Potential For Alkali–Silica Reaction In Radiation Shielding Concrete Containing Special Aggregates,
2016
Institute of Fundamental Technological Research
Potential For Alkali–Silica Reaction In Radiation Shielding Concrete Containing Special Aggregates, Daria Jóźwiak-Niedźwiedzka, Michał A. Glinicki, Karolina Gibas
International Conference on Durability of Concrete Structures
In the present study, the potential for the alkali–silica reaction (ASR) in radiation shielding concrete containing special aggregates is presented. The tests were performed on two kinds of aggregate: (1) high-density aggregate to absorb the gamma radiation (barite, magnetite, and hematite) and (2) mineral with high bound water content to attenuate the neutron flux (serpentinite). The optical microscopy in transparent light on thin sections, XRD and XRF method, was used to assess the mineral composition of aggregates. ASTM C1260 test method for potential alkali reactivity of aggregates was applied also to investigate the effect of different content and crystal size …
Effect Of Superabsorbent Polymers (Sap) On Fresh State Mortars With Ground Granulated Blast-Furnace Slag (Ggbs),
2016
Glasgow Caledonian University
Effect Of Superabsorbent Polymers (Sap) On Fresh State Mortars With Ground Granulated Blast-Furnace Slag (Ggbs), Fernando Do Couto Rosa Almeida, Agnieszka Joanna Klemm
International Conference on Durability of Concrete Structures
Although cementitious materials are the main construction materials and worldwide produced, there is still a major concern about their sustainability and durability, especially in terms of conserving resources, reducing wastes, and decreasing the environmental impacts of repair and replacement. In general, cementitious materials are very susceptible to cracking provoked by autogenous shrinkage due to their associated self-desiccation process. The problem is even more critical in concrete with blended cements, including Portland cement with ground granulated blast-furnace slag (GGBS). The current paper evaluates efficiency of superabsorbent polymers (SAP) as internal curing agents; shrinkage reduction in mortars with different levels of cement …
Designing Repeatable Self-Healing Into Cementitious Materials,
2016
University of California, Irvine
Designing Repeatable Self-Healing Into Cementitious Materials, Mo Li, Shuai Fan
International Conference on Durability of Concrete Structures
Designing self-healing into cementitious materials can open a new world of opportunities for resilient concrete infrastructure under service loading conditions. The self-healing process should be robust as well as repeatable, allowing for self-repair after multiple damage events. The repeatability poses great challenges when self-healing strategies mainly rely on the formation of low-strength calcium carbonate healing product, complicated by the localized cracking behavior of cementitious materials. This study aims at formulating a new cementitious material system with designed physical and chemical characteristics that favour repeatable self-healing. Advanced experimental methods, coupled with micromechanics theory, are adopted to probe and design repeatable self-healing …
Progress In Durability Study Of Frp Materials,
2016
Shenzhen University
Progress In Durability Study Of Frp Materials, Zeng-Zhu Zhu, Ying-Wu Zhou, Li-Li Sui, Feng Xing, Jia Du
International Conference on Durability of Concrete Structures
During the past decades, FRP strengthened RC structures have attracted worldwide interest in both application and research. Nowadays, as more and more infrastructures are being suffered from severe corrosions due to harsh and extreme environments, the durability of FRP strengthened RC structures has generally emerged as the most important issue in research. Thus, the paper presents the latest progress in durability study of the FRP materials through an in-depth review and analysis on existing extensive investigations. The time-dependent performances of two types of FRP materials of carbon FRP (CFRP) and glass FRP (GFRP) under severe environments of humidity, high temperature, …
Durability-Based Optimal Design Methodology For Rc Members In Corrosive Environment,
2016
King Fahd University of Petroleum & Minerals
Durability-Based Optimal Design Methodology For Rc Members In Corrosive Environment, Saeid A. Alghamdi, Shamsad Ahmad, Adamu Lawan
International Conference on Durability of Concrete Structures
No abstract provided.
