著者

Zhenzhen Wang Abudushalamu Aili Masayo Minami Ippei Maruyama

出版者

Japan Concrete Institute

雑誌

Journal of Advanced Concrete Technology (ISSN:13473913)

巻号頁・発行日

vol.21, no.11, pp.934-940, 2023-11-22 (Released:2023-11-22)

参考文献数

34

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Capturing atmospheric CO2 into cement-based materials is a way to set off the CO2 emissions of concrete production. This study proposes an experimental method to track the origin of cement paste that fixes CO2 directly from the air under natural conditions. By exposing powders of well-hydrated cement paste to air, carbonated cement paste powders are obtained with different carbonation degrees. The inorganic carbon of these carbonated samples is extracted by dissolution in phosphoric acid, and the isotopic characteristics related to 13C and 14C are measured. The experimental results show that the 14C value of carbonated cement paste can be used as an indicator for tracing the origin of carbon.

著者

Osamu Kontani Takashi Okayasu Keishi Kawasumi Shunsuke Ishikawa Hiroshi Masaki Norihiko Tanaka Yasuyuki Goto Shinichi Ishioka

出版者

Japan Concrete Institute

雑誌

Journal of Advanced Concrete Technology (ISSN:13473913)

巻号頁・発行日

vol.20, no.7, pp.444-483, 2022-07-27 (Released:2022-07-27)

参考文献数

46

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The Fukushima Daiichi Nuclear Power Plant lost its core cooling function due to the massive tsunami generated by the 2011 off the Pacific coast of Tohoku Earthquake, which caused core meltdown, resulting in high temperature inside the containment vessel and exposing the RPV pedestal, a reinforced concrete structure, to an unusually high temperature environment. After the earthquake, water was poured into the containment vessel to cool the molten core, and the con-crete structure was gradually cooled in the process. Since it will take at least 40 years to remove the fuel from the core, the integrity of the RPV pedestal is a major concern for the decommissioning of the Fukushima Daiichi Nuclear Power Plant. In order to assess the long-term integrity of the RPV pedestal, a horizontal loading test was conducted using a 1/6 scaled model of the RPV pedestal of Unit 1 considering the effect of the high temperature heating and subsequent wet conditions. And then, the static stress analysis of the RPV pedestal was performed considering the degradation phenomena revealed by the experiments. As a result, it was confirmed that the RPV pedestal of Unit 1 would be structurally sound for 40 years against the current design basis earthquake even if the material degradation due to severe accident and aging was considered.

著者

Daisuke Kambayashi Hiroshi Sasano Shohei Sawada Kiyoteru Suzuki Ippei Maruyama

出版者

Japan Concrete Institute

雑誌

Journal of Advanced Concrete Technology (ISSN:13473913)

巻号頁・発行日

vol.18, no.10, pp.618-632, 2020-10-27 (Released:2020-10-27)

参考文献数

29

被引用文献数

8

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In nuclear power plants, concretes used for biological shielding walls are exposed to radiation such as neutrons and gamma rays over the long-term operation of the plant. Previous studies have reported that neutron irradiation causes aggregate expansion due to the metamictization of quartz and feldspar leading to reduced density and a loss of the compressive strength and Young' s modulus of the concrete. Therefore, it is crucial to understand the current state of a concrete biological shield (CBS) and predict its future soundness. In this study, a rigid-body spring model, which can easily evaluate fracture behavior by using springs between each element, is used to conduct numerical analyses on a CBS. A three-phase (mortar, aggregate, and interfacial transition zone) model of a 2000 mm thick CBS is used to investigate the varying deformation responses depending on the presence or absence of reinforcing bars (rebar), creep, and an inner steel plate with five types of analyses, i.e. analysis to understand the impacts of temperature distribution, re-inforcement bars, an internal steel plate, and creep of mortar. The results show that cracking and delamination occur inside the CBS, resulting in a lack of cracking on the outside. They also show that the cracks are reduced by rebar and creep, resulting in cracks extending from the innermost edge to a depth of approximately 150 mm.

