2014.07, In this study, crumb rubber was used as fine aggregate at 10%, 15% and 20% sand volume replacement to produce rubberized concrete with satisfied compressive strength. Rubberized concrete was tested on its fresh properties, mechanical strength and effective diffusion coefficient of chloride ion. In addition, silica fume as 10% of cement was added to investigate the effect on the strength and resistance against chloride penetration. Results shows mechanical strength reached to the acceptable value for satisfied strength as structural concrete and chloride ion resistance was improved with silica fume..
33.	Nurazuwa MD NOOR, Daisuke Yamamoto, 濵田秀則, 佐川康貴, Potential in usage of used tire as sand replacement in high strength mortar, セメント・コンクリート論文集, 67, 573-578, 2014.03, Every year, tire generated from vehicles that is not biodegradable are increasing, and if it is not managed properly it could bring harm to the environment. Thus, this research was conducted to study the utilization potential of used tire as mortar material. Crumb rubber with size of 1 mm – 3 mm from waste tire was mixed as fine aggregate at 10% of sand volume in mortar mixture. In addition, silica fume was added as a binder at 10% and 15% of cement weight. Six series of cylindrical rubberized mortar specimen with size of 50 mm diameter and 100 mm height for compressive strength and 40 mm x 40 mm x 160 mm prism for flexural strength were prepared. Water to cement ratio was set at 0.35, 0.30 and 0.25 and all series were tested on its fresh properties, compressive strength, flexural strength, hardened density and elastic modulus. Results shows the strength of rubberized mortar without silica fume achieved more than 50% of control mixture strength and gave a good resistance against brittleness. Meanwhile, addition of 10% silica fume in the mixture helped to increase the strength. In conclusion, this study strongly suggests the potential of the crumb rubber to be used as sand replacement with or without silica fume..
34.	Md Noor Nurazuwa, Yamamoto Daisuke, Goda Hiroki, ゴムチップ混和モルタルの強度特性とすり減り抵抗性に関する検討, 土木構造・材料論文集九州橋梁・構造工学研究会論文集編集委員会編, 29, 91-96, 2013.12.
35.	Adiwijaya, 山本大介, Amry Dasar, Hidenori Hamada, Yasutaka SAGAWA, Effects of Seawater Mixing and Curing on Strength and Carbonation of Fly Ash Concrete, 土木構造・材料論文集、第29号, 29, 97-103, 2013.12, In this study, effects of seawater mixing and seawater curing on compressive strength, porosity, and carbonation depth of concrete with 20% fly ash replacement were investigated. Concrete cylinder specimens with water-binder ratio of 0.5 were prepared using natural seawater or tap water as mixing water. At 24 hours after casting, specimen was demolded and followed by different curing conditions, such as tap water curing, seawater curing and air curing in 20C, RH 60% controlled room for 28 days. Result shows that compressive strength of concrete mixed with seawater at 28 days was improved compared with tap water mixed concrete for each curing condition and no significant difference in compressive strength of concrete is observed for tap water curing and seawater curing. In addition, a good correlation between compressive strength and carbonation coefficient in seawater mixed and tap water mixed concrete was also obtained..
36.	山本大介, Hidenori Hamada, Yasutaka SAGAWA, Nurazuwa Md Noor, Diagnosis of Load Bearing Capacity of Sewage Pipes Deteriorated by Sulfuric Attack, Proceedings of the Seventh International Conference on Concrete under Severe Conditions - Environment and Loading, Volume 2, 1280-1288, 2013.09, It has been frequently reported that concrete sewage facilities has deteriorated in short term than expected service life time of 50 years. This is serious problem in durability and maintenance of the sewage facilities. It is clear that this deterioration originates from sulfuric acid generated by the micro-organism activity in the sewage, thus nowadays a routine corrosion inspection of the sewage pipes is carried out. However, deterioration in sewage pipe has not well verified by current checking techniques, thus to ensure the required performance during service period is difficult. In this paper, the method for deterioration diagnosis for sewage pipes is investigated. As a result, the degree of deterioration can be examined, and methodology for estimation of service life with satisfy required performance of sewage pipe is proposed..
37.	池田隆徳, Hidenori Hamada, Yasutaka SAGAWA, 舟橋政司, EXPERIMENTAL INVESTIGATION OF AIR VOID FORMED AROUND STEEL BAR USING X-RAY CT SCANNING, Proceedings of the Seventh International Conference on Concrete under Severe Conditions - Environment and Loading, Volume 1, 742-748, 2013.09, Corrosion of Steel bar is affected by several factors such as chloride ion concentration, oxygen and water supply. Interfacial zone between concrete and steel bar is also important factor on steel corrosion. It is well known that air void formed around steel bar accelerates corrosion, however air void structure such as size and distribution were not fully understood. This study presents the observation results of three dimensional structure of air void around steel bar obtained by X-ray CT (Computed Tomography) scanning. Mortar specimens with height of 500mm and cross section of 150×150mm are prepared. Water to cement ratio of mortars are varied 3 types to change bleeding ratio. Aluminum bar are used as alternative material for steel bar because X-ray can not transmit in steel. Two bars with different height, 30mm from top and bottom, are embedded in each specimen. One month after casting, observation using X-ray CT scanning is carried out. As a result, 2~5mm of thickness of air void is formed around top bar. On the other hands, the average thickness of air void around bottom bar is 0.1~0.3mm. However, several air voids with mm-ordered size are detected on bottom bar which can cause macro-cell corrosion. Air void size around top bar depended on water to cement ratio, larger void is formed in specimen with higher water to cement ratio. Using X-ray CT scanning is effective to evaluate air void structure quantitatively..