Investigation Of The Spatial Variability Of Steel Weight Loss And Corrosion Cracking: A Novel X-Ray Technique,
2016
Waseda University
Investigation Of The Spatial Variability Of Steel Weight Loss And Corrosion Cracking: A Novel X-Ray Technique, Sopokhem Lim, Haitao Jiang, Mitsuyoshi Akiyama
International Conference on Durability of Concrete Structures
The performance of corrosion-affected RC members depends strongly on localized damages of reinforcement. Therefore, modeling the spatial variability of steel corrosion is very important for the assessment of the remaining service life of corroded structures or time for maintenance. To study the changes of spatial variability of steel weight loss over time, a continuous monitoring is necessary. In this paper, a novel procedure of X-ray technique application in monitoring the spatial growth of a corroded bar in a RC specimen is demonstrated along with the digital image processing of X-ray images to estimate the steel weight loss. The relationship of …
Influence Of Concrete Moisture Condition On Half-Cell Potential Measurement,
2016
Technical University of Munich
Influence Of Concrete Moisture Condition On Half-Cell Potential Measurement, Sylvia Kessler, Christoph Gehlen
International Conference on Durability of Concrete Structures
The detection of on-going corrosion is one of the main issues during inspection of reinforced concrete structures. The half-cell potential measurement method is the most common and established non-destructive technique to support this task. But a lot of infrastructures are exposed to rain or seawater, which can cause heterogeneous moisture condition within one component. In turn, this can have influence on the potential mapping results, and as a consequence, the interpretability of the half-cell potential measurement is impaired. This paper focuses on the influence of concrete moisture condition on half-cell potential measurement. Laboratory and practical tests’ results are analyzed qualitatively …
Electrical Response Of Mortar Saturated With Nacl Solutions Under Freeze–Thaw Cycles,
2016
Hokkaido University
Electrical Response Of Mortar Saturated With Nacl Solutions Under Freeze–Thaw Cycles, Yi Wang, Fuyuan Gong, Tamon Ueda, Dawei Zhang
International Conference on Durability of Concrete Structures
This paper presents the test results of electrical response of mortar saturated with sodium chloride (NaCl) solutions under freeze–thaw cycles (FTCs). To quantitatively evaluate the salt frost damage of mortar based on its electrical response, mesoscale samples are prepared to assure the uniform pore solution concentration. The reduction of electrical resistivity shows the same tendency with elastic modulus, but with less degree. The investigation shows that electrical resistivity of mortar decreases with temperature and the phase changes can be observed based on their relationship. The freezing and thawing points decreasing with increment of solution concentration can be found, but their …
Basic Examination On Assessing Mechanical Properties Of Concrete That Has Suffered Combined Deterioration From Fatigue And Frost Damage,
2016
Civil Engineering Research Institute for Cold Region
Basic Examination On Assessing Mechanical Properties Of Concrete That Has Suffered Combined Deterioration From Fatigue And Frost Damage, Hiroshi Hayashida, Yasuhiko Sato, Tamon Ueda
International Conference on Durability of Concrete Structures
An examination including an evaluation of mechanical properties of concrete that had suffered combined deterioration from fatigue and frost damage was done using cylindrical specimens. The order of deterioration and degree of deterioration of the specimens were used as variables. The examination clarified that certain mechanical properties of concrete that had undergone combined deterioration were able to be evaluated by measuring the propagation speed of ultrasonic waves. The decrease in the elastic modulus and the ultrasonic velocity that accompanies the increase in the number of freeze–thaw cycles was smaller in the specimens that experienced fatigue first and then frost damage …
The Effect Of Nano-Sio2 Dispersed Methods On Mechanical Properties Of Cement Mortar,
2016
University of Jinan & Shandong Provincial Key Laboratory of Preparation and Measurement of Building Material
The Effect Of Nano-Sio2 Dispersed Methods On Mechanical Properties Of Cement Mortar, Mingle Liu, Zonghui Zhou, Xiuzhi Zhang, Xiangzi Yang, Xin Cheng
International Conference on Durability of Concrete Structures
Nano-SiO2 is added to the cement by using different dispersion methods, through the macroscopic mechanical properties to characterize its dispersion in the cement, it can be used to explore the best experimental process. The results show that the compressive strength of cement samples with different dispersion methods is different. When the physical dispersion method is used, the intensity is not improved, but the ultrasonic dispersion method is the smallest, and the dispersion of nano-SiO2 is -9.11%. When the surfactant is used as dispersant, the dispersion of nano-SiO2 by Naphthalene water reducer is the best, and the compressive …
