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LUAN Yao
| Environmental Science and Civil Engineering Division | Assistant Professor |
| Department of Civil and Environmental Engineering |
Performance information
■ Paper- Experimental Study on Chloride Binding of Slag-Blended Portland Cement with Different Slag Ratios
Fahmida Parvin; Yao Luan; Asiya Nurhasanah Habirun
Journal of Materials in Civil Engineering, Aug. 2024, [Reviewed], [Corresponding]
Scientific journal
DOI：https://doi.org/10.1061/JMCEE7.MTENG-17374
DOI ID：10.1061/JMCEE7.MTENG-17374, ORCID：160206103 - Numerical simulation on capillary absorption of cracked SHCC with integral water repellent treatment
Yao Luan; Tetsuya Ishida
Volume：34, Number：1, First page：123, Last page：135, Jul. 2024, [Reviewed], [Lead, Corresponding]
Scientific journal - A multi-scale experimental investigation of the feasibility of using integrated coal gasification combined slag as a supplementary cementitious material
Yuqian Zheng; Satya Medepalli; Tiao Wang; Tetsuya Ishida; Yuichiro Kawabata; Seishi Goto; Yao Luan
Journal of Cleaner Production, Apr. 2024, [Reviewed]
Scientific journal
DOI：https://doi.org/10.1016/j.jclepro.2024.141491
DOI ID：10.1016/j.jclepro.2024.141491, ORCID：154820981 - Consideration of coupling of crack development and corrosion in assessing the reliability of reinforced concrete beams subjected to bending
Tiao Wang; Chunhe Li; Jian-jun Zheng; Jürgen Hackl; Yao Luan; Tetsuya Ishida; Satya Medepalli
Reliability Engineering & System Safety, May 2023, [Reviewed]
Scientific journal
DOI：https://doi.org/10.1016/j.ress.2023.109095
DOI ID：10.1016/j.ress.2023.109095, ORCID：126498197 - Experimental study on mortar with the addition of hydrophobic silicone oil for water absorption, strength, and shrinkage
Yao Luan; Shingo Asamoto
Volume：367, First page：130323, Feb. 2023, [Reviewed], [Lead, Corresponding]
Scientific journal
DOI：https://doi.org/10.1016/j.conbuildmat.2023.130323
DOI ID：10.1016/j.conbuildmat.2023.130323, ISSN：0950-0618 - Repair of Alkali-Silica Reaction-Induced Cracks Using Bacteria: Crack Recovery and Other Properties
Yao Luan; Takumi Arasawa; Hiroshi Mutsuyoshi; Rikako Kawana
ACI Materials Journal, Volume：118, Number：4, Jul. 2021, [Reviewed], [Lead, Corresponding]
American Concrete Institute, Scientific journal
DOI：https://doi.org/10.14359/51732798
DOI ID：10.14359/51732798, ISSN：0889-325X, eISSN：0889-325X - A multi-scale approach for simulation of capillary absorption of cracked SHCC based on crack pattern and water status in micropores
Yao Luan; Tetsuya Ishida
Materials and Structures, Volume：54, Number：2, Apr. 2021, [Reviewed], [Lead, Corresponding]
Springer Science and Business Media {LLC}, Scientific journal
DOI：https://doi.org/10.1617/s11527-021-01664-3
DOI ID：10.1617/s11527-021-01664-3, ORCID：100327009 - Experimental investigation of pozzolanic reaction and curing temperature-dependence of low-calcium fly ash in cement system and Ca-Si-Al element distribution of fly ash-blended cement paste
Tiao Wang; Tetsuya Ishida; Rui Gu; Yao Luan
Construction and Building Materials, Volume：267, First page：121012, Last page：121012, Jan. 2021, [Reviewed]
Elsevier BV, Scientific journal
DOI：https://doi.org/10.1016/j.conbuildmat.2020.121012