38.	Hiroshi Yokota, Hidenori Hamada, Mitsuyasu Iwanami, Evaluation and prediction on performance degradation of marine concrete structures, Proceedings of Third International Conference on Sustainable Construction Materials and Technologies - SCMT3, 2013.08, Typical deterioration of concrete structures in marine environments is chloride-induced corrosion of rebar. After starting corrosion, it progresses rapidly and loss in structural performance or even structural collapse may be consequences. To meet these facts, it is extremely important to coordinate durability design and strategic maintenance and essential to establish life-cycle management strategies. The authors have been conducting several research programs for the core parts of the life cycle management system of marine concrete structures. In this paper, the results and discussions are introduced how deterioration of concrete members and structural performance degradation should be evaluated and assessed. In addition, the effect of marine fouling organisms attaching the surface of concrete is experimentally discussed. Finally, prediction with the Markov-chain is proposed in the life-cycle management. Some of the practical considerations have been introduced in the design and maintenance standards for port and harbor structures..
39.	Rita Irmawaty, Daisuke Yamamoto, Hidenori Hamada, Yasutaka SAGAWA, Deterioration of Prestressed Concrete Beams Due to Combined Effects of Carbonation and Chloride Attack, Proceedings of Third International Conference on Sustainable Construction Materials and Technologies - SCMT3, 2013.08, Performance of prestressed concrete (PC) beams subjected to both carbonation and chloride ingress has not been clarified well so far. This paper presents the evaluation results and discussion on materials deterioration and corrosion state of prestressing wire/tendons of 35 year’s test PC beams. All beams were exposed to the actual marine tidal environments at the Sakata Port more than 20 years, then transferred and stored in a constant temperature over 15 years. The results indicated that all beams showed deterioration on the exterior and the whole surface of beams was carbonated. Even carbonation did not cause corrosion of reinforcement, however, it may have contributed to degradation of cover concrete. In addition, even though tendons were protected by sheath and mortar grouting, however, corrosion area on tendons reached 40%, and prestressing wires corrosion length was 50 to 73%, indicating severe corrosion conditions for PC beams with 30 mm cover depth..
40.	Toru Yamaji, Yoshikazu Akira, Hidenori Hamada, Kazuo Yamada, Study on concrete deterioration and deterioration indicators in marine environments, Proceedings of Third International Conference on Sustainable Construction Materials and Technologies - SCMT3, 2013.08, In order to investigate the deterioration of concrete in marine environments, both concrete cores sampled from existing structures and test specimens exposed in an outdoor pool of natural seawater are used. These specimens were examined using the Vickers hardness test and EPMA (Electron Prove Micro Analyzer). The following behaviors were observed: 1) The penetration depth of Mg2+ was correlated with both the neutralization depth and the depth of SO4 2- penetration. 2) Deteriorated areas in concrete specimens determined by Vickers hardness were correlated with the penetration depth of Mg2+. One reason for this deterioration is considered to be the phase change of C-S-H (Calcium silicate hydrate) to M-S-H (Magnesium silicate hydrate), which has a lower strength than C-S-H. 3) The penetration depth of Mg2+ can be an indicator of concrete deterioration progress in marine environments..
41.	Mohammed Tarek Uddin, Hidenori Hamada, Mohammed Abdullah Al Mamun, Ariful Hasnat, Corrosion of cement paste coated steel bars in marine environment, Proceedings of Third International Conference on Sustainable Construction Materials and Technologies - SCMT3, 2013.08, A detailed experimental investigation was carried out to understand the performance of different cement paste coated steel bars against chloride-induced corrosion. Cylinder concrete specimens of diameter 100 mm and height 200 mm were made with steel bars embedded in concrete at a cover depth of 20 mm. Twenty-two separate cases were made with and without cement paste coated steel bars. W/C ratio of cement paste was varied from 0.3 to 1.0. After curing for one-month, the specimens were exposed to an accelerated chloride-induced corrosion environment. Each cycle of exposure consists 3.5 days under seawater exposure at 60oc and 3.5 days drying under atmospheric exposure. The specimens were tested after 10, 20, and 45 cycles of exposure. The test items include compressive strength of concrete, chloride ingress into concrete (acid soluble and water soluble chloride content), electrochemical evaluation of corrosion (half cell potential, polarization resistance of steel bars, concrete resistance, and anodic polarization curves), microscope investigations of steel-concrete interface, and physical evaluation of corrosion (corroded area, pit depth, weight loss) over the steel bars. Based on this investigation, it is revealed that time to initiate corrosion is significantly increased for cement paste coated steel bars, particularly for coating with a low W/C. It is understood that chloride threshold limit for initiation of corrosion over the steel bars is significantly influenced by the nature of the steel-concrete interface around steel bars. The relationship between water soluble chloride content in concrete and acid soluble chloride content in concrete is also proposed..
42.	Amry Dasar, Hidenori Hamada, Yasutaka SAGAWA, Takanori IKEDA, Durability of marine concrete with mineral admixture and marine aquatic organism layer, Proceedings of Third International Conference on Sustainable Construction Materials and Technologies - SCMT3, 2013.08, The high chloride ion concentration along with the presence of oxygen and water leads to accelerated corrosion process. It is fact that, durability of marine concrete depends corrosion resistance of concrete. On the other hand, addition of mineral admixture and covered marine aquatic organism layer has a potential to reduce the risk of corrosion. A total of 6 samples were prepared which had been exposed in the marine environment for 13 years. During the initial several years, marine aquatic organism layer was formed. In order to investigate the effect of mineral admixture and marine aquatic organism layer against corrosion, experimental laboratory study was carried out to measure corrosion potential and micro-pore structures related to the rate of chloride ion diffusion. Results show that mineral admixture can reduce the risk of corrosion. Moreover, marine aquatic organism layer had a positive effect to prevent the chloride ingress into concrete..