Effect Of Nano-Sio2 Content On The Setting Time And Mechanical Properties Of Tricalcium Silicate,
2016
University of Jinan
Effect Of Nano-Sio2 Content On The Setting Time And Mechanical Properties Of Tricalcium Silicate, Zhenhai Xu, Zonghui Zhou, Xin Cheng
International Conference on Durability of Concrete Structures
Using analytically pure calcium carbonate and silica as raw materials, high purity tricalcium silicate (C3S) is prepared by solid-state reaction. The tricalcium silicate was sintered at a temperature of 1550°C with the heat preservation time of 6 h. The final sample needs three times of calcination circles. Ultrasonic cleaning machine was used to disperse the water and different amount of nano-SiO2 (0, 1, 2, and 3 wt%) for 5 min, then mixed with C3S, and formed into standard blocks. The setting time and compressive strength of each age (1, 3, 7, and 28 days) was …
Effects Of Nano-Caco3 On The Properties Of Cement Paste: Hardening Process And Shrinkage At Different Humidity Levels,
2016
University of Jinan
Effects Of Nano-Caco3 On The Properties Of Cement Paste: Hardening Process And Shrinkage At Different Humidity Levels, Yamei Cai, Pengkun Hou, Zonghui Zhou, Xin Cheng
International Conference on Durability of Concrete Structures
The hardening process and volume stability of cement pastes with and without nano-CaCO3 (NC) were studied through investigations on the setting time and shrinkage. Results showed that NC shortened the setting time of cement paste: the initial setting time decreased by 3.9 and 11.1% when 1 and 3% NC were added, and the finial setting times were shortened by 6.2 and 15.2%, respectively. The shrinkage of cement paste was compensated by NC, and the effect was more obvious as more NC was added into the cement paste. Although the shrinkage decreased at the lower relative humidity, the degree of …
Effect Of Bfrp Grid On Crack Propagation Of Reinforced Concrete Beam With Thick-Cover Concrete,
2016
Dalian University of Technology
Effect Of Bfrp Grid On Crack Propagation Of Reinforced Concrete Beam With Thick-Cover Concrete, Li-Juan Cheng, Hua-Nan He
International Conference on Durability of Concrete Structures
For the purpose of solving the problem of large crack width in concrete beam with thick cover, BFRP grid is added to the concrete cover to control the crack development and to improve the distribution status of cracks. In this paper, the bending tests under four-point loading are adopted to investigate cracking properties of reinforced concrete beams with thick cover, in which BFRP grid is added. During test cracking load, crack width and the number of crack were recorded, which will be analysed later. Test results show that crack development of reinforced concrete beam with thick cover can be effectively …
Effect Of Pet Wrapping On Shear Performance Of Corroded Reinforced Concrete Columns,
2016
Zhejiang University
Effect Of Pet Wrapping On Shear Performance Of Corroded Reinforced Concrete Columns, Dawei Zhang, Yuxi Zhao, Weiliang Jin, Tamon Ueda
International Conference on Durability of Concrete Structures
In this paper, an experimental study is presented on the influence of PET warping on shear performance, such as diagonal shear cracking load, peak load, and energy dissipation of RC columns with stirrup corrosion before strengthening. The experimental program involved an electrochemical process to accelerate the migration of chlorides from an external electrolyte into the tested columns, a wetting–drying cycle process with a controlled current to speed up the corrosion of the stirrup in the tested columns, the strengthening of corroded columns with PET warping, and a pseudostatic test to determine the shear capacity of the tested beams. The shear …
Effect Of Cured Time On Creep Of Lightweight Aggregate Concrete,
2016
Shenzhen University
Effect Of Cured Time On Creep Of Lightweight Aggregate Concrete, Hongzhi Cui, Haibin Yang, Xiaoxiao Xu, Zitao Lin, Tommy Yiu Lo
International Conference on Durability of Concrete Structures
Creep and shrinkage are such properties that will occur in concrete when they are under load and exposed to surrounding. Since this property will cause deformation which may decrease the design strength of the concrete, it is necessary to do have more knowledge on this phenomenon. So, we will study the effect of creep on 7 and 14 days of cured time of specimens which sealed or unsealed will be considered, respectively. The specimens have shown how the concrete strains when they are under sustained load with time. Besides, the sealed specimens have shown how the basic creep is different …
Application Of Raman Spectroscopy For Tracing The Status Of Silica Fume In Cementitious Materials,
2016
University College London
