Diffusion in cementitious materials: II, further investigations of chloride and oxygen diffusion in well-cured OPC and OPC/30%PFA pastes

Ngala, V. T.; Page, C.L.; Parrott, L J; Yu, S. W.

doi:10.1016/0008-8846(95)00072-k

Cited by 99 publications

(36 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The measured chloride diffusivities in cement pastes obtained from the literature [8][9][10][11][12][13] are also shown in Fig.4. A comparison between the simulated and measured chloride diffusivities indicates that the simulated values for cement pastes with w/c ratio 0.40 are within one order of magnitude higher than the measured values.…”

Section: Resultsmentioning

confidence: 99%

Modelling of time dependency of chloride diffusion coefficient in cement paste

Zhang¹,

2010

J. Wuhan Univ. Technol.-Mat. Sci. Edit.

View full text Add to dashboard Cite

A computer-based model and method was presented to predict the time dependency of chloride diffusion coefficients in cement paste. The HYMOSTRUC3D model was applied to generate a 3D representative elementary volume (REV) of cement paste. In the simulation of microstructure, both of cement hydration and chloride binding were considered. With the simulated microstructure of cement paste, the finite element method was applied to simulate the diffusion process of chloride through the saturated cement paste. Based on the Fick's first law, the chloride diffusion coefficient can be calculated. In this method, the influences of age and w/c ratio on the chloride diffusion coefficient were evaluated. The simulated chloride diffusivities with various w/c at different time were compared to experimental data obtained from the literature. The experimental results indicate that the chloride diffusion coefficient decreases with the increase of time and the decrease of w/c ratio. The trend of simulated relationship (diffusion coefficient vs time, diffusion coefficient vs w/c ratio) fits very well with the experiments.

show abstract

Section: Resultsmentioning

confidence: 99%

Modelling of time dependency of chloride diffusion coefficient in cement paste

Zhang¹,

2010

J. Wuhan Univ. Technol.-Mat. Sci. Edit.

View full text Add to dashboard Cite

show abstract

“…This test was used to estimate the amount of interconnected pores (capillary porosity), as described by Ngala et al [12] and Parrott et al [13]. The saturated specimens specified for this study were dried at 90.7% relative humidity by placing them above saturated salt solution of barium chloride contained in a desiccator until a near-constant sample weight was obtained.…”

Section: De-sorption Testmentioning

confidence: 99%

“…Full details of the techniques and procedures of this test are described in [12][13][14]. The average capillary porosity results were calculated using five specimens.…”

Section: De-sorption Testmentioning

confidence: 99%

Modeling The Microstructure Of Slag Blended Cements Using Artificial Neural Network

Ahmed¹

2015

Third International Conference on Advances in Civil, Structural and Construction Engineering - CSCE 2015

View full text Add to dashboard Cite

This paper proposes the artificial neural network (ANN) as a numerical technique to simulate the microstructure of slagblended cements. The ANN model adopted in this research consists of three neurons in the input layer which represent contents of both water-cooled slag (WCS) and OPC and WCS finenesses and three neurons in the output layer which represent calcium silicate hydrate (C-S-H), Portalndite (CH), and capillary porosity. Back Propagation algorithm was employed for the ANN training in which a Tansig function was used as the nonlinear transfer function. Thermogravimetric analysis and de-sorption approaches were performed to study the microstructure of the different OPC/slag pastes. The results obtained from experiments agreed with that predicted by ANN, where, the prediction ANN model gives very close estimates of C-S-H, CH, and capillary porosity of OPC/WCS pastes. Therefore, the developed ANN model can be used as an alternative approach to evaluate the microstructure of slag-blended cements.

show abstract

“…Diffusion behaviors in HCP at different w/c ratio have been studied for ion species such as cesium [3,4], chloride [5][6][7], and iodide ions [3]. However, detailed diffusion mechanisms have been still ambiguous due to potential interactions between ions and cement hydrates including electrostatistical interaction [5,8], and sorption [6,7], in addition to the complexity of pore geometry (tortuosity and constrictivity).…”

Section: Introductionmentioning

confidence: 99%