scholarly journals Fractal Modeling of Pore Structure and Ionic Diffusivity for Cement Paste

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Yun Gao ◽  
Jin-yang Jiang ◽  
Kai Wu
Keyword(s):  
Pore Structure ◽  
Cement Paste ◽  
Mercury Intrusion Porosimetry ◽  
Fractal Model ◽  
Homogenization Method ◽  
Solid Mass ◽  
Fractal Modeling ◽  
Mass Fractal ◽  
Chloride Migration ◽  
Ionic Diffusivity

Pore structure in cement based composites is of paramount importance to ionic diffusivity. In this paper, pore structure in cement paste is modeled by means of the recently proposed solid mass fractal model. Moreover, an enhanced Maxwell homogenization method that incorporates the solid mass fractal model is proposed to determine the associated ionic diffusivity. Experiments are performed to validate the modeling, that is, mercury intrusion porosimetry and rapid chloride migration. Results indicate that modeling agrees well with those obtained from experiments.

Solid Mass Fractal Model for Pore Structure in Cement Paste

2016 ◽  
Vol 711 ◽  
pp. 1084-1089 ◽  
Author(s):  
Yun Gao ◽  
Song Mu ◽  
Jin Yang Jiang
Keyword(s):  
Pore Structure ◽  
Cement Paste ◽  
Parametric Analysis ◽  
Fractal Model ◽  
Wide Scope ◽  
Solid Mass ◽  
Fractal Approach ◽  
Mass Fractal ◽  
Practical Challenge ◽  
Self Similar

Though discussed a lot, it remains a practical challenge to modeling pore structure in cement paste. The fractal approach shows a great advantage since it allows to generate complex pore structure via simple geometric iterations and to incorporate the wide scope of pores in a self-similar manner. In this paper, the solid mass fractal model is proposed for pore structure in cement paste. The parametric analysis is performed in conjunction with the porosimetric test. It is shown that the proposed solid mass fractal well describes pore structure in cement paste.

RECENT ADVANCES ON FRACTAL MODELING OF PERMEABILITY FOR FIBROUS POROUS MEDIA

Fractals ◽  
2015 ◽  
Vol 23 (01) ◽  
pp. 1540006 ◽  
Author(s):  
JIANCHAO CAI ◽  
LIANG LUO ◽  
RAN YE ◽  
XIANGFENG ZENG ◽  
XIANGYUN HU
Keyword(s):  
Porous Media ◽  
Pore Structure ◽  
Fractal Geometry ◽  
Influence Factor ◽  
Fractal Model ◽  
Fibrous Materials ◽  
Permeability Model ◽  
Fractal Modeling ◽  
Fibrous Porous Media ◽  
Future Work

Permeability is an important hydraulic parameter for characterizing heat and mass transfer properties of fibrous porous media. However, it is difficult to be quantitatively predicted due to the complex and irregular pore structure of fibrous porous media. Fractal geometry has been verified to be an effective method for determining the permeability of fibrous porous media. In this study, recent works on the permeability of fibrous porous media by means of fractal geometry are reviewed, the advances for each presented fractal model are analyzed and summarized, parameter equations used in available fractal permeability models are also briefly compared and reviewed. Future work for more generalized permeability model of fibrous porous media need to conducted by considering the special characters of fibrous materials, uniform pore structure parameter model and the influence factor of capillary pressure, electrokinetic phenomena, etc.

Effect of Inorganic Salts on Pore Structure of Cement Paste

2009 ◽  
Vol 405-406 ◽  
pp. 378-383
Author(s):  
Wen Cui Yang ◽  
Yong Ge ◽  
Jie Yuan ◽  
Bao Sheng Zhang
Keyword(s):  
Pore Structure ◽  
Cement Paste ◽  
Mercury Intrusion Porosimetry ◽  
Cold Weather ◽  
Inorganic Salts ◽  
Early Age ◽  
Concrete Durability ◽  
Mercury Intrusion ◽  
Concrete Shrinkage ◽  
Concrete Property

Inorganic salts are important admixtures usually used in cold weather concrete. As research basic of influence of salts on concrete durability, effects of inorganic salts on pore structure of cement paste were studied in this paper, and possible implications of concrete property with pore structure was also analyzed. Pore structure of paste added CaCl2, NaCl, Na2SO4, NaNO2, Ca(NO3)2 and Ca(NO2)2 curing for 3 days and 28 days were tested through mercury intrusion porosimetry (MIP). The results showed that no matter 0.3 or 0.5 water-cement ratio, the pores whose diameter <50nm in paste with salts increased at 3 days, which was harmful for the control of concrete shrinkage and cracking at early age. Adding Ca (NO3)2 increased coarse pores (>200nm) of paste at 3 days, but these coarse pores turned into fine pores and reduced significantly at 28 days. Adding NaCl and Na2SO4 into cement paste raised coarse pores with size>1000nm at 3 days and 28days, which were harmful for the pore structure.

Modelling Pore Structure of Cement Based Material According to Continuous Network System

2014 ◽  
Vol 578-579 ◽  
pp. 1531-1537
Author(s):  
Sung In Hong ◽  
Joon Woo Park ◽  
Young Hee Jung ◽  
Ki Yong Ann
Keyword(s):  
Pore Structure ◽  
Cement Paste ◽  
Mercury Intrusion Porosimetry ◽  
Cement Matrix ◽  
Network System ◽  
Air Voids ◽  
Mercury Intrusion ◽  
Entrapped Air ◽  
Entrained Air

In this study, a modified pore structure of cement based material with respect to a path for ingressive ions was established. Of pores in a concrete, gel pores and other entrapped air voids were excluded from modelling the pore structure as no interests are given due to the ions immobilization of cement paste media. To setup the pore structure, the linear traverse method (LTM) was used to distribute air voids along the traverse line in a hexahedron cement paste structure, followed by including entrained air voids to fill up the least space of the cement matrix and making a network of the air voids through capillary pores at the variation in the diameters. Then the mercury intrusion porosimetry (MIP) was used to iteratively approach an accordance rate with calculated one from the above way to get into appropriate convergence value. As a result, for the OPC specimen the developed model shows a somewhat relevant value of 42.4 % of the accordance rate compared to empirical one and 64.24 of the ratio of ionic path to original distance within a concrete.

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