43.	Yoshikazu Akira, Kazuhiro Masuda, Toru Yamaji, Hidenori Hamada, Study on durability and corrosion protection performance of concrete cover method for port steel pipe structures, Proceedings of Third International Conference on Sustainable Construction Materials and Technologies - SCMT3, 2013.08, Researching on corrosion protection technologies for steel pipe piles have been under operation by the exposure test using real pier in HASAKI since 1984. This paper is reporting the durability and corrosion protection performance of concrete cover method obtained from the exposure test. Deterioration of concrete cover was differed by materials and environments. Concrete cover in splash zone and marine atmospheric zone after 25 years was spalled off and fracture of reinforcing bar due to corrosion was occurred. On the other hand, concrete cover in tidal zone was sound. Despite the chloride ion concentration at steel surface in concrete was about 20 kg/m3, steel had not been corroded. It is considered that diffusion of oxygen into the concrete was limited to the level that could not generate the steel corrosion..
44.	Daisuke Yamamoto, Hidenori Hamada, Yasutaka SAGAWA, Toshiumi Hiromitsu, Evaluation of compressive strength of concrete using small diameter core, Proceedings of Third International Conference on Sustainable Construction Materials and Technologies - SCMT3, 2013.08, In Japan, large number of concrete structures were constructed in the high economic growth period (60’s~70’s), and they are entering a period over the designed service life, therefore the proper life cycle management for life extension of these structures is becoming necessary. The use of small diameter core specimen for compressive strength test in conducting the maintenance procedures for existing structures is desirable technology because it gives minor damage to the structure and less risk to cut off reinforcements when the core sampling is done. However, it is known that the variance of compressive strength test result by a small diameter core becomes large and it is difficult to evaluate precisely the compressive strength. From this background, the research described in this paper focused on development of the compressive strength test method by using small diameter core..
45.	Rita Irmawaty, 山本大介, 濵田秀則, 佐川康貴, Performances of PC Sheet Pile after 12years Exposure in the Marine Tidal Environments, コンクリート工学年次論文集，Vol.34，No.1，2012, 34巻, 1号, 706-711, 2012.07, Performances of PC sheet piles were evaluated after 12 years exposure in the marine tidal environment. An evaluation of mechanical properties, carbonation depth, porosity, chloride content and PC steel condition were carried out. Overall, all specimens showed satisfactory performance: only a few concrete corner and edge chips, low chloride content and low rate of corrosion were observed. Investigation results indicated that BS5 (B = GGBFS, S = steam curing, and cover thickness of 5 cm) showed the best performance (more durable) although its strength was lower than the other..
46.	Hidenori Hamada, Yasutaka Sagawa, Daisuke Yamamoto, Some Studies on Performance Enhancement of Recycled Aggregate Concrete --2009-2011 in Japan --, Proceeedings of the 2nd UAP/SEL Seminar on Recycling of Demolished Concrete, 1-10, 2011.12.
47.	Toru Yamaji, Yoshikazu Akira, Tsutomu Fukute, Hidenori Hamada, Masanori Ito, Kenji Hayakawa, Studies on Applicability of Recycled Aggregate Concrete to Marine Environments in Port and Airport Research Institute, Proceedings of the 2nd UAP/SEL Seminar on Recycling of Demolished Concrete, 11-24, 2011.12.
48.	Yoshikazu Akira, Toru Yamaji, Hidenori Hamada, Tsutomu Fukute, Masanori Ito, Kenji Hayakawa, Penetration Property of Chloride Ion into Recycled Concrete, Proceedings of the 2nd UAP/SEL Seminar on Recycling of Demolished Concrete, 25-37, 2011.12.
49.	Hidenori Hamada, Yasutaka sagawa, Toru Yamaji, Anti-Corrosion Technologies on Bridges Affected by Marine Environment, Proceedings of the 2011 International Forum on Bridge Engineering, Taipei, Taiwan, September 8-9, 2011, 81-102, 2011.09.
50.	Rita Irmawaty, Hidenori HAMADA, Yasutaka SAGAWA, Sho Yamatoki, A DISCUSSION ON DURABILITY OF HIGH STRENGTH CONCRETE (HSC) IN VIEW POINT OF MICRO PORE STRUCTURE, Proceedings of The 3rd International Conference of European Asian Civil Engineering Forum, Yogyakarta, 20-22 September 2011, S-49 - S-54, 2011.09.
51.	A Study on Method of Diagnosing Deterioration for Concrete Sewage Pipe.
52.	Toru Yamaji, Yoshikazu Akira, and Hidenori Hamada, Effect of Exposure Environment and Period on Chloride Diffusion in Concrete with Inhibitor., Advances in Concrete Structural Durability. (Proceedings of the 2nd International Conference on Durability of Concrete Structures ICDCS2010), 311-319, 2010.11.
53.	Mingdi Gao, Hidenori Hamada, Yasutaka Sagawa, and Takanori Ikeda, Evaluation on Chloride Diffussion Coefficient of Blast - Furnace Slag Cement Concrete., Advances in Concrete Structural Durability (Proceedings of the 2nd International Conference on Durability of Concrete Structures ICDCS2010), 243-248, 2010.11.
54.	Takanori Ikeda, Yuichiro kawabata, Hidenori Hamada, and Kazuo Yamada, Mitigating effect of Fly Ash on the ASR-related Exposure of Mortar Using Reactive Aggregate at the Pessimum Proportion., Advance in Concrete Structural Durability (Proceedings of the 2nd International Conference on Durability of Concrete Structures ICDCS2010), 473-481, 2010.11.
