Research Excellence Award

Koichi MAEKAWA (The University of Tokyo)

'Multi-scale modeling for kinematics of cementitious composites and structural mechanics'

Thesis Award

Title:  STUDY ON A DETERIORATION AND DETERIORATION INDICATOR OF CONCRETE UNDER MARINE ENVIRONMENTS

Awardees:

Toru YAMAJI (Port and Airport Research Institute)

Yoshikazu AKIRA (Port and Airport Research Institute)

Hidenori HAMADA (Kyusyu University)

Kazuo YAMADA (Taiheiyo Cement Corporation)

Abstract:  In order to investigate the deterioration of concrete under marine environments, both concrete cores sampled from structures and test specimens exposed in the outdoor pool of nature seawater were examined by Vickers hardness test, EPMA and Cl penetration and carbonation depth measurements. Correlation analysis for the distributions of various elements was carried out and following interesting behavior were observed: 1) The depth of maximum Mg2+ concentration was correlated with the carbonation depth. 2) Deteriorated areas in concrete specimens based on Vickers hardness were correlated with the penetration depth of Mg2+. This result means that the penetration depth of Mg2+ can be a simple indicator of concrete deterioration under marine environments.

Incentive Award

Title:  EVALUATION OF DEFORMATION CAPACITY RELATED TO DAMAGE DEGREE FOR REPAIRED REINFORCED CONCRETE MEMBERS

Awardee: Tatsuya NIHEI (Railway Technical Research Institute)

Abstract:  In this paper, we studied the evaluation method of deformation capacity related to damage degree for repaired reinforced concrete (RC) members. Based on experimental and analytical investigations, we clarified the deformation capacity of repaired RC members is affected by buckling of axial reinforcement: First, in the case of damage without buckling of axial reinforcement before the repair, the deformation capacity of repaired RC members is more than or equal to that of no-damaged RC members. Secondly, in the case of damage with buckling of axial reinforcement before the repair, the deformation capacity of repaired RC members is inferior to that of no-damage RC members. In addition, we proposed the calculation methods of rigidity and maximum load of repaired RC members.

Yoshida Award

 Yoshida Award for Research Accomplishment

Takeshi HIGAI (Emeritus Professor of Yamanashi University) 

'Study on prediction of shear strength of reinforced concrete members'

Yoshida Award for Thesis

Title:  HYDRATE COMPOSITION ANALYSIS AND MICRO STRUCTURE CHARACTERISTICS OF PORTLAND CEMENT-BLAST FURNACE SLAG SYSTEM

Awardees:

Takahiro SAGAWA (Nittetsu Cement)

Tetsuya ISHIDA (The University of Tokyo)

Yao LUAN (The University of Tokyo)

Toyoharu NAWA (Hokkaido University)

Abstract:  Using several types of Portland cement and blast furnace slag(BFS), composition of hydration products and micro structure characteristics of Portland cement-BFS system were studied. Hydration of blastfurnace cement shows  nonlinear behavior of development for gel water with hydrate precipitate, C-S-H produced from BFS hydration at later age has larger amount of gel water. it is quite different tendency in the case of Portland cement hydration. From the modified microstructure development model, gel porosity of C-S-H has nonlinear increasing as a function of hydration degree of BFS. The proposed model can well predict the strength development of blastfurnace cement.

 Yoshida Award for Research Encouragement

Katsufumi HASHIMOTO (Hokkaido University)

'Clarification of Deterioration Mechanism of Frost Damaged Concrete with Multidimensional Pore Structure Analysis'

Kozo ONOUE (Miyazaki University)

'Prediction of compressive fatigue life and consideration on compressive fatigue fracture process of steel-making slag concrete in water'

Isao KURASHIGE (Central Research Institute of Electric Power Industry)

'Development of nondestructive air-permeability testing method for in-depth quality profiling of concrete structures'

Seiji NAGATA (Central Research Institute of Electric Power Industry)

'Influence of failure modes on vibration characteristics of RC walls subjected to out-plane cyclic loads'

Tanaka Award

Tanaka Award for Research Accomplishment

Shigeyuki MATSUI (Osaka Institute of Technology)

'Studies on Mechanism of Fatigue Damage and Assessment of Fatigue Durability for Reinforced Concrete Slabs and Composite Decks Having Concrete on Top and the Related Research Achievements'

Tanaka Award for Thesis

Title:  EVALUATION ON PROPERTIES OF CONCRETE AND STEEL IN PC BRIDGE GIRDERS SEVERELY DAMAGED BY CHLORIDE INDUCED DETERIORATION

Awardees:

Ichiro IWAKI (Nihon University)

Akihisa KAMIHARAKO (Hirosaki University)

Yasuhiro KODA (Nihon University)

Hideki NAITO (Tohoku University)

Hiroshi MINAGAWA (Tohoku University)

Motoyuki SUZUKI (Tohoku University)

Abstract:  First, in PC bridge girders severely damaged by chloride induced deterioration on the Japan Sea Shore in Aomori, the field inspection was performed. Next, using concrete cores sampled from the blocks of girders, the compressive strength, Young's modulus, carbonation depth, and chloride ion concentration of concrete ware measured. Additionally, by removing whole concrete from blocks, the corrosion condition of steel inside was observed. After measuring the mass loss of steel due to corrosion, the load-elongation relation of steel was examined. From the results of these inspections and experiments, it was recognized that this bridge was exposed to an extremely severe corrosive environment. Further, the influence of various factors on the corrosion of steel, and the relation between mechanical properties of steel and its mass loss due to corrosion were revealed.

Title:  FATIGUE LIFE SIMULATION AND FAILURE MODE FOR STEEL-CONCRETE COMPOSITE BRIDGE DECK BASED UPON A DIRECT PATH-INTEGRAL SCHEME

Awardees:

Chikako FUJIYAMA (The University of Tokyo)

Feng SHANG (Tsinghua University)

Nobuaki SAKURAI (Nippon Steel Engineering)

Koichi MAEKAWA (The University of Tokyo)

Abstract:  This paper shows a fine representation of damage process of steel-concrete composite deck subjected to the high-cycle moving load by using path-dependent fatigue constitutive models for concrete as well as direct integral method with respect to time and deformation path. The high-cycle moving load was applied directly to the composite deck model based on the three dimensional nonlinear finite element analysis. As a result, the propagation of horizontal cracks which were observed in past experiments was successfully reproduced. Furthermore, fatigue life prediction was obtained since the plasticity of material and damage are simulated until ultimate state of structure. Consequently, the high durability performance of the composite deck studied herein was confirmed in 100 years traffic. An assessment method and a usage of S-N diagram for composite slab were also discussed as one of the conclusions.

Book of the Year Award

"Multi-Scale Modeling of Structural Concrete"  Taylor & Francis  2008

Authors:

Koichi MAEKAWA (The University of Tokyo)

Tetsuya ISHIDA (The University of Tokyo)

Toshiharu KISHI (The University of Tokyo)

Table of Contents of the book:

1.  Introduction  ----Multi-phase, Multi-Chemo-Physical Modeling of Structural Concrete

2.  Hydration of Cement in Concrete

3.  Micro Pore Structure and Moisture

4.  Transport of Carbon Dioxide and Carbonation

5.  Calcium Ion Transport and Leaching

6.  Chloride Ion Transport and Corrosion

7.  Time Dependent Mechanics of Cement Hydrates

8.  Time Dependent Mechanics of Structural Concrete

9.  Structural Mechanics of Damaged Concrete Structures

10.  Fatigue Life of Structural Concrete