DOI ID：10.1016/j.conbuildmat.2020.121012, ISSN：0950-0618 - EXPERIMENTAL STUDY ON REPAIR OF ASR INDUCED CRACK IN CONCRETE USING MICROORGANISMS
LUAN Yao; MUTSUYOSHI Hiroshi; FANG Jie; KAWANA Rikako
Cement Science and Concrete Technology, Volume：72, Number：1, First page：328, Last page：335, Mar. 2019, [Reviewed], [Lead, Corresponding]
Cracks generated in concrete structures accelerate the penetration of harmful substances, resulting in decrease of durability. Several methods are used for repairing crack in concrete. Recently, a new method using microorganisms has been proposed. In this method, carbon dioxide, which is a metabolite of microorganisms, reacts with calcium ions in a crack and clogs it by precipitation of calcium carbonate. In order to obtain a better effect, it is necessary to use microorganisms that can survive for a long time in alkaline concrete. In this study, the authors conducted repair experiment for artificially cracked specimens and alkali silica reaction（ASR）specimens using two repair agents including yeast fungus and Bacillus pasteurii. Permeability test and water absorption test were performed to evaluate the healing effect. The result showed that water permeability and absorption of all the specimens reduced remarkably after the repair. Microscope observation indicated that the cracks in mortar specimens were almost closed because of calcium carbonate precipitate.
Japan Cement Association, Japanese
DOI：https://doi.org/10.14250/cement.72.328
DOI ID：10.14250/cement.72.328, ISSN：0916-3182, eISSN：2187-3313, CiNii Articles ID：130007626855 - Experimental Study of Chloride Diffusion Properties of Mortar Mixed with Ion-Exchange Resin
Yao Luan; Osamu Sanada; Hiroshi Mutsuyoshi
ACI Materials Journal, Volume：115, Number：5, Sep. 2018, [Reviewed], [Lead, Corresponding]
American Concrete Institute, Scientific journal
DOI：https://doi.org/10.14359/51706845
DOI ID：10.14359/51706845, ISSN：0889-325X - Application of GGBFS and Bentonite to Auto-Healing Cracks of Cement Paste
J J Ekaputri; M S Anam; Y Luan; C Fujiyama; N Chijiwa; D H E Setiamarga
Journal of Advanced Civil and Environmental Engineering, Volume：1, Number：1, First page：38, Last page：38, Apr. 2018, [Reviewed]
Cracks are caused by many factors. Shrinkage and external loading are the most common reason. It becomes a problem when the ingression of aggressive and harmful substance penetrates to the concrete gap. This problem reduces the durability of the structures. It is well known that self – healing of cracks significantly improves the durability of the concrete structure. This paper presents self-healing cracks of cement paste containing bentonite associated with ground granulated blast furnace slag. The self-healing properties were evaluated with four parameters: crack width on the surface, crack depth, tensile strength recovery, and flexural recovery. In combination with microscopic observation, a healing process over time is also performed. The results show that bentonite improves the healing properties, in terms of surface crack width and crack depth. On the other hand, GGBFS could also improve the healing process, in terms of crack depth, direst tensile recovery, and flexural stiffness recovery. Carbonation reaction is believed as the main mechanism, which contributes the self-healing process as well as the continuous hydration progress.
