scholarly journals The Influence of Calcium Chloride Salt Solution on the Transport Properties of Cementitious Materials

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Yaghoob Farnam ◽  
Taylor Washington ◽  
Jason Weiss
Keyword(s):  
Transport Properties ◽  
Calcium Hydroxide ◽  
Calcium Chloride ◽  
Chemical Reaction ◽  
Oxygen Permeability ◽  
Gas Transport ◽  
Degree Of Saturation ◽  
Dominant Factor ◽  
Reaction Products ◽  
Friedel’S Salt

The chemical interaction between calcium chloride (CaCl2) and cementitious binder may alter the transport properties of concrete which are important in predicting the service life of infrastructure elements. This paper presents a series of fluid and gas transport measurements made on cementitious mortars before and after exposure to various solutions with concentrations ranging from 0% to 29.8% CaCl2by mass. Fluid absorption, oxygen diffusivity, and oxygen permeability were measured on mortar samples prepared using Type I and Type V cements. Three primary factors influence the transport properties of mortar exposed to CaCl2: (1) changes in the degree of saturation, (2) calcium hydroxide leaching, and (3) formation of chemical reaction products (i.e., Friedel’s salt, Kuzel’s salt, and calcium oxychloride). It is shown that an increase in the degree of saturation decreases oxygen permeability. At lower concentrations (<~12% CaCl2at room temperature), the addition of CaCl2can increase calcium hydroxide leaching, thereby increasing mortar porosity (this is offset by the formation of Friedel’s salt and Kuzel’s salt that can block the pores). At higher concentrations (>~12%), the formation of chemical reaction products (mainly calcium oxychloride) is a dominant factor decreasing the fluid and gas transport in concrete.

The Effect of the Type and Concentration of the Crosslinking Diene on the Gas Transport Properties of Membranes Based on Polyoctylmethylsiloxane

2020 ◽  
Vol 2 (6) ◽  
pp. 399-406
Author(s):  
E. A. Grushevenko ◽  
I. L. Borisov ◽  
D. S. Bakhtin ◽  
V. V. Volkov ◽  
A. V. Volkov
Keyword(s):  
Transport Properties ◽  
Gas Transport ◽  
Gas Transport Properties

New poly(ether imide)s with pendant di-tert-butyl groups: Synthesis, characterization and gas transport properties

2019 ◽  
Vol 217 ◽  
pp. 183-194 ◽  
Author(s):  
N. Belov ◽  
R. Chatterjee ◽  
R. Nikiforov ◽  
V. Ryzhikh ◽  
S. Bisoi ◽  
...  
Keyword(s):  
Transport Properties ◽  
Gas Transport ◽  
Tert Butyl ◽  
Gas Transport Properties

scholarly journals A Molecular Simulation Study of Silica/Polysulfone Mixed Matrix Membrane for Mixed Gas Separation

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2199
Author(s):  
Khadija Asif ◽  
Serene Sow Mun Lock ◽  
Syed Ali Ammar Taqvi ◽  
Norwahyu Jusoh ◽  
Chung Loong Yiin ◽  
...  
Keyword(s):  
Transport Properties ◽  
Molecular Simulation ◽  
Gas Separation ◽  
Membrane Separation ◽  
Gas Transport ◽  
Mixed Matrix ◽  
Mixed Gas ◽  
Gas Transport Properties ◽  
Simulation Results ◽  
Mixed Gases

Polysulfone-based mixed matrix membranes (MMMs) incorporated with silica nanoparticles are a new generation material under ongoing research and development for gas separation. However, the attributes of a better-performing MMM cannot be precisely studied under experimental conditions. Thus, it requires an atomistic scale study to elucidate the separation performance of silica/polysulfone MMMs. As most of the research work and empirical models for gas transport properties have been limited to pure gas, a computational framework for molecular simulation is required to study the mixed gas transport properties in silica/polysulfone MMMs to reflect real membrane separation. In this work, Monte Carlo (MC) and molecular dynamics (MD) simulations were employed to study the solubility and diffusivity of CO2/CH4 with varying gas concentrations (i.e., 30% CO2/CH4, 50% CO2/CH4, and 70% CO2/CH4) and silica content (i.e., 15–30 wt.%). The accuracy of the simulated structures was validated with published literature, followed by the study of the gas transport properties at 308.15 K and 1 atm. Simulation results concluded an increase in the free volume with an increasing weight percentage of silica. It was also found that pure gas consistently exhibited higher gas transport properties when compared to mixed gas conditions. The results also showed a competitive gas transport performance for mixed gases, which is more apparent when CO2 increases. In this context, an increment in the permeation was observed for mixed gas with increasing gas concentrations (i.e., 70% CO2/CH4 > 50% CO2/CH4 > 30% CO2/CH4). The diffusivity, solubility, and permeability of the mixed gases were consistently increasing until 25 wt.%, followed by a decrease for 30 wt.% of silica. An empirical model based on a parallel resistance approach was developed by incorporating mathematical formulations for solubility and permeability. The model results were compared with simulation results to quantify the effect of mixed gas transport, which showed an 18% and 15% percentage error for the permeability and solubility, respectively, in comparison to the simulation data. This study provides a basis for future understanding of MMMs using molecular simulations and modeling techniques for mixed gas conditions that demonstrate real membrane separation.

Gas transport properties of liquid crystalline poly(p-phenyleneterephthalamide)

1992 ◽  
Vol 25 (2) ◽  
pp. 788-796 ◽  
Author(s):  
D. H. Weinkauf ◽  
H. D. Kim ◽  
D. R. Paul
Keyword(s):  
Transport Properties ◽  
Liquid Crystalline ◽  
Gas Transport ◽  
Gas Transport Properties

Synthesis, characterization and gas transport properties of MOF-5 membranes

2011 ◽  
Vol 382 (1-2) ◽  
pp. 82-90 ◽  
Author(s):  
Zhenxia Zhao ◽  
Xiaoli Ma ◽  
Zhong Li ◽  
Y.S. Lin
Keyword(s):  
Transport Properties ◽  
Gas Transport ◽  
Gas Transport Properties
Sign in / Sign up

Export Citation Format

Share Document