Temperature Control Measures and Temperature Stress of Mass Concrete during Construction Period in High-Altitude Regions

Wang, Zhenhong; Li, Tao; Liu, Yi; Yunhui, Jiang

doi:10.1155/2018/9249382

Cited by 12 publications

(7 citation statements)

References 14 publications

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“…x T S 􏼁 � (1 − P%)r +(P%)x 0 ; for a constant reference r, (21) where ( 20) and ( 21) indicate how close x(t) is to the reference at time T S , and selecting an adequate percentage %P, the time T S can be modifed supposing diferent values of k (19).…”

Section: Approaching the Desired Referencementioning

confidence: 99%

“…A self-tuning proportional-integral-derivative control was proposed in [20] to address the matter of controlling temperatures for drawn-texturing yarn machines. Finally, the temperature control in [21,22] was designed to avoid temperature cracks in mass concrete structures, where the temperature drop process can be optimised in time, and the temperature drop rate can be controlled to prevent excessive scale and temperature drop rates.…”

Section: Introductionmentioning

confidence: 99%

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Novel Nonlinear Control Method for First‐Order Systems and Its Implementation in a Temperature System

Chapa¹,

Ibarra

Guzman³

2023

Mathematical Problems in Engineering

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In this work, a novel nonlinear control theory design for first-order systems is developed, contributing to the improvement of the existing theory. The theory will allow a design of the open loop and closed-loop controllers that ensure the tracking of any reference, constant, or variant in time with a free initial condition where the Laplace transform was used to find all the analytical solutions, avoiding the transfer function theory. Moreover, the closed-loop control will be the best option to speed up or slow down the reference convergence rate in the desired finite time. Then, an algorithm indicating the steps for designing a closed-loop controller and achieving proper tuning for a real-time application is shown. Finally, this manuscript presents the results and discussions of the theory implemented in a prototype tank of a liquid temperature control system, where the effectiveness of the applied temperature control can be seen.

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Section: Approaching the Desired Referencementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Novel Nonlinear Control Method for First‐Order Systems and Its Implementation in a Temperature System

Chapa¹,

Ibarra

Guzman³

2023

Mathematical Problems in Engineering

View full text Add to dashboard Cite

show abstract

“…e different heat release rate of hydration heat and the amount of heat released have a great influence on the spatial and temporal distribution of the concrete temperature field [6,7]. erefore, the temperature control measures commonly used to control hydration heat include the use of lowcalorie cement, increasing the aggregate content when mixing, controlling the temperature of concrete pouring, and cooling by water [8,9]. However, in actual engineering project, it is difficult to adjust the concrete mix ratio.…”

Section: Introductionmentioning

confidence: 99%

Effect of Hydration Heat Inhibitor on Thermal Stress of Hydraulic Structures with Different Thicknesses

Shen

et al. 2020

Advances in Civil Engineering

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Concrete hydration heat inhibitor can inhibit the early hydration reaction of concrete and reduce the initial heat release of concrete. However, there is no in-depth research on the effect of hydration heat inhibitor on hydraulic structures with different thicknesses and constraints. In this paper, numerical simulation is used to study the change of temperature and stress field after adding hydration heat inhibitor by establishing the finite element models of tunnel lining, sluice, and gravity dam. The results show that the effect of the hydration heat inhibitors on reducing the temperature peak is inversely proportional to the thickness of the structure. A formula is put forward to evaluate their relation in this paper. When the thickness of the structure is about 6 m, there is no peak cutting effect. For the stress field, hydration heat inhibitor can greatly reduce the thermal stress of the thin-walled structure and make the structure meet the temperature control requirements; for the medium wall thickness structure, it can reduce the internal tensile stress about 50% and the surface tensile stress about 20%, and other temperature control measures are still needed to ensure that the surface tensile stress of the structure meets the requirements; for hydraulic structures with large volume and thickness, the application effect of the inhibitor has limitations, which can reduce the internal tensile stress about 30%, but the tensile stress in the surface area will increase about 7% due to the increase of the internal and external temperature difference; therefore, other temperature control measures such as arranging cooling water pipe, strengthening surface insulation, and so on are needed to ensure that temperature cracks do not occur. This paper provides references and suggestions for the research and engineering application of hydration heat inhibitor.

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“…ere is a considerable amount of literature about extensive thermal performance tests and temperature control crack prevention on ordinary concrete [6][7][8][9], RCC [10,11], rockfill concrete [12], and other materials. e investigations for the CSG materials are mainly focused on the relevant mechanical properties [13][14][15][16][17], while the impact of adiabatic temperature rise on the CSG material is not fully understood.…”

Section: Introductionmentioning

confidence: 99%

Adiabatic Temperature Rise Test of Cemented Sand and Gravel (CSG) and Its Application to Temperature Stress Prediction of CSG Dam

Jiang

Cai

Guo

et al. 2020

Advances in Materials Science and Engineering

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An adiabatic temperature rise test of cemented sand and gravel (CSG) is conducted, a model for temperature rising of CSG is proposed, and its application to temperature stress prediction of CSG dam is presented. Adiabatic temperature rise tests are first conducted to investigate the temperature rise properties of CSG material with different cementing agent contents. The results demonstrate that the hydration reaction time is longer for CSG material with higher cementing agent content, and a linear relationship is presented between cementing agent contents and final value of adiabatic temperature rise. Then, a calculation model considering different cementing agent contents is developed based on the regression analysis of the test data. The proposed model is implanted into the ANSYS software platform for predictions of temperature distributions and stress fields of a typical CSG dam. The results show that the distributions of temperature and temperature stress are similar to those of roller compacted concrete (RCC) dam. Due to the high temperature stress at the long intermittent surface and downstream surface of the dam, the thermal insulation measures on the surface of the dam should be considered in the CSG dam with high cementing agent contents and in the severe cold environment. Therefore, it cannot be generally considered that the temperature control of the CSG dam does not need to be considered, and it should be determined according to the specific working conditions.

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Temperature Control Measures and Temperature Stress of Mass Concrete during Construction Period in High-Altitude Regions

Cited by 12 publications

References 14 publications

Novel Nonlinear Control Method for First‐Order Systems and Its Implementation in a Temperature System

Novel Nonlinear Control Method for First‐Order Systems and Its Implementation in a Temperature System

Effect of Hydration Heat Inhibitor on Thermal Stress of Hydraulic Structures with Different Thicknesses

Adiabatic Temperature Rise Test of Cemented Sand and Gravel (CSG) and Its Application to Temperature Stress Prediction of CSG Dam

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