Universitas Islam Sultan Agung, Scientific journal
DOI：https://doi.org/10.30659/jacee.1.1.38-48
DOI ID：10.30659/jacee.1.1.38-48, eISSN：2599-3356 - Evaluation of carbonation service life of slag blended concrete considering climate changes
Xiao-Yong Wang; Yao Luan
Computers and Concrete, An International Journal, Apr. 2018, [Reviewed] - Modeling of Hydration, Strength Development, and Optimum Combinations of Cement-Slag-Limestone Ternary Concrete
Xiao-Yong Wang; Yao Luan
International Journal of Concrete Structures and Materials, Volume：12, Number：1, Feb. 2018, [Reviewed]
Springer Science and Business Media LLC, Scientific journal
DOI：https://doi.org/10.1186/s40069-018-0241-z
DOI ID：10.1186/s40069-018-0241-z, ISSN：1976-0485, eISSN：2234-1315 - Study on internal water repellency and mechanical characteristics of cementitious materials with the addition of hydrophobic agent
Asamoto Shingo; Furuta Haruka; Luan Yao; Yoneda Taiju
Concrete Research and Technology, Volume：29, First page：11, Last page：19, 2018, [Reviewed]
In order to inhibit water penetration into concrete, hydrophobic surface impregnation is generally used to protect concrete, but there is concern that water repellency may decrease greatly when cracks occur. This study aims to develop an internal hydrophobic cementitious material by mixing several hydrophobic agents. Two mixing methods of the agents, direct mixing and sand spraying, were carried out. It was found that mortar with sand sprayed with silicone-based agent had a relatively high contact angle and hydrophobicity under wetting and drying cycles even if cracks occurred, although compressive strength decreased to some extent. Further, mortar with the addition of an alkyl-modified siloxane agent could greatly inhibit the water penetration after partial drying, and drying shrinkage was also found to be smaller than that of normal mortar.
Japan Concrete Institute, Japanese, Scientific journal
DOI：https://doi.org/10.3151/crt.29.11
DOI：https://doi.org/10.3130/aijs.87.171_references_DOI_TLfGRMVvjxxoZCtGQbKJnoP0STc
DOI ID：10.3151/crt.29.11, ISSN：1340-4733, eISSN：2186-2745, CiNii Articles ID：130006309080 - An experimental study of shrinkage behavior of bulk hydrophobic mortar
欒 堯; 浅本 晋吾; 米田 大樹
Volume：39, First page：409, Last page：414, 2017, [Reviewed]
Scientific journal - 各種撥水材を活用したセメント系材料の内部撥水性の評価と材料特性の検討
欒 堯; 浅本 晋吾; 米田 大樹
Volume：38, First page：693, Last page：698, 2016, [Reviewed]
Scientific journal - イオン交換樹脂を混和したＰＣグラウトの実用的な配合について
真田 修; 睦好 宏史; 欒 堯
Volume：25, First page：119, Last page：124, 2016, [Reviewed]
Scientific journal - イオン交換樹脂を混和したＰＣグラウトの分離性・流動性・塩化物拡散特性
真田 修; 睦好 宏史; 欒 堯
Volume：24, First page：385, Last page：390, 2015, [Reviewed]
Scientific journal - Simulation on water absorption behavior of ECC material with different crack density and distribution
欒 堯
Volume：36, First page：826, Last page：831, 2014, [Reviewed]
Scientific journal - Enhanced Shrinkage Model Based on Early Age Hydration and Moisture Status in Pore Structure
Luan Yao; Ishida Tetsuya
Journal of Advanced Concrete Technology, Volume：11, Number：12, First page：360, Last page：373, Dec. 2013, [Reviewed], [Lead, Corresponding]
In this research, an existing multi-scale model for shrinkage behavior is enhanced to improve its applicability and precision. The enhancement work focuses on the initial autogenous shrinkage and intrinsic driving forces of the shrinkage at the microscale. The existing model underestimates the rapid development of the autogenous shrinkage of cement with a low water/cement (w/c) ratio. Hence, combined with self-desiccation, the autogenous shrinkage at an early age is first discussed. As an approximation, a portion of the autogenous shrinkage at an early age is quantitatively calculated using the chemical volume change and distance between cement particles, and that portion is added to compensate for the underestimation in the existing model. Furthermore, in the existing model, capillary tension is assumed to be the principal driving force in all of the pores with various sizes, which would cause an overestimation of the long-term shrinkage in the analysis. Therefore in the enhanced model, the driving forces are discussed and modified. The capillary tension is assumed to only be active in relatively coarse pores, whereas the disjoining pressure dominates in fine pores on the nanoscale. These two driving forces are quantified by the water status in the pores using the proposed formulas. With the above enhancements, the autogenous and drying shrinkage behaviors with various w/c ratios and relative humidity can be simulated reasonably.
