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

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Minmin Jiang ◽  
Xin Cai ◽  
Xingwen Guo ◽  
Qinghui Liu ◽  
Tianye Zhang
Keyword(s):  
Temperature Stress ◽  
Temperature Rise ◽  
High Temperature Stress ◽  
Adiabatic Temperature ◽  
Hydration Reaction ◽  
Adiabatic Temperature Rise ◽  
Cemented Sand ◽  
Stress Prediction ◽  
Sand And Gravel ◽  
Cementing Agent

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.

Kinetic Model of Adiabatic Temperature Rise of Mass Concrete

2021 ◽  
Vol 13 (5) ◽  
pp. 771-780
Author(s):  
Shou-Kai Chen ◽  
Bo-Wen Xu
Keyword(s):  
Temperature Field ◽  
Temperature Rise ◽  
Initial Conditions ◽  
Dynamic Change ◽  
Adiabatic Temperature ◽  
Model Parameters ◽  
Hydration Reaction ◽  
Mass Concrete ◽  
Adiabatic Temperature Rise ◽  
Proposed Model

The adiabatic temperature rise model of mass concrete is very important for temperature field simulation, same to crack resistance capacity and temperature control of concrete structures. In this research, a thermal kinetics analysis was performed to study the exothermic hydration reaction process of concrete, and an adiabatic temperature rise model was proposed. The proposed model considers influencing factors, including initial temperature, temperature history, activation energy, and the completion degree of adiabatic temperature rise and is theoretically mature and definitive in physical meaning. It was performed on different initial temperatures for adiabatic temperature rise test; the data were employed in a regression analysis of the model parameters and initial conditions. The same function was applied to describe the dynamic change of the adiabatic temperature rise rates for different initial temperatures and different temperature changing processes and subsequently employed in a finite element analysis of the concrete temperature field. The test results indicated that the proposed model adequately fits the data of the adiabatic temperature rise test, which included different initial temperatures, and accurately predicts the changing pattern of adiabatic temperature rise of concrete at different initial temperatures. Compared with the results using the traditional age-based adiabatic temperature rise model, the results of a calculation example revealed that the simulated calculation results using the proposed model can accurately reflect the temperature change pattern of concrete in heat dissipation conditions.

scholarly journals A Study on Adiabatic Temperature Rise Test and Temperature Stress Simulation of Rock-Fill Concrete

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Xiaofei Zhang ◽  
Qian Liu ◽  
Xin Zhang ◽  
Yanlong Li ◽  
Xiaoping Wang
Keyword(s):  
Temperature Stress ◽  
Temperature Control ◽  
Temperature Rise ◽  
Calculation Model ◽  
Adiabatic Temperature ◽  
Gravity Dam ◽  
Dam Construction ◽  
Adiabatic Temperature Rise ◽  
Fill Ratio ◽  
Rock Fill

In the present study, we investigate the effect of the adiabatic temperature rise property of rock-fill concrete (RFC) on the temperature stress and crack resistance of RFC gravity dams. We conducted tests on the adiabatic temperature rise of RFC with a rock-fill ratio of 42%, 49%, and 55%, respectively. Based on the regression analysis of the test data, a calculation model of the adiabatic temperature rise, considering the rock-fill ratio, is developed, and the finite element analysis software ANSYS is employed to simulate the whole process of the temperature and temperature stress fields of a RFC gravity dam. The main findings of the study are as follows: (1) Both the adiabatic temperature rise rate and the final adiabatic temperature rise of RFC are negatively correlated with the rock-fill ratio. (2) The calculation model of the adiabatic temperature rise of RFC is characterized by its high accuracy, which can help predict the adiabatic temperature rise of RFC with different rock-fill ratios. (3) Without any temperature control measures, the maximum temperature stress of RFC generated by the temperature rise of hydration heat in the RFC gravity dam is 0.93 MPa, which meets the standard of temperature stress control. The results of the present study indicate that dam construction with RFC can simplify the measures of temperature control and crack prevention, improve the construction efficiency, and reduce the cost of dam construction.