55.	Daisuke Yamamoto, Hiromichi Matsushita, Isamu Sekino, and Hidenori Hamada, Detailed Investigation of 38 Year Old Concrete Sewerage Pipes Deteriorated by Sulphuric Acid Attack., Advances in Concrete Structural Durability (Proceedings of the 2nd International Conference on Durability of Concrete Structures ICDCS2010), 557-565, 2010.11.
56.	Detailed Investigation of 38 years' old Concrete Sewage Pipes Deteriorated by Sulfar .
57.	Hidenori Hamada, Yasutaka sagawa, Takanori Ikeda, Ryota Morikawa, Sevaral factors affecting the anodic polarization curve of steel bars embedded in mortar, Proceedings of the 6th International Conference on Concrete under Severe Conditions (CONSEC'10), Vol.1, 201-208, 2010.06.
58.	Hidenori Hamada, Shin Tanikawa, R. N. Swamy, The Role of Polymer Surface Coating in Sustainable Structural Rehabilitation of ASR affected RC Beams, Proceedings of 13th International Congress on Polymer in Concrete, 533-541, 2010.02.
59.	Mitsuyasu IAWANAMI, Toru YAMAJI, Hiroshi YOKOTA and Hidenori HAMADA, Effect of surface-attaching marine organisms on deterioration of concrete structures, Proceedings of the International Workshop on Life Cycle Management of Coastal Concrete Structures, Nagaoka, Japan, Nov. 2006, Edited by Yokota and Shimomura, pp.23-30, 2006.11.
60.	Hidenori HAMADA, Hiroshi YOKOTA, Toru YAMAJI and Tarek Uddin Mohammed, Long-term exposure test of concrete materials under marine environmnts carried out by PARI, Proceedings of the International Workshop on Life Cycle Management of Coastal Concrete Structures, Nagaoka, Japan, Nov. 2006, Edited by Yokota and Shimomura, pp.31-36, 2006.11.
61.	Tarek Uddin MOHAMMED and Hidenori HAMADA, Corrosion of steel bars in cracked concrete at the early age of exposure, Proceedings of the International Workshop on Life Cycle Management of Coastal Concrete Structures, Nagaoka, Japan, Nov. 2006, Edited by Yokota and Shimomura, pp.115-126, 2006.11.
62.	Yoshikazu AKIRA, Toru YAMAJI, Hiroshi YOKOTA, Hidekazu HORII, Hidenori HAMADA and Tarek Uddin MOHAMMED, Influence of the pore of the steel-concrete interface on the corrosion of steel bars due to chloride attack, Proceedings of the International Workshop on Life Cycle Management of Coastal Concrete Structures, Nagaoka, Japan, Nov. 2006, Edited by Yokota and Shimomura, pp.145-150, 2006.11.
63.	Toru YAMAJI and Hidenori HAMADA, Long-term durability of concrete with surface coating materials under marine environment, Proceedings of the International Workshop on Life Cycle Management of Coastal Concrete Structures, Nagaoka, Japan, Nov. 2006, Edited by Yokota and Shimomura, pp.209-216, 2006.11.
64.	Ryosuke Takahashi, Hidenori Hamada, Mechanical Property of Steel-making Slag Concrete with Japanese Specified Strength of An Airport Concrete Pavement, Proceedings of 2nd Asian Concrete Federation Conference, pp.CMT-16 - CMT 23, 2006.11.
65.	Yoshikazu Akira, Hidenori Hamada, Toru Yamaji, Nguyen Nam Thang, Experimental Study on Durability of Port RC Structure in Southeast Asian Countries in Marine Environment, Proceedings of 2nd Asian Concrete Federation Conference, pp.DCS-30-DCS-39, 2006.11.
66.	Tarek Uddin Mohammed and Hidenori Hamada, Corrosion of Horizontal Bars in Concrete and Method to Delay Early Corrosion, ACI Materials Journal, A Journal of The American Concrete Institute, Vol.103, No.5,pp.303-311, 2006.09, [URL].
67.	Tarek Uddin Mohammed and Hidenori Hamada, Corrosion of Steel Bars in Concrete with VArious Steel Surface Conditions, ACI MAterials Journal, Vol. 103, No.4, pp.233-242, 2006.07.