Japan Concrete Institute, English
DOI：https://doi.org/10.3151/jact.11.360
DOI：https://doi.org/10.3390/app8030394_references_DOI_G0vlo454Ysl6YeAy0n4KqLx4gJR
DOI ID：10.3151/jact.11.360, ISSN：1346-8014, eISSN：1347-3913, CiNii Articles ID：130003383558 - Enhanced Model and Simulation of Hydration Process of Blast Furnace Slag in Blended Cement
Luan Yao; Ishida Tetsuya; Nawa Toyoharu; Sagawa Takahiro
Journal of Advanced Concrete Technology, Volume：10, Number：1, First page：1, Last page：13, Jan. 2012, [Reviewed], [Lead, Corresponding]
A hydration model for cementitious materials was applied to slag blended cement. The original model was found to overestimate the hydration degree of slag, and the influence of the slag ratio on the hydration degree not to be well simulated either. The hydration mechanism of slag was investigated, considering the role of calcium hydroxide as activator and the Ca/Si ratio of C-S-H. It is assumed that for low Ca/Si ratio, the C-S-H inner product has a stronger resistance against ion diffusion and thus influences the hydration process significantly. Accordingly an enhanced model for slag hydration is proposed. Finally, the enhanced model is verified by both hydration degree and heat generation tests.
Japan Concrete Institute, English
DOI：https://doi.org/10.3151/jact.10.1
DOI：https://doi.org/10.14250/cement.71.232_references_DOI_GTx4EbkjEzCn9IyrxJsCwLa6m08
DOI ID：10.3151/jact.10.1, ISSN：1346-8014, eISSN：1347-3913, CiNii Articles ID：130001924762 - AN ENHANCED MODEL FOR SHRINKAGE BEHAVIOR BASED ON EARLY AGE HYDRATION AND MOISTURE STATE IN PORE STRUCTURE
ISHIDA Tetsuya; LUAN Yao
Journal of Japan Society of Civil Engineers, Ser. E2 (Materials and Concrete Structures), Volume：68, Number：4, First page：422, Last page：436, 2012, [Reviewed]
In this study a multi-scale constitutive model for shrinkage behavior is enhanced with the purpose of expanding its applicability and increasing the precision. The enhancement focuses on the intrinsic driving forces of shrinkage at the microscale, whereas the existing time-dependent constitutive law remains unchanged. First, with regard to the rapid development of autogenous shrinkage of low w/c ratio concrete at early age, the contribution of chemical shrinkage is taken into account in the enhanced model and quantified according to the dispersion and hydration of cement particles. Furthermore, the driving forces until long time are deeply discussed and reconstructed based on the moisture state in micro-pores with different sizes. Capillary tension is assumed only active in coarse pores, while disjoining pressure dominates in fine pores with nanoscale. With the enhanced model, autogenous and drying shrinkage behaviors with various w/c ratios and relative humidity can be simulated reasonably.
