|Hidenori Hamada||Last modified date：2018.08.16|
Professor / Engineering of Construction and Environmental Material Design / Faculty of Engineering
|Hidenori Hamada||Last modified date：2018.08.16|
|1.||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 ..|
|2.||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..|
|3.||Kazuhide Yonamine, 山路 徹, Yoshikazu Akira, Hidenori Hamada, 大即 信明, Study on Corrosion Property of Steel Bars in Concrete under Different Tidal Environments , International Symposium on Concrete and Structures for Next Generation: Ikeda & Otsuki Sysmposium (IOS2016), 2016.05.|
|4.||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.|
|5.||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. .|
|6.||Mohd Isneini, 佐川 康貴, 山本 大介, 濵田 秀則, AN EXPERIMENTAL STUDY ON MITIGATING ALKALI SILICA REACTION BY USING EXPANDED PERLITE POWDER, 平成26年度 土木学会西部支部研究発表会, 2015.03, Perlite is a pozzolan due to its glassy structure and high SiO2 and Al2O3 contents1). It is interesting to use perlite in blended cement, specially for mitigating alkali silica reaction (ASR). The previous studies showed that as a cement replacement expanded perlite powder (EPP) could be used as a cement replacement in small quantities due to its high water absorption capacity. The previous studies showed that when perlite powder incorporated into mortar bars, perlite powder has potential to suppress expansion induced by ASR2). In those programs, the mineral was added to mortar as mass replacement of the OPC. However, further investigation is needed to determine the adequate replacement ratio to suppress ASR in pessimum condition. This paper discusses the effect of EPP to mitigate ASR..|
|7.||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..|
|8.||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..|
|9.||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 (20C, R.H. 60%) were investigated.
|10.||Muh Akbar Caronge, 濵田 秀則, 佐川 康貴, 山本 大介, Toshihiro Takata, Effectiveness of Sacrificial Anode to Protect Embedded Steel in Ceacked Concrete, 平成25年度 土木学会西部支部研究発表会, 2014.03, Extensive cracking in reinforced concrete structure is a major durability problem. Cracks reduce the service life of the structure by permitting more rapid access of moisture, chloride ion and oxygen to the reinforcement, thus accelerating the onset of corrosion. The use of cathodic protection for new constructions is relatively expensive and can be more advantageously applied to reinforced concrete structure as a rehabilitation technique. Moreover, prevention of deteriorated reinforced concrete structures from further corrosion can be competitively achieved through cathodic protection. This paper aims to evaluate the effectiveness of sacrificial anode to protect embedded steel in cracked concrete.
|11.||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..
|12.||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..
|13.||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.
|14.||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..
|15.||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..|
|16.||Microscopic Observation of Corrsion Products Obtained from Structures in Different Environments.|
|17.||Evaluation of Crack Formation Prevention on Tunnel Concrete.|
|18.||Durability and Corrosion Preventive Effect of Under-water Concrete Exposed under Marine Environment for 21 years..|
|19.||Pessimum Phenomenon of Mortar with Highly Reactive Aggregate and ASR Prevention by Fly Ash.|
|20.||Relationship between Alkali Dissolution from Aggregate and ASR Expansion.|
|21.||Discussion on Chloride Diffusion Coefficient of Blast Furnace Slag Concrete.|
|22.||A Discussion on the Mechanism of ASR Prevention of Fly-ash Mixed Concrete.|
|23.||Expansive deterioration of concrete due to delayed ettringite formation.|