68.	Durability Evaluation of Prestressed Concrete Sheet Pile under Marine Corrosive Environments by Acceleration Test .
69.	A Fundamental Study on Application of Optical Fiber for Health Monitoring of Concrete Structures.
70.	Durability of 15 Year Old Concrete Specimens with Surface Coating under Marine Environments .
71.	An Experimental Study on Application of Surface Coating to ASR-occurred Concrete.
72.	Tarek Uddin MOHAMMED，濵田秀則，山路徹, Long-term Durability of Concrete Made with Slag Cements under Marine Environments , 港湾空港技術研究所　報告　042-02-07, 42, 2, 155-192, 2003.06, [URL], 多くの海洋コンクリート構造物において，海水中の塩化物イオンがもとで生じる鉄筋腐食による早期劣化が発生している．塩化物イオンの浸透をどのように抑制するかは，構造物の長期耐久性を実現するための重要な課題である．各種の比較的短期間の実環境暴露試験や促進試験の結果から，スラグセメントを使用したコンクリートにおいては普通ポルトランドセメントを使用したコンクリートに比べて塩化物イオンの浸透が抑制されていることが明らかになっている．この抑制効果の長期的挙動を把握するために，３種の異なるシリーズの，スラグセメントを用いたコンクリートの長期暴露試験を港空研構内の海水循環水槽において実施した．これらのシリーズの暴露期間が各々30年，15年，10年に達したことから，供試体の評価試験を実施した．コンクリートの外観性状，圧縮強度，中性化深さ，含水率，コンクリートの電気抵抗，塩化物イオン含有量（全塩化物・可溶性塩化物），細孔構造，鉱物組成，埋設鉄筋の腐食状況，鉄筋－コンクリート界面の観察，を実施し，普通ポルトランドセメントコンクリートとの比較を行った．これらの一連の実験の結果を本文では取りまとめる．本文において述べられている結果は，海洋環境下におけるコンクリートの長期耐久性を考察する上で貴重な資料となるものである．　長期間の暴露を経た供試体の試験結果では，スラグセメントを使用することによるマイナス面の効果は皆無であった．普通ポルトランドセメントを使用したコンクリートに比べて，スラグセメントコンクリートの方が長期的な強度の増進を示した．スラグセメントコンクリートの供試体の表層部は，長期間の暴露後に密実になる傾向を示し，それにより塩化物イオンが表層部で遮へいされていた．また，内部鉄筋の腐食もスラグセメントコンクリートの方が軽微であった．また，スラグセメントの方が緻密な細孔構造を示すと同時に，鉄筋－コンクリート界面構造も緻密であった．これより．スラグセメントコンクリートの方が長期耐久性に優れるものと判断された．　また，上記の結果に加え，鉄筋－コンクリート界面に空隙が存在すると塩化物イオン濃度がかなり低くても鉄筋の腐食が開始されることから，海洋コンクリート構造物の長期耐久性を向上させるためには，鉄筋－コンクリート界面の構造を改善することが極めて重要であることが明らかとなった．.
73.	An Experimental Study on Factors Affecting Electro-chemical Measurements of Steel Bars in Concrete .
74.	Development of A Model on Deterioration Progress for RC Deck of Wharf .
75.	Tarek Uddin MOHAMMED，濵田秀則，山路徹, Corrosion of RC Bars in RC Structures under Marine Environment Based on the Long-term Exposure Test, 港湾空港技術研究所　報告　040-03-03, 40, 3, 37-56, 2001.09, [URL], コンクリート中の鉄筋の腐食は海洋構造物の耐久性低下の最も大きな原因となっている．この問題に関しては，古くから多くの研究が実施されてきている．しかし，海洋環境下におけるＲＣ構造物の長期耐久性を確保するためには，まだまだ多くの研究が必要である．このために，海洋環境下におけるコンクリート構造物の耐久性に関する重要な幾つかの点に関して長期の暴露試験を実施し，幾つかの結論を導いた．　過去6年間にわたる一連の研究プログラムにおいて，コンクリート中鉄筋の電気化学的性質，物理的性質，例えば，鉄筋の配置方向が腐食に及ぽす影響，異型棒鋼と丸鋼の腐食状況の相違，コンクリートのひび割れが腐食に及ばす影響，普通セメント・高炉セメント・フライアッシュセメントといったセメントの種類が腐食に及ばす影響，などについて研究を実施してきた．本文においては，これらの研究より得られた結果を取りまとめ，以下に示す結論を得た． 1）鉄筋とコンクリートの間に空隙が存在する場合は，腐食発生時期を早めるとともに，一旦腐食が開始された鉄筋の腐食速度が大きくなる． 2）丸鋼に比べて異型棒鋼の方が腐食しやすい傾向にあった． 3）高炉スラグ置換率が比較的高い，高炉セメントC種が最も塩分浸透に対する抵抗性，内部鉄筋の腐食抵抗性が優れていた． 4）長期の暴露期間において，比較的幅の小さなひび割れは水和生成物により充填される傾向にあり，そのために内部鉄筋の腐食が抑制される傾向にあった．.
76.	Investigation on NOx Emission at the Area of Tokyo International Airport.
77.	Quantitative Evaluation of Environmental Factors Related to Chloride Attack of RC Harbour Structures .
78.	A Study on Application of Classified Fly Ash Mixed Concrete To Port and Harbour Structures or Marine Structures.
79.	A Discussion on the Chloride Penetration into Concrete in Various Marine Environment .
80.	Effect and Evaluation of Concrete Surface Coatings for the Prevention of Salt Attack .
81.	Durability of Steel-Concrete Composite Hybrid Members in Marine Environments.
82.	Effectiveness of Cement and Aggregate on DEF-Expansion of Cement Mortar..

1.	Hidenori Hamada, Dahlia Patah, Daisuke Yamamoto, Corrosion of Steel Bars in Seawater-mixed Concrete after 36 years' Exposure in Marine Condition, Advanced Materials Research GRAND MEETING, MRM2023, 2023.12.
2.	Ikuto Nozawa, Takayuki Fukunaga, Shunsuke Otani, Fumiya Inosaka, Hidenori Hamada, Application of Cathodic Protection to Steel Bars in Seawater-mixed Concrete, Advanced Materials Research GRAND MEETING, MRM2023, 2023.12.
3.	Takayuki Fukunaga, Ikuto Nozawa, Fumiya Inosaka, Xu Jiale, Hidenori Hamada, Corrosion Characteristics of Steel Bars in Seawater-mixed Concrete with Shirasu as Mineral Admixture, Advanced Materials Research GRAND MEETING, MRM2023 , 2023.12.
4.	Hidenori Hamada, What is Innovation ? Originality ? in Concrete Engineering / Research -Contribution and Collaboration of Foreign Students in Concrete Labo. in Kyushu University -, ISID 2020, The 5th International Symposium on Infrastructure Development, August 28, 2020, Makassar, Indonesia, 2020.08.