Application Of Raman Spectroscopy For Tracing The Status Of Silica Fume In Cementitious Materials, Yanfei Yue, Yun Bai, Jing Jing Wang
International Conference on Durability of Concrete Structures
Silica fume (SF) is an important component for manufacturing high performance concrete (HPC), owing to its superb pozzolanic reactivity and physical filling effects. However, application of SF in concrete may cause potential hazards issues. Although using SF in slurry form can somehow reduce the potential biotoxicity, the long-term stability and status of the SF particles within cementitious materials is still uncertain. In the current study, attempts were made to use Raman spectroscopy as an innovative alternative technique for tracing and identifying the status of SF both in its original SF slurry and in a 6-month-old hydrated cement paste. Light-optical microscope …
Delayed Ettringite Formation In Fly Ash Concrete Under Moist Curing Conditions,
2016
Nanjing Tech University
Delayed Ettringite Formation In Fly Ash Concrete Under Moist Curing Conditions, Zhuqing Yu, Jian Ma, Hu Shi, Xiaodong Shen, Guang Ye
International Conference on Durability of Concrete Structures
During the hydration of cement, tricalcium aluminate (C3A) reacts with gypsum and forms ettringite (AFt). Once all gypsum is consumed, ettringite can further react with remaining C3A and form monosulfate (AFm) at 1–2 days. Normally, at early ages, ettringite all transfers to AFm phase. After several months or years, ettringite can form again if a new source of sulfate becomes available in the pore solution of the paste, viz. delayed ettringite formation. In previous study, it was found that delayed ettringite forms in Portland cement concrete when the concrete samples were cured under moist conditions, …
Study On The Disposition Of Water In Fly Ash-Based Geopolymers Using Atr–Ir,
2016
Shenzhen University
Study On The Disposition Of Water In Fly Ash-Based Geopolymers Using Atr–Ir, Jian Liu, Yuan Fang, Obada Kayali
International Conference on Durability of Concrete Structures
This paper addresses the question of whether the main product of low calcium fly ash-based geopolymer is a hydrate, namely, sodium aluminosilicate hydrate (N-A-S-H). The answer to this question is important for understanding geopolymer characteristics. One of these is its fire resistance. In this study, fly ash-based geopolymers were synthesized using the combination of Na2CO3 and Ca(OH)2. Samples were cured at ambient temperature for 7 days, then placed in the oven at 105°C for 24 h, and then calcined at 1050°C for 48 h. IR was used to examine the produced geopolymers at each stage …
Micromechanical Modeling For Material Design Of Durable Infrastructural Materials: The Influence Of Aggregate And Matrix Modification On Elastic Behavior Of Mortars,
2016
Arizona State University
Micromechanical Modeling For Material Design Of Durable Infrastructural Materials: The Influence Of Aggregate And Matrix Modification On Elastic Behavior Of Mortars, Sumanta Das, Amit Maroli, Narayanan Neithalath
International Conference on Durability of Concrete Structures
This paper reports the fundamental difference in microstress distributions in traditional hardened cement paste with quartz inclusions and a cement paste with lightweight aggregate (LWA) inclusions using microstructurebased numerical simulation involving finite element method with periodic boundary conditions. Variation of relative stress distributions under varying component material properties and varying microstructural features in both the systems is elucidated for a comprehensive understanding. The presented microstructure-based numerical technique accurately captures the stress concentrations inside microheterogeneous systems, which is otherwise not detectible using analytical homogenization schemes. Numerical simulations reveal that strengthening and stiffening of matrix and interfacial transition zone (ITZ) with silica …
Research On Concrete Durability Improving For Existing Island-Building And Its Application,
2016
Zhejiang University
Research On Concrete Durability Improving For Existing Island-Building And Its Application, Mao Jianghong, Zhu Yaofeng, Xu Fangyuan, Jin Weiliang, Xu Yidong, Chen Xu
International Conference on Durability of Concrete Structures
China’s coastal cities contain a large number of islands with abundant human activities, in which buildings are in a typical marine corrosion environment and the corrosion of reinforced concrete structures is very prominent. This paper makes research work on two aspects: (1) the durability assessment and durability improvement after a thorough investigation of the architecture of Xiangtan County, Ningbo city, on an island and (2) the application research of the bidirectional electromigration rehabilitation (BIEM) technology to enhance the durability of existing island building life. This paper designs a set of BIEM equipment based on solar power supply and develops a …