著者

Hiroshi Sasano Ippei Maruyama Shohei Sawada Takahiro Ohkubo Kenta Murakami Kiyoteru Suzuki

出版者

Japan Concrete Institute

雑誌

Journal of Advanced Concrete Technology (ISSN:13473913)

巻号頁・発行日

vol.18, no.10, pp.648-677, 2020-10-28 (Released:2020-10-28)

参考文献数

80

被引用文献数

19

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To evaluate the radiation-induced degradation of concrete, a rigid-body spring network model is introduced that takes into account the three phases in concrete: mortar, aggregate, and the interfacial transition zone. The proposed model enables evaluation of the change in the physical properties of concrete affected by aggregate expansion under the free restraint condition. Good agreement with previous experimental data is found for the linear expansion of the concrete specimen and the compressive strength, Young’s modulus, and splitting tensile strength. Based on the numerical results, it is concluded that, to reproduce the physical property changes in concrete, the expansion of mortar due to the radiation-induced expansion of fine aggregate and/or creep behavior must be considered. In addition, it is clarified that an isolated expansion of mortar with a lack of expansion in the coarse aggregate also degrades the concrete and, consequently, analysis of the type of aggregate used is critical for predicting the properties of concrete under neutron irradiation. Furthermore, the impact of inhomogeneous expansion of rock-forming minerals in coarse aggregates on physical property changes is studied, showing that such a partial expansion in the aggregates and the resultant cracks in aggregates greatly influences the reduction of the Young’s modulus, with minimal impact on the reduction of compressive strength. The proposed model can be used to evaluate concrete degradation due to radiation-induced volumetric expansion of aggregate caused by the metamictization of rock-forming minerals.

著者

Hirozo Mihashi Tomoya Nishiwaki

出版者

公益社団法人 日本コンクリート工学会

雑誌

Journal of Advanced Concrete Technology (ISSN:13473913)

巻号頁・発行日

vol.10, no.5, pp.170-184, 2012-06-16 (Released:2012-06-19)

参考文献数

53

被引用文献数

28 146

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Challenging studies of engineered self-healing and self-repairing functions in concrete structures are briefly reviewed. While self-healing of concrete has been studied for a long time, it was only recently noticed that some engineered technologies are useful to stimulate the potential of concrete to be self-healed. For example, fiber reinforced cementitious composites (FRCC) have a much higher potential of self-healing than ordinary concrete because of their capability to keep cracks thinner and also because of the bridging network system in cracks; a specific bio-chemical approach, i.e. the application of mineral-precipitating bacteria, is now available; and various mineral admixtures are useful for practical application. Furthermore, the new concept of self-repairing concrete, which is based on the design concept of intelligent materials, is reported. Self-repairing concrete is concrete that incorporates devices for achieving the three key functions of an intelligent material, (1) sensing, (2) processing, and (3) actuating. This paper is a state-of-the-art report on the recent development of engineered self-healing and self-repairing concrete.

著者

José Granja Renan Rocha Ribeiro Thomas Russo Rodrigo Lameiras Miguel Azenha

出版者

Japan Concrete Institute

雑誌

Journal of Advanced Concrete Technology (ISSN:13473913)

巻号頁・発行日

vol.21, no.10, pp.803-820, 2023-10-26 (Released:2023-10-26)

参考文献数

59

被引用文献数

1

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The influence of temperature on the hydration of cementitious materials has been traditionally modelled using the maturity concept and Arrhenius law. This approach yields a single material property, called apparent activation energy (Ea), that describes the whole temperature dependence. Determining Ea experimentally has sparked controversy, such as whether the different properties (e.g., compressive strength, tensile strength, E-modulus) exhibit different Ea, whether a single Ea value exists for the entire hydration process, or whether cement paste and concrete possess the same Ea. Furthermore, studies measuring Ea from elastic modulus measurements are truly scarce, likely due to experimental challenges with measuring this property at early-ages. This work investigated the influence of temperature on the elastic modulus evolution of cement paste and concrete. A single mix for each material was tested with the EMM-ARM (Elasticity Modulus Measurement through Ambient Response Method) methodology under three different isothermal conditions. The resulting elastic modulus evolution curves were used to derive Ea evolution curves from two traditional computation methods: the ‘speed’ method and the ‘derivative of speed’ method. Results showed that the elastic modulus evolution of both materials initially presented a constant Ea, independent of temperature and hydration development as preconized by the classical Arrhenius law. However, as hydration progressed to later stages, the activation energy exhibited evident dependencies on both temperature and hydration levels. Cement paste and concrete consistently exhibited different Ea values throughout hydration, with concrete having higher values. The use of the Ea curves to superimpose the different experimental elastic modulus evolution curves by means of the equivalent age concept led to near-perfect superpositions, strengthening the validity of this concept when applied to elastic modulus evolution.