5.	Hidenori Hamada, Sea Water Utilization in Concrete Production in Future Water Stressed World -- From the View Point of Corrosion Prevention of Steel in Concrete --, CIMPAS 2020, Civil Engineering and Material Sciences, 2020.10, In near future, seawater mixing will be inevitable technique in concrete engineering almost all over the world. It is necessary the collaboration of concrete engineer and corrosion engineer..
6.	Daisuke Yamamoto, Hidenori Hamada, Yasutaka Sagawa, A Study on Expansion Estimation of Actual Concrete Structure Damaged by ASR, 3rd ACF Symposium on Assesment and Intervention of Existing Structures., 2019.09.
7.	Sabrina Harahap, Hidenori Hamada, Yasutaka Sagawa, Daisuke Yamamoto, The Effect of Calcium Nitrite Coating as Corrosion Inhibitor in Seawater - Mixed mortar, 3rd ACF Symposium on Assesment and Intervention of Existing Structures., 2019.09.
8.	Pinta Astuti, Rahmita Sari Rafdinal, Khalilah binti Kamarulzaman, Hidenori Hamada, Yasutaka Sagawa, Daisuke Yamamoto, Partially Repair Method of deteriorated RC beams by Sacrificial Anode Cathodic Protection and Corrosion Inhibitor, 3rd ACF Symposium on Assesment and Intervention of Existing Structures., 2019.09.
9.	Dahlia Patah, 濵田秀則, 佐川康貴, 山本大介, The effect of Seawater Mixing on corrosion of Steel Bar in 36- years Old RC Beams under Marine Tidal Environment, コンクリート工学年次大会2019（札幌）, 2019.07.
10.	Pinta Astuti, Rahmita Sari Rafdinal, Hidenori Hamada, Yasutaka Sagawa, Daisuke Yamamoto, Application of Sacrificial Anode cathodic Protection for Partially Repaired RC Beams Damaged by Corrosion, 4th International Symposium on Concrete and Structures for Next Generation, 2019.06.
11.	Hidenori Hamada, Sea Water Utilization in Concrete Production in Future Water Stressed World. -- From the View Point of Corrosion Prevention of Steel in Concrete --, 2019 International Corrosion Engineering Conference, 2019.10, [URL], In future, many countries will face a crisis of water scarcity. According to the report of the Organization for Economic Cooperation & the Development (OECD), nearly half of the worlds’ population will inhabit in areas with severe water stress by 2030. Thus, from a viewpoint of saving fresh water, it is important to conduct research on utilization of seawater in various fields including concrete industry. Actually, in japan, based on the experience of 2011 Great Earthquake, many researches were carried out in order to evaluate utilization of seawater in concrete production and saving fresh water for drinking or for life keeping. JCI (Japan Concrete Institute) are doing research activity from 2013. Some research results are introduced in this presentation. From world-wide literature surveys carried out in this JCI activity, it is concluded that many positive opinions are obtained for concrete performance mixed with seawater with mineral admixture, for example, GGBFS or FA. However, relatively negative opinions are concentrated on OPC used concrete without mineral admixtures. As anticipated, the survey shows that a very large number of standards, papers and opinions are absolutely opposed against the use of seawater. While some standards allow the use of seawater for plain concrete, no standards allow the use of seawater for RC. Further, serious degradation has been confirmed to occur as the result of inappropriate mix proportions, fabrication, construction and seawater use. In this presentation, I hope to discuss with many participants on sea water utilization in concrete production based on the experience in Japanese concrete and corrosion engineering. The overnight approval of seawater use in concrete engineering will not be in the world. Some concrete and corrosion engineer only hopes that the use of seawater will be one of the ways to save freshwater resources particularly in countries with freshwater shortages in near future..
12.	Zeinab OKASHA, 濵田秀則, 佐川康貴, 山本大介, An electrochemical conditions of conventional teel bars surface in carbonated concrete., 第71回セメント技術大会, 2017.05, This paper attempts to study the corrosion initiation of steel bars in accelerated carbonated concrete exposed in accelerated carbonation chamber. Using electro-chemical testing techniques such as the Critical carbonation depth (Xc) for corrosion initiation of steel bars, half-cell potential measurement (HCP), corrosion current density (icorr), and also destruction of passivity film due to carbonation is investigated [1]..
13.	Hidenori Hamada, Deterioration Rate of RC Structures under MArine COnditions, International Workshop on Structural Life Management of Eco-Power Structures, 2016.09, Korea and Japan is same situation geographically, that is, both countries are surrounded by sea. Therefore, coast line is very long and main roads and railways are located along coast line in both countries. This fact means that concrete and steel bridges of road and railway are under very severe condition for materials deteri-oration. As facts, many concrete bridges and steel bridges are damaged due to chloride supplied from sea wa-ter prematurely. In Japan, this problem became actualized in 1980’, and during several decades, many re-searches have been carried out, in deterioration mechanism, in performance design methodology, corrosion prevention technology and repair/reinforcement technology. In this paper, some topics related to anti-corrosion technologies on bridges affected by marine environment are presented based on Japanese experience. It is strongly believed that Korea and Japan can share knowledge on this engineering problem..
14.	関博, 大即信明, Hidenori Hamada, 山路徹, LCM of Open Type Wharf RC Deck Based on Nation-wide Surveys of Real Structures Carried Out by PARI (Former PHRI), International Symposium on Concrete and Structures for Next Generation: Ikeda & Otsuki Sysmposium (IOS2016), 2016.05, Chloride attack of RC structures are commonly occurred in marine, coastal and port structures. Among several kinds of port concrete structures, upper deck concrete structure of wharf is most severely damaged due to steel corrosion caused by sea water ingr.
