Early shrinkage experiment of concrete and the development law of its temperature and humidity field in natural environment

Wang, Yanlei; Zhu, Jie; Guo, Yongbin

doi:10.1016/j.jobe.2022.105528

Cited by 5 publications

(3 citation statements)

References 29 publications

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“…Zhang et al [20] found that higher RH can increase the content of pore water inside concrete, facilitating the diffusion of carbon dioxide, and the rate of concrete carbonation reaction is maximum when the RH is around 75%. Liu et al [21] reported that the depth of concrete carbonation first increases and then decreases as RH increases, with the maximum carbonation depth at a RH of 70%. Moreover, higher carbonation temperatures can cause significant strain changes on the concrete surface.…”

Section: Introductionmentioning

confidence: 99%

A method to analyze the long-term durability performance of underground reinforced concrete culvert structures under coupled mechanical and environmental loads

Li¹,

Wang²,

Nie³

et al. 2023

Journal of Intelligent Construction

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Keywordsunderground structures reinforced concrete (RC) coupling calculation sensitivity analysis top plate deflection durabilityThe coupling effect of mechanical and environmental loads is the main cause of deterioration in the performance of reinforced concrete (RC) structures. However, most studies on the durability of RC structures have focused only on mechanical or environmental loads. As a result, it is difficult to fully capture the effects of dry shrinkage and creep caused by temperature and humidity changes within the structure, as well as their impact on the overall deformation of the structure. To address this gap, this paper presents a numerical simulation of underground culvert projects using the durability concrete model-complex three-dimensional (DuCOM-COM3D) analysis software. The results of the simulation demonstrate that this approach offers a more precise characterization of the porosity, temperature, and humidity inside the concrete, resulting in improved accuracy in predicting the longterm deflection, crack width, and other macro-mechanical indices of the structure. Despite these advantages, some discrepancies were observed between the calculated and measured long-term deflection values. Additionally, a limit analysis was conducted to investigate the potential causes of the large deformation observed in the measurements. Overall, the results contribute to a better understanding of the complex mechanical and environmental loads affecting RC structures and provide a methodology for accurately simulating their long-term behavior.

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Section: Introductionmentioning

confidence: 99%

A method to analyze the long-term durability performance of underground reinforced concrete culvert structures under coupled mechanical and environmental loads

Li¹,

Wang²,

Nie³

et al. 2023

Journal of Intelligent Construction

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show abstract

“…Due to cement hydration and humidity diffusion, the internal humidity of concrete gradually decreases. Once the relative humidity begins to decrease, capillary pore tension is triggered, and the scale of the capillary pore tension then controls the macroscopic shrinkage deformation of the concrete; thus, the internal humidity change rule of concrete is necessary for analyzing concrete shrinkage deformation [15,16]. In an experimental study on the internal humidity of concrete, Persson [17] measured the changes in the humidity of concrete specimens exposed to air, immersion curing, and sealed conditions and established a simulation formula based on the water-cement ratio, cement hydration, or age.…”

Section: Introductionmentioning

confidence: 99%

Moisture Diffusion Coefficient of Concrete under Different Conditions

Zhou,

Li,

et al. 2023

Buildings

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Humidity change in concrete is the leading cause of concrete shrinkage. Moreover, the moisture diffusion coefficient of concrete is an essential parameter for assessing and predicting the internal moisture content of concrete. However, there is a lack of theoretical construction and experimental studies on the effect of different conditions, especially different constraints, on the moisture diffusion coefficient of concrete. Therefore, the internal humidity, pore structure parameters, and basic mechanical properties of concrete under different strength grades C30, C40, C50, and C60 (C stands for concrete and numbers indicate the strength class of the concrete), curing environments (dry and sealed curing conditions), and constraints were tested in this study. In addition, a calculation model of concrete’s internal humidity and humidity diffusion coefficient was established. The research findings show that the internal humidity of concrete decreased with age due to hydration and drying. External humidity had a significant effect on the moisture change of concrete, and the lower the external humidity, the larger the humidity diffusion coefficient and the faster the internal humidity of concrete decreases. Reinforcement (confinement) changes the pore structure parameters of the concrete, which in turn affects the transport of moisture within the concrete. The higher the reinforcement rate, the larger the pore structure parameters of the concrete, the larger the humidity diffusion coefficient, and the faster the concrete humidity decreases. The method proposed in the study can accurately predict the internal humidity of concrete using the humidity diffusion coefficient. The research results are a reference for preventing concrete shrinkage and cracking in construction.

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“…However, because of the limitations of time and cost, most experimental studies have focused on the temperature distribution of concrete in short-term extreme environments [17,20,21]. Although these studies on extreme concrete temperature distribution are helpful in quickly determining the design temperature, these results may not be applicable for all of the various climatic conditions during the full operation of a project.…”

Section: Introductionmentioning

confidence: 99%

Investigation and Analysis of the Influence of Environmental Factors on the Temperature Distribution of Thin-Walled Concrete

Yang,

Pang,

Xie

et al. 2023

Applied Sciences

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The temperature field of thin-walled concrete is susceptible to the influence of the external environment, which may endanger the safety of its operation in projects. Therefore, it is essential for construction designers to conduct a full cycle experiment to clarify the influence of various environmental factors on thin-walled concrete temperature. In this paper, based on a long-term outdoor measurement experiment, the mean temperature and gradient temperature were both statistically analyzed seasonally, and two extreme gradient temperature patterns were identified and summarized. In addition, random forest regression was introduced to conduct a sensitivity analysis. It was found that the air temperature controlled the mean temperature and that solar radiation was the dominant factor affecting the gradient temperature, while the effect of wind speed was overall negligible. In addition, correlations between the concrete’s temperature and environmental factors were analyzed. It was concluded that the concrete’s mean temperature was positively and linearly correlated with the air temperature, while the minimum gradient temperature for the bottom shadow surface and maximum gradient temperature for the top shadow surface, respectively, had negative and positive linear correlations with the average solar radiation.

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Early shrinkage experiment of concrete and the development law of its temperature and humidity field in natural environment

Cited by 5 publications

References 29 publications

A method to analyze the long-term durability performance of underground reinforced concrete culvert structures under coupled mechanical and environmental loads

A method to analyze the long-term durability performance of underground reinforced concrete culvert structures under coupled mechanical and environmental loads

Moisture Diffusion Coefficient of Concrete under Different Conditions

Investigation and Analysis of the Influence of Environmental Factors on the Temperature Distribution of Thin-Walled Concrete

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