著者

Ngoc Kien Bui Ryo Kurihara Wei Wang Manabu Kanematsu Hikotsugu Hyodo Miku Takano Hiroshi Hirao Takafumi Noguchi Ippei Maruyama

出版者

Japan Concrete Institute

雑誌

Journal of Advanced Concrete Technology (ISSN:13473913)

巻号頁・発行日

vol.21, no.3, pp.166-188, 2023-03-30 (Released:2023-03-30)

参考文献数

105

被引用文献数

1

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This study investigates the wet carbonation of concrete fines with CO2 and natural air gas bubbling in a carbonation system at low temperatures. After the air- and CO2-wet carbonations, the properties of a solution and hydrated cement paste powder are determined. In the air and CO2-wet carbonations, more Ca is extracted into the solution at a low temperature of 5°C. This high Ca concentration in the solution through air-wet carbonation primarily originates from the portlandite and unhydrated phases of the cement paste. Even in solutions with high pH values, the rehydration process and C–S–H decomposition occur simultaneously in air-wet carbonation. Moreover, CO2-wet carbonation indicates that the decalcification of C–S–H occurs rapidly, even in the presence of portlandite. Air-wet carbonation presents a potential method for the direct air capture of CO2 using concrete waste fines in a short period.

著者

Yuliia Khmurovska Petr Štemberk

出版者

Japan Concrete Institute

雑誌

Journal of Advanced Concrete Technology (ISSN:13473913)

巻号頁・発行日

vol.19, no.6, pp.668-686, 2021-06-24 (Released:2021-06-24)

参考文献数

40

被引用文献数

6

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This paper presents a catalogue of possible radiation-induced damage of rock aggregates, which was compiled using the relevant literature and confirmed numerically. The catalogue describes two common and six specific cases of rock aggregate damage. Additionally, the catalogue is supported by a validated numerical model, which is based on Rigid-Body Spring Model. The detailed numerical analysis and the result description of all the cases shown in the catalogue are presented in this paper. The main dependencies are also discussed and the related conclusions are drawn, of which the most important are that the damage of the rock can be delayed and increased rapidly after the delay; even a small amount (1%) of a highly expansive mineral leads to a significant reduction of mechanical properties of the rock; and a partial recovery of the elastic modulus of the rocks is possible even for significantly damaged rocks. It is believed that this paper will help to predict the radiation-induced degradation of rock aggregates as well as support the future development of related analytical models.

著者

Haonan Liu Zhao Xie Ruixue Yu Ning Zhang

出版者

Japan Concrete Institute

雑誌

Journal of Advanced Concrete Technology (ISSN:13473913)

巻号頁・発行日

vol.20, no.3, pp.127-138, 2022-03-11 (Released:2022-03-11)

参考文献数

50

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The pore structure of concrete is highly complex and random. Fractal theory is used to describe the characteristics of its pore structure. Ds (surface fractal dimension) is commonly used to characterize the surface roughness of the pores. However, the existing Ds model is limited to two dimensions and there are unreasonable assumptions about the shape of the pores and the method of measuring pores is not applicable. Therefore, this paper proposes a three-dimensional (3-D) model for calculating the Ds. The new parameter Dss represents the chaotic degree of element morphology in the 3-D pore system. When Dss=0, the pore morphology tends to be the same. The larger Dss value is, the more divergent and diversified pore morphology is. The specimens in two states of standard curing and high temperature drying were prepared and the pore structure parameters of the specimens were calculated by combining CT scanning, Deep Learning and 3-D reconstruction. By comparing Dss and Dv (volume fractal dimension) and other parameters, it is found the 3-D pore system of concrete is more chaotic and becomes more complex under the effect of high temperature drying. It also confirms the reliability of the 3-D fractal dimension model proposed in this paper.

著者

Hadiza Mohammed Inés Garcia-Lodeiro Hajime Kinoshita

出版者

Japan Concrete Institute

雑誌

Journal of Advanced Concrete Technology (ISSN:13473913)

巻号頁・発行日

vol.19, no.12, pp.1296-1308, 2021-12-23 (Released:2021-12-23)

参考文献数

28

被引用文献数

1

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Large quantities of aqueous secondary waste are generated from the processing of contaminated water after the nu-clear accident in Japan. Cementation of these wastes is challenging because their significant radioactivity may cause the radiolysis of water contents in cement, posing a risk of hydrogen gas generation. The application of calcium aluminate cement modified with phosphates (CAP), as an alternative cementing system, is interesting because this system is based on acid-base reaction, and its water content can be reduced by mild heating once the system is mixed. The present study focused in the use of Secar 71, a calcium aluminate cement with a high alumina and low silica compositions, and its effects of on the production of CAP system at elevated temperatures. The modification of Secar 71 with phosphates was successful, and the reduction of water content by about 35% was achieved in the CAP system containing SrCl2 after curing the system at 80°C for 7 days. The micro cracks, typically observed in the CAP system cured at lower temperature, was significantly reduced by curing at 80°C. The obtained results show a potential of Secar 71 to prepare CAP for cementation of aqueous secondary wastes.

