A method to determine the critical moisture level for unsaturated transport of ions

Åhs, Magnus; Nilsson, Lars-Olof; Haha, Mohsen Ben

doi:10.1617/s11527-013-0167-5

Cited by 4 publications

(3 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A similar method for monitoring the moisture homogeneity of cylindrical samples has been previously used in Ref. [20].…”

Section: Sample Preconditioning For Desired Moisture Contentmentioning

confidence: 99%

Influence of moisture condition on chloride diffusion in partially saturated ordinary Portland cement mortar

Zhang

2018

Mater Struct

View full text Add to dashboard Cite

Experiments have been carried out to study the influence of moisture condition, including moisture content and its distribution, on the chloride diffusion in partially saturated ordinary Portland cement mortar. The mortar samples with water-tocement (w/c) ratios of 0.4, 0.5 and 0.6, cured for 1 year, were preconditioned to uniform water saturations ranging from 18 to 100%. The interior relative humidities of these partially saturated cement mortars, i.e. water vapour desorption isotherm (WVDI), were measured. The WVDI results in relation to the pore structures obtained from the mercury intrusion porosimetry tests of paste samples with the same w/ c ratios were analyzed, which provided a basic insight into the moisture distribution in the non-saturated cement mortars. The relative chloride diffusion coefficients of cement mortars at various water saturations were determined based on the Nernst-Einstein equation and conductivity technique. It is found that the relative chloride diffusion coefficient D rc depends on the degree of water saturation S w and WVDI. At a given S w level, the D rc is larger for a higher w/c ratio. The role of the w/c ratio in the D rc -S w relation, however, becomes less pronounced with increasing w/ c ratio. There exists a critical saturation, below which the water-filled capillary pores are discontinuous and the D rc -value tends towards infinitely small. An increase of the w/c ratio results in a decrease of the critical saturation level.

show abstract

“…A similar method for monitoring the moisture homogeneity of cylindrical samples has been previously used in Ref. [20].…”

Section: Sample Preconditioning For Desired Moisture Contentmentioning

confidence: 99%

Influence of moisture condition on chloride diffusion in partially saturated ordinary Portland cement mortar

Zhang

2018

Mater Struct

View full text Add to dashboard Cite

show abstract

“…Similar methodological observations resulted from [17], although related to the normal weight concrete. The method of preparation of 100 mm cylindrical specimens with uniformly distributed RH, using the surface RH measurement, is also shown in [18].…”

Section: Introductionmentioning

confidence: 99%

Permeability testing of radiation shielding concrete manufactured at industrial scale

2018

View full text Add to dashboard Cite

The effect of the composition of industrial concrete designed for radiation shielding structures on the air permeability and the diffusion of moisture was studied. The mix design for heavyweight concrete of bulk density 3168-3317 kg/m 3 was developed using barite and magnetite aggregate and cements blended with fly ash and blastfurnace slag. Structural elements, like columns of a height of 4 m and massive blocks made of mixtures with different cements were manufactured using ready mixed concrete pumped into the formwork. Core specimens were taken from the elements at different locations. The air permeability index was tested using Autoclam device. Evaluation of the quality of concrete on the basis of API results varied from ''very good'' to ''good''. The moisture distribution inside concrete specimens was equilibrated to RH = 60 ± 5%. Observation of RH changes allowed to determine the moisture diffusion coefficient. Significant differences of the permeability and moisture diffusion coefficient depending on the location of the core specimens drilling and mix design of concrete were found. The D coefficient provided a good reflection of the different quality of heavyweight concrete in structural elements.

show abstract

“…They found that the gas did not permeate when the saturation degree reached approximately 82%. Åhs et al [11] investigated the critical moisture level for unsaturated transport of ions in cementitious materials using electrochemical impedance spectroscopy (EIS) and pointed out that the critical water saturation for ion transport was less than 78% RH. Some of these experimental results are not in agreement with each other, which can be attributed to the difficulty of maintaining a constant water saturation degree of specimens during the tests, and to the dependence of results on the complex microstructure of cementitious materials [10,12,13].…”

mentioning

confidence: 99%

Pore-scale modelling of 3D moisture distribution and critical saturation in cementitious materials

Zhang

et al. 2014

Construction and Building Materials

View full text Add to dashboard Cite

A method to determine the critical moisture level for unsaturated transport of ions

Cited by 4 publications

References 15 publications

Influence of moisture condition on chloride diffusion in partially saturated ordinary Portland cement mortar

Influence of moisture condition on chloride diffusion in partially saturated ordinary Portland cement mortar

Permeability testing of radiation shielding concrete manufactured at industrial scale

Pore-scale modelling of 3D moisture distribution and critical saturation in cementitious materials

Contact Info

Product

Resources

About