scholarly journals Experimental Study on the Creep Behaviour of Cemented Sand and Gravel (CSG) and Temperature Stress Prediction of CSG Dam under Seasonal Temperature Change

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Xin Cai ◽  
Minmin Jiang ◽  
Xingwen Guo ◽  
Jiaojiao Chen ◽  
Qian Zhao
Keyword(s):  
Numerical Simulation ◽  
Temperature Stress ◽  
Creep Behaviour ◽  
Great Influence ◽  
Creep Model ◽  
Seasonal Temperature ◽  
Cemented Sand ◽  
Sand And Gravel ◽  
Creep Temperature ◽  
Cementing Agent

Creep generally showed a great impact on the temperature stress of concrete structure. At present, little research has been done on the creep law of cemented sand and gravel (CSG), and the calculation of creep temperature stress mainly adopts a set of relevant parameters. In this context, experimental compressive creep tests were carried out on the specimens of large-sized cylinders with different cementing agent contents; the creep temperature stress of CSG was also calculated. The results showed that the creep of CSG increased with the increase of cementing agent content, but the specific creep was not obvious. In addition, the creep model of CSG with high accuracy was also obtained, which could provide a basis for the numerical simulation of CSG dam. Furthermore, the results of numerical simulation showed that creep has a great influence on the stress of CSG dam, and the thermal stress energy was less than 37%. At the same time, it was necessary to determine whether temperature control should be considered according to different cementing agent content and external climate conditions, which cannot be generalized.

Effect of Slag Characteristics on Adiabatic Temperature Rise of Blended Concrete

2022 ◽  
Author(s):  
Hai Zhu ◽  
Dhanushika Gunatilake Mapa ◽  
Catherine Lucero ◽  
Kyle A. Riding ◽  
A. Zayed
Keyword(s):  
Temperature Rise ◽  
Adiabatic Temperature ◽  
Adiabatic Temperature Rise

scholarly journals Convenient Evaluation Method of Adiabatic Temperature Rise using Mortar Sample

2010 ◽  
Vol 48 (12) ◽  
pp. 15-22
Author(s):  
E. Maruya ◽  
H. Misumi ◽  
T. Takahashi ◽  
E. Sakai
Keyword(s):  
Temperature Rise ◽  
Evaluation Method ◽  
Adiabatic Temperature ◽  
Mortar Sample ◽  
Adiabatic Temperature Rise

Influence of the Fly-Ash Content of Concrete at Low Water-Binder Ratio on Hydration Degree of Binders and Cement

2011 ◽  
Vol 250-253 ◽  
pp. 445-449
Author(s):  
Li Wei Xu ◽  
Jian Lan Zheng
Keyword(s):  
Fly Ash ◽  
Temperature Rise ◽  
High Performance Concrete ◽  
Ash Content ◽  
Adiabatic Temperature ◽  
Mineral Admixture ◽  
Hydration Degree ◽  
Adiabatic Temperature Rise ◽  
Binder Ratio ◽  
Water Binder Ratio

The hydration degree of binders and cement is investigated by measuring the adiabatic- temperature rise of concrete at low water-binder ratio with different fly-ash content. The results denote that, with a constant water-binder ratio, both of the hydration degree of binders and that of cement decrease with the increasing fly-ash content in the early stage. In a later stage, however, the hydration degree of cement increases with the increasing fly-ash content and the hydration degree of binders peaks when the fly-ash content is 35%. Fly ash is one of the mineral admixture of which high-performance concrete is made up. It brings down the rise of concrete temperature significantly and helps solve the problems of shrinkage and crack of concrete structure. Because the hydration mechanism in common concrete is different from that in concrete with low water-binder ratio, and the hydration environment is different between concrete and cement pastes, to determine the adiabatic-temperature rise of concrete directly conforms to the actual situation. The adiabatic-temperature rise, adiabatic-temperature-rise rate, hydration degree of both binders and cement are investigated by measuring adiabatic-temperature rise of concrete with different fly-ash content.

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