著者

Takeru Kanazawa Takuro Nakamura Junichi Sakaguchi Kazuhiro Kawaguchi

出版者

Japan Concrete Institute

雑誌

Journal of Advanced Concrete Technology (ISSN:13473913)

巻号頁・発行日

vol.20, no.1, pp.18-29, 2022-01-25 (Released:2022-01-25)

参考文献数

29

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This study presents a kinematic model for flexural analysis of RC beams and columns subjected to freeze-thaw action based on upper bound theorem. The developed model enables analytical derivation of the contribution of damaged concrete when actual deterioration profile is idealized as an assemblage of undamaged and damaged zones based on freeze-thaw depth obtained from concrete core specimens. The accuracy of the analysis is verified by comparing its predictions with available 21 RC columns and beams failing in flexure after freeze-thaw exposure. The predicted results show good agreement with the test results within error of 6% on average. Thereafter, the developed analysis predicts the ultimate moment capacity of a RC beam, which was taken from an existing bridge slab replaced because of the combined effect of frost damage and fatigue. Results demonstrate that the present analysis could support a rational decision-making regarding the need for repair or rehabilitation. This paper is the English translation from the authors’ previous work [Kanazawa, T., Nakamura, T., Sakaguchi, J. and Kawaguchi, K., (2021). “Flexural analysis combined with freeze–thaw depth for RC linear members.” Journal of Japan Society of Civil Engineers, Ser. E2 (Materials and Concrete Structures), 77(4), 177-186. (in Japanese)].

著者

Ippei Maruyama Wataru Kotaka Bui Ngoc Kien Ryo Kurihara Manabu Kanematsu Hikotsugu Hyodo Hiroshi Hirao Ryoma Kitagaki Masaki Tamura Masato Tsujino Satoshi Fujimoto Takafumi Noguchi

出版者

Japan Concrete Institute

雑誌

Journal of Advanced Concrete Technology (ISSN:13473913)

巻号頁・発行日

vol.19, no.10, pp.1052-1060, 2021-10-08 (Released:2021-10-08)

参考文献数

20

被引用文献数

15

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Countermeasures against carbon dioxide emissions are a concern in the construction field as well as in society. To solve this problem, a concept for new calcium carbonate concrete is proposed, and this concept is validated experimentally. In the proposed concept, calcium carbonate comprising Ca originating from demolished concrete or other Ca-containing industrial wastes and HCO3- from CO2 gas collected from the air or emitted by industrial plants acts as a binder for aggregates, which can be natural rocks or crushed demolished concrete. This short paper describes the details of the process of making calcium carbonate concrete and discusses future perspectives.

著者

Hongda Guo Qing Liu Jianyu Xu Guoxing Sun

出版者

Japan Concrete Institute

雑誌

Journal of Advanced Concrete Technology (ISSN:13473913)

巻号頁・発行日

vol.19, no.3, pp.240-247, 2021-03-20 (Released:2021-03-20)

参考文献数

35

被引用文献数

4

---

High-strength and lightweight are two of the most important parameters for composites in the construction field. Here, we developed a novel foam concrete structure with sandwich porous structure by using in-situ polymerized polyacrylamide and ultra-stable foam, which can obtain higher mechanical strength in comparison to the normal porous concrete with the same density. The ratio of stiffness to weight was maximized to achieve the optimal sandwich porous structure size. The SEM images showed that the interface bond between the foam concrete and the polymer modified cement paste was tight and robust. The flexural strength of the novel structure was 65.6% higher than that of the foamed concrete at the same density. The series model was established to calculate the composite thermal conductivity of the novel foam concrete structure, indicating that the heat insulation was slightly improved compared with the normal foam concrete. Moreover, water resistance displayed a slight increase by constructing this sandwich porous structure. Hopefully, the novel composite with sandwich porous structure can put a new way for designing the lightweight and high strength insulation thermal structure.