Japan Society of Civil Engineers, Japanese
DOI：https://doi.org/10.2208/jscejmcs.68.422
DOI：https://doi.org/10.2208/jscejmcs.78.1_105_references_DOI_67DMGvUsVdKEV19H16nmYFafco5
DOI ID：10.2208/jscejmcs.68.422, eISSN：2185-6567, CiNii Articles ID：130004962051 - Modeling of early age behavior of blast furnace slag concrete based on micro-physical properties
Tetsuya Ishida; Yao Luan; Takahiro Sagawa; Toyoharu Nawa
Cement and Concrete Research, Volume：41, Number：12, First page：1357, Last page：1367, Dec. 2011, [Reviewed]
Elsevier BV, Scientific journal
DOI：https://doi.org/10.1016/j.cemconres.2011.06.005
DOI ID：10.1016/j.cemconres.2011.06.005, ISSN：0008-8846 - 内部水和生成物の組織構造に着目した高炉セメントの複合水和発熱モデル
欒 堯,石田 哲也,名和 豊春,佐川 孝広
Volume：33, Number：1, First page：71, Last page：76, 2011, [Reviewed]
CiNii Articles ID：10029775280 - HYDRATE COMPOSITION ANALYSIS AND MICRO STRUCTURE CHARACTERISTICS OF PORTLAND CEMENT-BLAST FURNACE SLAG SYSTEM
SAGAWA Takahiro; ISHIDA Tetsuya; LUAN Yao; NAWA Toyoharu
Doboku Gakkai Ronbunshuu E, Volume：66, Number：3, First page：311, Last page：324, 2010, [Reviewed]
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 increasing as a function of hydration degree of BFS. The proposed model can well predict the strength development of blastfurnace cement.
Japan Society of Civil Engineers, Japanese
DOI：https://doi.org/10.2208/jsceje.66.311
DOI：https://doi.org/10.3130/aijs.88.1230_references_DOI_112qVKVjnNMO4IELQrgK935Oc10
DOI ID：10.2208/jsceje.66.311, eISSN：1880-6066, CiNii Articles ID：130004943174
- 高吸水性樹脂を混入した複数微細ひび割れ型繊維補強セメント複合材料の基礎特性と付着強度に関する実験的研究
神田英斗; 鈴木啓太; 欒堯; 中村太一
Volume：79th, 2024
J-Global ID：202402235879701824 - ANALYSIS ON TENSILE PERFORMANCE OF STRAIN-HARDENING CEMENTITIOUS COMPOSITES WITH ADDITION OF SUPERABSORBENT POLYMERS
YOSHINAGA Kohei; LUAN Yao
土木学会全国大会年次学術講演会(Web), Volume：79th, 2024
J-Global ID：202402237822219433 - EXPERIMENTAL STUDY ON STRENGTH PERFORMANCE OF CONCRETE MADE WITH FLY ASH-BASED ARTIFICIAL AGGREGATES
MITA Ayesha Ferdous; LUAN Yao; ZHANG Zhenfeng; ISHIDA Tetsuya; WANG Tiao
土木学会全国大会年次学術講演会(Web), Volume：79th, 2024
J-Global ID：202402260368413914 - STEADY STATE CHLORIDE MIGRATION TEST FOR SLAG BLENDED MORTAR WITH DIFFERENT SLAG RATIO AND FINENESS
ZHOU Xin; ZADAH Faizudin Hafiz; LUAN Yao
土木学会全国大会年次学術講演会(Web), Volume：78th, 2023
J-Global ID：202302243398841827 - STUDY ON CHEMICAL AND PHYSICAL CHLORIDE BINDING OF SLAG BLENDED CEMENT WITH DIFFERENT REPLACEMENT RATIOS
YAO Luan; FAHMIDA Parvin
土木学会全国大会年次学術講演会(Web), Volume：77th, 2022
J-Global ID：202302246756981745 - Self-healing of strain hardening cementitious composites (SHCC) under sustained load
鈴木啓太; LUAN Yao; 佐久間智; 平野勝彦
土木学会全国大会年次学術講演会(Web), Volume：77th, 2022
J-Global ID：202302247794719055 - Experimental study on effective diffusion coefficient of cracked concrete with chloride migration test
ZHOU Xin; LUAN Yao; WANG Tiao; MEDEPALLI Satya; ZHENG Yuqian
土木学会全国大会年次学術講演会(Web), Volume：77th, 2022
J-Global ID：202302265225890792 - 微生物を用いたASRひび割れの補修効果に関する実験的検討
荒澤拓海; 欒堯; 太細裕斗
Volume：75th, 2020
J-Global ID：202102269677584241 - STUDY OF HYDRATION AND CHLORIDE BINDING PROPERTIES OF SLAG-BLENDED CEMENT WITH DIFFERENT BLENDING RATIOS
