scholarly journals Hydration Model and Evaluation of the Properties of Calcined Hwangtoh Binary Blends

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Han-Seung Lee ◽  
Xiao-Yong Wang
Keyword(s):  
Calcium Hydroxide ◽  
Reaction Model ◽  
Pozzolanic Reaction ◽  
Mineral Admixture ◽  
Binary Blends ◽  
Kinetic Reaction ◽  
Pozzolanic Material ◽  
Hydration Model ◽  
Kinetic Reaction Model ◽  
Boundary Reaction

AbstractCalcined hwangtoh is a pozzolanic material that is increasingly being used as a mineral admixture in the concrete industry. This study shows a hydration model for cement–hwangtoh blends and evaluates the various properties of hwangtoh-blended concrete using reaction degrees of binders. First, a kinetic reaction model is proposed for analyzing the pozzolanic reaction of hwangtoh. The reaction of hwangtoh includes three processes: the initial dormant period, boundary reaction process, and diffusion process. The mutual interactions between the binary reactions of cement and hwangtoh are thought to be in line with the items in capillary water and calcium hydroxide. Second, the reaction degrees of cement and hwangtoh are determined based on a blended hydration model. Furthermore, the chemical (chemically combined water and calcium hydroxide contents), mechanical (compressive strength), thermal (hydration heat), and durability aspects (carbonation depth) of hwangtoh-blended concrete are systematically predicted. The results show good agreement with experimental results.

Modeling of hydration reactions to predict the properties of slag blended concrete

2014 ◽  
Vol 41 (5) ◽  
pp. 421-431
Author(s):  
Xiao-Yong Wang ◽  
Ki-Bong Park
Keyword(s):  
Portland Cement ◽  
Cement Hydration ◽  
Blended Cement ◽  
Numerical Procedure ◽  
Reaction Model ◽  
Heat Evolution ◽  
Mineral Admixture ◽  
Temperature History ◽  
Granulated Blast Furnace Slag ◽  
Hydration Model

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.

Experimental, detailed, and global kinetic reaction model for NO oxidation over platinum/alumina catalysts

2015 ◽  
Vol 117 (1) ◽  
pp. 15-34 ◽  
Author(s):  
Travis Wentworth ◽  
Sudarshan Loya ◽  
Christopher Depcik ◽  
Susan Stagg-Williams
Keyword(s):  
Reaction Model ◽  
No Oxidation ◽  
Kinetic Reaction ◽  
Kinetic Reaction Model ◽  
Alumina Catalysts

Radiolytic Corrosion of 238Pu-doped UO2 Pellets in 5 M NaCl Solution

2004 ◽  
Vol 824 ◽  
Author(s):  
M. Kelm ◽  
E. Bohnert
Keyword(s):  
Reaction Model ◽  
Chemical Processes ◽  
Nacl Solution ◽  
Radiation Chemical ◽  
Kinetic Reaction ◽  
Dose Rates ◽  
Radiolysis Products ◽  
Order Of Magnitude ◽  
Reference Experiment ◽  
Kinetic Reaction Model

AbstractDeaerated 5 M NaCl solution is alpha-irradiated up to 700 days in the presence of UO2 pellets. Experiments are conducted with 238Pu-doped pellets in pure brine and with undoped UO2 pellets in a 238Pu containing brine. The long-lived radiolysis products H2, O2 and ClO3- are formed in all cases proportional to the dose applied on the solution and with yields corresponding to 200, 80 and 7 nMol/(L*Gy).The U concentrations increase with time but do not exceed about 10−4 Mol/L thus indicating Uranium to be solubility limited. Moreover, the rinse solutions of the vessels at the end of the experiments contain up to one order of magnitude more U than found in the solutions. The total amounts of mobilized U deviate by less than a factor 10 from each other regardless of the large ratio of surface dose rates (ratio up to 2300) or mean dose rates (ratio up to 100), applied while the reference experiment (UO2 pellet in pure brine) yields only some 10−7 Mol/L U which is over 3 orders of magnitude lower than observed in experiments with radiation present.The simulation of the radiation chemical processes using a kinetic reaction model can reasonably reproduce the findings of the experiments with respect to the formation of H2 and O2 and give the order of magnitude for the concentrations of chlorine species and of oxidized UO2.

scholarly journals A kinetic reaction model: Decay to equilibrium and macroscopic limit

2016 ◽  
Vol 9 (3) ◽  
pp. 571-585 ◽  
Author(s):  
Lukas Neumann ◽  
Christian Schmeiser
Keyword(s):  
Reaction Model ◽  
Kinetic Reaction ◽  
Kinetic Reaction Model
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