著者

Kenichi Horiguchi Toshinobu Yamaguchi Tsuyoshi Maruya Koji Takewaka

出版者

Japan Concrete Institute

雑誌

Journal of Advanced Concrete Technology (ISSN:13473913)

巻号頁・発行日

vol.18, no.10, pp.571-587, 2020-10-16 (Released:2020-10-16)

参考文献数

47

被引用文献数

1 2

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In this study, a method was developed to estimate accurately the chloride threshold value for corrosion initiation in reinforced concrete. In this method, chlorides are supplied through a part of the specimen surface, and half-cell potential between the rebar and reference electrode embedded in a concrete specimen was measured in every ten minutes. A sudden drop of half-cell potential was observed as the continuation of the measurement. At that time, the specimen was broken and corrosion of rebar on its narrow surface was confirmed. The chloride threshold value can be estimated by determining the chloride concentration at the time of the potential drop. The estimated chloride threshold values for normal Portland cement concrete with cement content between 254 and 446 kg/m3 are in the range of 1.6 to 3.6 kg/m3. This paper is an English translation from the authors’ previous work [Horiguchi, K., Yamaguchi, T., Maruya, T. and Takewaka, K., (2015). “A study on the method of measuring the chloride threshold value of corrosion and on the estimation of the values.” Journal of JSCE, Ser. E2, 71(2), 107-123. (in Japanese)].

著者

Yongqin Liang Licheng Wang

出版者

Japan Concrete Institute

雑誌

Journal of Advanced Concrete Technology (ISSN:13473913)

巻号頁・発行日

vol.18, no.11, pp.699-715, 2020-11-20 (Released:2020-11-20)

参考文献数

112

被引用文献数

7

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Rebar corrosion is a main cause affecting the durability and safety of reinforced concrete structures. Many mathematical models (empirical and analytical models) have been proposed to predict the corrosion-induced cracking of concrete cover over the recent decades. These models have differences in many aspects, such as constitutive laws for cracked concrete. However, each of them claimed that it could well agree with the test data. This may be due to the fact that a small amount of test data were used to verify their models. Besides, there are many uncertain factors such as the rust volumetric expansion factor and elastic modulus relating to these predictive models, which seriously weaken their effectiveness and accuracy. Thus, in this paper, the predictive performances of various mathematical models are tested by collecting an amount of test data. After that, the uncertain factors are summarized, and the reasons are analyzed though reviewing relevant knowledge in various literature. It is found that different performances are obtained for different mathematical models and test data. These uncertain factors involve many fields, such as electro-chemical factors (corrosion current density, corrosion current efficiency, corrosion rate, loading effect of corrosion current), rust properties (rust volumetric expansion factor, rust elastic modulus), long-term behavior of concrete (creep coefficient), rust penetration into concrete (amount of rust penetrated into concrete pores and cracks) and corrosion morphology. These uncertain factors are raised due to either the limit of experimental techniques, the discrepancy of parameter values, time-dependent properties, or the lack of detailed environmental information. In addition, other factors are too complex to be delicately taken into account, which have to be ignored in the predictive models. Through parameter analysis, it is found that these factors have large effects on cracking time of concrete cover. Prospective modifications of these factors are suggested, and more detailed and systematic tests should be carried out by using novel and sophisticated apparatuses in future.

著者

Toshifumi Kikuchi Yasuhiro Kuroda

出版者

Japan Concrete Institute

雑誌

Journal of Advanced Concrete Technology (ISSN:13473913)

巻号頁・発行日

vol.9, no.1, pp.115-124, 2011-02-23 (Released:2011-02-22)

参考文献数

12

被引用文献数

28 78

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One of the largest contributors of the greenhouse gas emission is the production of cement for use in concrete. However, concrete is well-known for its carbon dioxide (CO2) uptake by carbonation. The purpose of this study was to consider the CO2 uptake in demolished and crushed concrete. In this study, three kinds of experiments and survey were carried out, including (1) an experiment using mortar specimens made in the laboratory so as to identify the conditions that accelerate CO2 uptake, (2) an experiment using concrete obtained from the demolition site and (3) a survey on the CO2 uptake in recycled crusher-run stone obtained from recycling plants. The experiment on new mortar and demolished concrete pointed out that the CO2 uptake in cement hydrate increases significantly when the particles are relatively small and when they are alternately wetted and dried. Furthermore, the survey on concrete at recycling plants found the amount of CO2 uptake in one ton of recycled crusher-run stone to be approximately 11 kilograms. Finally, using this value, the life cycle of CO2 of concrete structures was calculated and shown to be approximately 5.5% less when the CO2 uptake is taken into account compared to when it is not taken into account.