15.	Hidenori Hamada, Possibility of Sea-water Utilization in Concrete Production, Mixing water and Curing Water, 9ｔｈ Asia Pcific Structural Engineering and Construction Conference, 2015.11, In future, many countries will face a crisis of water scarcity. According to the report of the Organization for Economic Cooperation & the Development (OECD), nearly half of the worlds’ population will inhabit in areas with severe water stress by 2030. Thus, from a viewpoint of saving fresh water, it is important to conduct research on utilization of seawater in various fields including concrete industry. Actually, in japan, based on the experience of 2011 Great Earthquake, many researches were carried out in order to evaluate utilization of seawater in concrete production and saving fresh water for drinking or for life keeping. In this presentation, performance of sea water mixed concrete is introduced based on the experimental work carried out in Kyushu University. Especially, strength development, durability aspects, such as carbonation, alkali-silica reaction (ASR), and steel corrosion. The effects of seawater mixing, curing, mineral admixtures (FA, GGBFS) and environmental exposure conditions are discussed. Also. JCI (Japan Concrete Institute) are doing research activity from 2013. Some research results are introduced in this presentation. From world-wide literature surveys carried out in this JCI activity, it is concluded that many positive opinions are obtained for concrete performance mixed with seawater with mineral admixture, for example, GGBFS or FA. However, relatively negative opinions are concentrated on OPC used concrete without mineral admixtures. In this keynote presentation, I hope to discuss with many participants on sea water utilization in concrete production based on the experience in Japanese concrete engineering..
16.	Muhhamad Akbar Caronge, Hidenori Hamada, Yasutaka SAGAWA, 山本大介, Rahmita Sari Rafdinal, Potential Performance of Sacrificial Anode to Prevent Corrosion of Steel in Repaired RC Member, The 6th International Conference of Asian Concrete Federation, 2014.09, This paper presents the result of a study on the performance of sacrificial anode to prevent corrosion of steel bars in repaired concrete. Experimental tests were carried out on reinforced concrete beams with sizes of 150 mm x 150 mm x 500 mm and cover thickness of 30 mm. Mix proportions were divided to two categories; firstly, existing concrete (EC) with w/c ratio of 53.5% and 40%. Both concrete contained 4 kg/m3 or 10 kg/m3 of chloride. Secondly, concrete with 46.9% of w/c ratio without chloride was mixed as repaired concrete (RPC). Results showed that at the very beginning polarization, sacrificial anode is effective to protect the steel bars in all mix concrete, however, slightly decreased the protective effectiveness was slightly decreased after one year due to the high resistivity of repaired concrete. Furthermore, results of visual observation indicate that the sacrificial anode delayed anodic reaction in RPC..
17.	Adiwijaya, Hidenori Hamada, Yasutaka SAGAWA, 山本大介, Effects of Mineral Admixtures on Strength Characteristics of Concrete Mixed with Seawater, The 6th International Conference of Asian Concrete Federation, 2014.09, Studies on strength performance of seawater-mixed concrete have been revealed by several researchers. However, it is still unclear whether seawater-mixing improve strength development of concrete. In this study, strength characteristics of seawater mixed or tap water mixed concrete incorporating mineral admixtures such Fly Ash, Ground Granulated Blast Furnace Slag were investigated. Concrete cylinder specimens with 40%, 50% and 60% of W/B were prepared. At 24 hours after casting, specimens were demolded and then cured in tap water curing, seawater curing or air curing. After 28-days and 91-days curing, concrete specimens were tested. Results showed that seawater-mixed OPC concrete improved compressive strength up to 91-days compared with tap water mixed in all curing conditions. Moreover, effectiveness of seawater-mixing on strength enhancement is larger for OPC concrete than concrete with mineral admixtures, and there is no significant effect of mineral admixtures on strength increment up to 91-days of seawater-mixed concrete in both tap water curing and sea water curing..
18.	ADIWIJAYA, 濵田秀則, 佐川康貴, 山本大介, Effects of mix proportions and curing conditions on strength performance of sea-water mixed fly ash concrete, 第68回セメント技術大会, 2014.05, Since 1974 to 2011, 68 papers have been published, which are related to concrete mixed with seawater. 42 papers among them stated strength performance1). Nevertheless, the investigation on strength of seawater mixed concrete is not still achieved the agreement among researcher whether seawater-mixing improved strength of concrete2). Effects of seawater as mixing and curing on strength of OPC concrete and fly ash concrete were discussed in previous study2). However, influences of mix proportions under various curing conditions are not entirely revealed. In this study, strength performance of seawater or tap water mixed fly ash concrete with various W/B of 40%, 50% and 60% in tap water curing, seawater curing and air curing (20C, R.H. 60%) were investigated..
19.	Daisuke YAMAMOTO, Hidenori Hamada, Yasutaka SAGAWA, Rita Irmawaty, A study on chloride ion penetration of concrete under long-term marine exposure test and wet-dry cycle short-term accelerated test, NACE International East Asia & Pacific Rim Area Conference & Expo 2013, 2013.11, Corrosion of reinforcing bar embedded in concrete is one of the most severe degradation from the standpoint of load bearing characteristics and durability of its structure. Therefore, forecasting and prevention of corrosion of reinforcing bar is quite important for keeping the RC structure in good condition through the whole service period of the structure. In recent years, performance design on durability is becoming standard, where the long-term prediction of chloride ion penetration into concrete is indispensable. In general, the prediction of chloride ion penetration is done by applying diffusion coefficient of the concrete. However, obtaining the diffusion coefficient under real environment needs significant exposure test time. One method to obtain diffusion coefficient in a short period is the acceleration test, such as repeated cycle of wet-dry condition. In this paper, a long-term exposure test in real severe marine environment (seawater splashing environment) and wet-dry accelerated test were conducted and compared with its permeability of chloride ion using PC members consist of high strength concrete (70MPa equivalent). Based on the test results, chloride diffusion coefficients obtained by exposure test and accelerated test were compared. Finally, the significance of the accelerated test as an evaluation method of chloride ion penetration is discussed..
