|Hidenori Hamada||Last modified date：2019.06.26|
Professor / Engineering of Construction and Environmental Material Design / Faculty of Engineering
|1.||＃Dahlia Patah、 濱田秀則、 ＠佐川康貴、＠山本大介、, The Effect of Seawater Mixing on Corrosion of Steel Bar in 36-Yeras Old RC Beams under Marine Environment, コンクリート工学年次論文集, 第41巻, 2019.06, Visual observation, chloride ingress, porosity, and corrosion of steel bars in RC beam made with seawater and tap water were investigated in this paper based on 36 years of exposure under marine tidal environment. After long-term exposure, seawater mixing shows better performance against corrosion of steel bar as well as strength, concrete resistance, oxygen permeability and microstructure compared with tap water mixing. It shows high possibility to use seawater as mixing water with precautions, such as minimum 50mm in cover depth which has influence significantly for the service life of RC structure.
|2.||Comparison between ASR expansion model based on chemical kinetics and the results in exposure test.|
|3.||Experimental Study on the Influence of Material Covering Anode under Differing Exposure Conditions in Galvanic Anode Method.|
|4.||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. .|
|5.||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. .|
|6.||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..|
|7.||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..
|8.||Muhammad Akbar Caronge, Hidenori Hamada, Yasutaka SAGAWA, Daisuke Yamamoto, Application of Sacrificial Point Anode for Prevention of Steel Corrosion in Cracked Concrete, Journal of Advanced Concrete Technology (ACT), 10.3151/jact.13.479, Vol. 13, 479-488, 2015.10, The effectiveness of commercially available sacrificial point anode for corrosion prevention of steel in the cracked concrete is presented. Reinforced concrete prism in the size of 150 mm x 150 mm x 500 mm with water to cement ratio (W/C) of 40% and pre-cracked width 0.1 to 0.4 mm was prepared. Specimens were exposed to three conditions: (1) air curing (temperature of 20±2°C and relative humidity of 60%); (2) immersed in 3% NaCl solution; and (3) the dry/wet cycles of above mentioned conditions. Measurement items were the potential value, polarization behavior of sacrificial point anode, anodic- cathodic polarization curve and visual observation. The test results shows that the sacrificial point anode was effective to prevent the steel corrosion in cracked concrete. Specimens exposed to dry/wet cycles or immersed in 3% NaCl solution presented a better protection than that in air curing due to the high moisture condition. Thus, sacrificial point anode becomes active to protect the steel bars even in creacked concrete..|
|9.||Experimental Study on Cathodic Protection Area in Galvanic Anode Method
|10.||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..
|11.||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..
|12.||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...
|13.||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..|
|14.||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..
|15.||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。.|
|16.||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. .|
|17.||Muhammad Akbar Caronge, 濵田 秀則, Yasutaka SAGAWA, 山本 大介, Sumargo, Deterioration Evaluation and Life-Extension Strategy of 77 Year-Old Concrete Structure Exposed to Indonesian Marine Environment, Proceedings of the International Conference on the Regenaration and Conservation of the Concrete Structures., CDのためページ掲載なし, 2015.06, Deterioration due to steel corrosion induced by chloride ion is the major cause of the damage of reinforced concrete structures exposed to marine environment. For this, a durability investigation of a 77 year-old concrete structure located in a tropical marine environment in an Indonesian port was carried out. Site investigation and laboratory testing that are commonly used in corrosion investigations were conducted to observe long-term performance of the concrete. A quantitative evaluation related to steel corrosion products was also observed by fluorescence microcscope. Results show that the principal mechanism responsible for the extensive deterioration of the structure studied is chloride-induced reinforcement corrosion. This mechanism lead to loss of rebar and concrete cross-section, loss of steel-concrete bond, cracking, delamination and spalling of concrete noted as the most common defect occuring at structure elements after being
exposed over for long-term period. Repair strategies for extending the service life of these
structures are also presented in this paper..
|18.||Muhammad Akbar Caronge, 山本 大介, 小林浩之, 大谷俊介, 濵田 秀則, Development of Steel Passivity in Concrete by Cathodic Protection with Environmental Improvement Effects, Proceedings of the International Conference on the Regenaration and Conservation of the Concrete Structures., CDのためページ掲載なし, 2015.06, The 100 mV decay potential is most widely used as cathodic protection (CP) criteria in reinforced concrete structure. However, in some cases the 100 mV decay potential criteria could not achieve due to the environment condition, even steel is protected. In this paper, the effect of environmental improvement on the steel surface as a secondary effect of CP was studied. Nine levels of constant current densities were applied on the steel bar embedded in concrete specimens with chloride ion of 2 kg/m3, 5 kg/m3 and 10 kg/m3. The instant-off potential (Eio), depolarization test, anodic-cathodic polarization curve and visual observation were evaluated. From test results, it was found that current density of 5 mA/m2, 10 mA/m2 and 20 mA/m2 is sufficient to achieve the 100 mV decay potential criterion at the beginning polarization time for concrete with chloride content of 2 kg/m3, 5 kg/m3 and 10 kg/m3 respectively. In the concrete with 10 kg/m3 of chloride, the decay potential slightly decreased at 230 days due to the diffusion of dissolved oxygen (DO). In addition, a small current density also improved the passivity film of steel bars..|
|19.||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.|
|20.||Mohd Isneini, Yasutaka SAGAWA, 山本大介, Hidenori Hamada, Experimental Study on Mitigating ASR ｂｙUsing Fly Ash and Silica Fume, 一般社団法人 九州橋梁・構造工学研究会、 公益社団法人 土木学会西部支部, 第30号, 149-156, 2014.12.|
|21.||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..|
|22.||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..|
|23.||Study on the Relationships between Damaged Condition and Physical Property of Concrete Deteriorated Due to Alkali Silica Reaction
|24.||The influence of specimen size on variation and values of compressive strength
|25.||The influence of specimen size on variation and values of compressive strength
|26.||Fundamental Study on Application of Potential as Cathodic Protection Criterion for RC Cathodic Protection Standards in Wet Environment
|27.||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..