著者

Peiyi Zhang Atsushi Teramoto Takaaki Ohkubo

出版者

Japan Concrete Institute

雑誌

Journal of Advanced Concrete Technology (ISSN:13473913)

巻号頁・発行日

vol.18, no.9, pp.521-531, 2020-09-24 (Released:2020-09-24)

参考文献数

32

被引用文献数

6

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The adhesion failure of the interface between concrete and rendering mortars often leads to the degradation of the reinforced concrete building envelopes. Although several methods to improve the adhesion properties between concrete and rendering mortar have been proposed, there is no system to evaluate the effectiveness of these methods from the perspective of durability. To this end, this study proposed an experimental method to evaluate the durability of rendering mortar and concrete adhesion systems at the laboratory level. In this technique, a cyclic thermal load is applied to a part of the rendering mortar surface to accelerate the degradation; this part represents an external wall subjected to solar radiation. Subsequently, appropriate constraints are applied to the loaded part of the mortar to reproduce the actual degradation mechanism. Numerical simulation and experimental results support the effectiveness of the proposed accelerated degradation method. Considering the rate of decrease in the bond strength as a criterion to evaluate the durability, the influence of several known factors on the durability can be explicitly ranked. The durability assessment method can facilitate the comparison of novel solutions during the development stage.

著者

Daisuke Yamazaki Mitsuyasu Iwanami Masaaki Isa

出版者

Japan Concrete Institute

雑誌

Journal of Advanced Concrete Technology (ISSN:13473913)

巻号頁・発行日

vol.18, no.8, pp.463-472, 2020-08-28 (Released:2020-08-28)

参考文献数

9

被引用文献数

4

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The steel-plate bonding method used to reinforce concrete slabs in bridges has a long record of adoption, and has played an important role for many years. Favorable conditions have been observed with this method in periodic inspections; however, as part of durability tests, decreases in strength of the epoxy resin adhesive (which is one of its component materials) have been observed following over time outdoor exposure under standard environmental conditions. Investigations into the causes of decreased strength of epoxy resin adhesive are useful for increasing long-term durability in future infrastructure maintenance. The estimation of environmental factors that incorporate exposure conditions and the results of conducting accelerated tests revealed that the performance of epoxy resin adhesive was influenced by humidity. Additionally, decreases in strength accompanying reaction progress of epoxy resin were also observed. These results indicate that the degradation due to water absorption and the generation of internal stress due to the progress of the curing reaction of the epoxy resin are the causes of the decrease in the strength of the epoxy resin.

著者

Wengui Li Zhihui Sun Zhiyu Luo Surendra P. Shah

出版者

Japan Concrete Institute

雑誌

Journal of Advanced Concrete Technology (ISSN:13473913)

巻号頁・発行日

vol.15, no.3, pp.110-125, 2017-03-22 (Released:2017-03-22)

被引用文献数

3 8

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We reported “Influence of Relative Mechanical Strengths between New and Old Cement Mortars on the Crack Propagation of Recycled Aggregate Concrete” in Journal of Advanced Concrete Technology, Vol. 15 (2017) No. 3 p. 110-125; doi: 10.3151/jact.15.110. After publication of the paper, we have become aware of the copyright violation from the original research. We therefore wished to retract the paper and apologize for any inconvenience caused by the retraction.

著者

Nolan Wesley Hayes Qiang Gui Ammar Abd-Elssamd Yann Le Pape Alain Benjamin Giorla Sihem Le Pape Eric R. Giannini Zhongguo John Ma

出版者

Japan Concrete Institute

雑誌

Journal of Advanced Concrete Technology (ISSN:13473913)

巻号頁・発行日

vol.16, no.4, pp.179-190, 2018-04-26 (Released:2018-04-27)

参考文献数

41

被引用文献数

23

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A large-scale testing program on alkali silica reaction (ASR)-affected concrete structural members without shear rein-forcement representative of structural members found in nuclear power plants is presented. Three concrete specimens, designed to experience a free expansion rate of approximately 0.15% per year were fabricated and placed within a controlled environmental chamber (38 ± 1°C (100 ± 2°F) and 95 ± 5% relative humidity (RH)). Sixty-four (64) embed-ded transducers and twelve (12) long-gauge fiber-optic sensors provide evidence of strong anisotropic expansion and oriented ASR-induced cracking resulting from the confinement effect caused by the reinforcement layout and addi-tional structural boundary conditions. Surface cracking is not indicative of internal ASR-induced damage/expansion.