Pore size and shape in mortar by thermoporometry

Sun, Zhenhua; Scherer, George W.

doi:10.1016/j.cemconres.2009.11.011

Cited by 199 publications

(122 citation statements)

References 30 publications

Supporting

Mentioning

106

Contrasting

Order By: Relevance

“…Sun's experimental data show that λ is usually between 0.1 and 0.5 for cement-based materials (Sun, 2010b). The melting point is always higher than the freezing point for the same pores.…”

Section: Ice Formation and Permeabilitymentioning

confidence: 99%

“…(15)) and melting curve (Eq. (16)) are not the same, because the freezing point is usually controlled by the size of pore entry while the melting point is by that of pore body (Sun, 2010b), and the pore shape factor λ can be defined as:…”

Section: Ice Formation and Permeabilitymentioning

confidence: 99%

“…Crystallization pressure and cryosuction pressure are static pressures that only rely on the temperature and pore size distribution, while the hydraulic pressure is a dynamic pressure which depends on the permeability of the material. Previous studies have shown that there is no significant change in pore size distribution during the first few FTCs (Sun, 2010b), so it means the crystallization pressure and cryosuction pressure are not responsible to this tendency change (expansion at the beginning but converted to contraction at last), and the main reason is the hydraulic pressure reduction due to the permeability increment caused by frost damage accumulation (Yang et al, 2006). The measured deformation in different cycles is used to verify the proposed model.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Stress Analysis for Concrete Materials under Multiple Freeze-Thaw Cycles

Gong

Sicat

Zhang

et al. 2015

ACT

View full text Add to dashboard Cite

Once ice forms in highly saturated concrete material, internal tensile stress will be generated and causes damage to the material, which is a serious problem for concrete structures in cold and wet regions. On one hand, each component (porous body, ice and liquid) should satisfy the compatibility of stress and strain, which has been discussed by the poromechanical theories. On the other hand, if some empty voids exist, the hydraulic pressure will release when liquid water escapes from the expanded area according to Darcy's law. Recent closed freeze-thaw tests on the saturated mortar showed a consistent tendency: as the number of freeze-thaw cycles (FTC) increases, the deformation changes from the expansion to the contraction. In order to make clear the physical and mechanical changes during this process, a more comprehensive hydraulic model is developed, which combines both the mechanisms mentioned above. The estimated strain behavior by this model is in a good agreement with experimental measurements, and also, it has good potential and is more flexible to be applied to different cases such as different saturation degrees and cooling rates. The permeability change can be also considered in this model as a reflection of frost damage level.

show abstract

“…Sun's experimental data show that λ is usually between 0.1 and 0.5 for cement-based materials (Sun, 2010b). The melting point is always higher than the freezing point for the same pores.…”

Section: Ice Formation and Permeabilitymentioning

confidence: 99%

Section: Ice Formation and Permeabilitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Stress Analysis for Concrete Materials under Multiple Freeze-Thaw Cycles

Gong

Sicat

Zhang

et al. 2015

ACT

View full text Add to dashboard Cite

show abstract

“…The use of other probe liquids such as cyclohexane or decane as non-reactive solvents and the tracking of a solid-solid phase transition could allow evaluating a wider range of pores, with a higher sensitivity of the experiment [27,49].…”

Section: Comparison Between the Different Techniquesmentioning

confidence: 99%

“…However, not only the ranges of pore sizes are different, also the specific structural features measured vary between techniques. Thus, MIP evaluates the pore entrance size [12], whereas the gas adsorption technique allows measuring both pore size and pore entrance size, using the adsorption and desorption curves respectively [20,27]. TPM allows the determination of the size of the cavity of the pore during the melting cycle and the pore entrance size during the freezing cycle [21,27].…”

Section: Introductionmentioning

confidence: 99%

Multiple characterization study on porosity and pore structure of calcium phosphate cements

2015

View full text Add to dashboard Cite

Being able to thoroughly characterize the intricate pore structure of calcium phosphate cements is a key step to successfully link the structural properties of these synthetic bone grafts with their most relevant properties, such as in vitro or in vivo behaviour, drug loading and release properties or degradation over time. This is a challenging task, due to the wide range of pore sizes compared to most other ceramic biomaterials. This work provides a critical assessment of three different techniques based on different physical phenomena, namely Mercury Intrusion Porosimetry (MIP), Nitrogen sorption and Thermoporometry (TPM) for the detailed characterization of four calcium phosphate cements with different textural properties, in terms of total porosity, Pore Size Distribution (PSD) and Pore Entrance Size Distribution (PESD). MIP had the advantage of covering a much wider size range than TPM and Nitrogen sorption, offering a more comprehensive information at the micrometric level. TPM, and specially Nitrogen sorption, besides being non-destructive techniques, and although covering a limited size range, provided complementary information regarding pore structure associated to crystal shape at the nanoscale, recording both PSD and PESD in a single experiment. MIP tended to register smaller sizes, especially at low L/P ratios, due to the network effect, that has a strong influence on the outcome of this technique.¡

show abstract