Extending Zavitsas’ Hydration Model to the Thermodynamics of Solute Mixtures in Water

2021 ◽  
pp. 118309
Author(s):  
Jacob G. Reynolds ◽  
Trent R. Graham ◽  
Carolyn I. Pearce
Keyword(s):  
2016 ◽  
Vol 68 (19) ◽  
pp. 981-994 ◽  
Author(s):  
Wei Zhou ◽  
Chuqiao Feng ◽  
Xinghong Liu ◽  
Shuhua Liu ◽  
Chao Zhang

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 858 ◽  
Author(s):  
Cristian Ponce-Farfán ◽  
David Santillán ◽  
Miguel Á. Toledo

Mathematical models for the simulation of the thermal evolution of roller-compacted concrete (RCC) dams during construction constitute an important tool for preventing excessive temperature rise, which may lead to cracking and losses of functionality. Here, we present a framework for the simulation of the thermal process. We define the boundary conditions of the problem using a careful description that incorporates the main heat exchange mechanisms. We adopt both a non-adiabatic and an adiabatic heat generation model for the simulation of the cement hydration. Our numerical framework lets us study the effect of the adopted heat generation model on the thermal field. Moreover, we study the influence of the weather conditions on the evolution of the hydration, and on the starting date of construction. Our simulations have shown that the hydration model has an important influence over the temperature field during the construction and the heat generation rate. Moreover, the hydration process and the temperature evolution are driven by the weather conditions. Once the next lift is cast, its thermal insulation effect makes the hydration take place under quasi-adiabatic conditions. As expected, dams built in cold months are prone to dissipate more heat than those built in warm seasons.


2005 ◽  
Vol 58 (11) ◽  
pp. 803 ◽  
Author(s):  
Norman W. H. Cheetham ◽  
Paramita Dasgupta

Molecular dynamics simulations have been used to assess the conformational behaviour of seven disaccharides in aqueous solution. Solvation decreased the overall conformational fluctuations of the sugars, compared to in vacuo simulations using a high dielectric constant. The most significant finding was a linear correlation between the experimental chromatographic retention parameter K´ and a molecular modelling parameter based on the next-nearest oxygen–oxygen distances in the disaccharides. The results support previous proposals for a stereospecific hydration model for carbohydrates and demonstrate the utility of a combined experimental/molecular modelling approach to its study.


Author(s):  
H. J. Engelhardt ◽  
M. Kreienmeyer ◽  
C. Lerch ◽  
N. Mu¨ller-Hoeppe ◽  
R. Ko¨ster ◽  
...  

The Repository of LILW Radioactive Waste Morsleben (ERAM) is located in the Federal State Saxony Anhalt, Germany. After an operational phase of about 20 years it is now under licensing for closure. As the repository was erected in a former salt mine, there exists a void volume of approx. 6 million m3. Consequently, a closure concept was developed serving three main functional requirements: stabilization, limitation of leaching processes and sealing. It relies on a comprehensive backfilling of the openings using two mixtures of salt concretes. The concretes will be used to backfill cavities as well as to construct seals. As the salt concretes are used in the sense of a mass concrete the heat of hydration induces thermal restraint stresses inside the concrete bodies and the neighboring rocks. To show the integrity of the geological and technical barriers thermo-mechanical computations were carried out. In the numerical code which is used for safety analyses a so-called hydration model was implemented describing the evolution of strength and Young’s modulus of the concretes in relation to the degree of hydration. The hydration model includes a transformation of the temperature-dependent setting process from real time into an equivalent age, which is equal to the setting time at a temperature of 293 K. Thereafter, a coupling of the equivalent age to the degree of hydration leads to a temperature-independent description of the setting process. As the hydration of concretes strongly correlates with the amount of the generated hydration heat, the model parameters were derived from laboratory tests including measurements of the adiabatic temperature rise.


1980 ◽  
Vol 6 (S1) ◽  
pp. 52-52
Author(s):  
G. Peschel ◽  
P. Belouschek ◽  
I. Belouschek ◽  
S. Erfle ◽  
H. M�hser ◽  
...  

2006 ◽  
Vol 247 (1-2) ◽  
pp. 1-7 ◽  
Author(s):  
Efthymios Balomenos ◽  
Dimitrios Panias ◽  
Ioannis Paspaliaris

2014 ◽  
Vol 41 (5) ◽  
pp. 421-431
Author(s):  
Xiao-Yong Wang ◽  
Ki-Bong Park

The granulated blast furnace slag is commonly blended with Portland cement or clinker to produce slag blended cement after being ground to the fineness comparable to Portland cement. Hydration of slag-blended cement is much more complex than that of ordinary Portland cement because of the mutual interactions between the cement hydration and the slag reaction. In this paper, by considering the production of calcium hydroxide in cement hydration and its consumption in the reaction of slag, a numerical procedure is proposed to simulate the hydration of concrete containing slag. The numerical procedure includes two sub components, a cement hydration model and a slag reaction model. The heat evolution rate of slag concrete is determined from the contributions of the cement hydration and the slag reaction. Furthermore, the temperature history in hardening blended concrete is evaluated by combining the proposed numerical procedure with a finite element method. The proposed model is verified through experimental data on concrete with different water–cement ratios and mineral admixture substitution ratios.


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