|28.||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..
|29.||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. .|
|30.||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 20C, 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.
|31.||Nurazuwa Md Noor, 山本 大介, 合田 寛基, Hidenori Hamada, Yasutaka SAGAWA, Strength and Surface Abrasion Resistance of Crumb Rubber Mixed Mortar
, 土木構造・材料論文集、第29号, 29, 91-96, 2013.12, This study is focusing on physical properties, such as strength and abrasion resistance, of crumb rubber mixed mortar. Also, effectiveness of crumb rubber on in-plane displacement under compression was studied by using two-dimensional digital image correlation method. Deformation of mortar surface containing 10% crumb rubber and 10% silica fume before and after compression loading was digitally recorded and measured. Meanwhile, abrasion test was carried out to achieve better understanding on the crumb rubber effect against surface abrasion wearing. Experimental results show that axial strain under compression was larger in mortar with crumb rubber followed by the strength reduction. As for abrasion test, crumb rubber could give significant improving effect on wear resistance in the mixture with the water to cement ratio (w/c) of 0.35 and 0.30, however, this effect cannot be found in w/c = 0.25.
|32.||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..|
|33.||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.
|34.||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..
|35.||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..|
|36.||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..|
|37.||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..
|38.||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) 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.
|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.||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..
|41.||Examination on The Durability Enhancement of Concrete Surface Layer Using A Form with Film .|
|42.||An Experimental Study on Relationship Between Chloride Content in Mortar and Passivity Condition of Embedded Steel Bar.|
|43.||An Experimental Study on the Effect of Cross-sectional Repair Method and Re-degradation Prevention of Concrete Members Including Inherent Salt .|
|44.||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..|
|45.||A Prposal of Diagnostic Procedure for Deteriorated Concrete Sewwage Pipes.|
|46.||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.|
|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.||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.|
|49.||Experimental Study on field Method to Evaluate the Applying condition of Silicate Type Impregnants for Improving Quality of Concrete Surface.|
|50.||Surface Improvement Effect of Silicate Type Impregnants on Permeability of Concrete.|
|51.||An Experimental Study on Variation of Measured Values of Compressive Strength Obtained by Small Size Core Specimens .|
|52.||Properties of Concrete using Ground granulated Blast-Furnace Slag after 20years Exposure under Marine Condition .|
|53.||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.|
|54.||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.|
|55.||Experimental study on shrinkage properties of concrete used with ground granulated blast-furnace slag 6000.|
|56.||A Study on Method of Diagnosing Deterioration for Concrete Sewage Pipe.|
|57.||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.|
|58.||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.|
|59.||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.|
|60.||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.|
|61.||Detailed Investigation of 38 years' old Concrete Sewage Pipes Deteriorated by Sulfar .|
|62.||Research on Application of By-products Concrete to Marine Concrete Structures.|
|63.||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.|
|64.||Study on the Corrosion Resistant Property of Stainless Steel Bars under Marine Environment.|
|65.||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.
|66.||Experimental Study on Relationship Between Void Under Reinforcement And Its Corrosion .|
|67.||Study on A Deterioration and Deterioration Indicator of Concrete under Marine Environments.|
|68.||Fundamental Study on Mechanical Performance of Rigid Joint PCaPC Member to Cast-in-place Bottom Slab .|
|69.||A Study on Steel Corrosion of Repaired RC Bridge under Chloride Attack Environment.|
|70.||Estimatin Method of Sulfuric Deterioration Depth of Concrete by Using Ultrasonic Pulse Method.|
|71.||Expansion Behaviour of Fly Ash Mixed Concrete Due to ASR.|
|72.||Chloride Diffusivity of Concrete under Different Marine Environments and Exposure Duration.|
|73.||Study on The Verification of Steel Corrosion in Port Reinforced Concrete Structures Based on Site Survey and Long Term ExposureTest.|
|74.||Discussion on Ideal Way of Infrastructure Development Based on Asset Evaluation --A Case Study of the Bridges in Fukuoka City--
Proceedings of The 51st Japan Congress on Materials Research.
|75.||Petrological Study on Evaluation of ASR-Expansion of Andesite Aggregates.|
|76.||Fundamental Study on Marine Durability of Sulfur Concrete Mixed with By-product Aggregates..|
|77.||Funddamental Property of Steel-slag Concrete Used for Airport Pavement .|
|78.||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.|
|79.||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.|
|80.||By-products used hardened matrix applicable to marine structures.|
|81.||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.|
|82.||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.|
|83.||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.|
|84.||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.|
|85.||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.|
|86.||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].|
|87.||Results of Apparent Diffusion Coefficientof Chloride Ion in Port Reinforced Structures and Study on its Simple Estimation Method.|
|88.||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.|
|89.||Phisical Characteristics of Steel Slag Made HArdened Matrix with Bending Moment of 5N/mm2..|
|90.||A Energetic Discussion on The Propagation of Hair Cracks in Concrete under Compressive Stress.|
|91.||Mechanical Properties of Modified-Sulfur Concrete Mixed with Several Kinds of Aggregates.|
|92.||Long-term Field Test for Corrosion Protection of Steel Pipe Piles (Interim Report for 20-year Exposure Test).|
|93.||Effectiveness of Cement and Aggregate on DEF-Expansion of Cement Mortar..|
|94.||Cathodic Protection Characteristics of Marine Steel Structure Sheathed with Seawater Resistant Stainless Steel.|