20.	Hidenori Hamada, Yasutaka SAGAWA, Daisuke YAMAMOTO, Takanori Ikeda, An observation on strata system of corrosion products by fluorescence microscope and scanning electron microscope, NACE International East Asia & Pacific Rim Area Conference & Expo 2013, 2013.11, Corrosion of steel in concrete is a major problem on the durability of concrete structures. From previous many researches on this problem, 1) threshold chloride content in concrete for steel corrosion, or 2) corrosion rate of steel in concrete, are well studied. However, there are still many problems to be studied, such as quantitative evaluation of environmental conditions related to steel corrosion. As environmental conditions affecting steel corrosion, 1) chloride supply under marine condition, especially tidal zone and splash zone, 2) temperature, or 3) humidity can be listed up. Quantitative evaluation of influence of these factors on steel corrosion is not evaluated. Furthermore, the loss of passivity film on steel surface is an initiation of corrosion reaction, therefore, corrosion rate after loss of passivity film should be related to the environmental factors. In this study, observation of corrosion products (rust) was carried out to evaluate the influence of environmental condition on corrosion process after the loss of passivity film. The authors noticed a feature of rust (corrosion products), that is, the structure of corrosion products is a piling of several layers (strata), like a tree ring. Also, the authors thought that the thickness of each layer (stratum) is closely related to each environmental condition. The objective of this study is to find the relation between feature of the layer (stratum) and environmental condition. In previous study, observation on the structure of rust (corrosion product) is not done. Also, discussion on relation between the structure of rust (corrosion product) and environmental condition is not existed. Therefore, this study is a corrosion study from a new viewpoint. In this study, firstly, observation method is developed. As a second step, corrosion products obtained two different structures are observed by fluorescence microscope and scanning electron microscope. Through these observations, several features of the layer in corrosion products were found..
21.	Hidenori Hamada, Masanori Annoura, Daisuke Yamamoto, Yasutaka SAGAWA, Amry Dasar, Corrosion Properties of Steel Bar Embedded in Cement Mortar Mixed with Seawter during Strength Developing Period, Seminar-Workshop on the Utilization of Waste Materials (2013), 2013.09, Generally, sea water is prohibited to use as mixing water in reinforced concrete due to high concentration of chloride ion which easily cause steel bar corrosion. However, in some area where the availability of fresh water for concrete is limited, the use of sea water as mixing water for reinforced concrete is necessary be considered. There are a few researches on properties of steel bar embedded in sea water mixed concrete. However, object of the study is to understand the properties of steel bar embedded in concrete mixed with sea water. Firstly, half-cell-potential of steel bar embedded in mortar is measured to evaluate the potential of corrosion. Tap water and sea water are used both for mixing and curing. Secondly, anodic polarization curve is measured for evaluating the condition of passivity film of steel bar, using the passivity grade proposed by Otsuki (1985). From experimental results, following conclusions are derived. (1) Half-cell-potential of steel bar embedded in sea water cured mortar showed lower value about 300mV than tap water cured mortar in both case of tap water mixing and sea water mixing. (2) Half-cell-potential of steel bar embedded in mortar mixed with sea water and Ordinary Portland Cement, also cured in sea water shows gradually increasing trend under the strength developing process. (3) Anodic polarization curve of steel bar embedded in mortar mixed with sea water is classified into the Grade 5 for tap water curing and the Grade 4 for sea water curing, at the age of 140 days. It seems that passivity film of steel bar embedded in mortar is not broken at the age of 140 days even sea water is used as mixing water..
22.	Hidenori Hamada, My small contribution to research field on durability of civil infra structure Sub title: Discussion on deterioration rate of concrete and steel structures especially under marine condition, The Third International Conference on Sustainable Construction Materials and Technologies - SCMT3, 2013.08, Corrosion of steel reinforcement is one of the important factors affecting long-term durability. Corrosion of steel bars in concrete usually occurs due to either carbonation or chloride attacks. Under marine condition, chloride in sea water easily access to concrete surface and penetrates into concrete even at very slow pace. Therefore, chloride diffusion takes long time until it reaches to steel surface in concrete. However, civil infrastructures are expected to have longer service life, at least five decades. It means that service life of infra structures under marine conditions are shorten by chloride attack. The author has been in the research on concrete durability for 30 years. The main research methods were field survey of actual deteriorated structures, long term exposure test of specimens under real marine environments, and laboratory evaluation of damaged materials, concrete and steel. Here, author introduce some of his research experiences and discusses the deterioration rate for the time span of several decades, of concrete, RC and steel structures under marine conditions..
23.	NURAZUWA MD NOOR, 濵田秀則, 佐川康貴, 山本大介, STRENGTH CHARACTERISTICS OF MORTAR MIXED WITH TIRE CRUMB RUBBER AS FINE AGGREGATE, 第67回セメント技術大会, 2013.05, Every year, large amount of used tire is generated throughout world which is not easily biodegradable even after a long period of landfill treatment. Research on utilizing this used tire as mortar/concrete mixture component has been started since early 90’s. However, in Asian countries, very rare information on the used tire as mixture component is existed. Thus, this research was conducted to study the potential of used tire produced in Japan as sand replacement in mortar mixture. All samples were tested in the laboratory to identify the fresh properties; air content, workability, density and hardened properties such as compressive strength and flexural strength..