PARVIN Fahmida; LUAN Yao; HABIRUN Asiya Nurhasanah
土木学会年次学術講演会講演概要集(CD-ROM), Volume：75th, 2020
J-Global ID：202102212962317200 - 撥水材を混合したセメント系材料の水和反応と空隙構造に関する実験的研究
欒堯; 小須田和貴; 廣嶋章吾
Volume：73rd, 2018
J-Global ID：201802232613466177 - A STUDY OF PROPERTIES OF FLY ASH BLENDED SELF-COMPACTING CONCRETE AT LOW TEMPERATURE
HASEBE Sho; LUAN Yao; GANTULGA Nergui
土木学会年次学術講演会講演概要集(CD-ROM), Volume：73rd, 2018
J-Global ID：201802271298226465 - 異なる微生物を用いたひび割れ補修剤の補修効果の実験的研究
川名梨香子; 房捷; 欒堯; 睦好宏史
Volume：72nd, 2017
J-Global ID：201702285009340203 - 微生物を用いたコンクリートのひび割れ修復技術の開発
川名梨香子; 房捷; 欒堯; 睦好宏史
Volume：71st, 2016
J-Global ID：201602257199118397 - イオン交換樹脂を混和したPCグラウトの開発
今村光希; 睦好宏史; 欒堯; 真田修
Volume：71st, 2016
J-Global ID：201602243750160275 - ひび割れを有するコンクリートにおける水分移動に関する研究
穴田洋輔; 欒堯
Volume：71st, 2016
J-Global ID：201602239054647804 - A COMPARISON STUDY OF TWO ION-EXCHANGE RESIN MIXED GROUTS: CHLORIDE ABSORPTION, STRENGTH AND FRESH PROPERTIES
LOAN Nguyen Thi; MUTSUYOSHI Hiroshi; LUAN Yao; IMAMURA Koki
土木学会年次学術講演会講演概要集(CD-ROM), Volume：71st, 2016
J-Global ID：201602273700194514 - イオン交換樹脂を混和したPCグラウトの性能に関する研究
欒堯; 睦好宏史; 真田修
Volume：70th, 2015
J-Global ID：201502216498263421 - イースト菌によるコンクリートひび割れ補修に関する研究
房捷; 睦好宏史; 欒堯
Volume：70th, 2015
J-Global ID：201502213547140722 - 内部撥水性を有するセメント系材料の開発
古田悠佳; 欒堯; 浅本晋吾; 米田大樹
Volume：70th, 2015
J-Global ID：201502219308594400 - 複合水和モデルに基づく高炉セメントの水和反応率解析
LUAN Yao; 石田哲也; 名和豊春; 佐川孝広
Volume：65th, 2011
J-Global ID：201102255232508483 - 高炉セメントの水和反応-微細構造形成と強度発現に関する研究
佐川孝広; 石田哲也; YAO Luan; 名和豊春
Number：776, 2011
ISSN：0371-0718, J-Global ID：201102244418433449
- A multi-scale approach for modeling self-healing concrete by coupling water ingress and crack healing process
01 Apr. 2022 - 31 Mar. 2025
Grant amount(Total)：4160000, Direct funding：3200000, Indirect funding：960000
Grant number：22K04257 - Modeling and re-corrosion evaluation of patch repaired concrete subjecting to chloride attack
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), 01 Apr. 2019 - 31 Mar. 2024
Luan Yao, Saitama University
Grant amount(Total)：4420000, Direct funding：3400000, Indirect funding：1020000
The research focuses on evaluating chloride transport and corrosion in patch repaired concrete subjected to chloride attack. Experimental investigations include studies on chloride migration in cracked repair mortars as well as the influence of incorporating supplementary cementitious materials (SCMs) and hydrophobic agents. These experiments evaluate factors such as crack width, repair material type, and surface treatments, revealing significant increase in chloride diffusion with increasing crack width and mitigation effect with SCMs and hydrophobic treatments. Numerical simulations using multi-scale models further explore water ingress and chloride penetration in cracked repair mortars. The obtained chloride amount in repaired concrete is used for evaluation of steel rebar corrosion initiation. The simulations provide insights into the influence of crack pattern on water absorption and chloride distribution, crucial for understanding long-term durability.
Grant number：19K04547 - A study on water tightness and chloride penetration of hydrophobic concrete
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Young Scientists (B), 01 Apr. 2016 - 31 Mar. 2019
Luan Yao; ASAMOTO Shingo; YONEDA Taiju, Saitama University
Grant amount(Total)：4030000, Direct funding：3100000, Indirect funding：930000
In this study, cement mortars that have bulk hydrophobicity were made, and their properties, for example, water absorption and chloride resistance, were studied experimentally. First, two types of hydrophobic mortars were made by directly adding a hydrophobic agent in mixing or spraying the agent on sand before mixing. Hydrophobicity was confirmed by measuring contact angle. Then, water absorption test was performed under uncracked and cracked conditions. It was found that, because of the bulk hydrophobicity, the surfaces of cracks were water repellent, leading to less water absorption for the hydrophobic mortars. After that, experiments of chloride penetration and corrosion were carried out. The results indicated that the hydrophobic mortars showed less chloride diffusion, resulting to a less corrosion for the rebars inside the mortars. Finally, strength and shrinkage behaviors were measured. The hydrophobic mortars were found to have a lower strength but less shrinkage.
Grant number：16K18130 - Maintenance and Long Life Sustainabilty of Prestressed Concrete Bridges
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), 01 Apr. 2015 - 31 Mar. 2018
MUTSUYOSHI Hiroshi; SANADA Osamu; AOKI Keiichi, Saitama University
Grant amount(Total)：17810000, Direct funding：13700000, Indirect funding：4110000
In order to clarify the flexural behavior of prestressed concrete (PC) beams having damaged tendons. The tendons of the PC beams were intentionally broken by a core drilling machine or accelerated corrosion process. The loading tests were carried out to investigate the influence of location and degree of damage of the tendons on the load carrying capacity of the PC beams. A nonlinear pushover analysis was also performed using fiber model and the analytical results were verified by the experimental results. From the analysis it was found that the load carrying capacity of the PC beams having damaged tendons can be estimated with good accuracy. Furthermore, the fiber model was applied for actual PC box bridges assuming the degree of corrosion damage of the PC tendons and the location of the corrosion. The analytical results were used to estimate the safety of the PC box bridges when the tendons are heavily corroded.
Grant number：15H04029 - Evaluation system on water transport properties of cracked concrete under environmental conditions
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Young Scientists (B), 01 Apr. 2014 - 31 Mar. 2016
LUAN Yao, Saitama University
Grant amount(Total)：3900000, Direct funding：3000000, Indirect funding：900000
In this research, water transport properties of cracked cementitious materials were studied. First, water absorption experiment was conducted, with different crack widths, absorption directions and saturation degrees before absorption. Second, a two-phase transport model was established and the water absorption of ECC materials with different crack conditions were analyzed numerically. Since crack becomes convenient channel for water ingression from cracks to cement matrix, the absorption process was greatly accelerated. Such an accelerated process was well reproduced using the model. Then, mortars with internal hydrophobicity were made. Based on absorption experiment, it is confirmed that the specimens with surface coating, when crack occurred, lost their water repellency, whereas the internal hydrophobized specimens remained water repellent state. Therefore, the internal hydrophobized mortar is promising to be used in practice.
Grant number：26820175